Paleomagnetism and geochronology of 23 Ma gabbroic intrusions in the Keku Strait, Alaska, and implications for the Alexander Terrane
Peter J. Haeussler, Robert S. Coe, Paul R. Renne
1992, Journal of Geophysical Research B: Solid Earth (97) 19641-19649
Samples of Tertiary gabbro from 24 sites in the Keku Strait, Alaska, help constrain the displacement history of the Alexander terrane. Step heating experiments on a plagioclase separate from these previously undated intrusions indicate a discordant 40Ar/39Ar age of 23.1 ± 1.7 Ma. The characteristic magnetization resides in magnetite, is...
Distribution, numbers, and habitat of Bristle-thighed Curlews (Numinous tahitiensis) on Rangiroa atoll
Robert E. Gill Jr., Roland L. Redmond
1992, Notornis (39) 17-26
We assessed the numbers, distribution, and habitat of Bristle-tithed Curlews (Numinous tahitiensis) on Rangiroa Atoll, Tuamotu Archipelago, during a visit in April 1988. We estimated a total of 250-350 curlews on the atoll. These birds were seen only on the southern and western rims, where they were most common on...
Paleomagnetism of the Late Triassic Hound Island Volcanics: Revisited
Peter J. Haeussler, Robert S. Coe, T.C. Onstott
1992, Journal of Geophysical Research B: Solid Earth (97) 19617-19639
The collision and accretion of the Alexander terrane profoundly influenced the geologic history of Alaska and western Canada; however, the terrane's displacement history is only poorly constrained by sparse paleomagnetic studies. We studied the paleomagnetism of the Hound Island Volcanics in order to evaluate the location of the Alexander terrane...
Suspension freezing of bottom sediment and biota in the Northwest Passage and implications for Arctic Ocean sedimentation
E. Reimnitz, L. Marincovich Jr., M. McCormick, W.M. Briggs
1992, Canadian Journal of Earth Sciences (29) 693-703
Ice observations and sediment collected in a summer transit through the Northwest Passage provide insights on suspension freezing, the most important sediment entrainment mechanism for the Arctic Ocean. No evidence was seen for entrainment by bottom adfreezing, bluff slumping, river flooding, dragging ice keels, or significant eolian transport from land...
Molt frequency and size class distribution in the California spiny lobster (Panulirus interruptus), at San Nicolas Island, California
James L. Bodkin, L.B. Browne
1992, California Fish and Game (78) 136-144
The study of the undiscovered mineral resources of the Tongass National Forest and adjacent lands, Southeastern Alaska
D. A. Brew, L.J. Drew, S. D. Ludington
1992, Nonrenewable Resources (1) 303-322
The quantitative probabilistic assessment of the undiscovered mineral resources of the 17.1-million-acre Tongass National Forest (the largest in the United States) and its adjacent lands is a nonaggregated, mineral-resource-tract-oriented assessment designed for land-planning purposes. As such, it includes the renewed use of gross-in-place values (GIPV's) in dollars of the estimated...
Heat flow and subsurface temperature as evidence for basin-scale ground-water flow, North Slope of Alaska
D. Deming, J.H. Sass, A.H. Lachenbruch, R. F. De Rito
1992, Geological Society of America Bulletin (104) 528-542
In conjunction with the U.S. Geological Survey's exploration program in the National Petroleum Reserve, Alaska (NPRA) several high-resolution temperature logs were made in each of 21 drillholes between 1977 and 1984. These time-series of shallow (average 600-m depth) temperature profiles were extrapolated to...
Late Cretaceous inoceramid bivalves of the Kuskokwim Basin, southwestern Alaska, and their implications for basin evolution
W.P. Elder, S. E. Box
1992, Journal of Paleontology (66)
Upper Cretaceous rocks of the Kuskokwim Group are exposed in a large region of southwestern Alaska and are mainly composed of deformed turbidite deposits that contain few fossils other than inoceramid bivalves. This paper documents the taxonomy of the inoceramids in the Kuskokwim Group, develops an inoceramid...
Preliminary evidence for the involvement of budding bacteria in the origin of Alaskan placer gold
J.R. Watterson
1992, Geology (20) 315-318
Lacelike networks of micrometre-size filiform gold associated with Alaskan placer gold particles are interpreted as low-temperature pseudomorphs of a Pedomicrobium-like budding bacterium. Submicron reproductive structures (hyphae) and other morphological features similar to those of Pedomicrobiummanganicum occur as detailed three-dimensional facsimiles in high-purity gold in and on...
