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Co-RICH Fe-Mn CRUSTS FROM THE MARSHALL ISLANDS (LEG 1) AND HYDROTHERMAL AND HYDROGENETIC Fe- Mn DEPOSITS FROM MICRONESIA (LEG 2), KODOS 98-3 CRUISE, WEST PACIFIC
By
James R. Hein 1 , Jai-Woon Moon2, Kyeong-Yong Lee2, Jennifer S. Bowling 1 , Ki- Hyune Kirn2, Malia Burrows 1 , Sung Hyun Park2, Youn-ji Choi2, Anthony A. Schuetze1 , Hoi Soo Jung2, Hyun-Sub Kim2, Gun Chang Lee2, Cheong-Kee Park2, Seung Kyu Son2, and Chan Young Park2
Open-File Report 99-412
1999
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government
!U.S. Geological Survey, 345 Middlefield Rd., MS 999, Menlo Park, CA, 94025, USA2Korea Ocean Research and Development Institute, P.O. Box 29, Ansan, 425-6000, Seoul, Korea
INTRODUCTION
The KODOS 98-3 cruise took place 13-28 August 1998 aboard the R.V. Onnuri and was divided into two legs. Leg 1 operations included mapping and sampling Litakpooki Ridge and mapping Lomilik Seamount, both within the Exclusive Economic Zone (EEZ) of the Republic of the Marshall Islands (RMI) (Figs. 1-3). Leg 2 operations included mapping and sampling a corridor of the Yap convergent margin (YCM) extending from the southwestern margin of the West Caroline Ridge west to the Yap back-arc region in the EEZ of the Federated States of Micronesia (FSM) (Figs. 4, 5). Members of the KODOS 98-3 cruise (Table 1) participated in this second cruise of a renewed effort by the Korea Ocean Research and Development Institute (KORDI) and the U.S. Geological Survey (USGS) to study seamount mineral deposits. Earlier efforts included three USGS-KORDI cooperative cruises aboard the R.V. Farnella, one each in the years 1989-1991, and more recently cruise KODOS 97-4 in 1997.
The first set of objectives of the KODOS 98-3 cruise was to map the distribution of thick ferromanganese oxyhydroxide crusts (Fe-Mn crusts) on Lomilik Seamount and Litakpooki Ridge and to determine the geologic and oceanographic conditions that promoted growth of thick Fe-Mn crusts. Reconnaissance sampling and mapping of Lomilik Seamount were completed in 1989 during the first cooperative USGS-KORDI cruise aboard the R.V. Farnella (F10-89-CP; Hein, Kang, et al., 1990) and both Lomilik and Litakpooki were studied during the KODOS 97-4 cruise (Hein, Moon, et al., 1998). Lomilik was chosen for detailed work because during the 1989 cruise, the thickest (180 mm) shallow-water Fe-Mn crust ever recovered from the ocean basins was collected from its summit; thick Fe-Mn crusts (up to 130 mm) were also collected in 1997. Thick Fe-Mn crusts up to 154 mm thick were collected on Litakpooki Ridge during cruise KODOS 98-3, which are described here.
The second set of objectives of the KODOS 98-3 cruise was sampling and mapping of the YCM. Reconnaissance sampling and mapping of that region was completed in 1990 and 1991 during the second and third cooperative USGS-KORDI cruises (F11-90-CP and F7-91-WP) aboard the R.V. Farnella (Hein, Ahn, et al., 1992). During the 1990 cruise, hydrothermal stratabound Mn-oxide deposits were recovered from the crest of Yap arc, along with hydrothermally altered rocks, serpentinite, blue-serpentinite muds, and abundant vein quartz. Additional hydrothermal deposits were collected during leg 2 of KODOS 98-3.
Representative Fe-Mn crust samples, hydrothermal stratabound Mn oxides, and substrate rock samples from the dredge hauls taken from those areas during KODOS 98-3 were analyzed for this study, which extends our previous work on Fe-Mn crusts collected in and around RMI and FSM (Hein et al., 1988; Hein, Kang, et al., 1990; Hein, Ahn, et al., 1992; Hein et al., 1997a; Hein, Moon, et al., 1998). This report presents data for all dredge hauls, including sample descriptions, detailed chemical (major, minor, platinum group, and rare earth elements) and mineralogical analyses of bulk Fe-Mn crusts, individual crust layers, hydrothermal Mn, and substrate rocks collected during KODOS 98-3. Correlation coefficients and Q-mode factor analysis are used to determine relationships between and among elements and associations of elements with mineralogical phases.
Shipboard Operations
Shipboard operations on Litakpooki Ridge included four dredge hauls, two piston cores, two CTD casts, and 534 km of SeaBeam bathymetric lines including 152 km of 12-channel airgun lines (Tables 2-5; Figs. 1-3). Operations on Lomilik Seamount included 279 km of SeaBeam bathymetric lines. Operations on the YCM included five dredge hauls, two piston cores, two box cores, two multiple cores, nine CTD casts, one deep-sea camera-video survey, and 737 km of SeaBeam bathymetric lines and 12-channel airgun lines (Tables 2-5; Figs. 4-5). Of the nine dredge hauls attempted, six provided usable samples, one contained mostly pumice, and two had no recovery (Tables 5, 6).
Bathymetry and Seafloor Descriptions
Litakpooki Ridge is located at the southwestern margin of the RMIEEZ (Fig. 1). The bathymetry of the central part of the ridge shows a relatively flat top at 2000-2800 m water depth dotted with small hills that rise as shallow as about 1600 m depth (Fig. 2). The ridge summit narrows and extends to the northeast to the edge of the survey area. A rift zone is defined by a ridge that extends to the northwest from the summit. The base of the Litakpooki ridge is at about 5000 m water depth. Channels characterize the very steep northern slope. Slope angles on the summit are mostly less than 5°, whereas those on the flanks are up to 30°, with an average slope angle of about 11° (KODOS, 1999a).
Foraminiferal sediment fills some lows and forms a thin blanket over the central and northeast parts of the summit where dredges D3 and D4 encountered only sediments (Fig. 2). Seismic- reflection profiles (KODOS, 1999a) show that much of the summit is underlain by sedimentary rocks, with protruding volcanic hills composed of basalt. Dredges Dl and D2 and dredges D14 and D15 from KODOS 97-4 (Hein, Moon, et al., 1998) show that those sedimentary rocks consist of bioclastic and foraminiferal limestones, breccia composed of mostly volcanic and phosphorite clasts in a carbonate fluorapatite cement, phosphorite, and minor ironstone. Most thick crusts were collected from saddles between summit hills.
Lomilik Seamount is located among a large group of seamounts to the west of Anewetak Atoll in the western Marshall Islands. The bathymetry reveals a flat-topped edifice with a summit at about 1500 m water depth and small hills rising to about 1350 m (Fig. 3). A broad, gently sloping summit terrace occurs on the NE flank down to about 2400 m which steepens in slope on the SE flank, but does not exist on the north, west, and south flanks. The terrace is separated from the summit by a 200-250 m-high scarp. Many volcanic pinnacles occur on the east, southeast, and west flanks of the seamount (Fig. 3). Lomilik Seamount is connected to Lami Seamount (Fig. 1) by a ridge on its NW flank (Fig. 3). A large landslide likely created the notch in the south flank which begins where the summit narrows before changing trend to the northwest along the ridge that connects with Lami Seamount. The seamount base is at about 4600 m water depth. The summit region slopes at less than 5° and the flanks up to 20°, with an average slope of Lomilik of about 11° (KODOS, 1999a).
The terrace and summit support a thin blanket of foraminiferal ooze between outcrops of basalt, volcaniclastic rocks, and foraminiferal and bioclastic limestones (Hein, Moon, et al., 1998). Most thick crusts were collected from the terrace and the scarp that separates the terrace from the summit, whereas the thinnest crusts were collected from the middle and upper steep flanks of the seamount; the lowermost flanks were not sampled.
YCM bathymetry from east to west is characterized by a gently dipping summit of the southwestern margin of West Caroline Ridge at about 1500-2200 m water depth (Fig. 5). West from the summit, the outer trench slope is characterized by an upper steep wall; rough, central ridge and valley topography; and a lower steep, irregular slope showing block faulting that bottoms at about 8600 m. The trench axis deepens to the south. The inner trench wall is more uniform in topography than the outer trench wall and rises through a series of thrust faults to a summit ridge at about 1500 m. A summit seamount shallows to about 500 m water depth (Fig. 5). Most sampling was completed on the west side of the summit ridge in the back-arc area at water depths of 1750- 2800 m. Seismic-reflection profiles (KODOS, 1999b) show that most of the region supports thin sediment cover, with basement highs cropping out in the arc and back-arc regions.
CTD Data
Water temperatures measured in CTD-1 (Litakpooki Ridge; Fig. 2) and CTD-2 (open-ocean between Litakpooki Ridge and Lomilik Seamount; Fig. 1) profiles range from 2.2° to 29.2° C and salinities from 34.4 to 34.9 psu, defining high temperature and low salinity surface waters and a seasonal thermocline at about 100 m water depth (KODOS, 1999a). Dissolved oxygen contents range from 1.3 to 4.3 ml/1, with maximum values occurring at about 100 m water depth and minimum values at about 300 m (Table 4). The depth to the top of the oxygen-minimum zone
(OMZ) is about the same (280 and 275 m), although the depth to the lowest oxygen content is 36 m deeper at the more northerly site. The 5° and 10° isotherms are also deeper at the more northerly site (Table 4).
Nine CTD profiles were taken at the YCM, where the lowest oxygen content at each site is very uniform at 2.0Q±0.08 ml/1. These values show that primary productivity in surface waters is not as high in this region as in the western RMI, where minimum values are 1.3 ml/1, indicating greater amounts of oxygen consumption during degradation of organic matter. Indications of hydrothermal activity were not seen in water column properties at any of the sites.
METHODS
X-ray diffraction was completed on a Philips diffractometer using Cuka radiation and a curved-crystal carbon monochromator. Abundances of the 10 major oxides and Cr, Ba, Sr, Y, Zr, Nb, and Rb in substrate rocks were determined by X-ray fluorescence spectroscopy (XRF; Taggart et al., 1987); Fe(II) by colorimetric titration (Peck, 1964); CO2 by coulometric titration(Engleman et al., 1985); H2O+ by water evolved at 925°C as determined coulometrically by Karl- Fischer titration (Jackson et al., 1987); E^O by sample weight difference at 110°C for greater than one hour (Shapiro, 1975); F and Cl by specific ion electrode, S by combustion and infrared spectroscopy (Jackson et al., 1987), and C by induction furnace; Y, U, Th, and rare earth elements (REEs) by inductively coupled plasma-atomic emission spectrometry-mass spectrometry (ICP-MS; Aruscavage et al., 1989; Lichte et al., 1987a,b); and Au, As, Sb, and W by neutron activation analysis (NAA; McKown and Millard, 1987). Low totals for the phosphorite sample occurs because of typically high F, Cl, and S contents, which are not included in the total.
For Fe-Mn crusts and hydrothermal stratabound Mn, the concentrations of Mn, Fe, Si, Al, Mg, Ca, Na, K, Ti, P, Ba, Nb, Rb, Zr, and Y were determined by XRF; Be, B, Co, Cu, Ge, Li, Mo, Ni, Pb, Sc, Sr, V, Zn, and Ag were determined by ICP; Bi, Cd, Ga, In, Sn, Tl, Y, Au, REEs, and platinum group elements (PGEs) by ICP-MS; As, Au, Br, Cr, Cs, Hf, Sb, Se, Ta, Th, U, and W by NAA; Te by graphite furnace atomic-absorption spectroscopy; Hg by wet chemical techniques; S by combustion and infrared spectroscopy; and Cl by specific ion electrode. REEs in plots are normalized to both chondrites (Anders and Grevesse, 1989) and shale (PAAS, Post- Archean Australian Shale; McLennan, 1989).
The usual Pearson product moment correlation coefficient was used to calculate the correlation coefficient matrices. For Q-mode factor analysis, each variable percentage was scaled to the percent of the maximum value before the values were row normalized and the cosine theta coefficients calculated. The factors were derived from orthogonal rotations of the principal component eigenvectors using the Varimax method (Klovan and Imbrie, 1971). Communalities for all samples are >0.97.
Growth rates of non-phosphatized crusts were determined using the empirical equations of Puteanus and Halbach (1988): GR = 1.28/Co-0.24, with cobalt content in weight percent; and Manheim and Lane-Bostwick (1988): Co" = Co-0.0012%, GR = 0.68/(Con) 1>f7 .
LITAKPOOKI RIDGE SUBSTRATE ROCKS
Descriptions
Substrate rocks based on dredges Dl and D2 as well as dredges D14 and D15 from KODOS 97-4, in decreasing order of abundance include limestone, breccia, phosphorite, basalt, and ironstone (Tables 5, 6; Hein, Moon, et al., 1998). As seen in hand samples, most limestones from KODOS 98-3 Litakpooki dredges are either friable to well-lithified foraminiferal limestone or bioclastic limestone composed of shell hash and foraminifera. Limestones are pale-brown to off- white, yellow-brown, or brown. They are commonly peppered with Fe-Mn oxyhydroxide grains,
contain Mn dendrites, or have vugs lined with Fe-Mn oxyhydroxides. Some limestone samples are partly phosphatized, which grade into phosphorites. Phosphorites are massive, vuggy, or pebbly. Pebbly phosphorite contains sparse, brown basalt clasts commonly coated with Fe-Mn oxyhydroxides, and yellow-green altered hyaloclastite clasts. Vugs in vuggy phosphorites are lined with Mn oxides. Carbonate fluorapatite (CFA) veins and Mn-oxide dendrites are common in all three types. Most of the phosphorite is CFA-replaced limestone, more rarely CFA-replaced basalt.
Breccias most commonly consist of white to brown phosphorite, brown basalt, and brown ironstone clasts in cream to pinkish CFA cement, rarely Fe-Mn oxyhydroxide cement. CFA veins are common and Fe-Mn oxyhydroxide veins also occur. Volcanogenic clasts are commonly partly to completely replaced by smectite. Basalt is altered, brown to red-brown, and may be laced with CFA and Fe-Mn oxyhydroxides and contain large yellow-green amygdules. Sample D2-2E consists solely of smectite, yet maintains relict volcanic textures.
Ironstone samples are brown to dark brown, massive, and dense. Ironstone also occurs as clasts in breccia and pebbly limestone and formed by replacement of basalt. Ironstone most likely formed from hydrothermal processes related to formation of the volcanic edifice during the Cretaceous (Hein et al., 1994).
X-ray Diffraction Mineralogy
For the four samples for which minerals were identified by X-ray diffraction, primary volcanogenic and sedimentary minerals include plagioclase and calcite; and secondary minerals include CFA and smectite (Table 7). Secondary CFA is the most abundant mineral in these samples and occurs in three of the four samples as a major or moderate constituent, regardless of rock type (Table 7).
Fresh basalt was not recovered in dredges Dl and D2. Altered basalt consists of plagioclase and various amounts (up to 100%) of smectite and CFA. The most altered basalts lack all primary minerals, but maintain volcanic textures. CFA replaces basalt and fills vesicles and fractures.
Limestones are composed chiefly of calcite, with various amounts of CFA, showing all gradations from limestone (only calcite) to phosphorite (only CFA). Most phosphorites have relict limestone textures, especially that of foraminiferal sand.
Chemistry
The most P2Os rich CFA-replaced sedimentary rock has a CaO^Os ratio of 1.63 (Table 8), whereas theoretical compositions for CFA produce ratios that range from 1.5 to 1.6 (Manheim and Gulbrandsen, 1979). The very slight excess Ca over P in some KODOS 98-3 samples may be due to additional Ca associated with minor contamination by volcanogenic plagioclase, phillipsite cement (an alteration product of volcanic debris), or to relict calcite in the phosphatized limestone. However, Hein, Moon, et al. (1998) showed that, CaO^Os ratios between 1.60 and 1.66 characterize chemically very pure phosphorites, indicating that CaO/P2O5 ratios between 1.58 and 1.66 are characteristic of uncontaminated marine CFA. Ratios in that range have been found in many of our previous studies (e.g., Hein, Kang, et al., 1990; Hein, Ahn, et al., 1992; Hein et al., 1993). The CaO^Os ratio of 1.63 is very near the most cation- and anion-substituted francolite (1.62) end of the fluorapatite (1.32)-CFA range (Manheim and Gulbrandsen, 1979; McClellan and van Kauwenbergh, 1990). The Sr content for the phosphorite sample is 1260 ppm, near the middle of the range (900-1600 ppm) found for other central Pacific phosphorite samples (Hein et al., 1993). Normalized REE plots of phosphatic limestone (Table 9) show a seawater-type pattern with large negative Ce anomaly, small positive Gd anomaly, and heavy REE enrichment (Fig. 6). These identical patterns indicate that the CFA as well as the calcite were derived from seawater.
Smectite occurs in major to moderate amounts in two of the four samples analyzed, and is especially abundant in the strongly altered basalts. The pure smectite sample (D2-2E) has relatively
high Si, Al, Fe, and Zr contents and low Mg content, indicative of an iron-rich montmorillonite (Tables 7, 8).
Most samples of basalt and basalt clasts in breccia are altered to smectite and goethite and are rarely replaced by phosphorite and phillipsite. Alteration is best characterized by increases in Fe2O3 and water and decreases in FeO and K2O contents (Table 8). Volcaniclastic mudstone and hyaloclastite have compositions comparable to highly altered basalts.
SOUTHWEST CAROLINE RIDGE SUBSTRATE ROCKS
Dredge D7 was taken on southwest Caroline Ridge and consists of pillow basalt wedges, limestone, and breccia in that order of abundance (Table 6). The basalt is gray (relatively fresh) to brown (altered), massive, and variably vesicular with a red-brown alteration rind underlain by a black basaltic glass rind. Small vesicles occur in the basalt below the glass rind, which grades into massive basalt. The basalt is composed of primary plagioclase, pyroxene, magnetite, and secondary smectite and hematite.
Foraminiferal limestone is white, friable, massive, and one sample contains a gray volcanic ash layer. The limestone is composed solely of calcite.
Breccias are composed of basalt, basaltic glass, and limestone clasts in (1) calcite cement; (2) calcite-phillipsite cement, with fine-grained volcanogenic minerals; (3) calcite-smectite-phillipsite cement; (4) phillipsite cement, with fine-grained plagioclase and smectite. The limestone clasts consist of foraminiferal limestone and reef fossils such as coral, bryozoans, and benthic foraminifera.
YAP ARC SUBSTRATE ROCKS
Descriptions and Composition
Substrate rocks based on dredges D5, D6, D8, and D9, in decreasing order of abundance are limestone, andesite and basalt, breccia, sandstone, serpentinite, and hydrothermal stratabound Mn deposits (Tables 5, 6). Carbonates consist of white to brown foraminiferal ooze; pale-brown, friable, burrowed, sandy foraminiferal limestone; pale-brown, argillaceous, burrowed micritic limestone with Mn veinlets interbedded with sandy foraminiferal limestone. Sand grains are basalt. A small amount of reef limestone and sandy chalk were also recovered. Foraminiferal sediment also comprise the matrix of some breccia samples. The limestones are composed of calcite and various amounts of volcanogenic minerals, chiefly plagioclase, and their alteration products, chiefly smectite (Table 7).
Volcanic rocks consist mainly of andesite, dacite, and basalt (Tables 6, 7, 10; KODOS, 1999b). Basalts are brown, mottled greenish-pale brown, and gray-brown, altered, commonly plagioclase phyric, and show a brown, altered chill margin. Some samples are amygdaloidal, have calcite veins, or disseminated sulfides. Basalts consist chiefly of plagioclase and pyroxene, with minor amounts of magnetite, smectite, and hematite. Vesicles are lined with phillipsite or filled with smectite. A large hydrofracture vein in basalt sample D9-8D is composed of altered glassy basalt fragments in Mn oxide, smectite, and phillipsite cement with small grains of disseminated amphibole. Andesites are fresh to mildly altered (Table 10), gray, massive, vesicular, and plagioclase phyric; or black, plagioclase phyric, andesite glass with an altered, soft, gray rind. Andesite from dredge D5 is composed chiefly of plagioclase and pyroxene, with minor tridymite and quartz and the secondary minerals calcite and smectite. Andesite from dredge D7 is composed chiefly of tridymite, cristobalite, plagioclase, and pyroxene, with minor hematite and smectite. Phillipsite is abundant and magnetite occurs in moderate amounts in the alteration rind of andesite glass (Table 7, sample D9-6-2).
Breccia in dredge D5 is matrix supported and consists of clasts of volcaniclastic sandstone, andesite, breccia, and rarely hydrothermal(?) quartz in a fine-grained matrix of plagioclase, pyroxene, tridymite, smectite, and calcite (Table 6). Fe-Mn-oxide cement occurs near the contact with crusts. Two fragments of breccia consisting of serpentinite clasts in a quartz-calcite cement were also recovered. Breccia sample D5-2B is enriched in Au about 4 times over its earth's crust mean content of 4 ppb (Govett, 1983; Table 10). Breccia in dredge D8 is matrix supported and consist of altered brown basalt clasts in a pale-brown matrix of carbonate with blue serpentine grains, Mn oxides, and metamorphic rock fragments. Three types of breccia occur in dredge D9: 1. Andesite and altered basalt clasts in clast-supported fine-grained volcaniclastic matrix; 2. Black andesite glass, andesite, and altered basalt in brown to yellow-green smectite matrix; 3. Gray, aphyric to feldspar phyric basalt and andesite clasts in yellow-green smectite matrix, phillipsite cement and veinlets, and Mn veinlets and grains.
Reworked pyroclastic rocks were recovered in dredge D9 and consist predominantly of sandstone, siltstone, and mudstone, which are commonly interbedded. Primary grains and glass have been completely replaced by phillipsite and smectite (Table 7). Different beds are black, brown, and yellow-green, display soft-sediment deformation and burrowing, and are peppered with Mn-oxide grains that also form laminae and graded beds. Smectite veins are also present. Gold is enriched about 4 times over its earth's crust mean content in some beds (Table 10). Volcaniclastic sandstone and siltstone consist of black glassy andesite grains with Fe-oxide and minor Mn-oxide cements (Fe2O3 is 19.5%, MnO is 0.88%, Table 10). The sandstone is composed of plagioclase, smectite, and X-ray amorphous Fe-oxide. Volcaniclastic siltstone and mudstone are pale-brown, yellow-green, and greenish, with Fe-Mn veinlets, dendrites, and grains. Those rocks are completely altered to smectite. The sandstone is enriched in Au about 6.5 times over its earth's crust mean content (Table 10).
Serpentinite from dredge D5 is partly replaced gabbro that is mottled white, dark-gray, blue- gray, green, and yellow-brown, and is dense and heavy. The serpentinite is composed of serpentine (probably lizardite), pyroxene, plagioclase, and minor smectite, talc, tridymite, and magnetite as determined by XRD and also minor brucite, tremolite, chlorite, and hornblende as determined by thin-section petrography. The dominant replacement texture is bastite, indicating that pyroxene (less commonly amphibole) was the dominant mineral that was replaced (Wicks et al., 1977). Minor mesh texture also occurs, indicating replacement of minor olivine. Some replaced grains are laced with magnetite, which also forms veins, surrounds the margin of grains, and is disseminated. Serpentinite from dredge D8 is nearly completely replaced peridotite(?) that is brown with black patches and contains Mn dendrites, large lizardite plates, and extensive magnetite veins. Coarse-grained magnetite and lizardite indicate that the serpentinite is at a mature stage of development. The mineral composition is lizardite, magnetite, and chromite. The replacement texture is approximately 70% mesh and 30% bastite, indicating replacement predominantly of olivine and secondarily of pyroxene (Wicks and Whittaker, 1977; Wicks et al., 1977). Compared to other serpentinites (Faust and Fahey, 1962), serpentinites from dredges D5 and D8 have high Cr (to 3560 ppm) and Fe (to 10.3% Fe2O3) contents, reflecting their high contents of magnetite and chromite (Tables 7, 10).
