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Articles 5761 - 5790 of 6800

Full-Text Articles in Environmental Indicators and Impact Assessment

Residence Times And Temporal Variations Of 210Po In Aerosols And Precipitation From Southeastern Michigan, United States, Daphne Mcneary, Mark Baskaran Feb 2007

Residence Times And Temporal Variations Of 210Po In Aerosols And Precipitation From Southeastern Michigan, United States, Daphne Mcneary, Mark Baskaran

Environmental Science and Geology Faculty Research Publications

Daughter products of 222Rn (such as 210Pb, half-life = 22.1 years, and 210Po, half-life = 138 days) have been widely used as tracers to determine the removal rates of aerosols as well to obtain analog information on the behavior of other chemical species in the lower atmosphere. To establish the first data set on the depositional fluxes of 210Po in bulk precipitation and concentrations in air samples from the midwestern United States, we measured the depositional fluxes of 210Pb and 210Po in the bulk (wet plus dry) and dry fallout by deploying a rain …

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Stratification Of Southern Georgia Streams For Rapid Bioassessment Focusing On Differences In Structure And Function Of Black Water And Clear Water Streams, Salini Pradeep Pillai Feb 2007

Stratification Of Southern Georgia Streams For Rapid Bioassessment Focusing On Differences In Structure And Function Of Black Water And Clear Water Streams, Salini Pradeep Pillai

Theses and Dissertations

As part of a rapid bioassessment project for the state of Georgia, relatively unimpaired reference streams and impaired sites were sampled for biological, chemical and physical parameters, and macroinvertebrates were identified. The metrics, biological, physical and chemical metrics, were selected using Ecological Data Application System Version 3.3.2k (EDAS). Discrimination efficiency and correlations were performed to determine the best metrics that separated impaired streams from reference streams and later on to form the index of stream water quality. Principal components analysis of the selected metrics showed that some of the blackwater reference streams and clearwater reference streams are randomly placed over …

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Allagash Wilderness Waterway Working Group On Structure, Management And Oversight: Choosing Common Ground And Moving Ahead, Allagash Wilderness Waterway Working Group Jan 2007

Allagash Wilderness Waterway Working Group On Structure, Management And Oversight: Choosing Common Ground And Moving Ahead, Allagash Wilderness Waterway Working Group

Maine History & Policy Development

In his June 19, 2006, Executive Order, Governor John E. Baldacci directed the Working Group to “offer its best guidance and advice to the Governor respecting the long-term governance, management, and oversight structure for the Allagash Wilderness Waterway” (AWW). In the intervening six months the members of the Working Group have engaged in an examination of the forty-year history of the Waterway and an analysis of the conditions and circumstance that led to the Governor’s Executive Order. We have reviewed documentation of the AWW history, taken testimony at numerous public meetings and hearings, conducted correspondence with members of the several …

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Final Draft Seagrass Transect Monitoring And Aerial Photography In Old Tampa Bay (Task D), J. O. R. Johansson, W. M. Avery, K. B. Hennenfent, J. J. Pacowta Jan 2007

Final Draft Seagrass Transect Monitoring And Aerial Photography In Old Tampa Bay (Task D), J. O. R. Johansson, W. M. Avery, K. B. Hennenfent, J. J. Pacowta

Reports

In 2004, the TBEP and partners were again granted funds from the PCEF to conduct additional seagrass and water quality research primarily in the Feather Sound area of the OTB study area. The overall purpose of this work was to formulate a seagrass restoration and preservation management strategy for, specifically, the NW quadrant. The BSG participated in this project, from here on called PCEF II, and performed Task D of this project named “Seagrass Transect Monitoring and Aerial Photography in OTB.” In addition to the tasks originally identified for Task D, late in the project, the BSG also applied an …

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Allagash Wilderness Waterway Working Group On Structure, Management And Oversight: Choosing Common Ground And Moving Ahead (Executive Summary), Allagash Wilderness Waterway Working Group Jan 2007

Allagash Wilderness Waterway Working Group On Structure, Management And Oversight: Choosing Common Ground And Moving Ahead (Executive Summary), Allagash Wilderness Waterway Working Group

