Volume 44 Number 6 February 2014 Page 1 Late Jurassic through Cretaceous Tectonics and Basin Evolution, Chukchi Shelf and Northwestern Alaska David W. Houseknecht US Geological Survey, Reston, VA [email protected]The Late Jurassic through Cretaceous geological history of the Chukchi Shelf and adjacent onshore Alaska is the focus of an integrated study using seismic, well, outcrop and geochronological data across a 150,000 km 2 area. This work suggests several fundamental linkages between tectonics and basin evolution, and clarifies offshore-onshore relations. Inherited tectonic elements influenced Late Jurassic and subsequent structural response to stresses related to the Chukotka (Late Jurassic through Cretaceous) and Brooks Range (Early Cretaceous and Tertiary) orogenies, as well as Beaufortian and Brookian sediment routing and accumulation patterns. Particularly important elements include the Chukchi Platform, a long-lived and high-standing block of pre-Mississippian rocks beneath the western Chukchi shelf; Hanna Trough, a Late Paleozoic failed rift system that bisects the shelf from north to south; and Alaska rift shoulder, a Jurassic and younger uplift related to opening of the Amerasia Basin. Contractional deformation, apparently related to the Chukotka orogeny, spanned at least the Late Jurassic through Late Cretaceous on the Chukchi Shelf. The initial pulse of contraction is evidenced by a series of en-echelon, north- south trending reverse or transpressional faults, which display up to 1 km of structural relief and root into older normal faults associated with the Hanna Trough. These inversion structures likely reflect maximum stress oriented obliquely to relict normal faults. Petroleum-prospective Upper Jurassic – Neocomian strata display eastward growth across the faults, and include east-dipping clinoforms. East-facing shelf-margins in this clinothem merge beneath the east-central Chukchi Shelf with southwest-facing shelf margins in younger parts of the Kingak clinothem, which trends northwest- ward across the North Slope, thus forming a southeast-facing embayed shelf margin. The Chukchi clinothem, project- ed onshore to the south, crops out in the western Brooks Range as the Tingmerkpuk sandstone, whose origin has been considered enigmatic. (continued) AGS Luncheon Date & Time: Feb. 20 h , 11:30 am – 1:00 pm Program: Late Jurassic through Cretaceous tectonics and basin evolution, Chukchi shelf and northwestern Alaska Speaker: David Houseknecht, US Geological Survey, Reston, VA Place: BP Energy Center Reservations: Make your reservation before noon Tuesday, Feb. 18 th , 2014 Cost: Seminar only, no meal: Free Reserve a box lunch: $15 Lunch with no reservation: On an “as-available” basis only E-mail reservations: [email protected]or phone (907) 564-4028. For more information visit: www.alaskageology.org
Transcript
Volume 44 Number 6 February 2014 Page 1
Late Jurassic through Cretaceous Tectonics and Basin Evolution, Chukchi Shelf and Northwestern Alaska
The Late Jurassic through Cretaceous geological history of the Chukchi Shelf and adjacent onshore Alaska is the focus of an integrated study using seismic, well, outcrop and geochronological data across a 150,000 km2 area. This work suggests several fundamental linkages between tectonics and basin evolution, and clarifies offshore-onshore relations.
Inherited tectonic elements influenced Late Jurassic and subsequent structural response to stresses related to the Chukotka (Late Jurassic through Cretaceous) and Brooks Range (Early Cretaceous and Tertiary) orogenies, as well as Beaufortian and Brookian sediment routing and accumulation patterns. Particularly important elements include the Chukchi Platform, a long-lived and high-standing block of pre-Mississippian rocks beneath the western Chukchi shelf; Hanna Trough, a Late Paleozoic failed rift system that bisects the shelf from north to south; and Alaska rift shoulder, a Jurassic and younger uplift related to opening of the Amerasia Basin.