Petrogenesis of the Pd-rich intrusion at Salt Chuck, Prince of Wales island: an early Paleozoic Alaskan-type ultramafic body
R. A. Loney, G. R. Himmelberg
1992, Canadian Mineralogist (30) 1005-1022
The early Paleozoic Salt Chuck intrusion has petrographic and chemical characteristics that are similar to those of Cretaceous Alaskan-type ultramafic-mafic bodies. The intrusion is markedly discordant to the structure of the early Paleozoic Descon Formation, in which it has produced a rather indistinct contact aureole a few meters wide. Mineral...
Utility of radiocarbon-dated stratigraphy in determining late Holocene earthquake recurrence intervals, upper Cook Inlet region, Alaska
S. Bartsch-Winkler, H. R. Schmoll
1992, Geological Society of America Bulletin (104) 684-694
During the great 1964 earthquake, parts of coastal southern Alaska subsided tectonically as much as 2 m, and this led to burial of high-intertidal organic-rich marshes by low-intertidal and tidal silt. In the tectonically active part of upper Cook Inlet, the presence of stratigraphic sections containing numerous prehistoric interbedded layers...
Placer and lode platinum-group minerals in south Kalimantan, Indonesia: Evidence for derivation from Alaskan-type ultramafic intrusions
M. L. Zientek, B. Pardiarto, H. R. W. Simandjuntak, A. Wikrama, Robert L. Oscarson, A. L. Meier, R. R. Carlson
1992, Australian Journal of Earth Sciences (39) 405-417
Platinum‐group element minerals (PGM) occur in significant proportions in placer deposits in several localities in South Kalimantan. They consist of Pt‐Fe alloy that may be intergrown with or contain inclusions of Ir‐Os‐Ru alloy, laurite and chromite. Alluvial PGM found along Sungai Tambanio are in part derived from chromitite schlieren in...
Pyroclastic deposits of the Mount Edgecumbe volcanic field, southeast Alaska: eruptions of a stratified magma chamber
J.R. Riehle, D.E. Champion, D. A. Brew, M. A. Lanphere
1992, Journal of Volcanology and Geothermal Research (53) 117-143
The Mount Edgecumbe volcanic field in southeastern Alaska consists of 5-6 km3 (DRE) of postglacial pyroclasts that overlie Pleistocene lavas. All eleven pyroclast vents align with the long axis of the field, implying that the pyroclast magma conduits followed a crustal fissure. Most of these vents had previously erupted lavas...
The plinian eruptions of 1912 at Novarupta, Katmai National Park, Alaska
J. Fierstein, W. Hildreth
1992, Bulletin of Volcanology (54) 646-684
The three-day eruption at Novarupta in 1912 consisted of three discrete episodes. Episode I began with plinian dispersal of rhyolitic fallout (Layer A) and contemporaneous emplacement of rhyolitic ignimbrites and associated proximal veneers. The plinian column was sustained throughout most of the interval of ash flow generation, in spite of...
Computer Monte Carlo simulation in quantitative resource estimation
D. H. Root, W. D. Menzie, W.A. Scott
1992, Nonrenewable Resources (1) 125-138
The method of making quantitative assessments of mineral resources sufficiently detailed for economic analysis is outlined in three steps. The steps are (1) determination of types of deposits that may be present in an area, (2) estimation of the numbers of deposits of the permissible deposit types, and (3) combination...
Paleoecology of late-glacial peats from the bering land bridge, Chukchi Sea shelf region, northwestern Alaska
S. A. Elias, S. K. Short, R. L. Phillips
1992, Quaternary Research (38) 371-378
Insect fossils and pollen from late Pleistocene nonmarine peat layers were recovered from cores from the shelf region of the Chukchi Sea at depths of about 50 m below sea level. The peats date to 11,300-11,000 yr B.P. and provide a limiting age for the regional Pleistocene-Holocene marine transgression. The...
Submarine sedimentary features on a fjord delta front, Queen Inlet, Glacier Bay, Alaska
Paul R. Carlson, Ross D. Powell, Andrew C. Phillips
1992, Canadian Journal of Earth Sciences (29) 565-573
Side-scan sonar images provide a view of an actively changing delta front in a marine outwash fjord in Glacier Bay, Alaska. Numerous interconnected gullies and chute-like small channels form paths for the transport of sand and coarse silt from the braided glacial outwash streams on the delta plain to the...
