silts tone/mudstone and interbedded fine-grained sandstone. Internally, the coarser sandstone units consist of scour-bound- ed cosets of 0.2- to 0.5-meter thick trough cross-beds. In some cases, thin siltstone drapes have preserved original dune geom- etry. Horizontal trails and vertical burrows occur along these surfaces and penetrate downward through crossbeds. The greenish gray siltstone/mudstone units typically contain root structures and locally preserve dark gray organic matter, sug- gesting that they were originally carbonaceous. Sandstones in the Fremouw contain an increasing proportion of volcanic detritus upward in the section. The proportion of sandstone to siltstone/mudstone diminishes in the middle member. At some localities the middle member is predomi- nantly fine grained; in others, it is very sandy. The upper member is predominantly trough cross-bedded, medium- grained volcaniclastic sandstone with some greenish gray or dark gray carbonaceous siltstone/mudstone interbeds. The overlying Triassic Falla Formation, a coarse-grained, quartzose sandstone, is channeled deeply into the Fremouw Formation. Vertebrate and plant fossils are locally abundant in the Fre- mouw Formation. Vertebrate fossils occur in the lower member and in the lower part of the upper member (see Hammer et al., Antarctic Journal, this issue). They are most abundant at the tops of channel-form sandstone units. Silicified plant fossils, includ - ing blocks of peat, large logs, and in situ stumps, occur in the upper part of the upper member (See Taylor, Smoot, and Collin- son, Antarctic Journal, this issue). The basal Fremouw sandstones are interpreted as sandy braided stream deposits that filled topographic relief on the Permian-Triassic unconformity. Paleocurrent data gathered this past field season do not support the approximately 180° reversal in paleoslope from Permian to Triassic suggested by Barrett (1969, 1970). The northward swing in paleocurrent dispersal that began with the deposition of the upper part of the Buckley Formation apparently continued into the Triassic (figure). Tri- assic dispersal directions were predominantly northward. The lower and middle members of the Fremouw were deposi- ted by low sinuosity braided to anastomosing streams, on an extensive flood plain. Sheet sandstones represent major cre- vasse splays. The proportion of sandstone to siltstone/ mudstone is an indication of the proximity of the section to a major channel. The thick sandstones of the upper member recorded a large increase in the amount of sand-sized volcanic detritus in the drainage system, producing an extensive braid plain. We wish to express appreciation to fellow scientists, es- pecially David Elliot and John Splettstoesser, and the support crew at the Beardmore South camp. We particularly thank mem- bers of th Vanderbilt University group led by Molly Miller and Julia Miller, the Augustana College/Wayne State University group led by Bill Hammer, and the Ohio State University group led by Tom Taylor, with whom we worked side by side. This research was supported by National Science Foundation grant DPP 84-18354. References Barrett, P.J. 1969. Stratigraphy and petrology of the mainly fluviatile Permian and Triassic Beacon rocks, Beardmore Glacier area, Ant- arctica. Institute of Polar Studies Report, 34. Barrett, P.J. 1970. Paleocurrent analysis of the mainly fluviatile Permian and Triassic Beacon rocks, Beardmore Glacier area, Antarctica. Journal of Sedimentary Petrology, 40(1), 395-411. Hammer, W.H., S.L. DeFauw, W.J. Ryan, and J.T. Tamplin. 1986. New vertebrates from the Fremouw Formation (Triassic), Beardmore Glacier region, Antarctica. Antarctic Journal of the U.S., 21(5). Miller, ME, and R.S. Frisch. 1986. Depositional setting of the (Permian) Mackellar Formation, Beardmore Glacier area. Antarctic Journal of the U. S., 21(5). Taylor, T. N., E. L. Smoot, and J. W. Collinson. 