High-resolution airborne gravity imaging over James Ross Island (West Antarctica)
T.A. Jordan, Fausto Ferraccioli, P.C. Jones, J.L. Smellie, M. Ghidella, H. F. J. Corr, A.F. Zakrajsek
2007, Open-File Report 2007-1047-SRP-060
James Ross Island (JRI) exposes a Miocene-Recent alkaline basaltic volcanic complex that developed in a back-arc, east of the northern Antarctic Peninsula. JRI has been the focus of several geological studies because it provides a window on Neogene magmatic processes and paleoenvironments. However, little is known about its internal structure....
Main Andean sinistral shear along the Cooper Bay Dislocation Zone, South Georgia?
M.L. Curtis
2007, Open-File Report 2007-1047-SRP-034
The Cooper Bay Dislocation Zone (CBDZ) represents a major NW-SE trending tectonic boundary within the island of South Georgia that juxtaposes components of a Middle Jurassic to mid-Cretaceous island-arc and back-arc- basin system. New detailed structural data from the southern end of the dislocation zone reveal that earliest displacement along the boundary appears...
Extensive debris flow deposits on the eastern Wilkes Land margin: a key to changing glacial regimes
C. Escutia, F. Donda, F.J. Lobo, M. Tanahashi
2007, Open-File Report 2007-1047-SRP-026
Glacial sequences deposited on the base-of-slope and upper continental rise off the eastern Wilkes Land margin show that depositional systems vary with time. During the early Oligocene to middle-late Miocene times glacial sequences are dominated by extensive glacigenic debris flow deposits (GDFs) that have lens or wedge shaped external geometries and internal chaotic...
Antarctic ice-rafted detritus (IRD) in the South Atlantic: Indicators of iceshelf dynamics or ocean surface conditions?
Simon H.H. Nielsen, D.A. Hodell
2007, Open-File Report 2007-1047-SRP-020
Ocean sediment core TN057-13PC4/ODP1094, from the Atlantic sector of the Southern Ocean, contains elevated lithogenic material in sections representing the last glacial period compared to the Holocene. This ice-rafted detritus is mainly comprised of volcanic glass and ash, but has a significant input of what was previously interpreted as quartz...
Summary of Survival Data from Juvenile Coho Salmon in the Klamath River, Northern California, 2006
John W. Beeman
2007, Open-File Report 2007-1023
Little is known about the survival of ESA-listed juvenile coho salmon during their seaward migration in the lower Klamath River. In 2006, the Bureau of Reclamation funded a study to estimate the survival of radio-tagged juvenile coho salmon in the Klamath River downstream of Iron Gate Dam. A series of...
Zircon U-Pb Ages from an Ultra-High Temperature Metapelite, Rauer Group, East Antarctica: Implications for Overprints by Grenvillian and Pan-African Events
Yanbin Wang, Laixi Tong, Dunyi Liu
2007, Open-File Report 2007-1047-SRP-023
SHRIMP U-Pb dating of zircon from an ultra-high temperature (UHT, ~1000 °C) granulite-facies metapelite from the Rauer Group, Mather Peninsula, east Antarctica, has yielded evidence for two episodes of metamorphic zircon growth, at ~1.00 Ga and ~530 Ma, and two episodes of magmatism in the source region for the protolith...
U.S. Geological Survey Georgia Water Science Center and City of Brunswick–Glynn County Cooperative Water Program— Summary of activities, July 2005 through June 2006
Gregory S. Cherry
2007, Open-File Report 2006-1368
Since 1959, the U.S. Geological Survey has conducted a cooperative water resources program (CWP) with the City of Brunswick and Glynn County in the Brunswick, Georgia, area. Since the late 1950s, the salinity of ground water in the Upper Floridan aquifer near downtown Brunswick, Georgia, has been increasing, and its...
Type region of the Ione Formation (Eocene), central California: Stratigraphy, paleogeography, and relation to auriferous gravels
Scott Creely, Eric R. Force
2007, Open-File Report 2006-1378
The middle Eocene Ione Formation extends over 200 miles (320 km) along the western edge of the Sierra Nevada. Our study was concentrated in the type region, 30 miles (48 km) along strike. There a bedrock ridge forms the seaward western side of the Ione depositional tract, defining a subbasin...