Maine History & Policy Development

In his June 19, 2006, Executive Order, Governor John E. Baldacci directed the Working Group to “offer its best guidance and advice to the Governor respecting the long-term governance, management, and oversight structure for the Allagash Wilderness Waterway” (AWW). In the intervening six months the members of the Working Group have engaged in an examination of the forty-year history of the Waterway and an analysis of the conditions and circumstance that led to the Governor’s Executive Order. We have reviewed documentation of the AWW history, taken testimony at numerous public meetings and hearings, conducted correspondence with members of the several …

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Environmental Magnetic Records Of Mid-Late Pleistocene Drift Sedimentary Sequences From The Antarctic Peninsula, Pacific Margin, A. Venuti, F. Florindo, A. Caburlotto Jan 2007

Environmental Magnetic Records Of Mid-Late Pleistocene Drift Sedimentary Sequences From The Antarctic Peninsula, Pacific Margin, A. Venuti, F. Florindo, A. Caburlotto

ANDRILL Related Publications of Affiliates

The Pacific Continental Margin of the Antarctic Peninsula was the area of interest of the Sediment Drift of The Antarctic Offshore Project (SEDANO Project). A paleomagnetic and environmental study was carried out on four Pleistocene sequences from Drift 7. High resolution measurements were performed on u-channels and about forty-three discrete samples. This work focus on the definition of the mineralogy of the main magnetic carriers which is still matter of debate and on the study of the short time variability of magnetite grain-size which results particularly evident during the last glaciation. ARM/κ magnetic parameter resulted to be a good record …

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A Pleistocene Warming Event At 1 Ma In Prydz Bay, East Antarctica: Evidence From Odp Site 1165, G. Villa, C. Lupi, F. Florindo, Stephan Pekar Jan 2007

A Pleistocene Warming Event At 1 Ma In Prydz Bay, East Antarctica: Evidence From Odp Site 1165, G. Villa, C. Lupi, F. Florindo, Stephan Pekar

ANDRILL Related Publications of Affiliates

Magneto-stratigraphic and nannofossil assemblage data from ODP Site 1165 evidence an anomalous warming event of the surface waters in and around Prydz Bay during the Early Pleistocene. This results from an increase in the abundance of nannofossils at Site 1165, that occurred at 1 Ma. High-resolution sampling permits a new bio-magnetostratigraphic interpretation for ODP Site 1165. A decrease in δ18O values at Sites 1165 and 1167 also occurs at this time, supporting the presence of warming conditions in the Prydz Bay area. A return to colder surface waters, indicated by the absence or rare occurrence of nannofossils in …

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100 Million Years Of Antarctic Climate Evolution: Evidence From Fossil Plants, J. E. Francis, A. Ashworth, D. J. Cantrill, J. A. Crame, J. Howe, R. Stephens, A.-M. Tosolini, V. Thorn Jan 2007

100 Million Years Of Antarctic Climate Evolution: Evidence From Fossil Plants, J. E. Francis, A. Ashworth, D. J. Cantrill, J. A. Crame, J. Howe, R. Stephens, A.-M. Tosolini, V. Thorn

ANDRILL Related Publications of Affiliates

The evolution of Antarctic climate from a Cretaceous greenhouse into the Neogene icehouse is captured within a rich record of fossil leaves, wood, pollen, and flowers from the Antarctic Peninsula and the Transantarctic Mountains. About 85 million years ago, during the mid-Late Cretaceous, flowering plants thrived in subtropical climates in Antarctica. Analysis of their leaves and flowers, many of which were ancestors of plants that live in the tropics today, indicates that summer temperatures averaged 20°C during this global thermal maximum. After the Paleocene (~60 Ma) warmth-loving plants gradually lost their place in the vegetation and were replaced by floras …

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Herbivory In Antarctic Fossil Forests: Evolutionary And Palaeoclimatic Significance, C. M. Mcdonald, J. E. Francis, S. G.A. Compton, A. Haywood, A. C. Ashworth, Luis Felipe Hinojosa, J. Smellie Jan 2007

Herbivory In Antarctic Fossil Forests: Evolutionary And Palaeoclimatic Significance, C. M. Mcdonald, J. E. Francis, S. G.A. Compton, A. Haywood, A. C. Ashworth, Luis Felipe Hinojosa, J. Smellie