Contractional deformation, apparently related to the Chukotka orogeny, spanned at least the Late Jurassic through Late Cretaceous on the Chukchi Shelf. The initial pulse of contraction is evidenced by a series of en-echelon, north-south trending reverse or transpressional faults, which display up to 1 km of structural relief and root into older normal faults associated with the Hanna Trough. These inversion structures likely reflect maximum stress oriented obliquely to relict normal faults. Petroleum-prospective Upper Jurassic – Neocomian strata display eastward growth across the faults, and include east-dipping clinoforms. East-facing shelf-margins in this clinothem merge beneath the east-central Chukchi Shelf with southwest-facing shelf margins in younger parts of the Kingak clinothem, which trends northwest-ward across the North Slope, thus forming a southeast-facing embayed shelf margin. The Chukchi clinothem, project-ed onshore to the south, crops out in the western Brooks Range as the Tingmerkpuk sandstone, whose origin has been considered enigmatic. (continued)
AGS Luncheon Date & Time: Feb. 20h, 11:30 am – 1:00 pm
Program: Late Jurassic through Cretaceous tectonics and basin evolution, Chukchi shelf and northwestern Alaska
Speaker: David Houseknecht, US Geological Survey, Reston, VA
Place: BP Energy Center
Reservations: Make your reservation before noon Tuesday, Feb. 18th, 2014
Cost: Seminar only, no meal: Free Reserve a box lunch: $15 Lunch with no reservation: On an “as-available” basis only
E-mail reservations: [email protected] or phone (907) 564-4028. For more information visit: www.alaskageology.org
Volume 44 Number 6 February 2014 Page 2
About the Speaker:
Dave Houseknecht is a research geologist with the U.S. Geological Survey (USGS) focusing on basin analysis, geo-logical controls of petroleum resource distribution, and petroleum resource assessment. This work is mainly concen-trated in Arctic Alaska and adjacent Arctic regions. He frequently represents the USGS scientific perspective on petro-leum resources in ANWR, NPRA, and other areas of Alaska and the global Arctic to the Administration and Congress. Dave joined the USGS in 1992, served as Energy Program Manager through 1998, and then moved to a research po-sition. Previously, Houseknecht was a professor of geology at the University of Missouri (1978-1992) and consultant to the oil industry (1981-1992), working on domestic and international projects. He received geology degrees from Penn State University (Ph.D. 1978, B.S. 1973) and Southern Illinois University (M.S. 1975).
Figure 1. Main tectonic elements of northeastern Russia and Arctic Alaska. Elles-merian elements of the Chukchi Shelf that were deformed by subsequent Chukot-kan-Brookian tectonism are shown with faded boundaries and labels.
Figure 2. A. Reverse or transpressional fault trends south of Klondike well, isochron map (color ramp) of strata between Jurassic unconformity (JU) and Lower Cretaceous unconformity (LCU), and trends of shelf margins (cyan) and inferred sediment routing (yellow arrows) based on clinoform dip in those strata. Herald arch structural front and exposures of Tingmerkpuk sandstone in Brooks Range thrust belt also are shown. B. Schematic cross section of strata (yellow) between the JU and LCU illustrating overall stratal geometry and internal, basinward-dipping clinoforms. Magenta lines depict reverse or transpressional faults. Line of cross section shown by red dashed line in A.
Brookian strata of the Chukchi Shelf – in contrast to the adjacent onshore – lack an asymmetrical foreland-basin pro-file, include an Upper Cretaceous succession, are thinner, contain limited deep marine deposits, and display relatively thin depositional sequences punctuated by numerous unconformities. Aptian-Albian strata thicken from the Chukchi Shelf eastward across 100 km into the Colville foredeep, and the Torok Formation grades into deeper marine facies. These changes were accommodated by the relict boundary between the Chukchi Platform and Hanna Trough, and syndepositional uplift along the Wrangel-Herald arch. The latter is expressed onshore by the presence of an Early Creta-ceous, northward-tapering tectonic wedge between the Lisburne Hills and western Brooks Range. Torok strata thin by onlap southwestward onto the tectonic wedge, and shallow marine strata of the Nanushuk Formation locally lie directly on the wedge. These relations demonstrate that the Early Cretaceous wedge formed the southwestern margin of the Colville basin and controlled Torok-Nanushuk accommodation and sediment routing.
Upper Cretaceous strata (as young as Coniacian or Campanian) on the Chukchi Shelf comprise mainly nonmarine facies that include air-fall tephra. Upper Cretaceous growth strata associated with transpressional faults are common. Cenomanian and younger unconformities dramatically cut through older strata west of Hanna Trough, and are ex-pressed as subtle sequence boundaries on the eastern shelf and onshore. These observations are interpreted as evi-dence of pulses of contractional deformation on the Wrangel-Herald arch throughout the Cretaceous.
Apatite fission track (AFT) and detrital zircon U/Pb (DZ) data from Chukchi exploration wells and a shallow core on the Herald arch suggest prolonged uplift and exhumation of the central Chukchi Shelf perhaps spanning 90 to 30 Ma, and rapid exhumation of the Herald arch at 80 Ma – including exhumation of strata at least as old as Lower Jurassic (Toarcian). DZ data from Paleogene strata above the Middle Brookian unconformity (MBU) in a transtensional tectonic setting indicate cooling of a deeply buried provenance during the Late Cretaceous, which may reflect exhumation of the Chukotka hinterland or volcanism. Integration of geochronological data and seismic stratigraphy suggests that the Chuk-chi Shelf was progressively uplifted in discrete pulses during the mid to Late Cretaceous, thus evolving into an area of low accommodation with most sediment bypassing to the North Chukchi basin, Canada Basin, and Colville basin.