LITAKPOOKI RIDGE FERROMANGANESE CRUSTS
Description
Fe-Mn crusts collected during KODOS 98-3 vary in thickness from a patina to 154 mm (Tables 5, 6). Dredge Dl had a maximum crust thickness of 120 mm and an average crust thickness of 80 mm. Dredge D2 has a maximum crust thickness of 154 mm and an average crust thickness of 48 mm. Thicker crusts are composed of two or more layers, five being the maximum and three and four layers being the most common. The typical bedding sequence is an uppermost massive black layer (layer 1); which is underlain by a black, porous to vuggy layer that is stained reddish (layer 2); which in turn is underlain by a dense, massive, black, phosphatized layer (layer 3). Layer 3
may contain CFA-filled veins and lenses in addition to being impregnated by CFA. Layer 3 can be sub-divided into as many as four layers based on content and form of CFA and degree and orientation of fractures. All crusts greater than 60 mm thick have a phosphatized older crust generation. CFA in the 32-mm-thick crust D2-6A results from contamination from the substrate phosphorite, which has a gradational contact with the crust.
The growth rates and ages of nonphosphatized, or very mildly phosphatized bulk crusts and crust layers were determined using the empirical equation of Puteanus and Halbach (1988), which is based on Co contents and assumes a constant flux of Co in space and time, and that of Manheim and Lane-Bostwick (1988) (Table 11). The Puteanus and Halbach (1988) equation produces growth rates that range from 2.7 to 9.3 mm/Ma (mean 5.8 mm/Ma) for bulk crusts and 1.5 to 7.5 mm/Ma (mean 4.0 mm/Ma) for crust layers. In contrast, growth rates determined by the Manheim and Lane-Bostwick (1988) equation are much slower, with a range for bulk crusts of 1.2 to 3.5 mm/Ma (mean 2.4 mm/Ma) and for crust layers a range of 0.6-3.0 mm/Ma (mean 1.7 mm/Ma). The latter growth rates are much more in line with those determined by U-series and Be isotopes, which range from <1-10 mm/Ma, but mostly fall within the range of 1-3 mm/Ma (Hein et al., 1999). Using the slower growth rates, the age range for the beginning of growth of bulk crusts is 16.0-30.3 Ma. The 30.3 Ma age for the 100-mm-thick crust D1-1A is probably much too young and that age needs to be confirmed with Be isotope dating. The ages for initiation of crust growth are much younger than the age of the volcanic edifices on which they grew. Marshall Islands seamounts range in age from about 76-138 Ma old, ages of 76-86 Ma being most common (Davis et al., 1989; Lincoln et al., 1993). The fast growth rates determined by the Puteanus and Halbach (1988) equation produce unreasonably young ages for initiation of crust growth, especially for the thick crusts. Analytical precision in the chemical composition of the crusts produces growth rates and resulting crust ages with relative differences that range from 6-13%.
X-Ray Diffraction Mineralogy
Great care was taken in sampling crusts for chemical and mineralogical analyses. Contamination from recent sediments was removed, which was especially critical in porous crust layers. Also, special attention was paid to obtaining a clean separation of the lowest crust layer from the substrate; however, that was not possible with crust D2-6A where the contact was gradational. Any minerals or elements determined to exist in the various crust layers were incorporated into those layers during deposition or diagenesis and are not due to sampling procedures or post-depositional infiltration of sediment. Finally, encrusting organisms and other debris were cleaned from the crust surfaces before subsampling. Bulk always refers to the entire crust thickness, whether composed of layers or not.
6-MnO2 (vernadite) contents of bulk crusts and crust layers range from 69% to 100% (Table 12). 6-MnO2 has only two X-ray reflections at about 2.42A and 1.41 A. X-ray amorphous Fe oxyhydroxide epitaxially intergrown with the 6-MnO2 is also a dominant phase in these crusts, but is not included with the crystalline phases listed in Table 12. Part of this X-ray amorphous iron phase crystallized to goethite in 56% of the layers analyzed. CFA occurs in 78% of the bulk crusts and 44% of the layers analyzed. Crust layer samples contain up to 26% CFA, always within the lowermost one or two layers of the crust. CFA is not found in the outer layers of thick crusts or in thin crusts. CFA is found in such a high percentage of the bulk crusts because most of the crusts analyzed are thick.
Quartz occurs in 24% of the samples analyzed; it was detected in 11% of the bulk crusts and 31% of the crust layers (Table 12). Quartz contents are less than or equal to about 1%. Plagioclase (<1 to 7%) was found in six samples and K-feldspar in one sample. The quartz and some of the plagioclase are of eolian origin, earned by the westerlies from Asia, as there is no local or regional source for quartz in the west-central Pacific. The Marshall Islands are south of the main westerly wind belt which is reflected in lower quartz contents compared to crusts from higher latitudes (Hein et al., 1985, 1987; Hein, Kang, et al., 1990). The remainder of the plagioclase, as well as the smectite, phillipsite, K-feldspar, and calcite were reworked from local outcrops and
incorporated into the crusts during precipitation of the Fe-Mn oxyhydroxides. Smectite occurs in about 24% of the samples.
Calcite occurs in two crust layers. The outermost layer of crust D2-1B contains calcite that probably resides in the outermost few millimeters of that layer. Calcite is replaced by Fe-Mn oxyhydroxides after burial by more than a couple of millimeters of crust. Calcite in the inner layer (25-55 mm) of crust Dl-2 is probably the result of contamination.
Chemistry
Twenty-five Fe-Mn crust samples (9 bulk crusts and 16 crust layers) were analyzed for chemical composition (Tables 13-18). Data are presented including hygroscopic water (Table 13)and on a hygroscopic water-free basis-that is normalized to 0% H2O" (Tables 14-17). Hygroscopic water varies from about 6% to 19% (to 30% in other samples from the region) and consequently can significantly affect the contents of all other elements. Sample compositionsnormalized to 0% H2O can be more meaningfully compared and also more closely represent the grade of the potential ore. The following discussion is confined to hygroscopic water-free compositional data.
Bulk Crusts: The mean Fe and Mn contents of the 9 bulk crusts are 20.1% and 25.2%, respectively (Tables 14, 16). The mean Fe/Mn ratio (0.8) is higher than the mean ratio for the entire central Pacific region (0.72; Hein et al., 1992), the ratio for the entire Marshall Islands EEZ (0.64; Hein et al., 1999), and the ratio for the area to the northwest of the Marshall Islands EEZ (0.76; Hein et al., 1997a). For the entire Marshall Islands EEZ, the mean Mn content is more (26.3%), while the Fe content is less (16.9%) compared to bulk crusts from this study. The mean contents of the economically important metals Co (0.48%), Ni (0.34%), and Pt (0.54 ppm) are less than the mean contents of 0.79%, 0.57%, and 0.63 ppm, respectively, for the entire Marshall Islands EEZ (Hein et al., 1999). The mean Co and Ni contents are less and Pt about the same compared to mean contents for crusts from the entire equatorial Pacific region. Phosphorus, a potential byproduct of mining crusts for Co and Ni, has a mean value of 2.2%, higher than the central Pacific mean of about 1%, and the mean content of 1.8% for crusts from the entire Marshall Islands EEZ. Analysis of a large number of thick crusts lowers the mean contents of many metals, and that is probably why this study shows mean concentrations below the regional and Marshall Islands means for Co, Ni, and other metals. Studies that include only analyses of thin crusts yield mean concentrations higher than those of regional means (for example, Pichocki and Hoffert, 1987; see Hein et al., 1992 for discussion). The Co+Ni+Cu mean content for all bulk crusts is 0.92% and the maximum mean percent is 1.40%. If Pb is added to that group of elements, the mean content is 1.07% and the maximum mean content is 1.57%. The mean content of Co+Ni+Cu decreases with increasing crust thickness, for example the mean is 1.22%; for crusts <60 mm thick, and 0.83% for crusts >60 mm thick. That decrease in metals is controlled by Co and Ni contents because Cu contents increase in thick crusts, 0.07% for <6() mm-thick crusts versus 0.11% for crusts >60 mm thick. Mean Pb contents are about the same in thin and thick crusts. The relationship of Co+Ni+Cu to Fe and Mn contents can be seen on a Bonatti et al. (1972) diagram (Fig. 7), on which the KODOS 98-3 data fall in the range typical for central Pacific Fe-Mn crusts (Halbach et al., 1982; De Carlo et al., 1987; Hein et al., 1992).
Other metals of potential economic interest that are concentrated in the Fe-Mn crusts include Zr (535 ppm), Tl (121 ppm), Te (95 ppm), Bi (mean 52 ppm), W (-36 ppm), and Pt (0.5 ppm). Only recently have crusts been analyzed for Tl, Te, and Bi. Te contents are remarkably high compared to its earth's crust mean content of about 1 ppb-95,000 times enrichment for the Fe-Mn crust mean of 95 ppm and 145,000 times enrichment for the maximum Te content of 145 ppm in bulk crusts. However, the mean Te content of the earth's crust is poorly known and some estimates have placed it as high at 10 ppb, which would lower those enrichments by a factor of 10. The interesting aspect is that the mean content of two of those elements, Bi and Te increase in thick crusts, while Tl, Zr, and W decrease in thick crusts, that is, they are 39, 80, 159, 569, and 44 ppm in <60 mm-thick crusts and 58, 102, 102, 519, and 32 ppm, respectively, in >6() mm-thick
crusts. Mean contents of Ca, P, S, As, Cr, Cu, Mo, Pb, Sr, Th, U, V, Y, and Pt increase in thick crusts, whereas the other elements decrease except for Be, Ga, Hf, Rb, Sb, Sc, Sn, Rh, and Os, which are about the same in both crust thickness groups. This means that the ore grade for some rare metals (Bi, Te, Pt) increases with tonnage (thickness), the reverse of the situation for Co in crusts, the chief metal of economic interest. This decrease in grade with increase in tonnage is typical for metals of interest in most types of ore deposits. The increases in Ca and P contents are the result of phosphatization of the older generation of thick crusts.
Crust Layers: Individual layers from five crusts were analyzed: Two crusts were split into four layers, two crusts into three layers, and one crust into two layers (Tables 14, 17). Crust D2-5 was divided into two layers and the change in element contents is controlled by the high content of detritus in the inner layer. Therefore, Si, Al, and other aluminosilicate-associated elements are higher in the inner layer and Fe and Mn oxide-associated elements are higher in the outer layer (Table 14). For the crusts divided into three layers, Dl-1 shows uniform increases toward the substrate for Ca, P, Ba, Cu, (CFA associated elements) and Te and uniform decreases in Mn, B, Cd, Co, Ga, Ni, Tl, Hg, Ru, mostly Mn oxyhydroxide-associated elements. Aluminosilicate- associated elements are highest in the middle layer and residual biogenic-associated elements are lowest in the middle layer. For crust D2-2, there are uniform increases toward the substrate for Ca, P, Ba, Be, and Sr (CFA-associated elements), similar to Dl-1, and uniform decreases in Fe and Mn oxyhydroxide-associated elements. Aluminosilicate-associated elements are lowest in the middle layer and residual biogenic-associated elements are highest in the middle layer. For the crusts divided into four layers, Dl-2 shows uniform decreases to the substrate of Mn, B, Co, Tl, and Hg and a uniform increase in Cu. Only the lowermost layer of the crust is phosphatized. All other elements have maximum values in one of the four layers, with variable distributions in the other layers. For crust D2-1, there are uniform decreases to the substrate only for Cd and uniform increases for Be, Bi, and Sr. The lower two layers are phosphatized with layer 3 having the highest P content; consequently, most other elements have their highest contents in layer 1, 2, or 4. Platinum typically increases with depth in thick crusts, although here it increased in one crust and decreased in another. In general, the trends indicate that there is a decrease of manganophile elements with depth in the crusts accompanied by increases in elements characteristic of the residual biogenic phase. Non-phosphatized crust layers generally have higher trace metal contents relative to Fe and Mn contents than do phosphatized crust layers.
Platinum Group Elements and Gold
Four bulk crusts and six crust layers were analyzed for PGEs, and nine bulk crusts and 12 crust layers for Au (Table 14). Mean palladium (mean 8 ppb), Os (2 ppb), and Au (~5 ppb) contents are roughly at their earth's crust mean content. One high Au outlier (54 ppb) raises the mean Au content to its earth's crust mean, otherwise it would be lower than its earth's crust mean. Two samples analyzed from the KODOS 97-4 cruise had high Au contents of 543 and 51 ppb, but overall crusts from that cruise had a mean Au content about at its earth's crust mean. The other PGEs are enriched over their earth's crust mean content by 7 times for Ir (Fe-Mn crust mean of 7 ppb), 20 times for Ru (mean 20 ppb), 30 times for Rh (mean 31 ppb), and 130 times for Pt with a mean content of 648 ppb. Crust layer D2-2B has an uncommonly high Pt content of 1930 ppb, the maximum measured content being 2650 ppb (Hein et al., 1997a). The high content in D2-2B is especially unusual in that it occurs in the outermost layer of the crust rather than the innermost phosphatized layer, which is more common. That same layer has the highest Mn, Ti, Te, Sn, As, Sb, Nb, Au, Ir, Rh, and Ru contents measured in this study, all of which decrease toward the substrate; Co has its second highest content. These element enrichments are likely associated with the high Mn content, that is with the S-MnO2 phase. There is also an uncommonly low Pt content of 151 ppb for the outermost layer of crust D1-1B. The mean Pt content of 648 ppb is comparable to the mean for the entire RMIEEZ (634 ppb; Hein et al., 1999) and lower than the mean content for a large area of the northwest Pacific, 777 ppb (Usui and Someya, 1997).
Enrichment of PGEs in the inner parts of crusts is common for central Pacific crusts. The highest Pd and Ru concentrations occur in crusts from the Yap and Mariana arcs, as do other
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elements indicative of clastic input. As shown in previous studies, Pt, Ir, and Rh are derived predominantly from seawater, whereas Pd and much of the Ru are derived from clastic debris, the remainder of the Ru being derived from seawater. The extraterrestrial component (meteorite debris) in the bulk crusts is small. However, meteorite debris may be concentrated locally in the crusts by formation of dissolution unconformities, or by proximity of the crust to meteorite fallout during formation of the layer. Localized extraterrestrial debris-rich horizons, however, do not alter the overall hydrogenetic signature of the PGEs. In addition, the PGE ratios are non-chondritic, with Fe-Mn crust compositions showing more than an order of magnitude more Pt relative to Ir and Rh relative to Ir. More likely, Pt is a redox sensitive element and its changing concentration reflects changing redox conditions, and diagenesis in the inner parts of the crusts (see Hein et al., 1997b).
Rare Earth Elements
For 7 bulk crusts and 6 crust layers, total REEs vary from about 0.15% to 0.27% (Table 18). For bulk crusts, total REE contents range from 0.15% to 0.24%, with a mean of 0.20%. The range and mean for individual crust layers are somewhat higher than for bulk crusts, 0.15%;- 0.27% and 0.21%, respectively. Mean total REE content differences between thick and thin crusts is 0.22% and 0.18%, respectively. The two samples for which layers were analyzed show different patterns of REE concentrations with depth in the crusts. The three layers of crust D1-1 generally show a decrease of light REEs (La to Gd) from the innermost layer 3 to the outer two layers, which have similar contents; the heavy REEs (Gd-Lu) have their highest content in the outermost layer, next highest in the innermost layer and lowest content in the middle layer. Total REEs and the Ce anomalies follow the pattern of the light REEs. The three layers of crusts D2-2 show the highest content of each element in the middle layer (except La), the next highest content in the lowermost layer, and lowest content in the uppermost layer. Total REEs follow the same pattern, but the Ce anomalies decrease from the surface to the substrate. These two trends are not related to degree of phosphatization of the crust layers. For crusts from the area northwest of the RMI, 11 of 13 crusts analyzed showed decreases in REE contents from the substrate to the crust surface (Hein et al., 1997a), as did total REEs for crust Dl-1 here.
Chondrite-normalized REE patterns show moderate to large positive Ce anomalies, small positive Gd anomalies, light REE enrichments, and slight decreases in heavy REEs with increasing atomic number, or flat heavy REE patterns (Figs. 8-10). PAAS shale-normalized REE patterns show nearly flat heavy REEs, light REE depletion, and positive Ce and Gd anomalies. A small positive Gd anomaly is typical of hydrogenetic Fe-Mn crusts and of seawater (Hein et al., 1988). In crust Dl-1, the Ce anomalies increase through the crust from the surface to the substrate, where as the opposite trend in seen in crust D2-2.
Element Associations
Correlation coefficients and Q-mode factor analysis coupled with X-ray diffraction mineralogy can be used to interpret which elements are associated with the mineral phases that make up Fe-Mn crusts. We analyzed correlation coefficient matrices and Q-mode factor analyses for three data sets including nine bulk crusts from Table 14 (Table 19; Fig. 11), four bulk crusts <62 mm (Table 20), and five bulk crusts >85 mm (Table 21; Fig. 12). We interpret the data for bulk crusts to indicate that the following elements are associated with the following phases. Detrital (aluminosilicate) phase: Si, Al, Fe, Ti, K, Na, Zr, B, Nb, Hf, Li, Y; Mn-oxyhydroxide phase: Mn, Tl, Co, Ni, Pb, Ga, Mo, Cd, Na, Bi; Fe-oxyhydroxide phase: Fe, As; CFA phase: Ca, P, S, Sr, As, Te, Bi, Ba, Be, Cu, Sn, Hf, Pb, Sc; residual-biogenic phase: Sr, Ba, Cu, W, Zn, As, V, Bi.
Only minor differences exist between the data sets of bulk crusts <62 mm thick and all bulk crusts, but significant differences exist for crusts >85 mm thick. It has been shown that element associations for very thick crusts do not follow those typical of Fe-Mn crusts because of extensive phosphatization and remobilization of elements (e.g. Hein, Kang, et al., 1990; Koschinsky et al., 1997; Hein and Morgan, 1999). The detrital phase shows minor differences but the other three
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phases are mixed (Table 21; Fig. 12): Mn-oxyhydroxide plus residual biogenic phase includes Mn, W, As, Sr, Bi, Cu, Zn, V, Ca, P, Ba, Pb, Ni; the CFA-diagenetic phase includes Te, Sn, P, Tl, Ca, Co, Nb, Pb, Ti, Bi. This latter phase contains those elements that are known to be, or thought to be, incorporated into Fe-Mn crusts through an oxidation reaction (Co, Pb, Te, Tl, Bi, Ti, Sn).
Element associations indicate that the rare metals (Te, Tl, W, Bi, Hf, Zr, Nb, Sn) are associated with several phases. Tl is clearly associated solely with the Mn-oxyhydroxide phase. Te may be associated primarily with the CFA phase, secondarily with the residual biogenic phase, and possible also with the Mn phase. Hf, Zr, and Nb are predominantly part of the detrital phase, but Hf may also, in part, be associated with the CFA phase, Zr with the residual biogenic phase, and Nb with each of the other three phases. Bi appears to be associated predominantly with the CFA phase and secondarily with the residual biogenic and Mn phases. W may be associated with the residual biogenic phase and secondarily with the Mn oxyhydroxide phase. Sn may be predominantly associated with the CFA phase and, in part, with each of the other three phases. Tl, Hf, and Zr associations are very consistent among the various data sets analyzed here, but the other rare metals need to be analyzed in greater detail with a larger data set.
Correlation coefficients also show that the following elements increase with increasing crust thickness: Ba, S, Bi, Ca, P, Be, and Sr, whereas Si, Cd, B, Al, and K decrease with increasing crust thickness. These relationships indicate that the CFA and residual biogenic phases increase and the detrital phase decreases with increasing crust thickness. It has been noted many times that Co contents, the most important metal of economic interest, decreases with increasing crust thickness, but that correlation is not seen here at the 95% confidence level.
YAP CONVERGENT MARGIN FERROMANGANESE CRUSTS AND STRATABOUND MANGANESE DEPOSITS
Description
Fe-Mn crusts collected on the YCM during KODOS 98-3 are thin and vary in thickness from a patina to 15 mm for Yap Arc samples (D5, D6, D8-, D9) and a patina to 10 mm for dredge D7 from southwest Caroline Ridge (Tables 5,6). The Fe-Mn crusts are composed of one or two layers. Crust layers are black, massive, and porous and rarely dendritic or acicular. Crust surfaces are granular to smooth and rarely botryoidal. None of the crusts have been phosphatized.
Stratabound hydrothermal deposits consists of Mn oxyhydroxide-cemented volcaniclastic sandstone (D5) composed of medium sand-sized grains in gray to black cement; and a 15 mm- thick, submetallic, gray layer of Mn oxyhydroxide with adjacent layers of Mn-cemented volcaniclastic sandstone (D8). The submetallic luster and gray color is a hallmark of hydrothermal Mn deposits.
Growth rates of the Fe-Mn crusts based on the Manheim and Lane-Bostwick (1988) equation (3.1-6.1 mm/Ma) are typical of hydrogenetic precipitation. Based on those growth rates, the oldest crust began forming only 2.6 Ma ago. The growth rate of the Stratabound hydrothermal Mn layer is about 38 mm/Ma, which is slow compared to other hydrothermal Mn deposits (e.g. Hein, Ahn, et al., 1992). That relatively slow growth rate is the result of an anomalously high Co content for hydrothermal Mn. The ages for initiation of crust growth are much younger than the age of the volcanic edifices on which they grew, which is Oligocene for southwest Caroline Ridge and Oligocene and Miocene for Yap Arc (Hein, Ahn, et al., 1992).
X-Ray Diffraction Mineralogy
8-MnO2 (vernadite) contents of bulk crusts range from 91% to 95% (Table 12). X-ray amorphous Fe oxyhydroxide epitaxially intergrown with the S-MnO2 is also a dominant phase in these crusts, but is not included with the crystalline phases listed in Table 12. Quartz, plagioclase,
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and calcite occur as accessory minerals. Hydrothermal birnessite cements the volcaniclastic sandstone, which is composed of plagioclase, serpentine, pyroxene, amphibole, and quartz. The hydrothermal Mn layer is predominantly birnessite, with moderate smectite and quartz (Table 12). It is difficult to distinguish 8-MnO2 in the presence of birnessite because of overlapping peaks, so it is possible that 8-MnO2 occurs in addition to the birnessite.
Chemistry
Three bulk Fe-Mn crust samples, one Mn-cemented sandstone, and one stratabound Mn layer were analyzed for chemical composition (Tables 22-24).