1986. Paleoenvironmentof Upper Triassic plants from the Fremouw Formation. Antarctic Journal of the U. S., 21(5). Vavra, C.L. 1984. Provenance and alteration of the Triassic Fremouw and Falla formations, central Transantarctic Mountains, Antarctica. Institute of Polar Studies Report, 87, Sedimentology of fine-grained Permian clastics, central Transantarctic Mountains L.A. KRISSEK and T.C. HoRNEI Institute of Polar Studies and Department of Geology and Mineralogy Ohio State University Columbus, Ohio 43210 In the central Transantarctic Mountains, the Permian se- quence is composed of four formations. In ascending order, these are the Pagoda, Mackellar, Fairchild, and Buckley Forma- tions. These units were deposited in a range of environments but generally record a transition from a glaciated basin, through the infilling of a post-glacial basin, to a fluvially dominated terrestrial realm. The general nature of this sequence was de- scribed by Barrett (1969) and Lindsay (1969), but the entire sequence was examined in more detail during the 1985-1986 field season by a nine-person field team from Vanderbilt Uni- versity (see Miller and Waugh, Antarctic Journal, this issue; Mil- ler and Frisch, Antarctic Journal, this issue) and Ohio State Uni- versity (see Collinson and Isbell, Antarctic Journal, this issue). The objective of this paper is to outline briefly the results of our field work and to describe the directions of our continuing laboratory investigations. Our future work will complement the efforts of our colleagues, who are examining each unit within the Permian sequence. While operating out of the Beardmore South remote camp for approximately 2 months, we measured 24 sections at 21 lo- calities. These sections totalled 3,789 meters in thickness and 30 ANTARCTIC JOURNAL
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silts tone/mudstone and interbedded fine-grained sandstone.Internally, the coarser sandstone units consist of scour-bound-ed cosets of 0.2- to 0.5-meter thick trough cross-beds. In somecases, thin siltstone drapes have preserved original dune geom-etry. Horizontal trails and vertical burrows occur along thesesurfaces and penetrate downward through crossbeds. Thegreenish gray siltstone/mudstone units typically contain rootstructures and locally preserve dark gray organic matter, sug-gesting that they were originally carbonaceous.
Sandstones in the Fremouw contain an increasing proportionof volcanic detritus upward in the section. The proportion ofsandstone to siltstone/mudstone diminishes in the middlemember. At some localities the middle member is predomi-nantly fine grained; in others, it is very sandy. The uppermember is predominantly trough cross-bedded, medium-grained volcaniclastic sandstone with some greenish gray ordark gray carbonaceous siltstone/mudstone interbeds. Theoverlying Triassic Falla Formation, a coarse-grained, quartzosesandstone, is channeled deeply into the Fremouw Formation.
Vertebrate and plant fossils are locally abundant in the Fre-mouw Formation. Vertebrate fossils occur in the lower memberand in the lower part of the upper member (see Hammer et al.,Antarctic Journal, this issue). They are most abundant at the topsof channel-form sandstone units. Silicified plant fossils, includ-ing blocks of peat, large logs, and in situ stumps, occur in theupper part of the upper member (See Taylor, Smoot, and Collin-son, Antarctic Journal, this issue).
The basal Fremouw sandstones are interpreted as sandybraided stream deposits that filled topographic relief on thePermian-Triassic unconformity. Paleocurrent data gathered thispast field season do not support the approximately 180° reversalin paleoslope from Permian to Triassic suggested by Barrett(1969, 1970). The northward swing in paleocurrent dispersalthat began with the deposition of the upper part of the BuckleyFormation apparently continued into the Triassic (figure). Tri-assic dispersal directions were predominantly northward.
The lower and middle members of the Fremouw were deposi-ted by low sinuosity braided to anastomosing streams, on an
extensive flood plain. Sheet sandstones represent major cre-vasse splays. The proportion of sandstone to siltstone/mudstone is an indication of the proximity of the section to amajor channel. The thick sandstones of the upper memberrecorded a large increase in the amount of sand-sized volcanicdetritus in the drainage system, producing an extensive braidplain.