Main conclusions of this ongoing work include: (1) Contractional deformation and syntectonic sedimentation across the Chukchi Shelf spanned the Late Jurassic – Late Cretaceous, and were driven primarily by the Chukotka orogeny and development of the associated foreland thrust belt. (2) The abrupt shift from transpressional to transtensional defor-mation across the MBU likely reflects the shift in maximum stress orientation from Chukotka to Brooks Range. (3) Late Jurassic – Neocomian strata on the Chukchi Shelf include east-facing relict shelf margins that mirror southwest-facing shelf margins in the Kingak Shale onshore. (4) Brookian strata on the Chukchi Shelf represent proximal facies deposited in a relatively low accommodation, bypass setting.
Volume 44 Number 6 February 2014 Page 3
Membership Note
Membership renewal is Nov. 1
Annual dues are: Full members - $25 & Students - $5
From the President’s Desk:
February can be a tough month to get through in Alaska. The joy of the recent holiday season is a distant memory and thoughts of Spring are no where to be found even if that Groundhog in Pennsylvania doesn’t see his shadow. I remember the first year I was up here and dreading the coming of February. Where I grew up in western Michigan it seemed like the coldest, darkest, most miserable month. To my surprise here in Alaska I realized that February was the month when the daylight hours were getting back to something that seemed normal. Then there is always Spring Break in March to look forward to. Plus Fur Rondy and the Iditarod. In regards to the AGS there’s quite a lot to look forward to. We begin the process of considering scholarship ap-plications in February and this year we’re getting a bit of a kicker from the Pacific Coast Section of the AAPG. Plans for the Spring Tech Conference will be firming up and abstracts will start coming in. And don’t forget about getting your PFD application in with the very convenient Pick, Click, Give option to give to your favorite charity, like the AGS. Before you know it we’ll be enjoying another fantastic summer. ~ Matt
Volume 44 Number 6 February 2014 Page 4
THE ALASKA GEOLOGICAL SOCIETY
2013-2014 Season Luncheon Program. Updates on the web at: http://www.alaskageology.org
Thursday, August 22, 2013 James McCalpin, Geo-Haz; The Mountains Are Falling Apart; A Spectrum of Mass Failures; Rockslides, Sackungs and Unfolding
Thursday, September 19, 2013 Sue Karl, USGS; Quaternary Volcanoes in Southeast Alaska
Thursday, October 17, 2013 Erin E. Donaghy, Northen Arizona Univ.; South-Central Alaska: Modification of a Forearc Basin by Spreadng Ridge Subduction
Thursday, November 21, 2013 John Decker, Niko Resources; Seabed mapping and the search for oil and gas seeps offshore
Thursday, December 12, 2013 Leo Brown, COP & Daniel Yancey, BP, “4D Seismic at Alpine Field & Time-lapse 3D/4D observations at Simpson Lagoon, Milne Pt.”
Thursday, January 16, 2014 Richard O. Lease, USGS; Thrust belt propagation, canyon incision and hydrocarbon systems in the Central Andes
Thursday, February 20, 2014 David Houseknecht, USGS, “Alaska’s North Slope and the Chukchi Shelf”
Friday, April 11, 2014 Allison Thurmond, Statoil (AAPG Distinguished Lecturer), “Industry-Driven Advances in Predictive Earth Systems modelling” (Evening meeting; 6:00 pm, BP Energy Center)
Monday, April 14, 2014 John Kaldi, University of Adelaide, “Carbon Capture and Storage”, Main Conference Rooms A, B, C at BP Exploration Alaska
Thursday, May 15, 2014 Keynote Speaker at the AGS Technical Conference, University of Alaska. Anchorage
If you would like to volunteer a talk or would like to suggest a speaker, please contact Monte Mabry at 230-4488.
My Pet Rock Kirk Sherwood Bureau of Ocean Energy Management
The Valanginian-age Burger sandstone is the principal reservoir encountered by a single well that interrogated the Burger structure in Chukchi Sea in 1990. The Burger sandstone is associated with ~14 Tcf in discovered gas resources in the all-gas case hypothe-sized by Craig and Sherwood (2004). This marine sandstone was deposited in a rift-shoulder sag-basin on the south flank of the North Chukchi high, later inverted by Paleocene tectonism. Unlike most pre-Lower Cretaceous unconformity (LCU, Hauterivian) sandstones of the North Slope, the Burger sandstone is relatively rich in potassium feldspar and plagioclase (A), sourced from uni-dentified plutonic rocks (possibly suggested by magnetic data) contemporaneously exposed on the North Chukchi high. Secondary dissolution of framework grains (B, highlighted by arrows), presumably feldspars, forms on average 40% of the porosity observed in petrographic studies (Reservoirs Inc., 1990, tbl. 3). The Burger sandstone was incised by the LCU, a subaerial exposure event that may have promoted the development of the secondary porosity. Send a photo of your pet rock to the editor: [email protected] Craig, J.D., and Sherwood, K.W., 2004, Economic study of the Burger gas discovery, Chukchi shelf, northwest Alaska: Minerals Management Service/BOEM report, 73 p. Available for download at: http://www.boem.gov/uploadedFiles/BOEM/About_BOEM/BOEM_Regions/Alaska_Region/Resource_Evaluation/Burger-Fact-Sheet.pdf.