ANDRILL Related Publications of Affiliates

Many collections of Eocene Fossil leaves from Antarctica contain a rich store of insect trace fossils, indicating that insects were an important component of the unique forests that grew in polar regions. However, insect body fossils themselves are rare and so insect traces provide an excellent opportunity to examine both the palaeoentomology and the palaeoclimate of Antarctica. The fossils studied include Eocene leaves from both Seymour Island and King George Island on the Antarctic Peninsula. A database of all insect traces on the Antarctic fossil leaves was compiled and analysed in terms of the diversity of palaeoherbivory. The fossil leaves …

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The Neogene Biota Of The Transantarctic Mountains, A. C. Ashworth, A. R. Lewis, D. R. Marchant, R. A. Askin, D. J. Cantrill, J. E. Francis, M. J. Leng, A. E. Newton, J. I. Raine, M. Williams, A. P. Wolfe Jan 2007

The Neogene Biota Of The Transantarctic Mountains, A. C. Ashworth, A. R. Lewis, D. R. Marchant, R. A. Askin, D. J. Cantrill, J. E. Francis, M. J. Leng, A. E. Newton, J. I. Raine, M. Williams, A. P. Wolfe

ANDRILL Related Publications of Affiliates

Neogene fossil assemblages are described from three localities in the Transantarctic mountains. The plant fossils, include diatoms and algal spores, megaspores of Isoetes, pollen of angiosperms and gymnosperms, wood and leaves of Nothofagus, cushion growth forms of a vascular plant and a moss species, mats of exceptionally well- preserved moss species with delicate leaves attached to stems, and achenes and fruits of vascular plant species including Ranunculus. The invertebrate fossils include disarticulated chitinous parts of beetles and flies, cypridoidean ostracods and the shells of freshwater molluscs. The only vertebrate fossil is that of a fish. The fossil …

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Terminal Cretaceous Climate Change And Biotic Response In Antarctica, V. C. Thorn, J. E. Francis, J. B. Riding, R. W. Raiswell, D. Pirrie, A. Haywood, J. A. Crame, J. M. Marshall Jan 2007

Terminal Cretaceous Climate Change And Biotic Response In Antarctica, V. C. Thorn, J. E. Francis, J. B. Riding, R. W. Raiswell, D. Pirrie, A. Haywood, J. A. Crame, J. M. Marshall

ANDRILL Related Publications of Affiliates

Latest Cretaceous to early Palaeogene climates in Antarctica are being investigated from an exceptional sedimentary sequence on Seymour Island (James Ross Basin, Antarctic Peninsula) to determine the nature of climate change at the end of the Cretaceous. It has been suggested that, following peak mid Cretaceous warmth, cooling during the Maastrichtian (~71-65 Ma) may have been severe enough for short-term glaciations at high latitudes, challenging the current view of an ice-free, Cretaceous greenhouse world. High resolution records of palaeontological, sedimentological, and geochemical signals are being obtained to investigate the climate and environmental context at the Antarctic margin prior to the …

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Divergent Flow Of The West Antarctic Ice Sheet On The Outer Continental Shelf Of The Amundsen Sea During The Late Quaternary, T. J. Deen, R. D. Larter, K. Gohl, A. G.C. Graham, C.-D. Hillenbrand, G. Kuhn, J. A. Smith Jan 2007

Divergent Flow Of The West Antarctic Ice Sheet On The Outer Continental Shelf Of The Amundsen Sea During The Late Quaternary, T. J. Deen, R. D. Larter, K. Gohl, A. G.C. Graham, C.-D. Hillenbrand, G. Kuhn, J. A. Smith

ANDRILL Related Publications of Affiliates

Understanding the past glacial history of regions undergoing potential rapid deglaciation is essential in order to estimate the possible threat of sea level rise. Recently acquired data have given new images of mega-scale glacial lineations on the sea floor of the Amundsen Sea, which provide us a new understanding of the direction of glacial flow on the continental shelf of the Amundsen Sea region. Two adjacent areas of seafloor on the outer shelf of the Amundsen Sea embayment exhibit remarkably different styles of glacial lineations, and allow the interpretation of a divergent glacial trough for the Pine Island Glacier during …