Bulk Crusts: The mean Fe and Mn contents of the 3 bulk crusts are 22.2% and 22.6%, respectively (Tables 23, 24). The mean Fe/Mn ratio (1.0) is higher than the mean ratio for the entire central Pacific region (0.72; Hein et al, 1992), the Marshall Islands EEZ (0.64; Hein et al., 1999), the area to the northwest of the Marshall Islands EEZ (0.76; Hein et al., 1997a), and Fe-Mn crusts from Litakpooki Ridge from this study; but is about the same as the ratio for the FSM EEZ, 1.02 (Hein et al., 1999). Generally, island-arc Fe-Mn crusts form by both hydrogenetic and hydrothermal input and have Fe/Mn ratios greater than 1.0. However, only the bulk crust from southwest Caroline Ridge (D7) has more Fe than Mn. The Co contents, Fe/Mn ratios, and growth rates indicate that the YCM crusts are solely of hydrogenetic origin. The southwest Caroline Ridge crust is similar in composition to the Yap Arc crusts, but with somewhat higher Fe, Cl, Nb, Rb, and Zr contents and lower Al and Ba contents. The Caroline Ridge crust has an unusually high Si/Al ratio (>645) indicating a low detrital component and likely a high biogenic silica content.
Mean contents of the economically important metals Co (0.34%) and Ni (0.34%) are less than their mean contents (0.79% and 0.57%, respectively) for the RMI EEZ crusts (Hein et al., 1999). The Co+Ni+Cu mean content for bulk crusts is 0.75% and the maximum mean content is 0.86%. If Pb is added to that group of elements, the mean content is 0.86% and the maximum mean content is 0.98%. The relationship of Co+Ni+Cu to Fe and Mn (Fig. 7), show that the YCM samples have relatively less trace metals and more Fe compared to Litakpooki Ridge samples.
Other metals of potential economic interest that are concentrated in the YCM Fe-Mn crusts include Zr (554 ppm), Tl (98 ppm), Te (37 ppm), and Bi (mean 14 ppm). Zr is somewhat more, Tl somewhat less, and Bi and Te much lower that mean contents from Litakpooki Ridge crusts. The recovery of only thin crusts from the YCM limits their economic potential.
Stratabound deposits: The hydrothermal stratabound Mn-oxide layer (D8-1 A) has very high Mn (44%), Ba (1.18%), Ni (0.64%), and copper (0.2%) contents, as well as moderately high Zn (0.16%), Cd (16 ppm), and Li (179 ppm) contents, with an Fe/Mn ratio of 0.03 (Table 23). The high Mn and low Fe/Mn ratio are characteristic of hydrothermal Mn deposits. The high trace- metal contents are found in some hydrothermal Mn deposits (Hein et al., 1997b). Previously analyzed hydrothermal Mn samples (n=7) from Yap Arc also had high Mn (44%), Ni (0.45%), Ba (0.31%), Cu (0.26%), Zn (0.16%), Cd (44 ppm), and Cr (436 ppm) contents (Hein, Ahn, et al., 1992), although the sample from this study has much higher Ni and Ba contents. Yap Arc hydrothermal Mn deposits have higher trace metal contents than similar deposits from other regions (Hein et al., 1997b), which may be the result of intensive leaching of ultramafic rocks by the hydrothermal fluids and the lack of precipitation of sulfides at depth, or the leaching of sulfides that formed at depth in the hydrothermal system. A high serpentinite content (Table 12) in the Mn- cemented sandstone (D5-16A) attests to the ubiquitous occurrences of ultramafic and mafic rocks in the Yap Arc, which had previously been dredged from outcrops and collected as blue-green muds that formed from serpentinite diapers (Hein, Ahn, et al., 1992).
Rare Earth Elements
Total REE contents for the 3 bulk crusts vary from 0.14% to 0.16%, with a mean of 0.15%; whereas the total REE contents for the hydrothermal deposits are very low, 130 ppm for the Mn- cemented sandstone and 34 ppm for the stratabound Mn layer (Table 18).
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Chondrite-normalized REE patterns for the Fe-Mn crusts show small positive Ce and Gd anomalies, light REE enrichments, and decreases in heavy REEs with increasing atomic number (Fig. 13). These characteristics are typical of west Pacific hydrogenetic Fe-Mn crusts (Hein, Ahn, et al, 1992). PA AS shale-normalized REE patterns show nearly flat heavy REEs, light REE depletion, convex up middle REEs, and small positive Ce and Gd anomalies. The stratabound Mn layer shows a strong negative Ce anomaly, typical of hydrothermal Mn deposits, and a positive Eu anomaly, which reflects weathering of the basement rock and sediments by the mineralizing fluids (Fig. 14). The REE pattern for the Mn-cemented sandstone is very similar to those of the Fe-Mn crusts, but with an order of magnitude less enrichment relative to chondrites and shale. This indicates that there is a hydrogenetic component in the hydrothermal Mn-cemented sandstone. The negative Yb anomaly probably results from analytical error because of the very low contents of the heaviest REEs.
RESOURCE CONSIDERATIONS
The commonly cited cut-off grade for potential economic development is 0.8% Co and the cut off thickness is 40 mm. On a water-free basis, KODOS 98-3 samples have moderate mean Pt (0.54 ppm), Mn (25.2%), Co (0.48%), Ni (0.34%), and Cu (0.10%) contents, with a mean Co+Ni+Cu content of 0.92%. The mean crust thickness is >40 mm for dredge hauls from Litakpooki Ridge, with one being 80 mm; none of the dredge hauls from the YCM yielded thick crusts. It is not known whether ultimately grade or tonnage (thickness) will be the most important factor in choosing a potential mine site, but if it is tonnage, then both Litakpooki Ridge and Lomilik Seamount in the RMIEEZ are excellent sites for additional work.
It is important that several very rare metals, such as the PGEs, Te, and Bi increase in grade with increasing crust thickness in the RMI crusts. Te contents are especially interesting because its earth's crust abundance may be as much as 5 times less than that of Pt, but its concentration in Fe- Mn crusts is about 200 times greater than that of Pt. Te, Bi, Nb, Tl, W, and Zr need to be looked at in detail in terms of their resource potential in Fe-Mn crusts. Elevated gold contents in some of the dredged Yap Arc rocks indicate that epithermal gold deposits like those that occur on nearby Gagil-Tamil and Maap Islands may also occur offshore.
ACKNOWLEDGMENTS
We thank the captain, crew, and scientific staff of the R. V. Onnuri cruise KODOS 98-3 for excellent support while at sea. We thank Jane Reid, U.S. Geological Survey (USGS), for reviewing this report, and C. Degnan, D. Mosier, and F. Wong of the USGS for help with the maps.
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Hein, J.R., Koschinsky, A., Halbach, P., Manheim, F.T., Bau, M., Kang, J.-K., and Lubick,N., 1997b, Iron and manganese oxide mineralization in the Pacific: in Nicholson, K., Hein,J.R., Biihn, B., and Dasgupta, S. (eds.) Manganese Mineralization: Geochemistry andMineralogy of Terrestrial and Marine Deposits. The Geological Society Special PublicationNo. 119, London, p. 123-138.
Hein, J.R., Moon, J.-W., Lee, K.-Y., Kirn, K.-H., Roberts, L., Burrows, M., Park, S.H.,Dowling, J., Choi, Y.-J., Zielinski, S.E., Chi, S.-B., Benninger, L., Kim, H.-S., and Park,C.-K., 1998. Composition of Co-rich ferromanganese crusts and substrate rocks from theMarshall Islands, cruise KODOS 97-4. U.S. Geological Survey Open File Report 98-375, 71pp.
Hein, J.R., Koschinsky, A., Bau, M., Manheim, F.T., Kang, J.-K., and Roberts, L., 1999,Cobalt-rich ferromanganese crusts in the Pacific. In, CRC Handbook of Marine Minerals,Cronan, D.S. (Ed.), CRC Press, Boca Raton (in press).
Jackson, L.L., Brown, F.W., and Neil, S.T., 1987, Major and minor elements requiringindividual determination, classical whole rock analysis, and rapid rock analysis: in Baedecker,P.A. (ed.) Methods for Geochemical Analysis. U.S. Geological Survey Bulletin 1770, p. Gl-G23.
Klovan, J.E. and Imbrie, J., 1971, An algorithm and FORTRAN-IV program for large-scale Q-mode factor analysis and calculation of factor scores. Mathematical Geology, v. 3, p. 61-77.
KODOS, 1999a, Distribution and genesis of Co-rich crusts in the Marshall Islands, WesternPacific. Korea Ocean Research and Development Institute, Technical Report Number BSPE98729-00-1172-7, 205 pp (in Korean with English summary).
KODOS, 1999b, A geochemical study for the submarine hydrothermal mineralization. KoreaOcean Research and Development Institute, Technical Report Number BSPE 98712-00-1162-7, 271 pp (in Korean with English summary).
Koschinsky, A., Stascheit, A., Bau, M., and Halbach, P., 1997. Effects of phosphatization onthe geochemical and mineralogical composition of marine ferromanganese crusts. Geochimicaet Cosmochimica Acta, v. 61, p. 4079-4094.
Lichte, F.E., Golightly, D.W., and Lamothe, P.J., 1987a, Inductively coupled plasma-atomicemission spectrometry: in Baedecker, P.A. (ed.), Methods for Geochemical Analysis. U.S.Geological Survey Bulletin 1770, p. B1-B10.
Lichte, F.E., Meier, A.L., and Crock, J.G., 1987b, Determination of the rare earth elements ingeological materials by inductively coupled plasma-mass spectrometry. Analytical Chemistry,v. 59, p. 1150-1157.
Lincoln, J.M., Pringle, M.S., and Silva, I.P., 1993, Early and Late Cretaceous volcanism andreef-building in the Marshall Islands. In, The Mesozoic Pacific: Geology, Tectonics, andVolcanism, Pringle, M.S., Sager, W.W., Sliter, W.V., and Stein, S. (Eds.), AmericanGeophysical Union Geophysical Monograph 77, Washington, D.C., p. 279-305.
Manheim, F.T. and Gulbrandsen, R.A., 1979, Marine phosphorites, in Burns, R.G. (ed.),Marine Minerals. Mineralogical Society of America Short Course Notes, v. 6, p. 151-173.
16
Manheim, F.T. and Lane-Bostwick, C.M., 1988, Cobalt in ferromanganese crusts as a monitor ofhydrothermal discharge on the Pacific sea floor. Nature, v. 335, p. 59-62.
McClellan, G.H. and van Kauwenbergh, S.J., 1990, Mineralogy of sedimentary apatites. In,Phosphorite Research and Development, Notholt, AJ.G. and Jarvis, I. (Eds.), The GeologicalSociety, London, p. 23-31.
McKown, D.M. and Millard, H.T., Jr., 1987, Determination of uranium and thorium by delayedneutron counting, in Baedecker, P.A. (ed.), Methods for Geochemical Analysis. U.S.Geological Survey Bulletin 1770, p. 11-112.
McLennan, S.M., 1989, Rare earth elements in sedimentary rocks: Influence of provenance andsedimentary processes: in Lipin, B.R. and McKay, G.A. (eds.) Geochemistry and Mineralogyof Rare Earth Elements. Mineralogical Society of America's Reviews in Mineralogy, v. 21,Washington D.C.
Peck, L.C., 1964, Systematic analysis of silicates. U.S. Geological Survey Bulletin 1170, 89 p. Pichocki, C. and Hoffert, M., 1987, Characteristics of Co-rich ferromanganese nodules and crusts
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U.S. Geological Survey Bulletin 1401, 76 p. Taggart, I.E., Lindsay, J.R., Scott, B.A., Vivit, D.V., Bartel, A.J., and Stewart, K.C., 1987,
Analysis of geologic materials by wavelength-dispersive X-ray fluorescence spectrometry: inBaedecker, P.A. (ed.), Methods for Geochemical Analysis. U.S. Geological Survey Bulletin1770, p. E1-E19.
Usui, A. and Someya, M., 1997, Distribution and composition of marine hydrogenetic andhydrothermal manganese deposits in the northwest Pacific, in Manganese Mineralization:Geochemistry and Mineralogy of Terrestrial and Marine Deposits, Nicholson, K., Hein, J. R.,Biihn, B., and Dasgupta, S. Eds., Geological Society Special Publication No. 119, London,p. 177-198, 1997.
Wicks, FJ. and Whittaker, E.J.W., 1977. Serpentine textures and serpentinization. CanadianMineralogist, v. 15, p. 459-488.
Wicks, F.J., Whittaker, E.J.W., and Zussman, J., 1977. An idealized model for serpentinetextures after olivine. Canadian Mineralogist, v. 15, p. 446-458.
17
Table 1. Scientific personnel on R.V. Onnuri cruise KODOS 98-3
Jai Woon MoonKyeong Young LeeJames R. HeinMalia BurrowsYoun-ji ChoiJennifer S. DowlingRaymond Freeman-LyndeYoung Geun JinHoi Soo JungHyun Sub KimDuk Kee LeeGun Chang LeeSang Heon NamChan Young ParkCheong Kee ParkSung Hyun ParkSeung Kyu SonIn Sung Yoo_______
Co-chief scientistCo-chief scientistGeochemistrySamplingCTD4SamplingSedimentologyAirgun SeismicSamplingSBP, PDRAirgun SeismicSampling DSCAirgun SeismicData ProcessingSeaBeam BathymetrySamplingCTDAirgun Seismic___
KORDI1KORDIUSGS2USGSKORDIUSGSUGA3KORDIKORDIKORDIKORDIKORDIKORDIKORDIKORDIKORDIKORDIKORDI
1 Korea Ocean Research and Development Institute 2United States Geological Survey 3University of Georgia, Athens4 CTD = conductivity, temperature, density; SBP= sub-bottom profiler; PDR precision depth recorder; DSC = deep sea camera
18
Table 2. Station locations and operations for cruise KODOS 98-3
Station Operation1 Location
Marshall Islands Fe-Mn crust leg
SB 1 CTD1SB 2 PCISB 3 PC2SB 4 DlSB 5 D2SB 6 D3SB 7 D4SB 8 CTD2
FSM Hvdrothermal leg
Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge SW of Litakpooki
HIH2H3H4H5H6H7H8H9H10H 11H 12H13H14HISH 16H17H18H19H20
CTD3CTD4CTD5BC1, 2PC3MCID5D6DSC1CTD6CTD7CTD8CTD9MC2D7PC4CTD 10D8D9CTD11
Yap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap TrenchW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeYap TrenchYap ArcYap ArcYap ArcYap Arc
CTD = conductivity, temperature, density, and oxygen profile; PC piston core; D = dredge; BC = box core; MC = multiple core; DSC = deep-sea camera
19
Table 3. Twelve channel, two-150 in3 airgun lines (AG); 3.5kHz and 12 kHz bathymetry lines (3.5, 12); and SeaBeam lines (SB) (see Figures 2, 3, and 5)
LocationMarshall Islands Fe-Mn crustLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountSubtotal
FSM Hydrothermal legAcross Convergent MarginYap ArcAcross Convergent MarginW. Caroline RidgeAcross Convergent MarginYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeSubtotalTotal
Line NumberlepSB1SB 1-1SB 2SB 2-1SB 3SB 3-1SB 4SB 5SB 6SB 6-1SB 7SB 8SB 9SB 10SB 11SB 12SB 13SB 14SB 15SB 16SB 17SB 17-1SB 17-2SB 18SB 19SB 20SB 21SB 22SB 23-
HIH 1-1H2H2-1H3H3-1H4aH4bH4cH4dH4eH5H5-1H6aH6bH6cH6dH6eH6fH6gH7aH7bH7cH7dH7eH7fH7gH7h -
Operation
3.5, 12, SB3.5, 123.5, 12, SB3.5, 123.5, 12, SB3.5, 123.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 123.5, 12, SB3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB
AG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SB -
Nautical Miles
23.784.98
23.794.98
23.792.49
16.857.47
23.804.98
23.8025.7928.2123.2930.413.677.079.35
26.414.35
11.733.24
11.402.8
26.3214.4117.3826.23
6.65439.42
78.95.1
78.98.2
78.83.0
10.25.64.88.67.6
20.35.6
17.82.52.12.02.24.9
12.74.97.32.23.03.03.84.1
10.0397.8837.2
Kilometers
44.049.22
44.059.22
44.064.61
31.2113.8344.079.22
44.0847.7652.2543.1456.31
6.813.0917.3148.91
8.0621.726.00
21.115.18
48.7426.6832.1948.5712.31
813.74
146.19.4
146.115.2
1465.6
18.810.38.9
1614.137.610.333.04.63.93.74.09.0
23.59.0
13.54.05.65.57.07.5
18.5736.7
1550.4
20
Table 4. Prelim
inary oxygen and temperature data from
CT
D casts, cruise K
OD
OS 98-3 (see Figures 2 and 5)
Latitude(N
)L
ongitude Station
(E) N
umber
Julian D
ayG
reenwich
Low
est O2
Mean
Content
Tim
e1 (m
l/1)
Water D
epth at m
inimum
0
2(m
)
Water D
epth at T
op of O
MZ2 (m
)
Water D
epth at!0°C
Isotherm
(m)
Water D
epth at5°C
Isotherm
(m)
Marshall Islands Fe-M
n crust lee
Litakpooki R
idge C
TD
1
CTD
2
8°09.15'N
10°24.31'N
160°
161
32.02'E
°9.61'E
18
226
227
1327-1457
0827-1010
1.34
1.33
307
343
280
275
279
308
890
919
FSM H
ydrothermal leg
Yap A
rcC
TD
3
CT
D 4
CT
D 5
CT
D 6
CT
D 10
CT
D 11
Yap Trench
CT
D 7
8°58.21'N
8°55.25'N
8°54.64'N
8°57.03'N
8°57.58'N
8°57.39'N
8°46.23'N
137°
137°
137°
137°
137°
137°
138° 28.67'E
32.04'E
37.73'E
40.96'E
41.05'E
34.94'E
08.15'E
9101118252819
234
234
235
236
237
238
236
0942-1216
1310-1510
1354-1600
2145-2335
0958-1200
0202-0418
0208-0651
2.01
1.98
2.03
2.07
2.06
1.94
2.04
406
440
467
479
482
419
434
350
350
340
300
360
275
310
301
285
315
279
313
270
288
887
886
878
910
913
903
904
W. C
aroline Ridge
CT
D 8
CT
D 9
8°35.07'N
8°31.75'N
138°
138° 45.07'E
36.57'E
2021
236
237
1200-1325
1423-1618
2.08
1.92
450
421
300
275
287
285
948
953
'Local Tim
e equals GM
T plus eleven hours for CTD
1 and 2 and GM
T plus ten hours for CTD
3-11 2O
MZ
= oxygen m
inimum
zone
Table 5. Dredge sum
mary for cruise K
OD
OS 98-3 (see Figures 2 and 5)
to
to
Dredge
number
Location
Marshall Islands Fe-M
n
Dl
D2A
2D
2B2
D3
D4
Litakpooki LitakpookiLitakpookiLitakpooki Litakpooki
Water depth on-off
bottom (m
)
crust leg
2058-1893 1862-16801610-14682200-1850 2700-2388
Water depth
Recovery
corrected (kg)
(m)1
2040-1900 1840-17701600-1500
:
55 14575:
Max. crust
thickness (m
m)
120 1541
Mean crust
Dom
inant thickness
substrate (m
m)
80 B
reccia 4g3
Basalt, lim
estone<1
Foram lim
estone
:: ::
Com
ments
Ironstone, phosphorite M
egacrustsLarge bouldersN
o recovery N
o recovery
FSM H
ydrothermal leg
D5
D6
D7
D8
D9
Yap A
rc Y
ap Arc
W. C
arolineR
idge Y
ap Arc
Yap A
rc
2757-2250 2720-1779 2280-1778
2672-1778 2676-2223
2600-2350 2720-1779 2250-1950
2600-2350 2650-2450
3.2 1.3 122
150 81
11
10615
3 B
reccia <1
Pumice
1 B
asalt
< 1 Foram
limestone
3 M
icritic limestone
Serpentinite, hydrothermal M
n 1 breccia fragm
ent Foram
iniferal limestone
Serpentinite, hydrothermal M
n A
ndesite, sandstone
1 Depth interval from
which sam
ples were likely recovered
2Dredge repositioned because of ship's drift off station, clear change in rock types from
lower to upper dredged sam
ples3A
verage for basalt substrate is 95 mm
and for limestone substrate is 19 m
m
Tabl
e 6.
Loc
atio
n an
d de
scrip
tion
of d
redg
e ha
uls,
Mar
shal
l Isl
ands
Fe-
Mn
crus
t and
FSM
hyd
roth
erm
al le
gs, K
OD
OS
98-3
cru
ise
to Ui
Dre
dge
num
ber
Dl
D2
Latit
ude
(ON
)1
08°1
3.97
' 08
°13.
42'
08°1
1.79
'08
°10.
77'
Long
itude
(°E)
160°
35.9
7'
160°
35.4
6'
160°
34.4
8'16
0°34
.59'
Tota
lre
cove
ry(k
g) 55 220
Bro
ken
from
outc
rop
(%)
100
99
Talu
s(%
)
0 1
Fe-M
nen
crus
ted
rock
100
66
Des
crip
tion
offe
rrom
anga
nese
oxi
des
Bot
ryoi
dal s
urfa
ce, r
arel
y gr
anul
ar to
smoo
th,
gran
ular
on
side
s; T
hick
crus
ts w
ith 3
or 4
lay
ers:
1. m
assi
vebl
ack,
2. p
orou
s to
vug
gy,
3.m
assi
ve d
ense
bla
ck, 4
. whe
repr
esen
t, an
upp
erm
ost <
10 m
m
mas
sive
laye
r; l
ayer
3 m
ay b
e su
bdiv
ided
into
up
to 4
laye
rs b
ybe
ddin
g pa
ralle
l fra
ctur
es &
occu
rren
ce o
f CFA
vei
ns a
nd b
lebs
;th
inne
r cr
usts
are
mis
sing
laye
r 3;
2no
dule
s w
ith l
arge
nuc
lei;
som
ebr
ecci
a w
ith F
e-M
n ce
men
t;th
ickn
ess:
max
=120
mm
, av
=80m
mT
hick
cru
sts
on b
asal
t+ph
osph
orite
:Sm
all/m
ediu
m b
otry
oids
on
surf
ace,
gran
ular
on
side
s; 3
to
4 la
yers
: 1.
blac
k m
assi
ve,
2. p
orou
s to
vug
gy &
colu
mna
r, Fe
sta
ined
, 3.
mas
sive
,de
nse,
bla
ck, d
isse
min
ated
CFA
&ve
ins;
lay
er 3
may
be
divi
ded
into
an
uppe
r la
yer
with
out a
ppar
ent C
FAan
d a
low
er la
yer
with
muc
h C
FA&
/or
frac
ture
s; 4
. Whe
re p
rese
nt, a
nup
perm
ost <
10m
m m
assi
ve la
yer;
TT
iin c
rust
s on
lim
esto
ne &
phos
phor
ite: L
arge
to m
odif
ied
botr
yoid
s on
sur
face
, gra
nula
r on
thin
crus
ts;
1-3
laye
rs:
1. m
assi
ve b
lack
,2.
por
ous,
few
vug
s, 3
. por
ous
&vu
ggy,
im
preg
nate
d lim
esto
ne o
rph
osph
orite
; 1
com
plet
ely
encr
uste
dco
bble
with
3 l
ayer
s: 1
. aci
cula
rbl
ack,
2. b
lack
, mas
sive
, fra
ctur
ed,
3.m
assi
ve,
CFA
vei
ns a
nd v
ug f
ill;
spar
se g
ranu
lar
crus
ts o
n fr
iabl
efo
ram
lim
esto
ne;
thic
knes
s on
bas
alt:
max
= 15
4mm
, av
=95m
m;
onlim
esto
ne:
max
=35m
m,
av=1
9mm
;on
fri
able
lim
esto
ne:
av=
<lm
m
Des
crip
tion
ofsu
bstra
te r
ocks
70%
bre
ccia
with
whi
te to
bro
wn
phos
phor
ite, b
row
n ba
salt,
& b
row
nir
onst
one
clas
ts in
cre
am to
pin
kish
CFA
cem
ent l
aced
with
Mn
dend
rites
and
cut b
y C
FA v
eins
; mor
e ra
rely
Fe-M
n ox
ide
cem
ent;
20%
peb
bly
phos
phor
ite w
ith s
pars
e br
own
basa
lt (s
ome
coat
ed w
ith F
e-M
n cr
ust)
&ye
llow
-gre
en a
ltere
d hy
aloc
last
itepe
bble
s; C
FA v
eins
& M
n de
ndrit
es;
5% b
asal
t, br
own,
alte
red;
5%
iron
ston
e, b
row
n, o
oliti
c to
mas
sive
,re
plac
ed b
asal
t
Roc
ks a
re d
ivid
ed in
to tw
o gr
oups
D
2A, e
ncru
sted
& D
2B n
oten
crus
ted-
beca
use
ship
was
repo
sitio
ned
durin
g op
erat
ion
&sa
mpl
es w
ere
colle
cted
from
two
plac
es o
n a
smal
l hill
at t
he s
umm
itof
theg
uyot
. D
2A:
65%
lim
esto
ne&
diff
eren
tially
CFA
-rep
lace
d lim
esto
ne, y
ello
w-b
row
n to
bro
wn,
fora
min
ifera
l, ha
rd to
sof
t dep
endi
ngon
deg
ree
of p
hosp
hatiz
atio
n,m
assi
ve to
vug
gy, l
aced
with
Mn
dend
rite
s, b
lebs
, & v
ein
& v
ug f
ill.