We wish to express appreciation to fellow scientists, es-pecially David Elliot and John Splettstoesser, and the supportcrew at the Beardmore South camp. We particularly thank mem-bers of th Vanderbilt University group led by Molly Miller andJulia Miller, the Augustana College/Wayne State Universitygroup led by Bill Hammer, and the Ohio State University groupled by Tom Taylor, with whom we worked side by side.
This research was supported by National Science Foundationgrant DPP 84-18354.
References
Barrett, P.J. 1969. Stratigraphy and petrology of the mainly fluviatilePermian and Triassic Beacon rocks, Beardmore Glacier area, Ant-arctica. Institute of Polar Studies Report, 34.
Hammer, W.H., S.L. DeFauw, W.J. Ryan, and J.T. Tamplin. 1986. Newvertebrates from the Fremouw Formation (Triassic), BeardmoreGlacier region, Antarctica. Antarctic Journal of the U.S., 21(5).
Miller, ME, and R.S. Frisch. 1986. Depositional setting of the (Permian)Mackellar Formation, Beardmore Glacier area. Antarctic Journal of theU. S., 21(5).
Taylor, T. N., E. L. Smoot, and J. W. Collinson. 1986. PaleoenvironmentofUpper Triassic plants from the Fremouw Formation. Antarctic Journalof the U. S., 21(5).
Vavra, C.L. 1984. Provenance and alteration of the Triassic Fremouwand Falla formations, central Transantarctic Mountains, Antarctica.Institute of Polar Studies Report, 87,
Sedimentology of fine-grainedPermian clastics,
central TransantarcticMountains
L.A. KRISSEK and T.C. HoRNEI
Institute of Polar Studiesand
Department of Geology and MineralogyOhio State University
Columbus, Ohio 43210
In the central Transantarctic Mountains, the Permian se-quence is composed of four formations. In ascending order,
these are the Pagoda, Mackellar, Fairchild, and Buckley Forma-tions. These units were deposited in a range of environmentsbut generally record a transition from a glaciated basin, throughthe infilling of a post-glacial basin, to a fluvially dominatedterrestrial realm. The general nature of this sequence was de-scribed by Barrett (1969) and Lindsay (1969), but the entiresequence was examined in more detail during the 1985-1986field season by a nine-person field team from Vanderbilt Uni-versity (see Miller and Waugh, Antarctic Journal, this issue; Mil-ler and Frisch, Antarctic Journal, this issue) and Ohio State Uni-versity (see Collinson and Isbell, Antarctic Journal, this issue).The objective of this paper is to outline briefly the results of ourfield work and to describe the directions of our continuinglaboratory investigations. Our future work will complement theefforts of our colleagues, who are examining each unit withinthe Permian sequence.
While operating out of the Beardmore South remote camp forapproximately 2 months, we measured 24 sections at 21 lo-calities. These sections totalled 3,789 meters in thickness and
30 ANTARCTIC JOURNAL
provide a good stratigraphic and geographic distribution of dataacross the northern portion of this Permian basin. The samplelocations are shown in the figure, and a key to the samplelocations is given in the table. Of these 24 sections, 9 includedPagoda strata, 13 included Mackellar rocks, 9 included Fairchildinterval, and 13 included the Buckley sequence. The 312 sam-ples collected from these sections were distributed as follows:48 from the Pagoda, 106 from the Mackellar, 21 from the Fair-child, and 138 from the Buckley. As a result of this field effort,we will be able to address several objectives.
Several approaches are necessary to study the sedimentologyof fine-grained clastic rocks (shales and siltstones). Althoughfield relations are important, a detailed laboratory analysis isgenerally necessary to extract important data about their sedi-mentologic history. The objective of our continuing efforts is touse geochemical and mineralogic data from these siltstones andshales to decipher the record of paleogeography, provenance,and paleoclimate in the Permian sequence of the central Trans-antarctic Mountains.