Volume 44 Number 6 February 2014 Page 5
ALASKA FOSSILS OF THE MONTH Monotis (Entomonotis) ochotica and Monotis (Pacimonotis) subcircularis –
Rulers of early late Norian (Cordillerianus Zone) Arctic seas of northern Yukon, northern Alaska, and Northeast Russia
by Robert B. Blodgett1, Maurice Colpron2, and Andrew W. Tainter1 1Blodgett & Associates LLC - Geological & Paleontological Consulting, 2821 Kingfisher Drive,
Much of the stratigraphic record of the Upper Triassic of Alaska, northern Yukon and Northeast Russia is dominated by mass occurrences of the genus Monotis (and many of its subgenera) in offshore (mid- to outer shelf) settings. The ge-nus is widely distributed globally (see Fig. 1) and its great abundance in more offshore environments make it a correla-tion tool par excellence. Areas within the perimeter of the Pacific Ocean margins where they have been intensively stud-ied include: Alaska (Blodgett, 2008, 2009, 2012; Blodgett and Bird, 2002; Dutro and Silberling, 1988; Grant-Mackie and Silberling, 1990; Martin, 1916; Silberling, 1963, 1985; Silberling et al., 1997; Smith, 1927); western and Arctic Canada (Tozer, 1961, 1962, 1967, 1970, 1980, 1982; Westermann, 1962, 1964, 1966, 1973; Westermann and Verma, 1967); Japan (Ando, 1987a, b; Bando, 1961; Hayami, 1975; Ichikawa, 1958 and many others not cited; Northeast Russia (Bychkov and Yefimova, 1968; Bychkov et al., 1976; Kiparisova, 1936, 1937, 1938a, b; Kiparisova et al. 1966; Tuchkov, 1955, and many others not cited); the Southwest Pacific region (Grant-Mackie, 1978, 1980a, b and many others not cit-ed); and Chile (Westermann, 1970). The genus is known from both the middle and upper Norian (see Fig. 2 for range distribution of various Monotis species and subspecies of Alaska).
The idea for this note came about from the recent discovery by one of us (M. Colpron) of beautifully preserved speci-mens of two early late Norian age monotid species in the British and Barn Mountains of northernmost Yukon during mapping of that area by the Yukon Geological Survey in 2013. The two species, Monotis (Entomonotis) ochotica Keyser-ling, 1848, and Monotis (Pacimonotis) subcircularis Gabb, 1864, are indicative of an early late Norian (Columbianus Zone) age (see Fig. 2). M. (Entomonotis) ochotica (see Fig. 3) is very typical for the present-day Arctic regions, while M. (Pacimonotis) subcircularis (see Figs. 4-7) is much more widespread, occurring not only in the Arctic, but also along the length of North America and South America, as well in the present-day South Pacific.
In light of their great abundance in the Arctic regions of the Northern Hemisphere, we think it’s worthwhile to discuss and illustrate them in a brief manner so that future geological investigators may recognize these key biostratigraphic markers in the field. Given that even photos may not clearly represent fossil species in 3-D, any persons interested in more de-tailed information on these fossils are encouraged to write us for rubber latex replicas of these species, which can be provided upon request.
Middle and Upper Triassic strata in the British and Barn Mountains have been considered by Mountjoy (1967), Dixon et al. (1996), and Dixon (1998) to belong to the coeval Shublik Formation of northernmost Alaska. In Alaska the Shublik Formation is well expressed in both the surface and subsurface of the northern part of the Arctic Alaska terrane, with more distal facies age equivalent strata belonging to part of the Otuk Formation exposed to the south in the northern foothills of the Brooks Range.
REFERENCES
Ando, H., 1987a, Paleobiological study of the Late Triassic bivalve Monotis from Japan. The University Museum, The University of Tokyo, Bulletin No. 30, 109 p., 14 pls.
Ando, H., 1987b, Evolution and paleobiogeography of Late Triassic bivalve Monotis from Japan. Proceedings of Shallow Tethys 2, Wagga Wagga, 1986. A.A. Balkema, Rotterdam, p. 233-246.
Bando, Y., 1961. Note on the Upper Triassic Monotidae from the Nariwa basin, Okayama Prefecture, Japan. Mem. Fac. Lib. Arts Kagawa Univ., v. 102, p. 1-9.