35%
bas
alt,
brow
n to
red-
brow
n,al
tere
d, la
rge
yello
w-g
reen
amyg
dule
s, la
ced
with
CFA
and
Fe-
Mn
oxid
es.
D2B
: 10
0%fo
ram
inife
ral l
imes
tone
, fria
ble,
pal
ebr
own
to o
ff w
hite
, lar
ge v
ugs
lined
with
gra
nula
r Fe-
Mn
oxid
es
Tabl
e 6
cont
inue
d
D3
D4
D5
D6
08°1
9.12
'08
°19.
01'
08°2
2.10
'08
°23.
06'
08°5
6.67
'08
°54.
38'
08°5
3.53
'08
°51.
81'
W4
3.4
21
160°
42.5
5'16
0°49
.19'
160°
44.4
5'
137°
40.7
4'13
7°4U
7'
137°
37.0
2'13
7°41
.36'
0 0 3.2
1.3
- 80 <1
- 20 >99
- 50 <1
No
reco
very
No
Rec
over
y
Smoo
th, g
ranu
lar,
and
mic
robo
tryo
idal
sur
face
s; 1
or 2
laye
rs:
1. b
lack
ver
y po
rous
, 2.
blac
k, p
orou
s, d
endr
itic;
for
one
laye
r=bl
ack,
por
ous,
mas
sive
; 1
sam
ple
of s
ands
tone
cem
ente
d by
hydr
othe
rmal
Mn
oxid
e; th
ickn
ess:
max
=llm
m,
av=3
mm
Spar
se, p
atch
y, g
ranu
lar p
atin
a on
brec
cia
frag
men
t; no
ne o
n pu
mic
e
No
reco
very
No
Rec
over
y
60%
bre
ccia
: gra
y vo
lcan
icla
stic
sand
ston
e, v
olca
nic,
& b
recc
ia c
last
sin
gre
enis
h-br
own
volc
anic
last
icm
atrix
; mat
rix
supp
orte
d; F
e-M
nox
ide
cem
ent n
ear s
urfa
ce w
ith F
e-M
n cr
usts
; rar
ely
hydr
othe
rmal
(?)
quar
tz c
last
s an
d ce
men
t; 2
sam
ples
with
ser
pent
inite
cla
sts
in q
uartz
-ca
lcite
cem
ent;
21%
ser
pent
inite
,m
ottle
d w
hite
, dar
k-gr
ay, b
lue-
gray
,gr
een,
and
yel
low
-bro
wn,
den
se a
ndhe
avy;
8%
alte
red
basa
lt, m
ottle
dgr
eeni
sh ta
n to
gra
y, s
ome
with
sulfi
des,
cal
cite
vei
ns, c
hill
mar
gin,
&/o
r am
ygda
loid
al; 4
% g
ray
volc
anic
last
ic s
ands
tone
, cal
cite
&/o
rqu
artz
cem
ent,
quar
tz c
ryst
als
invu
gs;
1 sa
mpl
e ce
men
ted
by F
e-M
nox
ides
; 5%
ree
f lim
esto
ne &
san
dych
alk;
1%
cru
st fr
agm
ents
with
out
subs
trate
; pum
ice
pebb
le &
gol
den
cora
l98
% g
ray
pum
ice;
2%
bre
ccia
,br
own
volc
anic
cla
sts
alte
red
to c
lay
min
eral
s in
gra
y-gr
een
mat
rix o
f cla
ym
iner
als;
vei
ns o
f qua
rtz &
hydr
othe
rmal
(?) M
n ox
ides
Tabl
e 6
cont
inue
d
to
D7
D8
08°4
3.42
'08
°42.
69'
08°5
5.05
'08
°53.
71'
138°
44.8
6'13
8°45
.24'
137°
39.9
7'13
7°42
.54'
122
150
100
95
- 52
75 <1
Gra
nula
r to
smoo
th s
urfa
ces;
pat
chy
crus
t w
ith 1
lay
er, b
lack
, por
ous,
in
plac
es c
appe
d by
lim
esto
ne;
fora
min
ifera
l lim
esto
ne b
ould
ers
with
spar
se, p
atch
y, g
ranu
lar
crus
t; so
me
vesi
cles
in b
asal
t may
be
fille
d w
ithhy
drot
herm
al b
oxw
ork,
Mn
oxid
es;
thic
knes
s: m
ax=1
0mm
, av=
lmm
Gra
nula
r to
smoo
th s
urfa
ces
onm
ostly
pat
chy
patin
a or
thin
cru
st;
1la
yer,
mas
sive
, bla
ck, p
orou
s, r
arel
yac
icul
ar;
1 pi
ece
of h
ydro
ther
mal
Mn
oxid
e, s
trata
boun
d, s
ubm
etal
lic g
ray
to b
lack
, mas
sive
to p
orou
s; c
rust
thic
knes
s: m
ax=6
mm
, av=
<lm
m
68%
pill
ow b
asal
t wed
ges:
1. g
ray,
mas
sive
, var
iabl
y ve
sicu
lar,
1-2
mm
red-
brow
n al
tera
tion
rind
und
erla
in b
y10
-12
mm
bla
ck g
lass
rin
d va
riabl
yal
tere
d, u
nder
lain
by
10-1
3 m
m o
fsm
all v
esic
les
in th
e ba
salt;
aph
yric
to p
lagi
ocla
se &
/or
oliv
ine
phyr
ic;
2. s
ame
as #
1, b
ut b
asal
t is
alte
red
brow
n; 3
. mas
sive
, gr
ay b
asal
t; 4.
amyg
dalo
idal
bas
alt;
limes
tone
encl
oses
man
y ba
salt
frag
men
ts;
31%
whi
te, f
riabl
e, m
assi
vefo
ram
inife
ral l
imes
tone
, 1
sam
ple
with
a g
ray
calc
areo
us a
sh la
yer;
1%1.
brec
cia
with
bas
altic
gla
ss, b
asal
t,an
d lim
esto
ne, c
last
s in
cal
cite
cem
ent,
grai
n su
ppor
ted;
2. l
arge
tabu
lar b
asal
tic g
lass
cla
sts
inye
llow
-whi
te to
gre
enis
h ca
rbon
ate
+sm
ectit
e m
atrix
, mat
rix
supp
orte
d;3.
gra
y ba
salt
clas
ts in
gre
enis
h so
ftsm
ectit
e m
atrix
, mat
rix s
uppo
rted,
zeol
ite v
ug f
ill60
% f
oram
inife
ral o
oze,
whi
te to
brow
n; 3
2% f
oram
inife
ral l
imes
tone
,fr
iabl
e, e
xten
sive
ly b
urro
wed
, pal
ebr
own,
silt
- &
san
d-si
zed
grai
ns o
fba
salt;
4%
ser
pent
inite
, bro
wn,
alte
red,
mot
tled
blac
k w
ith M
nox
ides
& M
n de
ndrit
es, l
arge
serp
entin
e fla
kes,
sof
t; 2%
bre
ccia
,al
tere
d vo
lcan
ic ro
ck c
last
s in
pal
ebr
own
carb
onat
e m
atrix
with
blu
ese
rpen
tine
grai
ns, M
n ox
ides
, and
met
amor
phic
rock
frag
men
ts, m
atrix
supp
orte
d; 1
% g
ray,
pla
gioc
lase
-ph
yric
and
esite
; 1%
hyd
roth
erm
alM
n, s
ubm
etal
lic g
ray
to b
lack
,m
assi
ve
Tabl
e 6
cont
inue
d
D9
08°5
0.18
'08
°48.
32'
137°
35.0
7'13
7°35
.10'
8190
1060
Gra
nula
r, sm
ooth
, &
bot
ryoi
dal
surf
aces
on
mos
tly p
atch
ypa
tina
or th
in c
rust
s; 1
lay
er,
mas
sive
, bla
ck, p
orou
s, r
arel
yde
ndrit
ic &
aci
cula
r; 1
cobb
le o
fan
desi
te w
ith 2
0 m
m th
ick
vein
of h
ydro
frac
ture
d an
desi
te c
last
sin
hyd
roth
emia
l Mn
oxid
e,sm
ectit
e, a
nd p
hilli
psite
cem
ent;
crus
t thi
ckne
ss:
max
=15m
m, a
v=<3
mm
38%
lim
esto
ne, m
uddy
, mic
ritic
, pal
ebr
own,
var
iabl
e am
ount
s of
sm
ectit
e, M
nve
inle
ts, e
xten
sive
ly b
urro
wed
, int
erbe
dded
with
for
amin
ifera
l lim
esto
ne w
ith b
asal
tgr
ains
; 26%
and
esite
, 1.
mild
ly a
ltere
d,gr
ay, m
assi
ve, h
ighl
y ve
sicu
lar,
feld
spar
phyr
ic;
2. f
resh
gla
ssy
blac
k, h
ighl
yve
sicu
lar w
ith g
ray
rind
alte
red
toph
illip
site
, bot
h fe
ldsp
ar p
hyric
; 17
%br
ecci
a, 1
. and
esite
cla
sts
as in
#1
unde
ran
desi
te &
yel
low
-bro
wn,
gra
y, b
row
nal
tere
d vo
lcan
ic c
last
s in
cla
st s
uppo
rted
silt
& c
lay
volc
anic
last
ic m
atrix
; 2.
bla
ckgl
assy
and
esite
cla
sts,
as
in #
2 un
der
ande
site
s, &
oth
er v
olca
nic
rock
cla
sts
inbr
own
to y
ello
w-g
reen
sm
ectit
e m
atrix
,so
me
yello
w-g
reen
sm
ectit
e cl
asts
; 3. d
ark
gray
to p
ale
gray
aph
yric
to fe
ldsp
ar p
hyri
cba
salt
& a
ndes
ite c
last
s in
yel
low
-gre
enm
atri
x of
sm
ectit
e &
phi
llips
ite c
emen
t &ve
inle
ts, M
n ve
inle
ts &
gra
ins;
17%
tuf
for
tuff
aceo
us s
ands
tone
-silt
ston
e-m
udst
one,
bla
ck, b
row
n, y
ello
w-g
reen
,da
rk b
row
n la
yers
def
orm
ed b
y so
ftse
dim
ent d
efor
mat
ion
& b
urro
win
g,pe
pper
ed w
ith M
n ox
ide
grai
ns th
at a
lso
form
lam
inae
, gra
ded
beds
, cla
y ve
ins,
mos
tly s
mec
tite;
2%
vol
cani
clas
ticsa
ndst
one:
1. s
ands
tone
with
gra
ins
ofbl
ack
glas
sy a
ndes
ite; 2
. med
ium
to d
ark
gray
mas
sive
, Fe-
oxid
e ce
men
t & f
ine
grai
ned
volc
anic
last
ic m
atrix
; pum
ice
pebb
le
'Lat
itude
s an
d lo
ngitu
des
for o
n an
d of
f bot
tom
2P
umic
e
Table 7. X-ray diffraction mineralogy of substrate rocks from KODOS 98-3 cruise
Sample Majorl Moderate Minor/Trace Rock/Sediment
Marshall Islands Fe-Mn crust leg
D1-5AD1-5BD1-10AD2-2ED2-4B
CFA2, plagioclaseCFA, plagioclaseCalciteSmectiteCFA
Smectite CFA -
-
Smectite Halite-
Phosphatized basalt clast from breccia3Phosphatized hyaloclastite clastPebbly phosphatic limestoneHighly altered basaltPhosphorite (Foraminiferal limestone)4
FSM Hydrothermal leg
D5-2B-CD5-2B-MD5-4A
D5-7A
D7-2-1A
D7-4-1A
D7-6-1A
D7-8-1AD7-9-1A
D7-10-1AD7-10-2AD7-10-2BD7-10-2CD7-13AD8-2AD8-4AD9-3-1AD9-3-1BD9-3-2AD9-3-2BD9-3-2CD9-3-2DD9-3-2ED9-4A
D9-6-2AD9-6-2B
D9-8CD9-8DD9-8ED9-11-1AD9-14A
Plagioclase, pyroxenePlagioclase, pyroxeneLizardite, pyroxene
Plagioclase
Plagioclase, pyroxene
Plagioclase, pyroxene
Plagioclase, pyroxene
CalciteCalcite
Phillipsite, plagioclaseCalciteCalcitePhillipsiteAmorphous, plagioclaseLizarditeLizarditePhillipsiteSmectite, phillipsiteSmectite, phillipsiteSmectiteSmectite, phillipsitePhillipsite, smectiteSmectite, phillipsiteTridymite, cristobalite
Cristobalite, plagioclasePhillipsite, plagioclase
Smectite, phillipsitePlagioclasePhillipsite, plagioclaseSmectite, plagioclaseCalcite
TridymiteTridymitePlagioclase
Pyroxene
-Plagioclase, phillipsiteSmectite-SmectiteCalciteCalciteMagnetiteMagnetiteMagnetite Phillipsite- -Plagioclase, pyroxenePyroxenePyroxene, magnetitePlagioclasePyroxene--Plagioclase
SmectiteSmectite, calciteSmectite, magnetite, talc, tridymiteTridymite, calcite, quartz, smectiteMagnetite, smectite, hematiteMagnetite, hematite, smectiteMagnetite, smectite, hematite-Smectite, hematite
SmectitePhillipsiteSmectiteSmectiteChromiteChromite, smectitePlagioclase, smectite - -Hematite, smectite
Smectite
-Hematite, smectiteAmphibole-High-Mg calcite, smectite
Volcaniclastic sandstone clast from brecciaAltered clay matrix of D5-2B-CSerpentinite
Amygdaloidal andesite
Pillow basalt with chill margins
Altered pillow basalt
Vesicular pillow basalt fragment
Breccia matrixBreccia matrix
Dark green matrix in brecciaWhite matrix in brecciaGreen matrix in brecciaBrown-rind on clast from brecciaVolcanic ash bed in limestoneSerpentiniteSerpentiniteSandy layer in bedded tuffMudstone layer in bedded tuffPale brown mudstone layer in bedded tuffGreen-gray sandstone layer in bedded tuffPale brown mudstone layer in bedded tuffBrown sandstone layer in bedded tuffMottled brown siltstone layer in bedded tuffAndesite
Black glassy andesiteGray rind on glassy andesite
Yellow and white vein in basaltBasaltVein in basaltVolcaniclastic sandstoneLimestone and micritic limestone
iMajor: >25%, Moderate: 5-25%, Minor: <5%; 2CFA and most are Volcaniclastic; 4Rock type in parentheses
is carbonate fluorapatite; 3AH breccias are sedimentary, is replaced by CFA
27
Table 8. Chemical composition of substrate rocks from Litakpooki Ridge, Marshall Islands Fe-Mn crust leg, KODOS 98-3 cruise
SiO2 wt%A12O3FeOFe2O3MgOCaONa2OK2OTiO2P205MnOLOI2Total
H20+H2O-CO2t-total
^total
FCl
Ba ppmCrNbRbSrYZrThU
CaO/P2O5
Rock type
D1-10A0.780.24
~0.220.3454.20.210.05
0.02410.00.0933.099.2
0.60.2032.49.000.20
0.9180.051
44<68<2<2650168
0.41.7
5.42
Phosphaticlimestone
D1-10A10.780.24
--0.220.3454.10.220.05
0.02410.00.0933.199.2
0.60.2032.39.010.19
0.9310.050
45<68
2<2653177
0.41.6
5.41
Phosphaticlimestone
D2-2E43.018.0<0.112.41.916.422.281.61
2.4902.980.037.1098.3
6.64.500.44
~----~
783401430
248147186--~
2.15
Alteredbasalt
D2-2E142.818.0<0.112.51.906.412.271.62
2.4982.990.037.0598.2
6.44.400.42
-- ~
773401329
249147185 ~
2.14
Alteredbasalt
D2-4B4.451.87<0.11.730.6248.71.270.13
0.16929.80.507.8097.1
2.40.604.92
----~
162<68
53
126025491 ~
1.63
Phosphorite
Duplicate analysis= loss on ignition at 925° C; dash means not analyzed
28
Table 9. Yttrium and rare earth element contents (in ppm) of a partly phosphatized limestone, Marshall Islands Fe-Mn crust leg, KODOS 98-3 cruise
YLaCePrNdSmEuGdTbDyHoErTmYbLuXREEs
Ce*Y/Ho
D1-10A168.75.71.35.81.40.381.70.21.50.371.20.21.30.2230.0
0.443
D1-10A1178.96.01.35.71.40.381.60.21.50.351.10.21.30.2230.2
0.449
Duplicate analysis;Ce* is Ce anomaly = chondrite-normalized
2Ce/La+Pr
29
Tabl
e 10
. C
hem
ical
com
posi
tion
of su
bstra
te ro
cks
from
FSM
hyd
roth
erm
al le
g, K
OD
OS
98-3
cru
ise
LO
SiO
2 W
t%A1
2O3
FeO
Fe20
3M
gOC
aON
a2O
K2O
TiO
2P2
Os
MnO
LO
I2T
otal
H20
+
H2cr
C0
2
As
ppm
Ba
Cr
Nb
Rb
Sb Sr W Y Zr
Au
ppb
Roc
k ty
pe
D5-
2B49
.814
.02.
05.
9610
.49.
791.
700.
520.
372
0.03
0.11
2.25
96.9
3
1.8
3.10
0.02 <2 <20
550 6 <2 <0.5 37 <2 11 30 16
Bre
ccia
D5-
4A42
.98.
52 3.5
5.11
22.4
6.63
0.69
0.19
0.20
00.
040.
136.
3596
.66
6.3
0.90
0.03 <2 <20
2390 5 4
<0.5
29 <2 2 24 <5
Serp
entin
ite
D7-
2-1A
46.4
13.1
6.4
8.49
4.73
9.32
2.97
0.52
3.17
90.
530.
250.
8096
.69
1.5
1.10
0.07 _ 22 68 15 5 167 66 192 -- B
asal
t
D7-
4-1A
46.2
18.8
2.5
10.5
1.51
11.1
3.91
0.46
1.51
10.
230.
191.
7098
.63
1.7
0.30
0.46 _ 41 270 8 6 298 24 75 ~ B
asal
t
D7-
6-1A
45.4
13.6
6.3
8.60 4.53
9.81
3.07
0.41
3.31
90.
620.
260.
55 96.4
7
1.3
0.08
0.07 __ 70 68 19 12 184 71 191 ~ B
asal
t
D7-
9-1A
38.3
11.3 11.7
3.13
14.7
2.18
2.34
2.08
10.
140.
21 12.9
98.9
8
3.2
<0.0
18.
70 _ 48 68 10 45 228 26 123 --
Bre
ccia
D8-
2A39
.50.
67 1.4
10.3
34.4
0.33
0.23
0.04
0.01
80.
060.
08 12.3
99.3
7
11.3
1.30
0.04 23 <20
3560 6 <2 1.4 12 <2 <2 14 <5
Serp
entin
ite
D9-
3-1A
46.8
13.7
<0.1
16.3
3.45
1.91
2.16
3.79
1.06
50.
080.
528.
0097
.88
7.6
5.70
0.04 7 112
68 12 64 4.0
104 4 9 208 15
Tuff
aceo
ussa
ndst
one
D9-
3-1B
48.2
16.4
<0.1
13.2
3.81
2.16
2.22
2.62
0.82
00.
110.
958.
5099
.09
6.8
6.10
0.07 9 170
140
11 37 3.2
138
<2 15 98 <5
Tuff
aceo
usm
udst
one
D9-
4A59
.515
.54.
03.
92 2.00
6.99
3.08
0.90
0.59
80.
260.
150.
3597
.25
0.9
0.30
0.04
<2 130
68 8 6<0
.531
9<2 24 63 <5
And
esite
D9-
6-2A
63.6
13.2
4.2
2.56 2.25
5.69
2.56
0.77
0.50
90.
160.
132.
7098
.33
3.1
0.40
0.01 <2 105
<68 6 7
<0.5
250
<2 14 60 <5
And
esite
D9-
11-1
A45
.812
.20.
119
.54.
243.
261.
423.
661.