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Late Quaternary Ice Sheet Dynamics And Deglaciation History Of The West Antarctic Ice Sheet In The Amundsen Sea Embayment: Preliminary Results From Recent Research Cruises, A. G.C. Graham, R. D. Larter, K. Gohl, C.-D. Hillenbrand, J. A. Smith, J. S. Johnson, G. Kuhn Jan 2007

Late Quaternary Ice Sheet Dynamics And Deglaciation History Of The West Antarctic Ice Sheet In The Amundsen Sea Embayment: Preliminary Results From Recent Research Cruises, A. G.C. Graham, R. D. Larter, K. Gohl, C.-D. Hillenbrand, J. A. Smith, J. S. Johnson, G. Kuhn

ANDRILL Related Publications of Affiliates

The threat, in terms of sea level rise, posed by the potential rapid deglaciation of West Antarctica means there is an urgent need to know more about the speed and style of marine ice sheet retreat. Quaternary deglacial events recorded in marine sediments provide an opportunity to understand the future of the modern day ice sheet. In this context, we examine the glacial history of a particularly poorly understood sector of the West Antarctic continental shelf – the Amundsen Sea Embayment –using new data from two recent research cruises. This extended abstract describes how marine geological and geophysical data are …

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Buried Oligocene Glacial Topography Beneath A Smooth Middle Miocene Unconformity In The Southeast Ross Sea: Evolution Of West Antarctic Glaciation, C. C. Sorlien, D. S. Wilson, B. P. Luyendyk, L. R. Bartek, R. C. Decesari, J. B. Diebold Jan 2007

Buried Oligocene Glacial Topography Beneath A Smooth Middle Miocene Unconformity In The Southeast Ross Sea: Evolution Of West Antarctic Glaciation, C. C. Sorlien, D. S. Wilson, B. P. Luyendyk, L. R. Bartek, R. C. Decesari, J. B. Diebold

ANDRILL Related Publications of Affiliates

Buried U-shaped troughs as much as 20 km-wide and flat-topped ridges adjacent to western Marie Byrd Land have recently been proposed as the result of late Oligocene West Antarctic glaciation. Here, additional evidence for pre-25 Ma glaciation is presented for the southeast Ross Sea, together with a different stratigraphic correlation path that establishes age constraints. Buried rough glacial topography interpreted to be of Oligocene age contrasts with a buried smooth and planar middle Miocene “Red” angular unconformity. The Red unconformity extends east-west 160 km near the ice shelf edge, and is 700 m-deep. Part of a 2 km section of …

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Contrasting Sub-Ice Shelf, Sub Glacial And Glacial Marine Deposition: Implications For Ice Shelf Stability, L. W. Boyd, L. R. Bartek, B. P. Luyendyk, D. Wilson Jan 2007

Contrasting Sub-Ice Shelf, Sub Glacial And Glacial Marine Deposition: Implications For Ice Shelf Stability, L. W. Boyd, L. R. Bartek, B. P. Luyendyk, D. Wilson

ANDRILL Related Publications of Affiliates

Data from cores collected from sites that were beneath the Ross Ice Shelf until 2000 and 2002 indicate that sub-ice shelf lithofacies are distinguishable from sub-glacial and glacial marine facies. Glacial marine sediment is characterized by diatom-rich, low-density, olive-green, sandy-muds, whereas sub-ice shelf sediment is defined by a lack of diatoms and muds that are enriched in silt and fine sand. Sub-glacial sediment is composed of diatom-poor, high density, coarse grained sandy-mud, rich in fine to coarse sized pebbles. Repetitive, fining-up packages, composed of fine-sand/silty-mud (distal sub ice-shelf deposits), grading into coarse pebbly-mud (sub ice-shelf proximal to the grounding line), …

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Cretaceous And Tertiary Extension Throughout The Ross Sea, Antarctica, Robert C. Decesari, D. S. Wilson, B. P. Luyendyk, Michael Faulkner Jan 2007

Cretaceous And Tertiary Extension Throughout The Ross Sea, Antarctica, Robert C. Decesari, D. S. Wilson, B. P. Luyendyk, Michael Faulkner