Blodgett, R.B., 2008, Paleontology and stratigraphy of the Upper Triassic Kamiskak Formation in the Puale Bay-Cape Kekurnoi-Alinchak Bay area, Karluk C-4 and C-5 Quadrangle, Alaska Peninsula, p. 131-160, in Reifenstuhl, R.R., and Decker, P.L., eds., Bristol Bay--Alaska Peninsula region, Overview of 2004--2007 Geologic Research. Alaska Division of Geological & Geophysical Surveys Report of Investigations 2008-1.
Blodgett, R.B., 2009, Report on day trip (5/16/07) to visit Mesozoic rocks exposed in Port Graham and near Seldovia, southern Kenai Peninsula, p. 109-116, in LePain, D.L., Preliminary results of recent geologic investigations in the Homer-Kachemak Bay area, Cook Inlet Basin: Progress during the 2006-2007 field season: Alaska Division of Geological & Geophysical Surveys Preliminary Interpretive Report 2009-8C, p. 109-116.
Blodgett, R.B., 2012. Alaska Fossil of the Month. Monotis (Pacimonotis) subcircularis Gabb, 1864. Alaska Geology – Newsletter of the Alaska Geologi-cal Society, v. 42, no. 6, p. 4-6.
Blodgett, R. B., and Bird, K. C., 2002, Megafossil biostratigraphy and T-R cycles of the Shublik Formation in the Phoenix #1 Well, northern Alaska. American Association of Petroleum Geologists Bulletin, v. 86, no. 6, p. 1137.
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Bychkov, Yu.M., Dagis, A.F., Yefimov, A.F., and Polubotko, I.V., 1976. Atlas Triasovoi Fauny i Severo-Vostoka SSSR. Moskva, “Nedra”, 268 p.
Bychkov, Yu.M., and Yefimova, A.F., 1968. New Late Triassic Monotis and Halobia of the northeastern USSR (in Russian). In New Species of Early Plants and Invertebrates of the USSR, no. 2, part 1, p. 186-188. Nedra, Moskva.
Dixon, J., 1998. Permian and Triassic stratigraphy of Mackenzie Delta, and the British, Barn, and Richardson Mountains, Yukon and Northwest Territo-ries. Geological Survey of Canada Bulletin 528, 46 p.
Dixon, J., Orchard, M.J., and Davies, E.H., 1996. Carnian and Norian (Triassic) strata in the British Mountains, northern Yukon, p. 23-28, in Geological Survey of Canada, Current Research 1996-B.
Dutro, J.T., Jr., and Silberling, N.J., 1988, Megafossil biostratigraphy of some deep test wells, National Petroleum Reserve in Alaska, p. 667-675, in G. Gryc (ed.), Geology and Exploration of the National Petroleum Reserve in Alaska, 1974 to 1982: U.S. Geological Survey Professional Paper 1399.
Gabb, W.M., 1864, Description of the Triassic fossils of California. California Geological Survey, Paleontology, volume 1, p. 19-35.
Grant-Mackie, J.A., 1976. The Upper Triassic bivalve Monotis in the Southwest Pacific. Pacific Geology, v. 11, p. 47-56.
Grant-Mackie, J.A., 1978a. Subgenera of the Upper Triassic bivalve Monotis. New Zealand Journal of Geology and Geophysics, v. 21, p. 97-111.
Grant-Mackie, J.A., 1978b. Systematics of New Zealand Monotis (Upper Triassic Bivalvia): subgenus Entomonotis. New Zealand Journal of Geology Geophysics, v. 21, p. 483-502.
Grant-Mackie, J.A., and Silberling, N.J., 1990, New data on the Upper Triassic bivalve Monotis in North America, and the new subgenus Pacimonotis. Journal of Paleontology, v. 64, p. 240-254.
Hayami, I., 1975. A systematic survey of the Mesozoic Bivalvia from Japan. Bull. Univ. Mus. Univ. Tokyo, v. 10, p. 1-249.
Ichikawa, K., 1958. Zur Taxonomie und Phylogenie der triadischen “Pteriidae” (Lamellibranch.) mit besonderer Berücksichtung der Gattungen Claraia, Eumorphotis, Oxytoma und Monotis. Palaeontographica Abt. A, v. 3, p. 132-214.
Keyserling, A.G., 1848. Fossile Mollusken. In Middendorf, A., Reise in den äusserten Norden und Osten Sibiriens, 1, (1), 1-20.
Kiparisova, L., 1936. Upper Triassic pelecypods from the Kolyma-Indigirka Land (in Russian). Transactions of the Arctic Institute, v. 30, p. 71-136.
Kiparisova, L., 1937. Fauna of the Triassic deposits of the Arctic regions of the Soviety Union. Transactions of the Arctic Institute, v. 31, p. 135-256.
Kiparisova, L.D., 1938a. Verkhnetriasovye plastichatozhabernye Sibiri. Monografiya po paleontologii SSSR, Tom 47, Vypusk 1, 56 p., Moscow.
Kiparisova, L.D., 1938b. Pelecypoda of the Triassic System of the USSR. Leningrad. Central Geological and Prospecting Institute.