154
0.09
0.88
7.40
99.6
9
-- - 0.07 6 122
140
14 82 5.3
130
<2 16 266
26
Sand
ston
e
Dup
lica
te a
naly
sis
2LO
I =
loss
on
igni
tion
at 9
25°
C; -
- = n
ot a
naly
zed
Table 11. Calculated growth rates and ages of bulk Fe-Mn crusts and crust layers that have <2% P content, KODOS 98-3 cruise
Sample Interval (mm)1
Type Growth rate (mm/Ma)2
Crust age(Ma)
Growth rate (mm/Ma)3
Crust age(Ma)
Marshall Islands Fe-Mn crust cruise
D1-1AD1-1A4D1-1BD1-1CD1-2BD1-2CD1-2DD1-4AD2-1BD2-1CD2-1C4D2-2BD2-4AD2-5AD2-6A
0-1000-1000-77-370-1010-2525-550-450-1010-6010-600-300-250-200-32
BulkBulkLayerLayerLayerLayerLayerBulkLayerLayerLayerLayerBulkLayerBulk
9.3 8.4 2.8 6.7 4.2 6.6 7.5 4.2 1.5 3.0 3.3 1.8 2.7 2.6 4.5
10.811.92.57
2.44.78.710.76.7
23.421.916.79.37.77.1
3.5 3.3 1.2 2.8 1.9 2.8 3.0 1.9 0.6 1.3 1.5 0.7 1.2 1.1 2.0
28.630.35.816.55.310.720.723.716.755.250.042.820.818.216.0
FSM Hvdrothermal cruise
D5-2AD5-2A4D7-11AD9-5-1AD9-6-1AD8-1A
0-8 Bulk0-8 Bulk0-5 Bulk0-5 Bulk0-9 BulkStratabound Mn
8.08.515.412.044.1
~
1.00.90.30.40.2
3.13.34.54.06.1
38.3
2.62.41.11.31.50.4
'Intervals measured from the outer surface of crusts2From equation of Puteanus and Halbach (1988); age of a layer is for the base of that layer3From equation of Manheim and Lane-Bostwick (1988)4Duplicate sample
31
Table 12. X-ray diffraction mineralogy of Fe-Mn crusts and hydrothermal deposits from Marshall Islands and FSM, KODOS 98-3 cruise
Sample Type & Interval (mm) 1
5-MnO2(%)2
Others(%)
Marshall Islands Fe-Mn crust leg
D1-1AD1-1BD1-1CD1-1DD1-2AD1-2BD1-2CD1-2DD1-2ED1-3AD1-4AD2-1AD2-1BD2-1CD2-1DD2-1ED2-2AD2-2BD2-2CD2-2DD2-3AD2-4AD2-5AD2-5BD2-6A
Bulk (0-100)Layer (0-7)Layer (7-37)Layer (37-102)Bulk (0-95)Layer (0-10)Layer (10-25)Layer (25-55)Layer (55-90)Bulk (0-62)Bulk (0-45)Bulk (0-142)Layer (0-10)Layer(10-60)Layer (60-100)Layer (100-150)Bulk (0-98)Layer (0-30)Layer (30-47)Layer (47-82)Bulk (0-1 10)Bulk (0-25)Layer (0-20)Layer (20-35)Bulk (0-32)
959899879196949585949795999982939010088749299946993
4-CFA, 1-goethite2-smectite1-goethite13-CFA,<1 -quartz6-CFA, 2-pyroxene , 1- smectite4-smectite2-plagioclase, 2-pyroxene, 1 -quartz, 1-goethite2-goethite, 1-plagioclase, 1 -quartz , <1- calcite12-CFA, 2-smectite, 1-goethite6-CFA3-K-feldspar5-CFA1 -calcite1-goethite1 6-CFA, 2-goethite5 -CF A, 1 -goethite, < 1 -quartz10-CFA~8-CFA. 3-phillipsite, 1-goethite26-CFA6-CFA, 2-smectite1-plagioclase4-smectite, 1-plagioclase, 1 -quartz14-CFA, 9-phillipsite, 7-plagioclase, 1-goethite5-CFA, 1-plagioclase, 1 -quartz
FSM Hydrothermal leg
D5-2AD5-16A
D7-11AD8-1AD9-5-1AD9-6-1A
Bulk (0-8)Mn sandstone
Bulk (0-5)Stratabound MnBulk (0-5)Bulk (0-9)
94?
949
9591
5-plagioclase, 1 -calcite25-birnessite, 50-plagioclase, 1 2-serpentine, 6-pyroxene, 4-amphibole, 3-quartz2-calcite, 2-plagioclase, 2-quartz78-birnessite, 17-smectite, 5-quartz3-plagioclase, 1 -calcite, 1 -quartz5-quartz, 2-calcite, 2-plagioclase
1 Intervals measured from the outer surface of crusts;2Percentages were determined by using the following weighting factors relative to quartz set at 1: 8-MnO2 70; todorokite 10; birnessite 12 (Hein et al., 1988); carbonate fluorapatite (CFA) 3.1; plagioclase 2.8; calcite 1.65; smectite 3.0; goethite 7.0; phillipsite 17.0; illite 6.0; pyroxene 5.0; halite 2.0 (Cook et al., 1975); the limit of detection for each mineral falls between 0.2 and 1.0%, except the manganese minerals which are greater, perhaps as much as 10% for 8-MnO2
32
Tabl
e 13
. C
hem
ical
com
posi
tion
of F
e-M
n ox
yhyd
roxi
de c
rust
s fr
om M
arsh
all I
slan
ds F
e-M
n cr
ust l
eg, K
OD
OS
98-3
cru
ise
Fe
wt%
Nfa
Fe/M
nSi N
aA
lK M
gCa Ti P S H
20'
LOI
As
ppm
B Ba Be Bi Cd a Co Cr Cu Ga
Hf
Li Ma
Mb
Ni
Pb Rb Sb Sc Sn Sr Te Th Tl U V w Zn Zr Au
ppb
Hg
Ir Os Pd Pt Rh
Ru Inte
rval
Type
DM
A18
.523
.70.
82.
71 1.08
0.34
0.36
0.89
5.79
1.30
51.
500.
21 16.6
18.7
198
178
3140
9.9
47.0
0.7
6560
3150
189
1150 61 8 3 497 37 2510
1310 15 34.9
6.6 6
1440
65.3
10.2
73.3
<0.5
646
<4 576
499 <2 <5 4 2 4 470 22 20
0-10
0Bu
lk
DM
A1
18.5
23.5
0.8
2.70
1.08
0.34
0.36
0.89
5.76
1.29
71.5
10.
21 16.3
18.6
170
184
3150
10.7
45.0 1.2
6440
3290
171
1180 63 7 3 515 36 2700
1360 16 27.8
6.7 8
1480
69.8
10.0
73.4
<0.5
727
<4 612
502
<2 <5 .. - - 0-
100
Bul
k
D1-
1B18
.926
.50.
73.
171.
300.
210.
42 1.04
2.66
1.27
30.
480.
2413
.9
20.1 - 228
1970
7.5
42.0
0.7
7230
6000 - 370 28 2 492 40 2990
1460 11 - 5.6 7
1400
56.4 152 - 648 528
513 5 9 2 2 6 130 12 20 0-7
Laye
r
D1-
1C20
.721
.7 1.0
4.77
1.25
0.89
0.52
0.97
2.90
1.65
90.
580.
1717
.6
17.9
200
204
2610
9.6
37.8
0.2
7850
3560
182
872
24 15 2 344
57 2300
1090 7
31.1 5.5 11 1300
64.3
6.5
91.0
11.5
556
74 635
652
<2 7 4 - 4 320
21 18 7-37
Laye
r
D1-
1D15
.718
.40.
92.
200.
840.
330.
200.
7412
.91.
064
4.19
0.27 15.0
16.5
185
147
2800
9.4
58.5
<0.2
5330
2230
183
1280 23 8 <1 423 31 1940
1300 9
32.1 5.4 9 1500
74.0
14.5
59.4 8.0
610
<4 549
367 6 <5 4 - 8 410 19 10
37-1
02La
yer
D1-
2A18
.119
.70.
94.
031.
070.
830.
420.
897.
721.
302
2.25
0.24
6.90 16.2
170
197
2860
11.1
45.8
0.8
6840
3320 <2 955
48 13 2 362 43 2840
1130 12 26.3
7.0 9
1500
71.8
<0.5
94.7
<0.5
676
<4 719
524
<2 6 -- - - - 0-95
Bul
k
D1-
2B20
.724
.40.
84.
03 1.31
0.50
0.47 1.02
2.59
1.60
80.
450.
18 10.5
17.9 - 242
2200
9.3
34.6 1.7
6950
4890 - 481 74 - 2 424
45 3190
1380 14 - 5.5 8
1340
56.6 - 122 - 704 - 626
481 - 16 - - - - - 0-10
Laye
r
D1-
2C19
.420
.90.
95.
841.
391.
340.
671.
003.
411.
603
0.71
0.17
11.3
16.3
165
202
3430
10.1
39.7
2.1
7430
3850 41 866
79 12 5 307 55 3250
1070 17 25.2
5.4 12 1260
80.1
<0.5
112
<0.5
624
<4 708
585
<2 9 .. - -- 10
-25
Laye
r
D1-
2D21
.021
.3 1.0
4.96
1.21
1.01
0.58
1.00
3.22
1.59
80.
620.
159.
40
17.0 - 206
2560
11.4
33.6 1.5
8250
3730 - 894
46 - 3 342
64 3200
1100 12 - 5.4 15 1260
76.6 - 104 705 - 741
685 - 8 - .. - - -
25-5
5La
yer
D1-
2E15
.315
.31.
03.
51 1.02
0.93
0.31
0.81 13.7
0.86
24.
670.
286.
30
14.7
135
155
2170
10.0
44.2
0.5
5290
1780 28 1170 40 13 5 281 27 2880
935 16 23.2 8.8 11 1440
57.4
6.3
60.4
13.2
552 <4 679
442 <2 6 -- .. - - -
55-9
0La
yer
D1-
3A18
.018
.41.
03.
961.
020.
850.
410.
849.
011.
268
2.76
0.26
8.60
16.3
206
188
2500
10.1
50.1 0.4
6650
3290
174
1210 26 12 2 398
45 2220
1170 13 31.7
8.3 8
1480
91.5
11.8
69.1
11.6
607
<4 627
488 <2 9 - - - - 0-62
Bul
k
D1-
4A19
.522
.80.
94.
82 1.19
1.02
0.56 1.03
2.59
1.73
30.
440.
188.
60
18.2
194
218
2700
10.0
38.2
0.9
7640
4970
162
937 33 14 3 383
55 3470
1330 11 30.6
6.5 12 1450
78.8
10.4
137
17.0
662
113
800
581 <2 <5 .. .. - 0-45
Bul
k
D2-
1A17
.322
.30.
82.
56 1.02
0.44
0.32
0.89
8.15
1.51
92.
270.
22 18.7
17.7
149
144
2900
10.1
48.8
0.4
7660
4240 <2 716 50 12 3 379 57 2830
1390 14 25.8
5.3 11 1230
118
11.8
116
<0.5
576 <4 520
471 <2 5 -- - - - - -
0-14
2B
ulk
D2-
1B16
.530
.1 0.5
2.26
1.23
0.01
0.37
1.09
2.89
1.16
20.
430.
198.
60
19.8 - 208
1680
6.9
38.1 2.4
7870
9790 - 410
61 - <1 583 39 5020
1610 13 - 4.8 8
1270
85.7 - 213 - 666 - 611
391 - 11 - - - - 0-10
Laye
r
Tabl
e 13
con
tinue
d
Fe
wt%
Mn
Fe/M
nSi N
aA
lK M
gCa Ti P S H
2Cf
LO
IA
s pp
mB Ba Be B
i Cd a Co
Cr
Cu
Ga
Hf
Li Mo
Nb
Ni
Pb Rb
Sb Sc Sn Sr Te Th
Tl U V w Zn
Zr Au
ppb
Hg
Ir On Pd Pt Rh
Ru
Inte
rval
Typ
e
D2-
1C
19.3
25.6
0.8
3.40
1.22
0.62
0.46
1.05
2.87
1.56
00.
480.
2212
.2
18.7
169
188
2270
9.0
41.7 1.9
9770
5850 <2 917
58 11 2 449
58 4260
1210 19 23.1
5.7 12 1260
101
<0.5
176
<0.5
615
<4 692
566
<2 <5 -- - .. - -10
-60
Lay
er
D2-
1C1
19.2
25.4
0.8
3.40
1.22
0.63
0.46
1.04
2.85
1.55
30.
470.
1912
.3
18.8
157
200
2280
10.1
45.6 1.7
9550
5470 <2 940 47 10 2 426
59 4350
1100 20 22.6
5.4 13 1270
104
6.2
164
<0.5
659
<4 653
567 <2 <5 -- - - - - -
10-6
0L
ayer
D2-
1D
14.5
17.1
0.8
1.94
0.82
0.35
0.17
0.72
14.7
0.84
74.
930.
316.
30
16.0
171
153
2140
10.3
68.8
<0.2
6120
2420 <2 914
51 9 3 391 25 2430
1060 12 21.5
10.2 9
1460
72.7
14.7
87.9
<0.5
644
<4 557
375
<2 6 -- - - - - -60
-100
Lay
er
D2-
1E
18.4
22.1
0.8
2.86
0.96
0.43
0.39
0.80
6.97
1.65
91.
880.
279.
40
17.1
160
166
4180
15.2
81.0
<0.2
9090
3250 <2 730
55 11 2 553
55 2490
2170 19 32.7
5.7 9 1550
127
13.5
101
10.6
814
<4 633
510
<2 <5 -- - - -10
0-15
0L
ayer
D2-
2A
15.0
21.4
0.7
1.80
0.91
0.23
0.21
0.80
11.3
1.32
53.
490.
2614
.1
17.5
181
138
2730
8.4
54.6
<0.2
6670
4200
163
700
25 8 <1 419
42 2300
1440 17 31.0
5.0 10 1430
109
16.0
112
15.4
563
<4 511
359
<2 <5 6 2 6 620
29 14 0-98
Bul
k
D2-
2B
18.0
28.2
0.6
2.20
1.25
0.15
0.35
1.04
2.94
1.71
30.
380.
1917
.1
20.4
210
158
2430
7.0
53.0 1.4
9680
8030
158
993
31 11 <1 401 86 3720
1450 15 35.8
5.5 16 1280
158
14.4
172
<0.5
541
<4 621
543
45 5 14 2 10 1600
70 34 0-30
Lay
er
D2-
2C
14.5
24.6
0.6
1.37
0.91
0.06
0.22
0.85
9.86
1.25
32.
840.
3210
.0
18.8 - 143
2810
8.5
88.0
<0.2
7120
5430 - 947 34 - <1 591 38 2990
1820 10 - 6.6 9
1630
143 - 154 - 611 - 629
394 - 6 6 2 4
700 27 12
30-4
7L
ayer
D2-
2D
14.6
16.1
0.9
1.88
0.79
0.44
0.16
0.66
15.1
1.44
55.
190.
327.
30
14.9
184
136
3130
10.6
80.4
0.7
5710
2710
140
535
27 8 137
0 43 1400
1880 14 37.0
4.2 8
1750
125
9.8
82.8
<0.5
545
<4 536
310
<2 <5 4 .. 4 540 24 8
47-8
2L
ayer
D2-
3A
16.2
23.0
0.7
2.09
0.93
0.28
0.29
0.86
9.36
1.10
42.
770.
2815
.7
17.7
197
146
2920
8.1
53.7
0.5
6520
3600
145
914
29 8 3 581 30 2650
1350 15 28.5
6.0 6
1510
71.1
11.4
61.4
12.7
617
144
628
353
<2 <5 4 6 340 16 12
0-11
0B
ulk
D2-
4A
18.0
26.3
0.7
3.89
1.27
0.65
0.47
1.09
3.07
1.49
60.
460.
208.
80
18.5
172
211
1940
7.5
43.2
2.5
7350
6440 <2 434
51 5 348
642 50
1014
30 15 23.1
4.6 8
1210
73.4
<0.5
182
<0.5
631
<4 651
445
<2 8 -- - - - - 0-25
Bul
k
D2-
5A
18.2
26.5
0.7
3.60
1.29
0.59
0.50
1.08
2.64
1.43
70.
410.
209.
70
18.5
169
213
2000
7.8
40.4
2.0
7540
6640 <2 381
64 <1 2 486
45 4690
1500 16 25.7
4.4 8
1220
68.6
5.0
165
<0.5
646
<4 651
462
<2 8 - - 0-20
Lay
er
D2-
5B
15.7
10.2
1.5
10.9
1.60
3.69
1.62
1.47
5.65
1.31
71.
830.
146.
30
13.2
129
165
1040
5.4
11.7
2.3
5340
2190 58 685
49 13 30 102
49 4590
507 37 28.1
10.8 7 559
30.0
<0.5
55.4
<0.5
420
<4 633
464
<2 212 -- - - -
20-3
5L
ayer
D2-
6A
18.4
20.7
0.9
5.05
1.20
1.19
0.53
1.12
5.02
1.60
71.
200.
1812
.9
17.4
185
183
1780
7.1
24.8 1.6
7880
4580
136
607 27 12 8 308
54 3100
1170 19 30.8
7.3 7 1130
64.0
7.8
112
<0.5
490
<4 598
509 10 11 8 2 14 420
21 20 0-32
Bul
k
All
Ag
cont
ents
<0.
2ppm
; B
r <
lppm
^D
uplic
ate
anal
ysis
of
sam
ple
Cs
<3pp
m;
Ge
<10p
pm;
In <
0.5p
pm;
Se <
5ppm
; T
a <
lppm
Tabl
e 14
. Hyg
rosc
opic
wat
er-f
ree
(0%
H2O
") c
ompo
sitio
n of
Fe-
Mn
crus
ts fr
om T
able
13
Fe
wt%
Mn
Fe/M
nSi N
aA
lK M
gC
aT
i P S As
ppm
B Ba
Be
Bi Cd a Co
Cr
Cu
Ga
Iff
Li Kb
Nb
Ni
Pb Rb
Sb Sc Sn Sr Te Th
Tl
U V W Zn
Zr
Au
ppb
Hg
Ir a Pd Pt Rh
Ru
Inte
rval
Typ
e
DM
A
22.1
28.4
0.8
3.25
1.29
0.41
0.43 1.07
6.94
1.56
41.
800.
25 237
213
3765
11.9
56.4
0.8
7866
3777
227
1379
73 10 4 596
44 3010
1571 18 41.8
7.9 7
1727
78.3
12.2
87.9
<0.6
775 <5 691
598
<2 <6 5 2 5 564
26 240-
100
Bul
k
DM
A'
22.1
28.1
0.9
3.23
1.29
0.40
0.43
1.07
6.88
1.54
91.
800.
25 203
220
3763
12.8
53.8 1.4
7694
3931
204
1410
75 8 4 615
43 3226
1625 19 33.2
8.0 10 1768
83.4
11.9
87.7
<0.6
869
<5 731
600
<2 <6 - - - - -0-
100
Bul
k
DM
B
21.9
30.8
0.7
3.69
1.51
0.25
0.49 1.21
3.09
1.47
90.
550.
28 -- 265
2288
8.7
48.8
0.8
8397
6969 - 430 33 - 2 571 46 3473
1696 13 - 6.5 8
1626
65.5 - 177 - 753 .. 613
596 6 10 2 2 7 151 14 23 0-7
Lay
er
D1-
1C
25.1
26.3 1.0
5.79
1.51
1.09
0.63
1.18
3.52
2.01
40.
700.
21 243
248
3167
11.7
45.9
0.2
9527
4320
221
1058 29 18 2 417
69 2791
1323 8
37.7
6.7 13 1578
78.0
7.9
110
14.0
675
90 771
791 <2 8 5 - 5 388
25 22 7-37
Lay
er
DM
D
18.4
21.6
0.9
2.59
0.99
0.39
0.23
0.87
15.1
1.25
24.
930.
32 218
173
3294
11.1
68.8
<0.2
6271
2624
215
1506
27 9 <1 498
36 2282
1529 11 37.8
6.4 11 1765
87.1
17.1
69.9
9.4
718
<5 646
432 7 <6 5 9 482
22 1237
-102
Lay
er
D1-
2A
19.5
21.2
0.9
4.33
1.15
0.89
0.45
0.95
8.29
1.39
82.
420.
26 183
212
3072
11.9
49.2
0.9
7347
3566 <2 1026
52 14 2 389
46 3050
1214 13 28.2
7.5 10 1611
77.1
<0.5
102
<0.5
726
<4 772
563
<2 6 .. -- - 0-95
Bul
k
D1-
2B
23.1
27.3
0.8
4.50
1.46
0.56
0.53
1.14
2.90
1.79
70.
510.
20 - 270
2458
10.4
38.7 1.9
7765
5464 - 537
83 - 2 474
50 3564
1542 16 6.1 9
1497
63.2 - 136 - 787 .. 699
537 - 18 -- .. - - 0-10
Lay
er
D1-
2C
21.8
23.6
0.9
6.59
1.56
1.51
0.76
1.12
3.84
1.80
70.
800.
19 186
228
3867
11.4
44.8
2.4
8377
4340 46 976 89 14 6 346 62 3664
1206 19 28.4
6.1 14 1421
90.3
<0.6
126
<0.6
703 <5 798
660
<2 10 - - - -10
-25
Lay
er
D1-
2D
23.2
23.5 1.0
5.47
1.33
1.11
0.64
1.11
3.55
1.76
40.
680.
17 - 227
2826
12.6
37.1 1.7
9106
4117 - 987
51 - 3 377
71 3532
1214 13 - 6.0 17 1391
84.5 - 115 - 778 - 818
756 - 9 -- - - - - -
25-5
5L
ayer
D1-
2E
16.3
16.4
1.0
3.74
1.08
0.99
0.33
0.86
14.6
0.92
04.
980.
30 144
165
2316
10.7
47.2
0.5
5646
1900 30 1249 43 14 5 300
29 3074
998 17 24.8
9.4 12 1537
61.3
6.7
64.5
14.1
589
<4 725
472
<2 6 .. -55
-90
Lay
er
D1-
3A
19.7
20.1 1.0
4.33
1.12
0.93
0.45
0.92
9.85
1.38
73.
020.
28 225
206
2735
11.1
54.8
0.4
7276
3600
190
1324
28 13 2 435
49 2429
1280 14 34.7
9.1 9
1619
100
12.9
75.6
12.7
664
<4 686
534
<2 10 -- - - - - 0-62
Bul
k
D1-
4A
21.3
24.9
0.9
5.27 1.31
1.12
0.62 1.13
2.84
1.89
60.
480.
20 212
239
2954
10.9
41.8 1.0
8359
5438
177
1025 36 15 3
419
60 3796
1455 12 33.5
7.1 13 1586
86.2
11.4
150
18.6
724
124
875
636
<2 <5 .. - - - - 0-45
Bul
k
D2-
1A
21.2
27.4
0.8
3.15
1.25
0.55
0.40
1.09
10.0
1.86
82.
800.
27 183
177
3567
12.4
60.0
0.5
9422
5215 <2 881 62 15 4 466
70 3481
1710 17 31.7
6.5 14 1513
145
14.5
143
<0.6
708 <5 640
579
<2 6 .- - - - -0-
142
Bul
k
D2-
1B
18.1
32.9
0.5
2.48
1.35
0.01
0.41 1.19
3.17
1.27
10.
470.
21 -- 228
1838
7.5
41.7
2.6
8611
1071
1- 44
967 - <1 63
843 54
9217
61 14 - 5.3 9
1389
93.8 - 233 - 729 - 668
428 - 12 -- - - - - - 0-10
Lay
er
Tabl
e 14
con
tinue
d
Fe
wt%
Mi
Fe/M
nSi N
aA
lK M
gCa Ti P S A
s pp
mB Ba B
e Bi Cd a Co
Cr
Cu
Ga
Hf
Li Nfo
Nb
Ni
Pb Rb
Sb Sc Sn Sr Te Th
Tl U V W Zn
Zr
Au
ppb
Hg
Ir Os Pd Pt Rh
Ru
Inte
rval
Typ
e
D2-
1C22
.029
.10.
93.
871.
390.
710.
531.
203.
271.
777
0.54
0.25 192
214
2585
10.3
47.5
2.2
1112
866
63 <2 1044
66 14 251
1 66 4852
1378 22 26.3
6.5 14 1435
115
<0.6
200
<0.6
700
<5 788
645
<2 <6 -- - - - 10
-60
Lay
er
D2-
1C1
21.9
29.0
0.9
3.88
1.40
0.72
0.53
1.19
3.25
1.77
00.