This work will be closely coordinated with on-going efforts ofthe other members of the Vanderbilt/Ohio State group. Forexample, the Pagoda Formation, which is composed ofglaciomarine and glacial deposits (Lindsay 1969), is being exam-
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-
Geographic distribution of measured sections, Beardmore Glacierarea. See table for further information about individual localities.
Locations of stratigraphic sections measured in theBeardmore Glacier area, and stratigraphic units
med in detail by Miller and Waugh (Antarctic Journal, this issue).We will use the mineralogy and geochemical of fine-graineddiamictites and rare black shales to evaluate sources (Fan 1976;Keller 1970) and weathering characteristics (Nesbitt and Young1982) of the Pagoda sediments. These data may provide clues tothe types of rocks removed from atop the Devonian AlexandraFormation during Permian glaciation.
The Mackellar Formation was deposited in a basin that may beanalogous to the Karoo Basin of South Africa, thereby raisingseveral questions about the depositional environments of theMackellar shales and siltstones. In conjunction with Miller andFrisch (Antarctic Journal, this issue), we are attempting to deter-mine if the Mackellar basin represents a closed basin, as sug-gested by Lindsay (1969) or if local oxygen variations influenceddeposition along an oceanic continental margin. Paleosalinitydeterminations (Cody 1971; Berner and Raiswell 1984), tracefossil diversity (Miller 1984), mineralogic data (Edzwald andO'Melia 1975), and field relations are all being brought to bearon the problem. In addition, the mineralogical and geochemicalrecord of the glacial-postglacial transition in this interval isunder investigation.
The Fairchild and Buckley Formations were deposited influvial environments and include overbank siltstones and shal-es. The Buckley Formation also contains autochthorious andallochthonous coals. While Collinson and Isbell examine thefacies architecture and petrology of the fluvial sediments (Ant-arctic Journal, this issue), we are concentrating on the record ofsediment provenance and paleoclimate in the overbankdeposits.
Our progress to date has seen the completion of the fieldstudy and sample collection. Initial laboratory results suggestsome alteration by Jurassic intrusions, but the bulk of the labo-ratory data is still forthcoming. We anticipate that the Permianpaleogeography, paleoclimatology, and provenance of the cen-tral Transantarctjc Mountains will be well constrained withinthe next year.
1986 REVIEW 31
We wish to express our sincere appreciation to the othermembers of the Vanderbilt/Ohio State University researchteam, our fellow scientists from the Beardmore South camp,and the civilian and military support personnel for their effortson our behalf.
This work is supported by National Science Foundation grantDPP 84-18354.
References
Barrett, P.J. 1969. Stratigraphy and petrology of the mainly fluviatilePermian and Triassic Beacon rocks, Beardmore Glacier area, Ant-arctica. institute of Polar Studies Report, Vol. 34. Columbus: Ohio StateUniversity Press.
Berner, R.A., and R. Raiswell. 1984. C/S method for distinguishingfreshwater from marine sedimentary rocks. Geology, 12, 365-368.
Cody, R.D. 1971. Adsorption and the reliability of trace elements asenvironment indicators for shales. Journal of Sedimentary Petrology, 41,461-471.
Collinson, J.W., and J.L. Isbell. 1986. Permian-Triassic sedimentology ofthe Beardmore Glacier region. Antarctic Journal of the U.S., 21(5).
Edzwald, J.K., and C.R. O'Melia. 1975. Clay distributions in recentestuarine sediments. Clays and Clay Mineralogy, 23, 39-44.
Fan, P.F. 1976. Recent silts of the Santa Clara River drainage basin,southern California: A mineralogical investigation of their origin andevolution. Journal of Sedimentary Petrology, 46, 802-812.
Lindsay, J.F. 1969. Stratigraphy and sedimentation of lower Beaconrocks in the central Transantarctic Mountains. Institute of Polar StudiesReport, Vol. 33. Columbus: Ohio State University Press.
Miller, M.F. 1984. Distribution of biogenic structures in Paleozoic non-marine and marine margin sequences: An actualistic model. Journal ofPaleontology, 58, 550-570.