Kiparisova, L.D., Bychkov, Y.M., and Polubotko, I.V., 1966. Pozdnetriasovye dvustvorchatye mollyuski Severo-Vostoka SSSR.. Magadan, 230 p. Vse-soyuznyy Nauchno-issledovatel’skii Instituta (VSEGEI).
Martin, G.C., 1916, Triassic rocks of Alaska. Bulletin of the Geological Society of America, v. 27, p. 685-718.
Mountjoy, E.W., 1967. Triassic stratigraphy of northern Yukon. Geological Survey of Canada, Paper 66-19, 44 p.
Silberling, N.J., 1963, Field guide to halobiid and monotid pelecypods of the Alaskan Triassic. U.S. Geological Survey Open-File Report 63-119, 10 p., 6 pls.
Silberling, N.J., 1970. Biostratigraphy of marine Triassic in northern Alaska [abst.]. American Association of Petroleum Geologists Bulletin, v. 54, p. 2504.
Silberling, N. J., 1985, Biogeographic significance of the Upper Triassic bivalve Monotis in circum-Pacific accreted terranes, in Howell, D. G., ed., Tec-tonostratigraphic Terranes of the Circum-Pacific Region: Circum-Pacific Council for Energy and Mineral Resources Earth Sciences Series No. 1, p. 63-70.
Silberling, N.J., Grant-Mackie, J.A., and Nichols, K.M., 1997, The Late Triassic bivalve Monotis in accreted terranes of Alaska. U.S. Geological Survey Bulletin 2151, 21 p.
Smith, J.P., 1927, Upper Triassic marine invertebrate faunas of North America: U.S. Geological Survey Professional Paper 141, 262 p., 121 pls.
Tozer, E.T., 1961. Triassic stratigraphy and faunas, Queen Elizabeth Islands, Arctic Archipelago. Geological Survey of Canada, Memoir 316, 116 p.
Tozer, E.T., 1962. Illustrations of Canadian fossils, Triassic of Western and Arctic Canada. Geological Survey of Canada, Paper 62-19, 27 p.
Tozer, E.T., 1967. A standard for Triassic time. Geological Survey of Canada, Bulletin 156, 103 p.
Tozer, E.T., 1970. Marine Triassic faunas. In Geology and Economic Minerals of Canada. R.J.W. Douglas, ed., Geological Survey of Canada, Eco-nomic Geology Report 1 (5th edition), p. 633-640.
Tozer, E.T., 1980. Latest Triassic (Upper Triassic) ammonoid and Monotis faunas and correlations. Rivista Italiana di Paleontologia, v. 85, no. 3/4, p. 843-876.
Tozer, E.T., 1982. Marine Triassic faunas of North America, their significance for assessing plate and terrane movements. Geologische Rundschau, v. 71, no. 3, p. 1077-1104.
Tuchkov, I.I., 1955. On Pseudomonotis fauna of the Norian stage from northeastern Siberia. Doklady Akademiya Nauk U.S.S.R., v. 104, p. 608-610 (in Russian).
Westermann, G.E.G., 1962. Succession and variation of Monotis and the associated fauna in the Norian Pine River Bridge section, British Columbia (Triassic, Pelecypoda). Journal of Paleontology, v. 36, p. 745-792.
Westermann, G.E.G., 1964. Species distribution of the world-wide Triassic pelecypod Monotis Bronn, in Sundavla, R.K., ed., Report of the Twenty-Second Session, International Geological Congress, New Dehli, India, Section B, p. 374-387.
Westermann, G.E.G., 1966. New occurrences of Monotis from Canada (Triassic Pelecypoda). Canadian Journal of Earth Sciences, v. 3, p. 975-986.
Westermann, G.E.G., 1973. The Late Triassic bivalve Monotis, p. 251-258, in Hallam, A. (ed.), Atlas of Palaeobiogeography. Elsevier, Amsterdam.
Westermann,G.E.G., 1970. Occurrence of Monotis subcircularis Gabb in central Chile and the dispersal of Monotis (Triassic Bivalvia). Pacific Geology, v. 2, p. 35-40.
Westermann, G.E.G., and Verma, H., 1967. The Norian Pine River bridge section, British Columbia, and the succession of Monotis. Journal of Paleon-tology, v. 41, p. 799-803.
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Figure 1. Upper Triassic global reconstruction showing distribution of Monotis species. From Westermann (1977) with modifications by Ando (1987a).
Figure 2. Chart showing the relative stratigraphic ranges of Monotis species and subspecies represented in Alaska (from Silberling et al., 1997).