540.
22 179
228
2600
11.5
52.0 1.9
1088
962
37 <2 1072 54 12 2
486 67 4960
1254 23 25.8
6.2
'15 14
4811
97.
118
7<0
.675
1 <5 745
647 <2 <6 - - - - -
10-6
0L
ayer
D2-
1D15
.518
.30.
92.
080.
880.
380.
180.
7715
.60.
904
5.26
0.33 182
163
2284
11.0
73.4
<0.2
6531
2583 <2 975 54 11 3
417 27 2593
1131 13 22.9
10.9 10 1558
77.6
15.7 94 <0.5
687 <4 594
400
<2 6 - - - - -60
-100
Lay
er
D2-
1E22
.226
.61.
03.
451.
150.
520.
470.
978.
412.
002
2.26
0.33 193
200
5042
18.3
97.7
<0.2
1096
539
20 <2 881
66 13 2 667
66 3004
2618 23 39.4
6.9 11 1870
153
16.3
122
12.8
982
<5 764
615
<2 <6 -- - -- -- - -10
0-15
0L
ayer
D2-
2A17
.424
.90.
82.
101.
060.
270.
240.
9313
.11.
543
4.06
0.30 211
161
3178
9.8
63.6
<0.2
7765
4889
190
815
29 10 <1 488
49 2678
1676 20 36.1
5.8 12 1665
127
18.6
130
17.9
655 <5 595
418
<2 <6 7 2 7 722 34 16 0-98
Bul
k
D2-
2B21
.834
.00.
82.
651.
500.
180.
421.
263.
542.
067
0.46
0.23 253
191
2931
8.4
63.9
1.7
1167
796
8619
111
98 37 14 <1 484
104
4487
1749 18 43.2
6.6 19 1544
191
17.4
207
<0.6
653
<5 749
655
54 6 17 2 12 1930 84 41 0-30
Lay
er
D2-
2C16
.127
.30.
71.
521.
010.
070.
240.
9411
.01.
392
3.16
0.36 - 159
3122
9.4
97.8
<0.2
7911
6033 1052 38 .. <1 657
42
33
2220
22 11 - 7.3 10 1811
159 - 171 - 679 - 699
438 - 7 7 2 4
778 30 13
30-4
7L
ayer
D2-
2D15
.817
.41.
02.
030.
850.
480.
170.
71 16.3
1.55
95.
600.
35 198
147
3376
11.4
86.7
0.8
6160
2923
151
577 29 9 1
399
46 1510
2028 15 39.9
4.5 9
1888
135
10.6 89 <0.5
588 <4 578
334 <2 <5 4 - 4 583 26 9
47-8
2L
ayer
D2-
3A19
.227
.30.
82.
471.
110.
330.
341.
0211
.11.
309
3.28
0.33 234
173
3464
9.6
63.7
0.6
7734
4270
172
1084 34 10 4 689-
36 3144
1601 18 33.8
7.1 7
1791
84.3
13.5 73 15.1
732
171
745
419
<2 <6 5 - 7 403 19 14
0-11
0B
ulk
D2-
4A19
.728
.80.
84.
261.
390.
710.
521.
193.
371.
640
0.51
0.22 189
231
2127
8.2
47.4
2.7
8059
7061 <2 476
56 6 353
346 54
9315
68 16 25.3
5.0 9
1327
80.5
<0.6
200
<0.6
692
<4 714
488
<2 9 -- - - - 0-25
Bul
k
D2-
5A20
.129
.30.
83.
991.
430.
660.
551.
202.
931.
591
0.46
0.22 187
236
2215
8.6
44.7
2.2
8350
7353 <2 422
71 <1 2 538
50 5194
1661 18 28.5
4.9 9
1351
76.0
6.1
183
<0.6
715 <4 721
512
<2 9 - - -- - - 0-20
Lay
er
D2-
5B16
.710
.91.
611
.71.
703.
941.
731.
576.
031.
405
1.95
0.15 138
176
1110
5.8
12.5
2.5
5699
2337 62 731 52 15 32 109
52 4899
541 39 30.0
11.5 7 597
32.0
<0.6
59 <0.5
448
<4 676
495 <2 226 -- - -
20-3
5L
ayer
D2-
6A21
.123
.71.
05.
801.
381.
360.
611.
295.
771.
845
1.37
0.21 212
210
2044
8.2
28.5 1.9
9047
5258
156
697 31 15 9 354
62 3559
1343 22 35.4
8.4 8
1297
73.5 9.4
129
<0.6
563 <5 687
584 11 13 9 2 16 482 24 23 0-32
Bul
k
All
Ag
cont
ents
<0.
2ppm
; B
r <l
ppm
; D
uplic
ate
anal
ysis
of
sam
ple
Cs
<3pp
m;
Ge
<10p
pm;
In <
0.5p
pm;
Se <
5ppm
; T
a <
lppm
Table 15 Statistics for 25 bulk Fe-Mn crusts and crust layers from Marshall Islands Fe-Mn crust leg KODOS 98-3 cruise; hygroscopic water-free data from Table 14
Fe wt. %MnFe/Mn4SiNaAlKMgCaTiPSH2O'
LOIAs ppmBBaBeBiCdClCoCrCuGaHfLiMoNbNiPbRbSbScSnSrTeThnuVwYZnZrAu ppbHgIrOsPdPtRhRuDepth5Thickness
N2525252525252525252525252525202525252525252520252520252525252525202525252520252025202525252125106101010102525
Mean20.024.90.84.041.270.780.491.087.531.5782.120.2611.317.4201204
286510.554.5-1.282005001-10291149-12-4
47153
35351513
1733.07.011
153696.6-9.7130-6.1697
-23.1287708543 5-17
728
6483120
187847
Median20.126.30.83.741.310.560.451.116.031.5641.800.2510.017.7196210
293110.748.8-0.880594340-10797651-13-2
47449
34731542
1633.66.610
155884.5-11.0126-0.6703 5
271699537 2-6527
5232619
180535
SD 12.65.40.52.080.220.770.300.194.68
0.3131.750.063.861.703035
7952.419.80.9
1571217992
3081946
13016
1026396
66.01.73
25836.36.4507.19547697511411444
0.14
4842098437
Min215.510.91.4
1.520.850.010.170.712.84
0.9040.460.156.3013.2138147
11105.812.5<0.256461900<2
42227<1<110927
1510541
822.94.57
59732.0<0.559
<0.5448<4195578334<2<5224
151149
18057
Max325.134.00.7
11.681.703.941.731.5716.272.0675.600.3618.720.4253270
504218.397.82.7
11677107112271506891832
689104
5493261839
43.211.519
188819118.623318.698217139387579154
22617216
19308441
1970142
Standard deviation; Minimum; depth in meters; 6Crust thickness
Maximum; Ratio of means, in millimeters
not a mean of the summation of ratios; JWater
37
Table 16. Statistics for 9 bulk Fe-Mn crusts from Marshall Islands Fe-Mn crust leg KODOS 98-3 cruise; hygroscopic water-free data from Table 14
Fe wt.%MnFe/Mn4SiNaAlKMgCaTiPSH2OLOIAs ppmBBaBeBiCdClCoCrCuGaHfLiMoNbNiPbRbSbScSnSrTeThTlUVWYZnZrAu ppbHgITOsPdPtRhRuDepth5Thickness6
N9999999999999999999999999999999999999999999999943444499
Mean20.125.20.83.881.230.730.451.077.931.6062.190.2612.317.6210202299010.451.7-1.080974786-1249674512-448551
3404149117
33.47.210
157194.7-10.4121-7.5693-36288712535 3-8629
5432619
187879
Median19.724.90.84.261.250.710.451.078.291.5642.420.2612.917.7212210307210.954.8-0.878664889-17210253613 346649
3144156817
33.87.19
161184.3-12.2129-0.6708 5304691563 2-6627
5232520180595
SD11.53.10.51.240.120.370.120.123.500.2221.240.054.230.921276031.611.40.873011299428816321061189317734.71.3216725.06.1418.36164588178322
0.15136658740
Minz17.420.10.92.101.060.270.240.922.841.3090.480.206.9016.218316120448.228.5<0.272763566<2476286<135436
2429121412
25.35.07
129773.5<0.573<0.5563<4205595418<2<5525
4031914
180525
Max"22.128.80.85.801.391.360.621.2913.11.8964.060.3318.718.7237239376512.463.72.794227061227137973159
68970
549317102241.89.114
179114518.620018.67751713668756361113921672234241970142
Standard Deviation; L Minimum; depth in meters; 6Crust thickness
""Maximum; "Ratio of means, in millimeters
not a mean of the summation of ratios; ''Water
38
Table 17. Statistics for 16 Fe-Mn crust layers from Fe-Mn crust leg KODOS 98-3 cruise; hygroscopic water-free data from Table 14
Fe wt. %MnFe/Mn4SiNaAlKMgCaTiPSH20LOIAs ppmBBaBeBiCdClCoCrCuGaHfLiMoMbNiPbRbSbScSnSrTeThTlUVwYZnZrAu ppbHgIrOsPdPtRhRuDepth5Thickness6
N16161616161616161616161616161116161616161616111616111616161616161116161616111611161116161612166366661616
Mean19.924.70.94.131.300.800.521.087.311.5632.080.2510.717.4194206279510.556.1-1.382575122-8488052-12-446354
3608152517
32.67.011
151697.6-9.0135-4.9699-12286707548-7-22727
7193420187729
Median21.026.50.83.711.370.540.481.133.701.5750.750.249.8517.5192207270610.547.3-1.283634330-4697652-14 247950
3502153615
30.06.510
154085.8-7.9124-0.6702~5263710525~2~8 o
526
5322618
180530
SD13.16.40.52.470.260.930.370.225.330.3602.010.073.642.035398962.723.51.01912262291324204814419
11164847
7.12.03
30042.16.8546.211226767413215555
0.13
62925128517
Min^15.510.91.41.520.850.010.170.712.900.9040.460.156.3013.213814711105.812.5<0.256461900<242227<1<11092715105418
22.94.57
59732.0<0.659<0.5448<4195578334<2<5224
151149
18057
Max"25.134.00.711.681.703.941.731.5716.272.0675.600.3617.620.4253270504218.397.82.6
11677107112211506891832667104549226183943.211.519
188819117.423314.1982903938187915422617212
19308441197065
Standard Deviation; Minimum; depth in meters; 6Crust thickness
Maximum; Ratio of means, in millimeters
not a mean of the summation of ratios;
39
Table 18. Concentrations of yttrium and rare earth elements (ppm) in Fe-Mn crusts from Marshall Islands (Dl, D2) and Fe-Mn crusts and Mn stratabound deposits from FSM (D5-D9), KODOS 98-3 cruise
YLaCePrNdSmEuGdTbDyHoErTmYbLuIREECe*Interval2
DMA264345
145054.024043.110.152.27.9
46.29.8029.64.3
28.64.5423252.3
B 0-85
DMA1
280359151057.424743.310.756.48.2
47.09.9430.84.5
28.54.6624172.3
B 0-85
D1-1B233 '28175544.8199
37.19.8050.67.7
47.510.732.34.8
31.34.9815171.5
L 0-7
D1-1C11124884141.9179
34.48.6742.26.5
36.57.7923.73.4
20.33.3414971.8
L 7-37
DMD248352
156055.522140.39.5147.47.2
39.98.3624.63.8
24.43.9123982.4
L 37-102
D1-3A220271124046.5193
36.49.2844.86.7
37.68.2023.63.5
23.73.8219482.5
B 0-62
D1-4A187279103048.220740.110.349.47.5
42.58.8725.83.7
25.13.9517812.0
B 0-45
D2-1C210318
117052.923243.110.151.28.0
46.39.3729.34.2
29.34.3420082.0
B 0-9
D2-2A313373
147052.921637.09.0446.77.0
40.89.0327.94.0
27.14.2423252.2
B 0-98
D2-2B175253142039.616430.47.6337.75.9
34.17.5722.43.3
21.33.4120503.1
L 0-30
YLaCePrNdSmEuGdTbDyHoErTmYbLuIREECe*Interval
D2-2C343359
179057.023140.29.6851.37.8
44.39.6630.04.5
30.04.4326692.7
L 30-47
D2-2D344398
175052.220832.58.1645.96.6
37.68.9626.93.7
24.64.1926072.6
L 47-82
D2-3A256333
123056.2233
41.19.9650.87.6
43.19.4427.84.0
27.24.0620772.0
B 0-110
D2-6A31927371046.720940.510.653.78.0
47.010.430.24.1
26.74.5914741.4
B 0-32
D5-2A20429971862.125853.813.061.99.4
50.410.228.83.6
27.64.1016001.2
B 0-8
D5-2A 119229866358.824751.312.658.99.0
48.19.5428.03.9
25.83.9015181.1
B 0-8
D5-16A24
23.155.15.1
21.54.81.305.80.94.91.103.00.42.0
0.511301.2
Mn SS
D7-11A20729059458.824752.911.158.69.1
50.210.127.93.4
30.54.0614481.0
B 0-5
D8-1A109.46.31.77.11.9
0.862.10.31.7
0.441.30.20.6
0.22340.4
Strat. Mn
D9-5-1A22430767363.927155.613.665.49.8
54.111.0313.7
32.24.4715961.1
B 0-5
Duplicate analysis of sampleIntervals measured from the outer surface of the crust; B = bulk, L = layer; Ce* = 2Ce/La+Pr from chondrite-normalized data
40
Tabl
e 19
. C
orre
latio
n co
effic
ient
mat
rix f
or 9
bul
k cr
usts
list
ed in
Tab
le 1
4; n
=9, e
xcep
t for
Cd,
Li =
8; T
h =
7; C
r, H
g =
6; Ir
, Pd,
Pt,
Rh, R
u, a
nd U
= 4
; the
zer
o co
rrel
atio
ns fo
r 9 p
oint
s, 8
poin
ts,
7 po
ints
, 6 p
oint
s, an
d 4
poin
ts a
t the
95%
con
fiden
ce le
vel
are
10.6
651,
10.
7061
, 10
.753
1, 1
0.81
31,
10.9
621,
res
pect
ivel
y;
stat
istic
ally
sig
nific
ant c
orre
latio
ns a
re in
bol
d; --
= in
suff
icie
nt c
orre
latio
n pa
irs
Mi
Fe/M
nSi N
aA
lK M
gC
aTi P S L
OI
As
B Ba
Be
Bi Cd a Co
Cr
Cu
Ga
Hf
Li Mo
Mb
Ni
Pb Rb
Sb Sc Sn Sr Te Th
Tl U V Y Zn
Zr
Hg
Ir Pd Pt Rh
Ru
Dep
thT
hick
Fe 0.25
0.16
10.
509
0.66
0.36
30.
633
0.62
-0.6
020.
636
-0.6
2-0
.558
0.36
90.
097
0.53
90.
095
0.31
1-0
.439
-0.0
620.
511
0.01
50.
202
0.25
80.
535
0.38
40.
393
-0.1
170.
440.
184
-0.0
83-0
.104
0.28
10.
38-0
.057
-0.2
11-0
.252
-0.7
620.
037
0.02
50.
211
-0.1
510.
335
0.85
8-0
.085
-0.0
420.
197
-0.4
42-0
.448
0.85
80.
342
-0.0
81
Mn
-0.8
12-0
.371
0.50
7-0
.537
-0.1
670.
404
-0.1
930.
269
-0.2
43-0
.144
0.88
90.
057
-0.0
720.
267
-0.1
70.
252
0.30
50.
390.
529
0.36
2-0
.283
0.56
3-0
.555
0.14
30.
673
-0.0
70.
548
0.82
10.
321
0.04
4-0
.624
-0.0
39-0
.017
0.08
50.
132
0.40
30.
564
0.38
80.
145
-0.1
17-0
.15
-0.1
68-0
.957
-0.8
18-0
.213
-0.3
28-0
.015
-0.4
710.
177
Fe/M
n
0.75
10
0.85
30.
546
0.10
9-0
.208
0.06
5-0
.174
-0.3
-0.6
80.
081
0.37
1-0
.564
-0.1
16-0
.664
-0.0
2-0
.046
-0.2
55-0
.488
0.14
5-0
.536
0.59
30.
271
-0.7
170.
273
-0.2
59-0
.839
-0.1
320.
048
0.75
7-0
.144
-0.3
41-0
.331
-0.6
13-0
.231
-0.5
43-0
.605
-0.1
310.
220.
412
0.58
40.
870.
982
-0.2
97-0
.187
0.50
10.
365
-0.5
27
S
0.54
60.
968
0.95
30.
615
-0.7
770.
468
-0.7
6-0
.837
-0.4
17-0
.193
0.80
1-0
.697
-0.2
31-0
.944
0.48
30.
257
0.23
4-0
.445
-0.1
9-0
.143
0.45
60.
368
-0.6
950.
425
0.34
2-0
.679
-0.2
51-0
.218
0.38
9-0
.026
-0.6
64-0
.534
-0.8
420.
289
0.02
2-0
.414
-0.3
750.
533
0.69
20.
465
0.71
80.
882
-0.3
76-0
.286
0.70
30.
309
-0.7
52
Na
0.40
30.
643
0.92
9-0
.76
0.76
1-0
.796
-0.8
470.
445
-0.2
170.
539
-0.4
37-0
.343
-0.6
310.
712
0.70
50.
702
-0.1
34-0
.499
0.39
1-0
.03
0.56
2-0
.18
0.50
10.
728
0.16
80.
231
-0.0
91-0
.198
0.03
3-0
.748
-0.2
07-0
.671
0.67
80.
621
-0.2
17-0
.014
0.08
80.
505
0.30
30.
522
0.64
3-0
.228
-0.1
690.
924
-0.2
39-0
.478
Al
0.87
10.
509
-0.6
080.
408
-0.5
86-0
.714
-0.5
27-0
.202
0.64
8-0
.716
-0.2
48-0
.932
0.36
0.24
0.14
2-0
.569
-0.1
98-0
.322
0.56
70.
407
-0.7
990.
461
0.18
1-0
.739
-0.1
72-0
.19
0.45
60.
016
-0.6
41-0
.45
-0.7
550.
201
-0.0
01-0
.566
-0.2
470.
441
0.60
80.
519
0.84
50.
961
-0.2
95-0
.19
0.57
40.
254
-0.7
04
K
0.71
4-0
.871
0.54
9-0
.864
-0.8
92-0
.266
-0.2
950.
848
-0.5
63-0
.134
-0.8
990.
558
0.34
50.
302
-0.3
71-0
.22
0.09
30.
418
0.33
9-0
.583
0.42
90.
481
-0.5
59-0
.317
-0.2
970.
248
0.01
8-0
.638
-0.5
48-0
.883
0.37
50.
171
-0.2
01-0
.436
0.63
40.
763
0.14
60.
561
0.78
3-0
.487
-0.4
150.
753
0.29
9-0
.64
Mg
-0.7
210.
634
-0.7
58-0
.832
0.33
4-0
.216
0.49
5-0
.498
-0.4
41-0
.745
0.76
30.
684
0.59
6-0
.351
-0.5
310.
295
0.06
0.76
4-0
.202
0.41
10.
679
00.
317
-0.1
46-0
.084
-0.1
48-0
.756
-0.3
92-0
.748
0.54
10.
523
-0.3
080.
089
0.16
90.
456
0.41
60.
561
0.78
3-0
.487
-0.4
150.
753
-0.2
99-0
.476
Ca
-0.5
250.
997
0.95
40.
008
0.16
9-0
.934
0.50
50.
249
0.74
1-0
.718
-0.2
44-0
.527
0.11
70.
275
-0.2
51-0
.003
-0.1
310.
262
-0.2
17-0
.717
0.26
50.
325
0.26
90.
058
0.02
0.56
20.
589
0.81
-0.5
63-0
.364
-0.0
290.
542
-0.6
44-0
.619
0.01
-0.3
-0.5
140.
419
0.38
3-0
.897
-0.2
570.
72
Ti
-0.5
42-0
.631
0.38
3-0
.324
0.32
-0.1
420.
06-0
.49
0.21
30.
860.
517
-0.2
07-0
.322
0.22
0.46
0.41
1-0
.443
0.88
30.
368
0.22
50.
051
0.03
7-0
.119
0.58
3-0
.537
0.23
8-0
.353
0.58
80.
721
-0.1
92 0 0.12
0.67
7-0
.158
0.75
30.
699
0.13
90.
218
0.85
-0.1
06-0
.165
P
0.95
8-0
.039
0.18
7-0
.915
0.50
10.
260.
732
-0.7
51-0
.287
-0.5
560.
117
0.30
4-0
.291
0.01
6-0
.166
0.23
7-0
.23
-0.7
470.
224
0.28
70.
279
0.08
40.
030.
586
0.57
20.
824
-0.5
84-0
.364
-0.0
270.
514
-0.6
1-0
.61
-0.0
1-0
.289
-0.5
110.
438
0.40
3-0
.889
-0.2
090.
699
S
0.00
50.
253
-0.8
440.
647
0.38
10.
865
-0.7
85-0
.407
-0.6
110.
285
0.44
8-0
.154
-0.0
85-0
.376
0.42
3-0
.378
-0.7
140.
260.
113
0.25
90.
062
-0.0
270.
745
0.51
30.
788
-0.6
47-0
.478
0.23
70.
335
-0.4
77-0
.603
-0.2
27-0
.636
-0.7
60.
256
0.18
1-0
.854
-0.0
820.
769
LO
I
0.26
2-0
.269
0.44
5-0
.002
0.28
10.
025
0.52
50.
287
0.43
6-0
.053
0.47
8-0
.28
0.34
50.
585
0.11
70.
195
0.84
80.
512
0.42
9-0
.346
0.01
20.
110.
255
0.12
30.
159
0.61
20.
276
0.42
7-0
.29
-0.0
27-0
.069
-0.8
12-0
.738
-0.0
4-0
.145
0.30
8-0
.424
0.35
5
As
-0.1
120.
27-0
.078
0.18
-0.3
34-0
.33
-0.4
350.
566
0.62
4-0
.258
-0.1
640.
151
0.50
4-0
.464
-0.4
560.
048
0.25
10.
789
0.48
7-0
.555
0.55
5-0
.295
-0.2
09-0
.641
-0.7
490.
119
0.20
80.
021
-0.1
450.
475
-0.8
88-0
.635
-0.4
78-0
.578
0.03
10.
215
-0.0
13
B
-0.4
8-0
.092
-0.6
910.
548
-0.0
390.
274
0.03
8-0
.044
0.20
90.
042
-0.1
34-0
.337
0.08
10.
526
-0.5
11-0
.524
-0.2
480.
142
-0.0
96-0
.427
-0.6
59-0
.781
0.36
20.
117
0.09
6-0
.683
0.68
90.
651
-0.0
440.
176
0.36
-0.3
31-0
.314
0.93
80.
537
-0.7
27
Ba
0.75
40.
75-0
.781
-0.1
07-0
.549
0.74
20.
640.
405
0.06
5-0
.351
0.51
3-0
.162
-0.5
260.
446
-0.0
910.
463
0.02
20.
145
0.83
10.
392
0.47
9-0
.509
0.25
60.
736
0.16
2-0
.094
-0.0
26-0
.793
-0.9
6-0
.984
0.13
50.
014
-0.2
630.