ANDRILL Related Publications of Affiliates

Marine geophysical data from the deep sea adjacent to the Ross Sea, Antarctica suggest that 170 km of extension occurred between East and West Antarctica from 46 to 21 Ma. The Northern and Victoria Land Basins in the western Ross Sea adjacent to the Transantarctic Mountains accommodated 95 km of this extension. Several kilometers of Oligocene sediments are found in the Central Trough and Eastern Basin in the eastern Ross Sea. Subsidence modeling accounts for these accumulations with about 40 km of extension in each basin centered on 35 Ma; therefore Ross Sea-wide Tertiary extension was comparable to extension in …

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Regional Seismic Stratigraphic Correlations Of The Ross Sea: Implications For The Tectonic History Of The West Antarctic Rift System, R. C. Decesari, C. C. Sorlien, B. P. Luyendyk, D. S. Wilson, L. R. Bartek, John Diebold, Sarah E. Hopkins Jan 2007

Regional Seismic Stratigraphic Correlations Of The Ross Sea: Implications For The Tectonic History Of The West Antarctic Rift System, R. C. Decesari, C. C. Sorlien, B. P. Luyendyk, D. S. Wilson, L. R. Bartek, John Diebold, Sarah E. Hopkins

ANDRILL Related Publications of Affiliates

Using existing and new seismic reflection data, new and updated correlations of late Oligocene-early Miocene RSS-2 strata were made between the southern parts of Ross Sea basins. Previous studies documented Cretaceous extension across much of Ross Sea. We interpret that Cenozoic extension also occurred across Ross Sea. Subsidence during and following this extension deepened existing basins and may have initiated basins in the west, subsiding ridges between basins below sea level during the late Oligocene. Pre-Oligocene strata record cessation of L. Cretaceous extension in easternmost Ross Sea. Successively younger Cenozoic extension occurred from east to west across the rest of …

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Scale Of Subglacial To Sub-Ice Shelf Facies Variability, Eastern Basin, Ross Sea, Audrey S. Loth, L. R. Bartek Iii, B. P. Luyendyk, D. S. Wilson, Christopher C. Sorlien Jan 2007

Scale Of Subglacial To Sub-Ice Shelf Facies Variability, Eastern Basin, Ross Sea, Audrey S. Loth, L. R. Bartek Iii, B. P. Luyendyk, D. S. Wilson, Christopher C. Sorlien

ANDRILL Related Publications of Affiliates

The Eastern Basin within the Ross Sea records changes in the volume of the West Antarctic Ice Sheet (WAIS). Examination of multibeam data revealed four acoustic facies that vary from west to east in a 900 km2 area. It is hypothesized that these facies, that formed nearly contemporaneously, are the result of differences in proximity to the grounding line and its relationship with the seafloor. The four facies are 1. Mega-Scale Lineation, 2. Slightly-Lineated Ridge Crest, 3. Discontinuous Ridges, 4. Irregular Mounds. These trends were also seen in SCS data, distinctively on the seafloor and mutedly at depth. Through determining …

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40Ar-39Ar Age Constraints On Volcanism And Tectonism In The Terror Rift Of The Ross Sea, Antarctica, S. E. Rilling, S. B. Mukasa, T. J. Wilson, L. A. Lawver Jan 2007

40Ar-39Ar Age Constraints On Volcanism And Tectonism In The Terror Rift Of The Ross Sea, Antarctica, S. E. Rilling, S. B. Mukasa, T. J. Wilson, L. A. Lawver

ANDRILL Related Publications of Affiliates

Volcanic sills and dikes inferred from seismic reflection profiles and geophysical studies of the Ross Sea are thought to be related to the rift basins in the region, and their emplacement to be coeval with extension. However, lack of precise geochronology in the Terror Rift of the Ross Sea region has left these inferred relationships poorly constrained and has hindered neotectonic studies, because of the large temporal gaps between seismic reflectors of known ages. New 40Ar/39Ar geochronology presented here for submarine volcanic rocks provides better age constraints for neotectonic interpretations within the Terror Rift. Several samples from …

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Lu−Hf Systematics Of The Ultra-High Temperature Napier Complex, East Antarctica: Evidence For The Early Archean Differentiation Of Earth’S Mantle, S. B. Mukasa, S. H. Choi, A. V. Andronikov, Y. Osanai, S. L. Harley, N. M. Kelly Jan 2007