Figure 3. . Monotis (Entomonotis) ochotica specimens from the British Mountains (locality13MC029) and Barn Mountains (locality 13MC045) of the northern Yukon. A. Cluster of speci-mens from locality 13MC045. B. Cluster of specimens from locality 13MC029. C. External mold of left valve from locality 13MC029. D. Right valve from locality 13MC045. Scale bar marked in centi-meters. C
B
A B
C D
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Figure 5. Line drawing for a specimen of Monotis (Pacimonotis) sub-circularis from Puale Bay (referred to at the time of publication as “Cold Bay”) on the Alaska Peninsula (from Martin, 1916).
Figure 6. Bedding plane in lower part of Kamishak Formation at Puale Bay, east (Pacific) side of the upper Alaska Peninsula, entirely covered with Monotis (Pacimonotis) subcircularis (from Blodgett, 2008).
Figure 7. Photo of fragmentary specimens of Monotis (Pacimonotis) subcircularis found in folded argillite on west side of Port Graham, Kenai Peninsula, south-central Alaska (photo from Blodgett, 2009, provided to him by Andrew Caruthers of University of British Columbia, Vancouver, B.C.). Scale bar marked in centimeters.
Figure 4. Bedding surface covered with Monotis (Pacimonotis) subcir-cularis from the west side of the Killik River, northern Alaska (from Sil-berling et al., 1997, Pl. 7, fig. 5).
AGS Logo T-Shirts ($25 ea.) (Black shown – also available in Gray and Dark
Volume 44 Number 6 February 2014 Page 9
AGS Technical Conference Thursday, May 15, 2014 at University of Alaska, Anchorage
Conference Field Trip on Friday, May 16, 2014
If you would like to help organize the conference contact Chad Hults: [email protected]
Calendar of Events
Date Time Organiza on Event Loca on
12/11/13 11:30 – 1:00pm
AMA/SME Lunch me seminar. Speaker ‐ Kurt Parkan, Donlin Gold.
Sourdough Mining Company Anchorage
12/12/13 11:30 – 1:00pm
Alaska Geological Society
Leo Brown and Daniel Yancey ConocoPhillips Alaska and BP Explora on Alaska “4‐d seismic at Alpine Field, Alaska” & “3d/4d observa ons at Simpson Lagoon, Milne Point, Alaska”. Joint mee ng with Geophysical Society of Alaska ‐
BP Energy Center, Anchorage
1/8/14 11:30 – 1:00pm
AMA/SME Lunch me seminar. Speaker – Cecil Ulrich, URS Cor‐pora on
Sourdough Mining Company Anchorage
1/15/14 12:00pm – 1:00pm
Alaska Arc User Group (GIS)
AAUG monthly mee ng, BP Energy Center, Anchorage
1/16/14 11:30 – 1:00pm
Alaska Geologi‐cal Society
Richard Lease, USGS, Thrust belt propaga on, can‐yon incision, and hydrocarbon systems in the Andes
BP Energy Center, Anchorage
1/20/14 – 1/24/14
Alaska Marine Science
Alaska Marine Science Symposium h p://www.alaskamarinescience.org/
Hotel Captain Cook, Anchorage
1/21/14 11:30am – 1:00pm
ASCE Monthly mee ng Moose Lodge, Anchor‐age
2/3/14 – 2/7/14
Alaska Forum Alaska Forum on the Environment www.akforum
Dena'ina Civic & Con‐ven on Center
2/12/14 11:30am – 1:00pm
Society of Pe‐troleum Engi‐neers
Arc c Petroleum Resources: Basis for Petroleum Ac vi es. Anatoly Zolotukhin, Professor at the Gub‐kin Russian State University of Oil and Gas
Bear Tooth Theater Pub, 1230 W. 27th Ave., Anchorage
2/20/14 11:30 – 1:00pm
Alaska Geologi‐cal Society
David Houseknecht, USGS; “Alaska’s North Slope and the Chukchi Shelf”
BP Energy Center, Anchorage
3/20/14 11:30 – 1:00pm
Alaska Geological Society
Greg Wilson, ConocoPhillips Alaska; “Devil’s Paw Prospect, Chukchi Sea Alaska” Joint mee ng with Geophysical Society of Alaska ‐
BP Energy Center, Anchorage
4/7/14 – 4/13/14
Alaska Miners Associa on
24th Fairbanks Biennial Conference Carlson Center, Fair‐banks
4/11/14 6:00 – 8:00pm
Alaska Geological Society
Allison Thurmond, Statoil (AAPG Dis nguished Lec‐turer); “Industry‐Driven Advances in Predic ve Earth Systems Modelling”)
BP Energy Center, Anchorage
4/14/14 11:30 – 1:00pm
Alaska Geological Society
John Kaldi, Univ. Adelaide (AAPG Dis nguished Lec‐turer); “Carbon Capture and Storage” (Joint mee ng with Society of Petroleum Engineers Alaska Sec on)
Main Conference rooms A,B,C at BP Explora on Alaska
UAA Geosciences Career Fair UAA Conoco‐Phillips Building, Anchorage
Volume 44 Number 6 February 2014 Page 10
Enhanced Alaska Digital Well Log Data Since 1989
OCS, 95 out of 100 Alaska OCS wells. Mud logs for some. North Aleutian Basin wells, onshore and offshore. North Slope, 556 wildcats and key field wells. Kuparuk River Field, first 567 wells drilled (pre-1985). Southern Alaska, 1063 wells including all wildcats and many field wells. Directional surveys for most.