Implementation of softcopy photogrammetric workstations at the US Geological Survey
C.D. Skalet, G.Y.G. Lee, L. J. Ladner
1992, Photogrammetric Engineering and Remote Sensing (58) 57-63
The US Geological Survey has provided the Nation with primary quadrangle maps and map products for the last 50 years. The Survey recently completed initial coverage of the conterminous United States and Hawaii at 1:24 000 scale. In Alaska, complete coverage exists at 1:63 360 scale. Effort is underway to...
The Mount Edgecumbe tephra deposits, a marker horizon in southeastern Alaska near the Pleistocene-Holocene boundary
J.R. Riehle, D.H. Mann, D.M. Peteet, D.R. Engstrom, D. A. Brew, C.E. Meyer
1992, Quaternary Research (37) 183-202
Late Pleistocene tephra deposits found from Sitka to Juneau and Lituya Bay are assigned to a source at the Mount Edgecumbe volcanic field, based on similarity of glass compositions to nearvent deposits and on thinning away from Kruzof Island. The sequence of near-vent layers is basaltic andesite and andesite at...
Geochemistry of waters in the Valley of Ten Thousand Smokes region, Alaska
T. E. C. Keith, J. M. Thompson, R. A. Hutchinson, L. D. White
1992, Journal of Volcanology and Geothermal Research (49) 209-231
Meteoric waters from cold springs and streams outside of the 1912 eruptive deposits filling the Valley of Ten Thousand Smokes (VTTS) and in the upper parts of the two major rivers draining the 1912 deposits have similar chemical trends. Thermal springs issue in the mid-valley area along a 300-m lateral...
A comparison of gas geochemistry of fumaroles in the 1912 ash-flow sheet and on active stratovolcanoes, Katmai National Park, Alaska
D.S. Sheppard, C. J. Janik, T. E. C. Keith
1992, Journal of Volcanology and Geothermal Research (53) 185-197
Fumarolic gas samples collected in 1978 and 1979 from the stratovolcanoes Mount Griggs, Mount Mageik, and the 1953-68 SW Trident cone in Katmai National Park, Alaska, have been analysed and the results presented here. Comparison with recalculated analyses of samples collected from the Valley of Ten Thousand Smokes (VTTS) in...
Impact origin of the Avak Structure, Arctic Alaska, and genesis of the Barrow gas fields
C.E. Kirschner, Arthur Grantz, M. W. Mullen
1992, American Association of Petroleum Geologists Bulletin (76) 651-679
Geophysical and subsurface geologic data suggest that the Avak structure, which underlies the Arctic Coastal Plain 12 km southeast of Barrow, Alaska, is a hypervelocity meteorite or comet impact structure. The structure is a roughly circular area of uplifted, chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km...
Variation of rock-forming metals in sub-annual increments of modern Greenland snow
T. K. Hinkley
1992, Atmospheric Environment - Part A General Topics (26 A) 2283-2293
Modern snowpack from central south Greenland was sampled in sub-seasonal increments and analysed for a suite of major, minor and trace rock-forming metals (K, Rb, Cs, Ca, Sr, Ba). There is a sharp seasonal concentration maximum for all six metals that comes in summer, later than mid-June. Metal concentrations in...
Reconnaissance exploration geochemistry in the central Brooks Range, northern Alaska: Implications for exploration of sediment-hosted zinc-lead-silver deposits
K.D. Kelley, D. L. Kelley
1992, Journal of Geochemical Exploration (42) 273-300
A reconnaissance geochemical survey was conducted in the southern Killik River quadrangle, central Brooks Range, northern Alaska. The Brooks Range lies within the zone of continuous permafrost which may partially inhibit chemical weathering and oxidation. The minus 30-mesh and nonmagnetic heavy-mineral...
Distribution and characteristics of metamorphic belts in the south-eastern Alaska part of the North American Cordillera
D. A. Brew, G. R. Himmelberg, R. A. Loney, A. B. Ford
1992, Journal of Metamorphic Geology (10) 465-482
The Cordilleran orogen in south-eastern Alaska includes 14 distinct metamorphic belts that make up three major metamorphic complexes, from east to west: the Coast plutonic–metamorphic complex in the Coast Mountains; the Glacier Bay–Chichagof plutonic–metamorphic complex in the central part of the Alexander Archipelago; and the Chugach plutonic–metamorphic complex in the...