Lu−Hf Systematics Of The Ultra-High Temperature Napier Complex, East Antarctica: Evidence For The Early Archean Differentiation Of Earth’S Mantle, S. B. Mukasa, S. H. Choi, A. V. Andronikov, Y. Osanai, S. L. Harley, N. M. Kelly

ANDRILL Related Publications of Affiliates

The Napier Complex comprises some of the oldest rocks on earth (~3.8 billion years old), overprinted by an ultra-high temperature (UHT) metamorphic event near the Archean−Proterozoic boundary. Garnet, orthopyroxene, sapphirine, osumilite, rutile and a whole rock representing an equilibrated assemblage from this belt yield a Lu−Hf isochron age of 2,403 ± 43 Ma. Preservation of the UHT mineral assemblage in the rock analyzed suggests rapid cooling with closure likely to have occurred for the Lu−Hf system at post-peak UHT conditions near a temperature of ~800°C. Zircon εHf values measured “see through” the UHT metamorphism and show that the source of …

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A Sediment Model And Retreat History For The Ross Ice (Sheet) Shelf In The Western Ross Sea Since The Last Glacial Maximum, R. M. Mckay, G. B. Dunbar, T. R. Naish, P. J. Barrett, L. Carter, M. Harper Jan 2007

A Sediment Model And Retreat History For The Ross Ice (Sheet) Shelf In The Western Ross Sea Since The Last Glacial Maximum, R. M. Mckay, G. B. Dunbar, T. R. Naish, P. J. Barrett, L. Carter, M. Harper

ANDRILL Related Publications of Affiliates

Three sediment gravity cores collected from beneath the McMurdo Ice Shelf and six piston cores from the Erebus Basin (in McMurdo Sound) and the Lewis Basin (north of Ross Island) were analysed in order to construct a retreat history for the West Antarctic Ice Sheet in the Ross embayment since the Last Glacial Maximum. The cores display a characteristic succession of sedimentary facies that record a transition from deposition beneath a marine terminating ice sheet to open-marine conditions. The base of the succession comprises a slightly consolidated, clast-rich muddy diamict dominated by basement clasts from the Transantarctic Mountains, and interpreted …

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Showing A Strong Link Between Climatic And PCo2 Changes: Resolving Discrepancies Between Oceanographic And Antarctic Climate Records For The Oligocene And Early Miocene (34-16 Ma), Stephan Pekar, N. Christie-Blick Jan 2007

Showing A Strong Link Between Climatic And PCo2 Changes: Resolving Discrepancies Between Oceanographic And Antarctic Climate Records For The Oligocene And Early Miocene (34-16 Ma), Stephan Pekar, N. Christie-Blick

ANDRILL Related Publications of Affiliates

An apparent mismatch between published oxygen isotope data and other paleoclimate proxies for the span from 26-16 Ma is resolved by calibration against eustatic estimates obtained from backstripped continental margin stratigraphy. Ice-volume estimates from calibrated oxygen isotope data compare favorably with stratigraphic and palynological data from Antarctica, and with estimates of atmospheric carbon dioxide for the early Oligocene through early Miocene (34-16 Ma). These isotopic data suggest that the East Antarctic Ice Sheet grew to as much as 30% greater than the present-day ice volume at glacial maxima. This conclusion is corroborated by seismic reflection and stratigraphic data from the …

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Constraints From Detrital Zircon Geochronology On The Early Deformation Of The Ross Orogen, Transantarctic Mountains, Antarctica, Edmund Stump, George Gehrels, Franco M. Talarico, Rodolfo Carosi Jan 2007

Constraints From Detrital Zircon Geochronology On The Early Deformation Of The Ross Orogen, Transantarctic Mountains, Antarctica, Edmund Stump, George Gehrels, Franco M. Talarico, Rodolfo Carosi

ANDRILL Related Publications of Affiliates

New ages of detrital zircons constrain the timing of the onset of deformation in the Ross orogen. In the Skelton Glacier area, Skelton Group was deformed before cross-cutting intrusion at 551 Ma. The youngest, significant, age-probability peaks from three samples of Skelton Group are 649 Ma, 684 Ma, and 691 Ma. The 649 Ma peak may be considered the maximum depositional age of Skelton Group, constraining the period of deformation to between 649 Ma and 551 Ma. In the upper Scott Glacier area, La Gorce Formation was deformed prior to cross-cutting intrusion at 526 Ma. The youngest, significant, age-probability peaks …