223
0.88
4
Be
0.42
2-0
.793
-0.0
85-0
.609
0.84
60.
685
0.45
70.
441
-0.5
21-0
.049
0.17
2-0
.51
-0.0
3-0
.492
0.23
20.
282
0.35
10.
534
0.36
80.
194
-0.4
07-0
.229
0.62
1-0
.187
0.07
10.
44-0
.729
-0.7
81-0
.848
0.27
20.
164
0.22
0.60
50.
677
Bi
-0.6
13-0
.352
-0.3
290.
524
0.36
40.
163
-0.3
72-0
.594
0.66
2-0
.409
-0.3
860.
568
-0.0
30.
154
-0.2
80.
092
0.73
90.
566
0.79
6-0
.358
-0.3
030.
550.
113
-0.4
02-0
.579
-0.5
42-0
.803
-0.9
220.
287
0.18
8-0
.664
-0.0
960.
768
Cd
0.19
90.
793
-0.5
22-0
.833
0.05
1-0
.481
0.34
6-0
.144
0.00
80.
865
0.00
10.
277
-0.4
7-0
.53
-0.1
7-0
.795
-0.4
53-0
.922
0.76
30.
997
-0.4
2-0
.042
0.01
5-0
.10.
436
0.99
0.95
10.
132
0.37
60.
545
-0.4
36-0
.739
a
0.51
2-0
.544
-0.4
530.
187
0.39
90.
642
-0.2
530.
831
0.33
90.
385
0.38
4-0
.006
-0.1
580.
407
-0.5
540.
346
-0.2
830.
478
0.88
1-0
.329
0.31
3-0
.146
0.39
40.
073
0.85
40.
961
-0.2
76-0
.17
0.57
6-0
.501
0.05
Co
-0.6
41-0
.858
0.04
9-0
.342
0.22
5-0
.046
0.32
40.
888
0.40
30.
137
-0.5
09-0
.716
0.29
9-0
.706
0.06
2-0
.049
0.93
70.
984
-0.2
72-0
.149
0.02
5-0
.068
0.08
20.
933
0.81
80.
151
0.26
5-0
.066
-0.5
8-0
.488
Cr
0.73
90.
798
-0.5
84-0
.504
0.40
7-0
.432
-0.4
630.
343
-0.1
710.
827
-0.0
11-0
.129
0.58
70.
138
0.28
2-0
.352
-0.2
050.
682
-0.0
59-0
.234
0.12
-0.4
93-0
.648
-0.7
850.
430.
333
0.31
20.
577
0.54
5
Cu
0.09
0.24
4-0
.367
0.22
6-0
.287
-0.7
32-0
.227
-0.3
160.
628
0.68
2-0
.236
0.76
6-0
.071
-0.1
14-0
.836
-0.8
520.
512
-0.1
160.
155
0.24
2-0
.263
-0.8
85-0
.767
-0.1
48-0
.258
0.18
10.
729
0.39
6
Ga
-0.2
13-0
.196
0.25
90.
025
0.30
60.
285
-0.1
05-0
.029
-0.2
34-0
.034
-0.0
03 0-0
.067
0.17
70.
515
0.61
9-0
.081
-0.0
50.
365
-0.5
18-0
.57
-0.5
150.
013
-0.0
670.
607
0.15
50.
341
Hf '
0.23
9-0
.677
0.68
4-0
.424
-0.4
18-0
.181
0.14
80.
575
0.40
9-0
.071
0.16
8-0
.523
-0.2
290.
125
-0.2
430.
032
0.24
10.
638
-0.1
670.
870.
982
-0.2
97-0
.187
0.50
10.
30.
143
Tabl
e 19
con
tinue
d
K)
Mo
Nb
Ni
Pb Rb
Sb Sc Sn Sr Te Th
Tl U V Y Zn
Zr
Hg
Ir Pd Pt Rh
Ru
Dep
thT
hick
Li-0
.195
0.37
30.
073
0.06
30.
874
0.33
0.20
7-0
.245
-0.4
87-0
.172
-0.6
880.
088
0.40
4-0
.69
0.80
3-0
.304
0.14
20.
673
10.
985
-0.0
110.
240.
419
-0.5
39-0
.227
Mo
-0.6
580.
048
0.60
10.
175
0.20
7-0
.291
-0.4
220.
568
-0.0
340.
291
-0.2
55-0
.189
0.57
80.
082
-0.0
94-0
.542
-0.2
37-0
.964
-0.8
11-0
.299
-0.4
06-0
.484
-0.2
30.
376
Nb
0.10
70.
070.
05-0
.039
0.03
90.
681
-0.5
40.
473
-0.2
040.
427
0.50
7-0
.398
0.09
2-0
.08
0.59
3-0
.089
0.95
0.84
30.
206
0.31
20.
571
-0.1
42-0
.015
Ni
0.19
8-0
.075
-0.6
36-0
.628
0.04
5-0
.669
-0.2
55-0
.527
0.84
90.
657
-0.0
17-0
.374
0.25
60.
061
0.00
40.
480.
803
-0.7
48-0
.675
0.44
6-0
.354
-0.5
22
Pb 0.39
80.
162
-0.6
630.
293
0.17
50.
581
0.67
70.
296
0.59
90.
256
0.34
1-0
.426
-0.3
78-0
.279
-0.6
83-0
.891
0.48
50.
396
-0.6
3-0
.594
0.45
6
Rb
0.41
4-0
.058
-0.3
09-0
.193
0.11
40.
108
-0.0
220.
067
-0.5
260.
921
-0.6
84-0
.354
0.76
51
0.90
10.
147
0.26
50.
296
-0.6
990.
081
Sb
0.50
6-0
.223
0.47
90.
031
-0.0
77-0
.571
0.04
20.
051
0.51
7-0
.247
0.14
70.
328
-0.3
42-0
.435
0.34
0.27
90.
70.
233
0.24
5
Sc
-0.3
920.
18-0
.311
-0.7
25-0
.73
-0.8
23-0
.171
0.04
90.
139
0.43
80.
390.
215
0.51
9-0
.636
-0.6
030.
759
0.55
6-0
.052
Sn
-0.1
040.
70.
401
0.47
40.
805
0.01
-0.1
690.
025
0.22
5-0
.818
0.35
-0.0
650.
877
0.90
3-0
.33
-0.0
430.
21
Sr
0.11
80.
48-0
.729
-0.2
290.
653
0.02
60.
066
-0.2
74-0
.654
-0.9
45-0
.954
0.06
7-0
.046
-0.5
270.
369
0.63
4
Te
0.74
40.
119
0.18
3-0
.037
0.26
-0.5
87-0
.199
-0.3
620.
023
-0.3
60.
814
0.80
4-0
.565
-0.3
50.
605
Th
0.04
90.
237
0.16
10.
271
-0.5
74-0
.691
-0.6
02-0
.26
-0.5
940.
721
0.67
9-0
.661
-0.3
40.
617
Tl
0.91
8-0
.207
-0.2
220.
045
0.09
7-0
.115
0.87
80.
585
0.60
20.
694
0.22
-0.3
99-0
.446
U
0.21
20.
126
0.26
60.
185
-1 1 1 1 1-0
.181
-0.0
97
V
-0.4
20.
356
0.09
2-0
.94
-0.9
82-0
.91
-0.0
69-0
.189
-0.1
280.
452
0.48
1
Y
-0.7
15-0
.295
0.57
90.
903
0.62
70.
556
0.65
20.
208
-0.5
410.
353
Zn
0.44
2-0
.514
-0.3
890.
048
-0.9
63-0
.987
0.01
40.
522
-0.3
62
Zr
Hg
Ir
Pd
Pt
Rh
Ru
Dep
th
-0.3
660.
250.
357
-
0.90
1-0
.157
-
0.14
7 -0
.292
-0.1
35
-
0.26
5 -0
.176
0.
993
0.98
6 -
0.29
6 0.
329
0.01
2 0.
035
0.57
6 -0
.418
-0
.522
-0
.508
0.
104
0.02
7 0.
634
-0.1
8 -0
.539
-0
.906
-0
.961
0.
162
0.05
2 -0
.563
-0
.078
Tabl
e 20
. C
orre
latio
n co
effic
ient
mat
rix
for
5 bu
lk c
rust
s >8
5mm
list
ed in
Tab
le 1
4; n
=5, e
xcep
t for
Cd,
Li,
and
Th =
4; t
he z
ero
corr
elat
ions
for
5 a
nd 4
poi
nts
at th
e 95
% c
onfid
ence
leve
l are
10.
8831
and
10.
9621
, res
pect
ivel
y; s
tatis
tical
ly s
igni
fican
t cor
rela
tions
are
in
bold
; -
= in
suff
icie
nt c
orre
latio
n pa
irs
Mn
FeM
n S
N
a A
l K
M
g C
a Ti
P S L
OI
As
B
Ba
Be
Bi Cd a Co
Cu
Ga
Hf
Li Mo
Nb
Ni
Pb Rb
Sb Sc Sn Sr Te Th
TI V Y Zn
Zr
Dep
thT
hick
Fe0.
511
-0.1
16
0.48
6 0.
882
0.14
1 0.
629
0.98
2 -0
.83
0.54
8 -0
.877
-0
.803
0.
493
0.08
2 0.
624
0.8
0.77
2 -0
.346
-0.0
660.
44-0
.216
0.66
90.
950.
278
0.48
20.
130.
286
0.63
40.
026
-0.2
310.
306
0.66
7-0
.209
-0.1
64-0
.156
-0.8
42-0
.128
0.80
6-0
.346
0.19
30.
850.
458
0.39
3
Mn
-0.8
96-0
.495
0.
649
-0.7
68
-0.3
2 0.
522
-0.0
49
0.39
5 -0
.118
0.
041
0.98
1 0.
612
-0.2
21
0.91
9 -0
.04
0.61
3-0
.628
0.50
80.
355
0.37
80.
301
-0.3
730.
989
0.73
10.
101
0.31
70.
792
0.65
90.
696
0.05
-0.1
970.
288
0.2
-0.9
84-0
.119
0.34
30.
453
-0.3
390.
039
-0.3
280.
471
Fe/M
n
0.80
8 -0
.408
0.
943
0.68
6 -0
.134
-0
.366
-0
.34
-0.3
06
-0.3
89
-0.9
2 -0
.566
0.
582
-0.6
65
0.33
2 -0
.867
0.73
-0.4
72-0
.616
-0.0
280.
060.
494
-1 -0.6
5-0
.132
-0.0
44-0
.96
-0.9
07-0
.672
0.36
4-0
.035
-0.2
64-0
.448 -
-0.1
040.
087
-0.7
760.
639
0.29
80.
612
-0.4
06
S
0.18
4 0.
926
0.97
70.
467
-0.7
9 0.
082
-0.7
69
-0.8
16
-0.5
18
-0.5
09
0.85
3 -0
.125
0.
778
-0.9
630.
739
-0.1
-0.6
140.
315
0.62
0.65
2-0
.877
-0.5
450.
124
0.36
3-0
.805
-0.9
36-0
.441
0.66
7-0
.081
-0.3
98-0
.419
-0.7
77-0
.094
0.50
9-0
.874
0.63
20.
780.
779
-0.0
75
Na
-0.1
1 0.
32
0.87
3 -0
.541
0.
833
-0.6
05
-0.6
34
0.70
4 0.
014
0.29
9 0.
827
0.71
5 -0
.057
-0.3
160.
70.
198
0.38
70.
862
0.25
70.
577
0.04
20.
576
0.54
80.
396
0.10
60.
436
0.26
40.
149
-0.3
540.
271
-0.5
640.
260.
468
0.06
3-0
.289
0.74
70.
167
0.56
8
Al
0.84
5 0.
144
-0.5
09
-0.0
26
-0.4
72
-0.5
84
-0.7
75
-0.7
08
0.64
9 -0
.479
0.
613
-0.9
240.
625
-0.1
81-0
.497
-0.0
160.
320.
718
-0.9
51-0
.742
0.15
0.21
6-0
.868
-0.9
62-0
.68
0.39
50.
121
-0.5
01-0
.287
-0.3
650.
069
0.17
1-0
.826
0.55
90.
557
0.62
3-0
.141
K
0.62
9 -0
.84
0.17
1 -0
.836
-0
.838
-0
.361
-0
.449
0.
841
0.05
4 0.
824
-0.8
90.
671
0.03
7-0
.558
0.38
50.
710.
669
-0.8
16-0
.419
0.17
30.
529
-0.6
97-0
.898
-0.3
940.
719
-0.1
17-0
.384
-0.3
92-0
.831
-0.1
30.
617
-0.8
890.
644
0.83
20.
721
0.08
Mg
-0.7
54
0.59
7 -0
.812
-0
.727
0.
492
-0.0
07
0.52
4 0.
785
0.76
9 -0
.286
-0.3
160.
556
-0.1
020.
555
0.90
30.
384
0.57
70.
123
0.37
70.
768
0.07
6-0
.254
0.18
10.
591
-0.1
23-0
.242
-0.0
55-0
.831
-0.0
670.
747
-0.3
830.
194
0.81
50.
327
0.54
2
Ca
-0.1
51
0.99
6 0.
94-0
.017
-0
.034
-0
.953
-0.4
34
-0.7
5 0.
753
-0.7
490.
067
0.69
-0.7
92-0
.881
-0.2
380.
279
0.06
80.
051
-0.3
280.
50.
57-0
.16
-0.9
090.
433
0.03
50.
572
0.86
20.
366
-0.8
810.
625
-0.5
37-0
.865
-0.8
630.
101
Ti
-0.2
18
-0.3
87
0.50
3 -0
.418
-0
.052
0.
465
0.67
4 0.
047
-0.4
830.
902
0.59
2-0
.18
0.59
20.
541
0.37
8-0
.331
0.92
40.
547
0.48
50.
109
0.08
9-0
.225
0.67
-0.7
490.
718
-0.0
430.
739
-0.0
530.
19-0
.578
0.58
6-0
.159
0.76
P
0.93
7-0
.085
-0
.03
-0.9
21-0
.497
-0
.775
0.
709
-0.6
62-0
.019
0.62
8-0
.783
-0.9
1-0
.266
0.18
40.
041
-0.0
07-0
.402
0.43
30.
543
-0.1
67-0
.893
0.40
40.
064
0.51
70.
873
0.33
6-0
.89
0.61
1-0
.506
-0.8
84-0
.813
0.01
2
S
0.01
1 0.
203
-0.9
-0
.346
-0
.897
0.
793
-0.5
92-0
.089
0.51
2-0
.592
-0.9
32-0
.41
0.30
90.
345
-0.2
23-0
.31
0.44
50.
562
-0.1
08-0
.717
0.12
30.
324
0.32
0.64
50.
039
-0.6
80.
52-0
.298
-0.9
66-0
.833
0.01
1
LO
I
0.54
8 -0
.246
0.
896
0.01
0.
613
-0.6
030.
559
0.43
30.
308
0.32
7-0
.351
0.96
70.
618
0.20
90.
249
0.84
30.
715
0.74
1-0
.047
-0.0
660.
183
0.31
3-0
.822
0.03
20.
246
0.56
-0.4
930.
077
-0.3
290.
472
As
-0.0
26
0.52
1 -0
.524
0.
447
0.01
8-0
.366
-0.2
570.
634
-0.0
83-0
.915
0.57
70.
897
-0.6
99-0
.356
0.32
0.59
70.
798
0.29
2-0
.768
0.91
3-0
.462
-0.4
19-0
.70.
409
0.38
60.
05-0
.339
0.01
4-0
.366
B
0.16
6 0.
659
-0.8
810.
925
-0.3
16-0
.834
0.73
0.73
50.
203
-0.5
6-0
.205
-0.1
930.
109
-0.7
11-0
.673
0.05
90.
894
-0.4
560.
002
-0.6
89-0
.795
-0.4
010.
777
-0.6
740.
615
0.77
30.
969
-0.3
49
Ba
0.29
4 0.
252
-0.4
320.
479
0.08
50.
621
0.63
7-0
.198
0.90
40.
595
0.12
70.
444
0.53
20.
363
0.67
0.37
8-0
.297
0.19
10.
001
-0.9
31-0
.20.
635
0.16
5-0
.123
0.40
10.
030.
426
Be
-0.6
80.
189
0.45
4-0
.146
0.24
30.
892
0.72
7-0
.239
-0.5
290.
606
0.57
4-0
.273
-0.5
75-0
.144
0.43
20.
263
-0.6
760.
068
-0.4
660.
315
0.43
6-0
.496
0.11
10.
976
0.54
20.
368
Bi
-0.8
530.
303
0.71
1-0
.327
-0.5
34-0
.505
0.87
60.
595
0.00
7-0
.099
0.88
10.
887
0.35
5-0
.642
0.12
30.
31 0.5
0.64
60.
119
-0.4
350.
779
-0.5
89-0
.703
-0.8
730.
317
Cd
-0.8
03-0
.943
0.51
10.
209
-0.1
39-0
.73
-0.3
38-0
.498
-0.8
5-0
.867
-0.6
140.
032
0.85
6-0
.446
0.19
5-0
.792
-0.9
93-0
.409
0.50
8-0
.612
0.65
40.
328
0.94
9-0
.9
a
0.75
6-0
.312
0.36
70.
531
0.54
4-0
.105
0.88
0.73
10.
627
0.17
8-0
.062
-0.3
360.
636
-0.6
460.
784
-0.0
80.
649
-0.1
150.
168
-0.4
980.
337
-0.4
770.
96
Co
-0.7
2-0
.276
0.17
80.
582
-0.0
550.
683
0.23
20.
811
0.56
3-0
.052
-0.8
540.
762
-0.4
480.
959
0.65
0.74
8-0
.673
0.61
5-0
.7%
-0.2
95-0
.87
0.71
1
Tabl
e 20
con
tinue
d
Ga
Hf
Li Mo
Mb
Ni
Pb Rb
Sb Sc Sn Sr Te Th
Tl V Y Zn
Zr
Dep
thT
hick
Cu
0.60
7-0
.377
0.21
20.
493
-0.4
990.
024
-0.2
28-0
.102
0.58
50.
894
-0.8
250.
548
-0.7
56-0
.83
-0.7
370.
932
-0.2
760.
483
0.44
50.
688
-0.3
3
Ga
0.36
80.
131
-0.1
370.
360.
494
-0.1
18-0
.334
0.26
30.
639
-0.0
8-0
.318
-0.1
36-0
.692
0.01
80.
715
-0.3
550.
130.
958
0.61
60.
263
Hf
-0.4
44-0
.721
0.73
60.
68-0
.295
-0.6
9-0
.741
-0.0
170.
607
-0.8
870.
36-0
.048
0.54
4-0
.066
-0.5
760.
125
0.57
10.
073
0.56
7
Li
0.72
90.
137
0.37
80.
961
0.98
0.65
6-0
.279
-0.0
770.
267
0.38
9-
-0.0
080.
217
0.97
9-0
.682
-0.1
9-0
.577
0.52
9
MD
-0.5
560.
006
0.44
40.
548
0.57
10.
221
-0.6
880.
824
-0.3
15-0
.592
-0.6
740.
399
0.26
20.
129
-0.3
94-0
.257
-0.0
12
Mb
0.54
90.
358
-0.0
46-0
.26
-0.4
230.
872
-0.9
180.
831
0.19
80.
887
-0.3
170.
093
-0.5
450.
448
-0.2
880.
784
Ni
0.11
2-0
.364
-0.3
650.
218
0.18
3-0
.453
0.23
6-0
.562
0.13
20.
36-0
.492
0.22
70.
498
-0.1
350.
844
Pb 0.87
20.
493
-0.5
690.
308
0.01
90.
680.
646
0.35
9-0
.30.
799
-0.7
72-0
.3-0
.745
0.55
3
Rb
0.69
8-0
.531
0.05
10.
368
0.40
60.
766
0.12
4-0
.336
0.94
8-0
.736
-0.5
37-0
.60.
075
Sb
0.16
5-0
.395
0.51
8-0
.131
-0.2
94-0
.247
0.32
10.
614
-0.3
780.
020.
122
-0.2
25
Sc
-0.7
480.
329
-0.8
31-0
.939
-0.7
150.
953
-0.6
750.
769
0.58
60.
814
-0.2
86
Sn -0.8
70.
904
0.64
30.
985
-0.7
280.
273
-0.6
650.
07-0
.454
0.54
Sr
-0.6
61-0
.279
-0.8
570.
345
0.16
40.
325
-0.5
050.
065
-0.5
69
Te
0.62
60.
904
-0.6
930.
533
-0.8
22-0
.1-0
.714
0.69
6
Th
0.62
-0.9
710.
878
-0.7
99-0
.592
-0.6
03-0
.167
Tl
V
-0.6
780.
355
-0.5
32-0
.745
0.
629
0.14
3 0.
594
-0.3
87
0.65
70.
509
-0.0
74
Y
Zn
Zr
Dep
th
-0.8
77-0
.492
0.
183
-0.5
54
0.53
7 0.
665
0.01
1 -0
.303
0.
241
-0.5
44
Tabl
e 21
. C
orre
latio
n co
effic
ient
mat
rix fo
r 4 b
ulk
crus
ts <
62m
m li
sted
in T
able
14;
n=4
; th
e ze
ro c
orre
latio
n fo
r 4 p
oint
s at
the
95%
co
nfid
ence
leve
l is
10.9
621;
sta
tistic
ally
sig
nific
ant c
orre
latio
ns a
re in
bol
d
Mi
Fe/M
nSi N
aA
lK M
jCa Ti P S LO
IAs B Ba Be Bi C
d a Co Cu Ga
Hf
Li Ma
Nb
Ni
Pb Rb Sb Sc Sn Sr Te Tl V Y Zn Zr
Hg
Dep
thTh
ick
Fe-0
.011
0.26
0.93
20.
379
0.82
80.
901
0.46
-0.4
550.
925
-0.4
19-0
.575
0.44
80.
192
0.28
50.
165
0.02
8-0
.779
-0.0
910.
775
0.01
2-0
.026
-0.3
720.
740.
557
-0.7
240.
969
-0.1
22-0
.079
0.17
70.
531
0.19
60.
499
-0.0
42-0
.489
0.03
4-0
.196
0.31
40.
593
0.92
3-0
.18
0.06
6-0
.146
Mi
-0.9
1-0
.06
0.80
8-0
.348
0.4
0.63
3-0
.857
0.36
8-0
.89
-0.7
950.
866
-0.9
760.
727
-0.4
37-0
.63
-0.1
830.
872
0.35
90.
996
-0.8
710.
93-0
.68
0.00
70.
603
-0.1
910.
993
0.96
90.
052
-0.8
47-0
.966
0.14
9-0
.602
-0.6
270.
999
0.29
8-0
.196
0.22
8-0
.268
-0.2
55-0
.604
-0.8
71
Fe/M
n
0.40
6-0
.492
0.67
-0.0
91-0
.255
0.73
7-0
.118
0.75
30.
522
-0.6
080.
895
-0.7
940.
145
0.32
3-0
.226
-0.6
550.
037
-0.8
720.
622
-0.9
60.
795
0.40
8-0
.844
0.47
2-0
.915
-0.9
770.
322
0.93
50.
985
-0.2
930.
272
0.24
8-0
.906
-0.6
290.
564
-0.3
130.
379
0.50
10.
302
0.59
9
S
0.47
10.
949
0.87
0.61
8-0
.302
0.82
7-0
.292
-0.5
560.