Miller, M.F., and R.S. Frisch. 1986. Depositional setting of the (Permian)Mackellar Formation, Beardmore Glacier area. Antarctic Journal of theU. S., 21(5).
Miller, J.M.G., and B.J. Waugh. 1986. Sedimentology of the PagodaFormation (Permian), Beardmore Glacier area. Antarctic Journal of theU. S., 21(5).
Nesbitt, H.W., and G.M. Young. 1982. Early Proterozoic climates andplate motions inferred from major element chemistry of lutites.Nature, 299, 715-717.
Sirius Formation basal contacts in theBeardmore Glacier region
M.C.G. MABIN
Institute of Polar StudiesOhio State University
Columbus, Ohio 43210
Sirius Formation outcrops examined in the Beardmore Glacierregion during the 1985-1986 season are described by Webb et al.(in preparation). The disconformity between the basal SiriusFormation and underlying rocks was examined at five localities.The morphology of the underlying surface exhibits varyingdegrees of ice moulding on a variety of rock types, as reportedfrom other sites (Mayewski and Goldthwait 1985). It is referredto by Webb et al. (Antarctic Journal, this issue; in preparation) asthe "Dominion erosion surface." At two locations, Mount Siriusand Plunket Point, it is extensively exposed and easily accessi-ble. Surveys of the contact were made using a theodolite andelectronic distance meter.
At the type locality, Mount Sirius (84°08'S 163°15'E), 85meters of diamictite rest on a platform of columnar jointeddolerite, which is approximately 2,200 meters above sea leveland 400 meters above the surrounding Bowden Névé. In planview, the platform is L-shaped, one limb extending north for 1.3kilometers, the other east for 0.9 kilometer. Width varies from125 to 500 meters, and it covers an area of 4 hectares. Theplatform edge varies between 2,179 and 2,226 meters above sealevel. It has two sets of undulations: one set is 20 meters deepand 300 meters apart, and the other set is superimposed on the
first at ito 5 meters deep and 20 to 30 meters apart. These formsprobably represent glacial whaleback features. Overall, the plat-form dips approximately 2° to the northwest. Where naturallyexposed, it is weathered, in places into small, irregularly shapedtors up to 40 centimeters high and 25 centimeters across. Re-moval of the overlying compacted diamictite reveals a fresh,heavily striated surface. Striation directions measured at sixlocalities along the eastern side of the platform trended between22° and 105°, with the predominant ice-flow direction being tothe east-northeast, as reported by McKelvey et al. (1984) andMercer (1972). On the western side of the platform, striationsare similarly oriented, and there are crescentic gouges up to 35centimeters across, convex in an east-northeast direction (Har-wood personal communication). Also exposed on this westernedge is a P-form feature 2 meters across and 0.5 meter deep,eroded into the dolerite (Harwood personal communication).This meandering channel is exposed for 5 meters and is ori-ented southeastward. It indicates the presence of subglacialmeltwater beneath the ice that overrode the platform.
Sirius Formation deposits are well exposed in the DominionRange in cliffs on the east side of the Beardmore Glacier, be-tween 2.2 and 3.9 kilometers southwest of Plunket Point(85°06'S 166°56'E) (Oliver 1964; Mercer 1972). The diamictiterests on an undulating surface of columnar-jointed dolerite atabout 1,750 meters above sea level and 15 to 95 meters above theglacier. The undulations vary from 3 to 36 meters high and 80 to300 meters apart and are interpreted as whaleback features.Striations on the dolerite trend between 355° and 25°, the varia-tions representing diverging and converging or north-north-east flowing ice over and around the whalebacks. Other glacialerosion features include minor plucking on the downglacier(northern) sides of the whalebacks, lunate fractures up to 8centimeters across, and small grooves. A fault has displacedboth the dolerite and overlying Sirius Formation diamictite. Thenorthern side is upthrown 55 meters, and the fault trace can befollowed south for 2.1 kilometers.