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Gold Bearing Veining Linked To Transcrustal Fault Zones In The Transantarctic Mountains (Northern Victoria Land, Antarctica), L. Crispini, G. Capponi, L. Federico, F. Talarico Jan 2007

Gold Bearing Veining Linked To Transcrustal Fault Zones In The Transantarctic Mountains (Northern Victoria Land, Antarctica), L. Crispini, G. Capponi, L. Federico, F. Talarico

ANDRILL Related Publications of Affiliates

Gold mineralization is associated with the paleo-Pacific margin of Gondwana and is related to processes of subduction/accretion and magmatism. Northern Victoria Land (Antarctica) was part of this margin during the Paleozoic, however no occurrence of gold has been reported up to now in the Transantarctic Mountains. Here we describe for the first time gold-bearing quartz veins in northern Victoria Land. The veins are hosted primarily by metabasalts and occur in a brittle-ductile high strain zone with curved geometry and reverse kinematic. Veins are extensional and shear veins; they often have ribbon/banded texture typical of crack and seal processes. Preliminary petrographic …

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Geology Of The Byrd Glacier Discontinuity (Ross Orogen): New Survey Data From The Britannia Range, Antarctica, R. Carosi, F. Giacomini, F. Talarico, Edmund Stump Jan 2007

Geology Of The Byrd Glacier Discontinuity (Ross Orogen): New Survey Data From The Britannia Range, Antarctica, R. Carosi, F. Giacomini, F. Talarico, Edmund Stump

ANDRILL Related Publications of Affiliates

Field activities in the Britannia Range (Transantarctic Mountains, Antarctica) highlighted new geological features around the so-called Byrd Glacier discontinuity. Recent field surveys revealed the occurrence of significant amounts of medium- to high-grade metamorphic rocks, intruded by abundant coarse-grained porphyritic granitoids. Most of the granitoids are deformed, with foliation parallel to the regional foliation in the metamorphics. Two main episodes of deformation are observed. Tight to isoclinal folds and penetrative axial plane foliation are related to the D1 phase, open folds to the D2. The main foliation (D1) trends nearly E-W in agreement with the trend in the southern portion of …

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Summary And Highlights Of The 10th International Symposium On Antarctic Earth Sciences, T. J. Wilson, R. E. Bell, P. Fitzgerald, S. B. Mukasa, R. D. Powell, C. Finn Jan 2007

Summary And Highlights Of The 10th International Symposium On Antarctic Earth Sciences, T. J. Wilson, R. E. Bell, P. Fitzgerald, S. B. Mukasa, R. D. Powell, C. Finn

ANDRILL Related Publications of Affiliates

The 10th International Symposium on Antarctic Earth Sciences (10th ISAES) was convened at the University of California, Santa Barbara, in August 2007. At the symposium about 350 researchers presented talks and posters with new results on major topics, including climate change, biotic evolution, magmatic processes, surface processes, tectonics, geodynamics, and the cryosphere. The symposium resulted in 335 papers and extended abstracts (Cooper et al., 2007, and this volume). Many science discoveries were presented spanning the last 2 billion years, from times when Antarctica was part of former supercontinents Rodinia and Gondwana to the present when Antarctica is an isolated, ice-covered …

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A High-Resolution Aeromagnetic Survey Over The Cape Roberts Rift Basin: Correlations With Seismic Reflection And Magnetic Susceptibility Log Data, E. Armadillo, F. Ferraccioli, M. Gambetta, F. Talarico, A. Zunino, M. Zangani, E. Bozzo Jan 2007

A High-Resolution Aeromagnetic Survey Over The Cape Roberts Rift Basin: Correlations With Seismic Reflection And Magnetic Susceptibility Log Data, E. Armadillo, F. Ferraccioli, M. Gambetta, F. Talarico, A. Zunino, M. Zangani, E. Bozzo

ANDRILL Related Publications of Affiliates

A high-resolution aeromagnetic survey (altitude 125 m asl, spacing 500 m , area 800 km2) was carried out in 1994 offshore of Cape Roberts by the GITARA (German ITalian Aeromagnetic Research in Antarctica) Group. The availability from drilling of whole-core physical properties logs for magnetic susceptibility, P-wave velocity and density/porosity data allows new insights to be inferred from reprocessed and reviewed HRAM aeromagnetic data. Aeromagnetic data have been reprocessed to image with greater detail the structural framework along the western flank of the Victoria Land Basin. New processing includes 2D Werner and 3D Euler deconvolution, the production of …