446
0.18
50.
007
-0.1
41-0
.22
-0.9
310.
044
0.88
8-0
.007
-0.1
56-0
.419
0.71
50.
816
-0.8
30.
974
-0.1
45-0
.207
0.51
40.
573
0.29
60.
153
-0.2
94-0
.64
-0.0
27-0
.532
0.63
50.
266
0.77
20.
185
-0.1
92-0
.26
Na
0.23
70.
739
0.96
6-0
.775
0.63
8-0
.82
-0.9
430.
967
-0.7
710.
427
-0.6
83-0
.845
-0.7
150.
887
0.82
0.85
3-0
.935
0.58
-0.2
760.
589
0.05
40.
297
0.78
10.
652
0.54
6-0
.438
-0.6
28-0
.062
-0.8
58-0
.965
0.81
4-0
.247
0.37
40.
075
0.01
50.
143
-0.8
16-0
.971
Al
0.67
0.44
10.
015
0.61
70.
024
-0.2
790.
166
0.43
6-0
.289
-0.1
12-0
.11
-0.8
47-0
.155
0.74
7-0
.288
0.05
4-0
.653
0.83
0.82
8-0
.957
0.93
9-0
.414
-0.5
0.56
80.
769
0.57
-0.0
21-0
.187
-0.4
6-0
.321
-0.6
810.
741
0.06
70.
723
0.36
3-0
.097
-0.0
34
K
0.76
4-0
.732
0.98
1-0
.723
-0.8
70.
79-0
.244
0.46
8-0
.157
-0.3
44-0
.866
0.34
50.
923
0.43
2-0
.452
0.03
50.
387
0.62
5-0
.458
0.82
30.
305
0.29
20.
322
0.14
7-0
.193
0.39
1-0
.399
-0.7
860.
437
-0.1
890.
336
0.52
10.
685
-0.1
32-0
.302
-0.5
56
Mg
-0.6
220.
638
-0.6
7-0
.878
0.88
6-0
.606
0.21
3-0
.748
-0.8
68-0
.849
0.81
20.
909
0.69
5-0
.87
0.37
5-0
.103
0.77
7-0
.17
0.43
70.
607
0.43
40.
723
-0.2
3-0
.412
-0.1
98-0
.896
-0.9
990.
637
-0.4
790.
596
-0.0
530.
084
0.34
-0.8
45-0
.912
Ca
-0.7
570.
996
0.91
6-0
.911
0.72
7-0
.897
0.10
40.
359
0.38
7-0
.603
-0.5
56-0
.845
0.65
5-0
.644
0.23
8-0
.08
-0.2
61-0
.247
-0.7
89-0
.852
0.09
10.
507
0.78
3-0
.55
0.36
10.
635
-0.8
83-0
.374
0.23
-0.6
43-0
.261
0.51
40.
314
0.71
5
Ti
-0.7
33-0
.827
0.73
5-0
.186
0.56
80.
028
-0.1
76-0
.766
0.22
30.
832
0.38
4-0
.332
0.00
90.
431
0.48
1-0
.428
0.82
0.26
0.30
40.
139
0.16
8-0
.192
0.55
9-0
.23
-0.6
640.
41-0
.026
0.17
50.
673
0.76
9-0
.307
-0.1
3-0
.444
P
0.93
3-0
.937
0.77
4-0
.867
0.18
70.
435
0.40
8-0
.669
-0.5
77-0
.883
0.71
7-0
.683
0.28
8-0
.119
-0.2
82-0
.219
-0.8
29-0
.869
0.02
60.
546
0.80
8-0
.477
0.43
60.
68-0
.912
-0.3
240.
182
-0.5
75-0
.20.
449
0.39
20.
772
S
-0.9
890.
69-0
.645
0.40
10.
618
0.70
1-0
.726
-0.8
26-0
.819
0.79
5-0
.516
0.11
7-0
.469
-0.0
02-0
.441
-0.7
33-0
.69
-0.3
090.
352
0.62
9-0
.269
0.63
90.
888
-0.8
160.
031
-0.1
81-0
.401
-0.2
770.
151
0.57
70.
861
LOI
-0.7
870.
639
-0.4
83-0
.692
-0.6
350.
815
0.77
10.
891
-0.8
690.
625
-0.2
590.
427
0.12
40.
312
0.81
90.
760.
323
-0.4
75-0
.715
0.18
8-0
.703
-0.8
90.
881
-0.0
170.
159
0.31
60.
132
-0.1
14-0
.655
-0.9
19
As
-0.5
840.
560.
711
0.10
7-0
.923
-0.2
7-0
.979
0.90
2-0
.965
0.8
-0.0
03-0
.677
0.34
1-0
.995
-0.9
31-0
.134
0.91
0.95
50.
045
0.67
30.
593-
-0.9
64-0
.216
0.13
9-0
.024
0.46
20.
104
0.69
40.
877
B
0.27
90.
030.
009
0.31
10.
171
0.67
7-0
.34
0.61
4-0
.266
-0.3
480.
445
0.03
80.
659
0.83
2-0
.52
-0.5
26-0
.761
0.78
50.
043
-0.2
280.
755
0.74
1-0
.629
0.81
90.
252
-0.8
290.
072
-0.3
89
Ba
0.96
60.
483
-0.8
21-0
.487
-0.5
090.
808
-0.4
020.
435
-0.6
49-0
.069
0.08
6-0
.495
-0.2
24-0
.864
0.36
40.
290.
769
0.96
10.
726
-0.4
070.
666
-0.6
870.
677
0.51
7-0
.758
0.97
70.
769
Be 0.56
1-0
.926
-0.6
08-0
.695
0.92
8-0
.539
0.46
3-0
.637
-0.1
240.
008
-0.6
66-0
.428
-0.7
910.
467
0.47
10.
578
0.99
70.
851
-0.6
090.
533
-0.5
910.
466
0.41
-0.5
80.
999
0.90
8
Bi
-0.3
83-0
.981
-0.2
520.
479
0.15
5-0
.434
-0.9
320.
659
-0.8
23-0
. 124
0.01
8-0
.735
-0.3
13-0
.077
0.09
0.62
30.
861
-0.2
030.
654
-0.7
62-0
.048
-0.5
-0.3
770.
538
0.55
9
Cd 0.49
80.
909
-0.9
930.
806
-0.6
640.
361
0.41
6-0
.162
0.89
90.
736
0.50
4-0
.733
-0.7
69-0
.321
-0.9
05-0
.796
0.85
5-0
.174
0.25
1-0
.22
-0.4
460.
25-0
.915
-0.9
72
a
0.42
1-0
.593
0.01
60.
314
0.86
3-0
.522
0.77
30.
296
0.17
30.
662
0.15
3-0
.109
0.00
6-0
.663
-0.9
20.
381
-0.5
230.
650.
151
0.47
40.
253
-0.5
79-0
.674
Co
-0.9
110.
911
-0.6
630.
092
0.55
3-0
.153
0.99
0.94
30.
142
-0.8
23-0
.941
0.08
6-0
.67
-0.6
880.
993
0.21
1-0
.107
0.17
4-0
.27
-0.1
75-0
.669
-0.9
12
Tabl
e 21
con
tinue
d
Ga
Hf
Li Nfo
Nb
Ni
Pb Rb
Sb Sc Sn Sr Te Tl V Y Zn
Zr
Hg
Dep
thT
hick
Cu
-0.7
620.
578
-0.4
32-0
.328
0.04
7-0
.885
-0.7
25-0
.532
0.67
0.74
50.
269
0.91
60.
858
-0.8
590.
204
-0.2
950.
156
0.34
-0.2
360.
913
0.99
3
Ga
-0.8
96-0
.254
0.84
5-0
.539
0.95
90.
942
-0.0
86-0
.983
-0.9
770.
018
-0.4
86-0
.36
0.91
40.
413
-0.3
610.
051
-0.5
62-0
.238
-0.5
27-0
.72
Hf
0.38
4-0
.927
0.83
4-0
.758
-0.7
040.
072
0.95
60.
788
0.28
50.
393
0.07
7-0
.646
-0.3
220.
340.
299
0.86
30.
018
0.47
30.
489
Li
-0.6
860.
679
-0.0
14-0
.229
0.91
60.
369
0.24
8-0
.428
-0.6
93-0
.779
0.01
1-0
.882
0.94
4-0
.306
0.27
30.
685
-0.6
31-0
.48
Mo
-0.8
680.
660.
716
-0.4
4-0
.92
-0.7
790.
029
-0.0
490.
188
0.57
90.
645
-0.6
67-0
.021
-0.7
21-0
.355
-0.1
29-0
.25
Nb
-0.2
88-0
.292
0.33
10.
683
0.39
40.
31-0
.069
-0.4
63-0
.151
-0.4
040.
498
0.40
10.
892
0.03
50.
036
-0.0
65
Ni
0.95
80.
08-0
.894
-0.9
70.
051
-0.6
31-0
.597
0.98
50.
272
-0.1
840.
123
-0.3
81-0
.186
-0.6
45-0
.87
Pb
-0.1
96-0
.881
-0.9
920.
313
-0.3
9-0
.43
0.97
10.
524
-0.4
320.
363
-0.2
55-0
.46
-0.4
-0.7
22
Rb
0.14
80.
163
-0.7
41-0
.823
-0.7
110.
035
-0.9
370.
959
-0.6
39-0
.131
0.88
7-0
.802
-0.5
31
Sb
0.93
30.
048
0.40
40.
212
-0.8
25-0
.448
0.42
30.
039
0.67
80.
217
0.46
20.
609
Sc
-0.2
080.
426
0.40
3-0
.961
-0.4
950.
417
-0.2
510.
376
0.38
60.
449
0.72
7
Sn
0.56
60.
170.
193
0.74
5-0
.666
0.98
90.
664
-0.9
390.
617
0.19
Sr 0.88
-0.5
830.
575
-0.6
380.
448
0.34
4-0
.595
0.99
40.
903
Te
-0.6
330.
47-0
.59
0.02
4-0
.117
-0.3
20.
826
0.90
3
Tl
V
0.31
3-0
.206
-0
.988
0.27
4 0.
673
-0.2
19
0.00
9-0
.287
-0
.928
-0.5
8 0.
551
-0.8
65
0.20
6
Y
Zn
Zr
Hg
Dep
th
-0.5
750.
074
0.70
70.
876
-0.8
98
-0.3
71-0
.602
0.
51
0.44
3 -0
.612
-0.3
11
0.06
8 0.
223
-0.1
92
0.88
7
Table 22. Chemical composition of Fe-Mn oxyhydroxide crusts and stratabound Mn deposits from FSM hydrothermal leg, KODOS 98-3 cruise
Fe wt.%MnFe/MnSiNaAlKMgCaTiPSH2OLOIB ppmBaBeBiCdClCoCuGaLiMoNbNiPbRbScSnSrTeTlVZnZrHg ppbIntervalType
D5-2A19.021.10.96.401.191.490.481.503.22
0.9330.410.177.7017.221314206.211.11.8
90903700763518
36444
35301080
1910.8
6116039.511753161948015
0-8Bulk
D5-2A119.021.10.96.401.191.490.481.493.21
0.9300.41
17.522514207.29.61.5
3600749548
36144
39801100209.26
1090 Ill58660748015
0-8Bulk
D5-16A7.906.971.1
17.11.053.340.4111.22.94
0.2820.060.042.109.9059
2671.72.12.7
56303098731885595
1520804
19.9<21492.2
37.62173538416
MnSandstone
D7-11A23.820.31.2
5.891.36
<0.010.671.242.83
0.7520.460.208.7016.622211806.712.11.4
93102950541285
35268
29001010407.25
115031.180.756850557816
0-5Bulk
D8-1A1.5043.10.032.760.982.350.672.551.02
0.0360.060.062.0019.256
115200.6
<0.515.37160889197058175359
26280
54113.7<26390.857.750616102518
StrataboundMn
D9-5-1A19.920.90.96.401.291.280.601.162.81
0.8950.450.1910.216.922214207.015.41.1
84003110620283
33739
25701020218.35
114034.086.9523493504
90-5
Bulk
D9-6-1A18.720.40.97.011.361.540.641.183.14
0.9000.610.207.8016.921913006.814.10.9
79402480507405
27737
3370863216.74
88228.972.0552452462240-9
BulkAll Ag contents <0.2ppm; Ge <10ppm; In <0.5ppm Duplicate analysis of sample
47
Table 23. Hygroscopic water-free (0% H2O~) composition of Fe-Mn crusts and stratabound Mn deposits from Table 22
Fe wt.%MnFe/MnSiNaAlKMgCaTiPSB ppmBaBeBiCdClCoCuGaLiMoNbNiPbRbScSnSrTeTlVYZnZrHg ppbIntervalType
D5-2A20.522.80.96.941.291.610.521.633.481.0110.440.1823115386.712.02.0
98484009827559
39448
3824117021
11.77
125742.812757522167152016
0-8Bulk
D5-2A120.522.80.96.941.291.610.521.613.481.0070.44
24415387.810.41.6
3900811599
39148
4312119222
10.07
1181~
12063520865852016
0-8Bulk
D5-16A8.077.121.1
17.41.083.420.4211.53.01
0.2880.060.0460
2731.72.12.8
57513168921887605
1553824
20.3<21522.2
38.422225
3618616
MnSandstone
D7-11A26.022.21.2
6.451.49
<0.010.741.353.10
0.8230.500.2224312927.313.31.5
101973231593315
38674
31761106447.95
126034.188.462222755363318
0-5Bulk
D8-1A1.5344.00.032.811.002.400.692.601.04
0.0370.060.0657
117550.6
<0.515.673069072010
59179366
26408
55113.8<26520.858.951610
16432618
StrataboundMn
D9-5-1A22.123.30.9
7.131.441.430.671.293.13
0.9970.510.2124715817.817.11.2
93543463690313
37543
28621136239.26
126937.996.858224954956110
0-5Bulk
D9-6-1A20.322.20.9
7.611.471.670.691.283.40
0.9770.660.2223814107.415.31.0
86122690550435
30040
3655936237.34
95731.378.1599249490501260-9
BulkAll Ag contents <0.2ppm; Ge<10ppm; In <0.5ppm Duplicate analysis of sample
48
Table 24. Statistics for 4 bulk Fe-Mn crusts from the Yap convergent margin hydrothermal leg KODOS 98-3 cruise; data from Table 23
Fe wt.%MnFe/Mn4SiNaAlKMgCaTiPSH2CTLOIB ppmBaBeBiCdClCoCuGaLiMoNbNiPbRbScSnSrTeTlVYZnZrHg ppbDepth5Thickness6
N44444444444444444444444444444444444444444
Mean22.222.61.07.031.42-1.180.651.393.280.9520.530.218.6016.924014567.3114.431.4295033348665406
36451
33791087289.05
118636.59859523756655417
24087
Median20.522.20.96.941.44-1.430.671.293.130.9770.500.217.8016.923814107.3413.251.2293543231593315
37543
31761106237.95
125734.18858222754952016
25045
SD1
10.210.11.03.170.640.860.300.641.480.4320.250.093.977.61076613.296.740.7342911570316213167271559494164.43
54616.94726710726125310
10994
Min'
20.322.20.96.451.29<0.010.521.283.100.8230.440.187.7016.623112926.7212.030.9886122690550313
300402862936217.34
95731.37857522149050110
20295
MaxJ
26.023.31.17.611.491.670.741.633.481.0110.660.2210.217.224715817.8017.151.95101974009827559
39474382411704411.77
126942.812762224967163326
25509
Standard deviation; Minimum; Maximum; Ratio of means, not a mean of the summation of ratios; Water depth in meters; Crust thickness in millimeters; LOI and H2O" from Table 22
49
160C
166
14C
RE
PU
BL
IC O
FJM
AR
SHA
LL
ISL
AN
D~
o~
« °~
u
172'
Figu
re 1
. A
tolls
and
sea
mou
nts
com
pris
ing
the
Mar
shal
l Isl
ands
with
the
two
boxe
d ar
eas
encl
osin
g L
omili
k Se
amou
nt a
nd
Lita
kpoo
ki R
idge
, whi
ch w
ere
stud
ied
durin
g cr
uise
KO
DO
S 98
-3; n
ote
the
loca
tion
of C
TD 2
bet
wee
n L
omili
k an
d L
itakp
ooki
se
amou
nts.
The
box
ed r
egio
ns in
the
inse
t map
sho
w lo
catio
ns in
Fig
ures
1 a
nd 4
160°30'E 160°35 'E 160°40'E 160°45 'E 160°50'E
&oo '
OO
o OO
o(So OO
OO
o OO
Figure 2. SeaBeam bathymetry, dredge (D), CTD, and piston core (PC) locations for Litakpooki Ridge, located south of Ujlan Atoll in the Marshall Islands group; D14 and D15 from KODOS 97-4 (Hein, Moon, et al., 1998); contour interval is 200m
51
161°
20'E
161°
25 'E
161°
30'E
161°
35 'E
161°
40 'E
161°
45 'E
Figu
re 3
. Se
aBea
m b
athy
met
ry f
or L
omili
k Se
amou
nt, l
ocat
ed w
est o
f Ane
wet
ak A
toll;
D4-
D13
fro
m K
OD
OS
97-4
(H
ein,
Moo
n, e
t al.,
199
8);
cont
our i
nter
val i
s 10
0m
136C
140
145C
Figu
re 4
. A
toll
and
isla
nd n
ames
with
in th
e Ex
clus
ive
Econ
omic
Zon
e of
the
wes
tern
Fed
erat
ed
Stat
es o
f Mic
rone
sia,
incl
udin
g th
e Y
ap c
onve
rgen
t mar
gin
and
the
wes
tern
edg
e of
Car
olin
e R
idge
; hat
chur
ed li
nes
are
basi
ns;
boxe
d ar
ea w
as s
urve
yed
durin
g K
OD
OS
98-3
; con
tour
inte
rval
is
100
0 m
; mod
ified
fro
m C
hase
et a
l. (1
988)
.
137°
30'E
137°
45'E
138°
00'E
138°
15'E
138°
30'E
138°
45 'E
Yap
Arc
Yap
Tre
nch
00
§0
Wes
t Car
olin
e R
idge
Figu
re 5
. Se
aBea
m b
athy
met
ry, d
redg
e (D
), C
TD, p
isto
n co
re (
PC),
box
core
(B
C),
and
mul
tiple
cor
e (M
C)
loca
tions
for
Yap
-Car
olin
e R
idge
co
nver
gent
mar
gin;
con
tour
inte
rval
is 2
00 m
100-,
Iu1. 10 H
A.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
wrj
1"E,
0.1-
0.01B.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Figure 6. REE plots of phosphatized limestone sample D1-10A, Litakpooki Ridge:(A) Chondrite (Anders and Grevesse, 1989) normalized, and (B) Post Archean AustralianShale (PAAS, McLennan, 1989) normalized
55
A. (Co+Ni+Cu)xlO
Bulk crusts, Litakpooki Ridge < 60 mm o Bulk crusts, Litakpooki Ridge > 60 mm Bulk crusts, Yap Arc+ Bulk crusts, SW Caroline Ridge Stratabound Mn, Yap Arc
Mn-cemented SS, Yap Arc
Fe Mn
B.(Co+Ni+Cu)xlO
Non-phosphatized crust layers (P < 1%) o Phosphatized crust layers (P > 1%)
Fe Mn
Figure 7. Mn-Fe-(Co+Ni+Cu)xlO ternary diagram after Bonatti et al. (1972) for: (A) bulk crusts, and (B) crust layers
56
ilooo-
100-
10-A.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
lOOn
10-
B.La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Figure 8. Range of REE plots for 13 Fe-Mn samples from Litakpooki Ridge: (A) Chondrite normalized, and (B) PAAS normalized
57
1000-
I I
100-
10-A.
I I I I I I I I I I I I V I
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
lOO-i
on
"cL 10-
c/3
B.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Figure 9. REE plots of bulk crusts and layers from dredge Dl, Litakpooki Ridge: (A) Chondrite normalized, and (B) PAAS normalized
58
1000-
I
C/3
C/3
|"a.
C/3
100-
10-
D2-2A D2-2B D2-2C D2-2D D2-3A D2-6A D2-1C*
A.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
lOO-i
10-
D2-2A D2-2B D2-2C D2-2D D2-3A D2-6A D2-1C*
B.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Figure 10. REE plots of bulk crusts and layers from dredge D2, Litakpooki Ridge: (A) Chondrite normalized, and (B) PAAS normalized
59
Fact
or 1
: CFA
pha
se
38.6
% o
f sam
ple
vari
ance
0.1
-0.1
-0.2
-0.3
0.5
0.4
0.3
o I
0.2
-o.i
-0.2
Al
Fact
or 2
: A
lum
inos
ilica
te p
hase
40
.2%
of s
ampl
e va
rian
ce
K
Si
ON O
0.8
fi
o o on i_i 1
0.6
UH
0.4
0.2
Fact
or 3
: Res
idua
l bio
geni
c ph
ase
13.6
% o
f sam
ple
vari
ance
0.4
0.3
0.2
0.1
-0.1
-0.2
-0.3
-0.4
Fact
or 4
: 5 M
nC>2
pha
se
6.5%
of
sam
ple
vari
ance
nu
n
iniiiii
Tl
Co
Ni
Ga
Mn
Pb
Na
Bi
P C
u A
l H
f
Figu
re 1
1. F
our
Q-m
ode
fact
ors
for 9
bul
k cr
usts
from
Lita
kpoo
ki R
idge
. Th
e fo
ur fa
ctor
s ac
coun
t for
98.
9% o
f the
var
ianc
e.
Fact
or s
core
s be
twee
n 0
and
10.14
1 ar
e no
t inc
lude
d be
caus
e ra
ndom
noi
se m
akes
it d
iffic
ult t
o re
solv
e th
e or
ient
atio
n of
the
fact
or to
with
in 1
0° o
f an
abso
lute
dire
ctio
n in
var
iabl
e sp
ace.
~ 0.1
-0.1
-0.2
-0.3
0.7
0.6
2 0.5
Factor 1: Aluminosilicate phase 39.6% of sample variance
0.4
0.2
0.1
w Factor 2: Mixed 6 MnO2 and residual biogenic phases 29.9% of sample variance
Zn Mn Cu
III III 11II11
1I
XI 03
'C!
Factor 3: CFA-diagenetic phase 29.9% of sample variance
Ca Co Nb Pb Ti Bi
-0.1
-0.2
-0.3
Figure 12. Three Q-mode factors for 5 bulk crusts >85mm from Litakpooki Ridge. The three factors account for 99.4% of the variance. Factor scores between 0 and 10.141 are not included because random noise makes it difficult to resolve the orientation of the factor to within 10° of an absolute direction in variable space.
61
lOOOn
I o
3 100-
10-
lOOn
10-
D5-2AD7-11A D9-5-1A
A.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
D5-2AD7-11AD9-5-1A
B.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Figure 13. REE plots of bulk crusts from dredges D5, D7, and D9, FSM: (A) Chondrite normalized, and (B) PAAS normalized
62
loo
c o
JGy0>
10--
A.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
10-r
0.1--
0.01
D5-16A D8-1A
B.
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Figure 14. REE plots of hydrothermal Mn-cemented sandstone (D5) and stratabound Mn layer (D8) from Yap Arc: (A) Chondrite normalized, and (B) PAAS normalized
63