New Rb-Sr mineral ages temporally link plume events with accretion at the margin of Gondwana
M.J. Flowerdew, J.S. Daly, T.R. Riley
2007, Open-File Report 2007-1047-SRP-012
Five of six Rb-Sr muscovite mineral isochron ages from the Scotia Metamorphic Complex of the South Orkney Islands, West Antarctica, average 190 ± 4 Ma. The muscovite ages are interpreted to date foliation-formation and thus also accretion and subduction at the Gondwana margin. Coincident picrite and ferropicrite magmatism, indicative of...
Major, trace element and stable isotope geochemistry of synorogenic breccia bodies, Ellsworth Mountains, Antarctica
J.P. Craddock, M.S. McGillion, G.F. Webers
2007, Open-File Report 2007-1047-SRP-078
Cambrian carbonates in the Heritage Range of the Ellsworth Mountains, West Antarctica host a series of carbonate-rich breccia bodies that formed contemporaneously with the Permian Gondwanide orogen. The breccia bodies had a three-stage genesis, with the older breccias containing Cambrian limestone (and marble) clasts supported by calcite, whereas the younger...
Synthetic seismograms and spectral cycles on the Andvord and Schollaert Drifts: Antarctic Peninsula
P.L. Manley, S. Brachfeld
2007, Open-File Report 2007-1047-SRP-018
The geological significance of seismic reflectors within large sediment deposits of the Gerlache Strait (Schollaert Drift) and the mouth of Andvord Bay (Andvord Drift) has been examined using synthetic seismograms. The seismograms generated from the physical properties in jumbo piston cores taken at each of these drifts (28JPC and 18JPC respectively)...
Holocene oceanographic and climatic variability of the Vega Drift deduced through foraminiferal interpretation
Phillip Szymcek, Scott E. Ishman, Eugene W. Domack, Amy Leventer
2007, Open-File Report 2007-1047-SRP-010
A sediment sequence recovered from the Vega Drift, Antarctica was analyzed for benthic foraminifera to determine Holocene oceanographic and climatic variability of the northern Antarctic Peninsula margin. Core NBP0003-JPC38, collected during cruise 00-03 of the R.V. Nathaniel B. Palmer recovered 20.53 meters of Holocene glacio-marine sediments. Samples were collected every...
The Cosmonaut Sea Wedge
K. Solli, B. Kuvaas, Y. Kristoffersen, G. Leitchenkov, J. Guseva, V. Gandyukhin
2007, Open-File Report 2007-1047-SRP-009
A set of multi-channel seismic profiles (~15000 km) acquired by Russia, Norway and Australia has been used to investigate the depositional evolution of the Cosmonaut Sea margin of East Antarctica. We recognize a regional sediment wedge below the upper part of the continental rise. The wedge, herein termed the Cosmonaut...
Sm-Nd and U-Pb isotopic constraints for crustal evolution during Late Neoproterozic from rocks of the Schirmacher Oasis, East Antarctica: geodynamic development coeval with the East African Orogeny
V. Ravikant, J.H. Laux, M.M. Pimentel
2007, Open-File Report 2007-1047-SRP-007
Recent post-750 Ma continental reconstructions constrain models for East African Orogeny formation and also the scattered remnants of ~640 Ma granulites, whose genesis is controversial. One such Neoproterozoic granulite belt is the Schirmacher Oasis in East Antarctica, isolated from the distinctly younger Pan-African orogen to the south in the central...
Landscape evolution of Antarctica
S.S.R. Jamieson, D.E. Sugden
2007, Open-File Report 2007-1047-KP-05
The relative roles of fluvial versus glacial processes in shaping the landscape of Antarctica have been debated since the expeditions of Robert Scott and Ernest Shackleton in the early years of the 20th century. Here we build a synthesis of Antarctic landscape evolution based on the geomorphology of passive continental...