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Mcmurdo Ice Shelf Seismic Reflection Data And Correlation To The And-1b Drill Hole, D. Hansaraj, S. A. Henrys, T. R. Naish, Andrill Mis-Science Team Jan 2007

Mcmurdo Ice Shelf Seismic Reflection Data And Correlation To The And-1b Drill Hole, D. Hansaraj, S. A. Henrys, T. R. Naish, Andrill Mis-Science Team

ANDRILL Research and Publications

Surface seismic reflection data from the ANDRILL-MIS Project site surveys are integrated with a regionally extensive McMurdo Sound seismic stratigraphic framework. In addition, these seismic data are correlated to the AND-1B drill hole using vertical seismic profiles acquired during drilling operations (December/January 2006/7). Six regionally interpreted reflectors are identified in core as distinct lithostratigraphic boundaries.

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Late Pleistocene To Holocene Strata From Soft-Sediment Coring At The And-1b Site, Andrill Mcmurdo Ice Shelf Project, Antarctica, Gavin B. Dunbar, F. Niessen, S. Vogel, S. Tulaczyk, K. Mandernack, L. Krissek, L. Carter, E. A. Cowan, T. Wilch, C. Peng, C. P. Strong, R. Scherer, C. Sjunneskog, D. Winter, R. Mckay, F. Talarico, M. Pompilio, Andrill-Mis Science Team Jan 2007

Late Pleistocene To Holocene Strata From Soft-Sediment Coring At The And-1b Site, Andrill Mcmurdo Ice Shelf Project, Antarctica, Gavin B. Dunbar, F. Niessen, S. Vogel, S. Tulaczyk, K. Mandernack, L. Krissek, L. Carter, E. A. Cowan, T. Wilch, C. Peng, C. P. Strong, R. Scherer, C. Sjunneskog, D. Winter, R. Mckay, F. Talarico, M. Pompilio, Andrill-Mis Science Team

ANDRILL Research and Publications

Prior to rotary coring, a range of soft-sediment coring tools were deployed to recover the sediment-water interface and the upper few metres of strata, whose integrity was threatened by embedment of the sea riser for drilling of the ANDRILL (AND)-1A/1B holes. These coring options included (1) a sediment gravity corer deployed through the ice-shelf hole, and (2) a push corer deployed through the sea riser suspended a few metres above the seabed. Within the AND-1A hole (during an attempt at sea-riser embedment) an extended-nose corer was advanced in front of the sea riser with limited success. The hydraulic piston corer …

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Comprehensive Downhole And Core Physical-Property Measurements At The And-1b Drillsite, Andrill Mcmurdo Ice Shelf Project, F. Niessen, Roger H. Morin, Trevor Williams, Stuart A. Henrys, T. Crosby, Dhiresh Hansaraj, D. Magens, A. C. Gebhardt, Andrill-Mis Science Team Jan 2007

Comprehensive Downhole And Core Physical-Property Measurements At The And-1b Drillsite, Andrill Mcmurdo Ice Shelf Project, F. Niessen, Roger H. Morin, Trevor Williams, Stuart A. Henrys, T. Crosby, Dhiresh Hansaraj, D. Magens, A. C. Gebhardt, Andrill-Mis Science Team

ANDRILL Research and Publications

As part of the ANDRILL McMurdo Ice Shelf (MIS) Project two comprehensive sets of geophysical data were collected on ice at the AND-1B drillsite. Whole-core physical properties were determined with high vertical resolution to a depth of 1285 mbsf. A multi-sensor-core-logger was used to determine bulk density, sonic velocity, magnetic susceptibility and electrical resistivity. After drilling, a set of downhole measurements was collected, which consisted of caliper, temperature, fluid conductivity, induction resistivity, magnetic susceptibility, natural gamma activity, acoustic televiewer, borehole deviation, and dipmeter. In addition, three vertical seismic profiles (VSP) were obtained. Physical properties were used for initial core characterization …

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