All digital log files Are depth shifted to match resistivity curves. Have core data rendered as a depth-shifted well log curve. Have SP both in original form and as a straightened curve. Have standardized mnemonics. Have Volume of Shale curves, derived from gamma ray for North Slope, derived from SP for Cook Inlet. Allow you to specify your own choice of mnemonics before delivery. Are updated periodically with new wildcat wells. Are delivered in LAS 2.0 format.
The Alaska Geological Society, Inc. P.O. Box 101288
Anchorage AK 99510 On the web at: h p://www.alaskageology.org
The Alaska Geological Society is an organiza on which seeks to promote inter‐est in and understanding of Geology and the related Earth Sciences, and to provide a common organiza on for those individuals interested in geology and the related Earth Sciences.
This newsle er is the monthly (September‐May) publica on of the Alaska Geological Society, Inc. Number of newsle ers/month: ~300
AGS annual memberships expire November 1. The annual membership fee is $25/year ($5 for students). You may download a membership applica on from the AGS website and return it at a luncheon mee ng, or mail it to the address above.
Contact membership coordinator Ken Helmold with changes or updates (e‐mail: ken.helmold at alaska.gov; phone: 907‐269‐8673)
All AGS publica ons are now available for on‐line purchase on our website. Check to see the complete catalogue:
h p://www.alaskageology.org/publica ons
ADVERTISING RATES
Adver sements may be purchased at the following rates: 1/10 Page‐‐$190/9mo, $75/1mo; size=1.8 x 3.5 inch
1/4 Page‐‐$375/9mo, $95/1mo; size=4.5 x 3.5 or 2.2 x 7.5 inch 1/3 Page‐ $470/9mo, $105/1mo; size=7.0 x 3.5 or 3.0 x 7.5 inch 1/2 Page‐‐$655/9mo, $125/1mo; size=9.0 x 3.5 or 4.5 x 7.5 inch
Full Page‐‐$1000/9mo, $165/1mo; size=7.5 x 9.0 inch 1mo rate=(9mo rate/9)+$50 (rounded up).
Contact Keith Torrance (907) 677‐9451 for adver sing informa on.
Volume 44 Number 6 February 2014 Page 12
Alaska Geological Society, Inc. P. O. Box 101288 Anchorage, AK 99510
2012 ‐ 2013 Alaska Geological Society Board
Commi ees and Delegates
Phone e-mail Workplace President Matt Frankforter 777-8376 mfrankforter at hilcorp.com Hilcorp Alaska, LLC Past-President Art Banet banetak at gci.net BLM emeritus President-Elect Keith Torrance 677-9451 ktorrance at apcservicesllc.com APC Services LLC Vice-President Monte Mabry 564-4028 monte.mabry at bp.com BP Treasurer Al Hunter 947-9010 paleoman at mac.com Secretary Eric Cannon 344-6001 eccannon at gmail.com Golder Associate Inc. Director 12-2014 Chad Hults 332-0740 chadcph at gmail.com Director 12-2014 Trystan Herriott 451-5011 trystan.herriott at alaska.gov DGGS Director 12-2014 Kirk Sherwood 334-5337 kirk.sherwood at boem.gov BOEM Director 13-2015 Richard Lease 786-7169 rlease at usgs.gov USGS Director 13-2015 Tom Morahan 230-1672 tmorahan at petroak.com PRA Director 13-2015 Jim Brown 276-2675 jbrown at alaskapacific.edu Alaska Pacific University
AAPG Delegate Marwan Wartes 451-5056 marwan.wartes at alaska.gov DGGS Advertising Keith Torrance 677-9451 ktorrance at apcservicesllc.com APC Services LLC Com. Ed./Science Fair Jana DaSilva Lage 677-7883 jldasilva5 at hotmail.com AeroMetric Field Trips Chad Hults 332-0740 chadcph at gmail.com Bylaws Sue Karl 786-7428 skarl at usgs.gov USGS Memberships Ken Helmold 269-8673 ken.helmold at alaska.gov AK DOG Newsletter Editor Ken Helmold 269-8673 ken.helmold at alaska.gov AK DOG Publications Peter Johnson 334-5329 peter.johnson at boem.gov BOEM Scholarship Sue Karl 786-7428 skarl at usgs.gov USGS Website Jan Hazen jan at homestead-graphics.com Consultant Fundraising Sunny Foster 269-7569 sunny.foster at alaska.gov AK DEC