Geologic Characterization of Young Alluvial Basin-Fill Deposits from Drill Hole Data in Yucca Flat, Nye County, Nevada
Donald S. Sweetkind, Ronald M. Drake II
2007, Open-File Report 2006-1390
Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada, that has been the site of numerous underground nuclear tests; many of these tests occurred within the young alluvial basin-fill deposits. The migration of radionuclides to the Paleozoic...
Lithospheric structure across the Transantarctic Mountains constrained by an analysis of gravity and thermal structure
Audrey D. Huerta
2007, Open-File Report 2007-1047-SRP-022
The Transantarctic Mountains demarcate the boundary between the highly extended lithosphere of the West Antarctic Rift System and the Proterozoic East Antarctic Craton. Although the last stage of relief development was in the Eocene, the TAM retain peak elevations in excess of 4500 m. This combination of old age and high relief...
Late Cenozoic Climate History of the Ross Embayment from the AND-1B Drill Hole: Culmination of Three Decades of Antarctic Margin Drilling
T.R. Naish, R.D. Powell, P. J. Barrett, R.H. Levy, S. Henrys, G.S. Wilson, L.A. Krissek, F. Niessen, M. Pompilio, J. Ross, R. Scherer, F. Talarico, A. Pyne, ANDRILL-MIS Science team
2007, Open-File Report 2007-1047-KP-07
Because of the paucity of exposed rock, the direct physical record of Antarctic Cenozoic glacial history has become known only recently and then largely from offshore shelf basins through seismic surveys and drilling. The number of holes on the continental shelf has been small and largely confined to three areas...
Advances through collaboration: sharing seismic reflection data via the Antarctic Seismic Data Library System for Cooperative Research (SDLS)
N. Wardell, J.R. Childs, A. K. Cooper
2007, Open-File Report 2007-1047-SRP-001
The Antarctic Seismic Data Library System for Cooperative Research (SDLS) has served for the past 16 years under the auspices of the Antarctic Treaty (ATCM Recommendation XVI-12) as a role model for collaboration and equitable sharing of Antarctic multichannel seismic reflection (MCS) data for geoscience studies. During this period, collaboration...
Paleocene and Maastrichtian calcareous nannofossils from clasts in Pleistocene glaciomarine muds from the northern James Ross Basin, western Weddell Sea, Antarctica
D.K. Kulhanek
2007, Open-File Report 2007-1047-SRP-019
Site NBP0602A-9, drilled during the SHALDRIL II cruise of the RV/IB Nathaniel B. Palmer, includes two holes located in the northern James Ross Basin in the western Weddell Sea, very close to the eastern margin of the Antarctic Peninsula. Sediment from both holes consists of very dark grey, pebbly, sandy...
Antarctica‘s continent-ocean transitions: consequences for tectonic reconstructions
K. Gohl
2007, Open-File Report 2007-1047-KP-04
100 Million Years of Antarctic Climate Evolution: Evidence from Fossil Plants
J.E. Francis, A. Ashworth, D.J. Cantrill, J.A. Crame, J. Howe, J. Stephens, A.-M. Tosolini, V. Thorn
2007, Open-File Report 2007-1047-KP-03
Antarctica Earth System Science in the International Polar Year 2007-2008
R.E. Bell
2007, Open-File Report 2007-1047-KP-02
IGY to IPY, the U.S. Antarctic oversnow and airborne geophysical-glaciological research program from 1957 to 1964 from the view of a young graduate student
John C. Behrendt
2007, Open-File Report 2007-1047-SRP-008
When 12 countries established scientific stations in Antarctica for the 1957-58 (IGY), the Cold War was at its height, seven countries had made claims in Antarctica, and the Antarctic Treaty was in the future. The only major field project of the U.S. IGY Antarctic program was series of oversnow traverses,...
The Ellsworth Mountains: critical and enduringly enigmatic
I.W.D. Dalziel
2007, Open-File Report 2007-1047-SRP-004
The Ellsworth Mountains, first mapped under the leadership of Campbell Craddock, pose critical geological enigmas, solved and unsolved. The isolation of the mountains, their abrupt structural terminations and Paleozoic stratigraphic affinities are explained by rotation from the cratonic margin during Gondwanaland breakup. The mechanism remains obscure. The absence of intense...
