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Articles 1111 - 1140 of 1215

Full-Text Articles in Environmental Indicators and Impact Assessment

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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Using New Tools To Explore Undiscovered Country: Understanding The Stratigraphic And Tectonic History Of Greenhouse To Icehouse Worlds Of Offshore New Harbor, Ross Sea, Antarctica, Stephan Pekar, M. A. Speece, D. M. Harwood, F. Florindo, G. S. Wilson Jan 2007

Using New Tools To Explore Undiscovered Country: Understanding The Stratigraphic And Tectonic History Of Greenhouse To Icehouse Worlds Of Offshore New Harbor, Ross Sea, Antarctica, Stephan Pekar, M. A. Speece, D. M. Harwood, F. Florindo, G. S. Wilson

ANDRILL Research and Publications

The Offshore New Harbor Project will investigate the stratigraphic and tectonic history of westernmost Southern McMurdo Sound. This will be used to address two widely recognized but unresolved issues regarding Antarctica’s history: 1) the mid-Paleogene cryospheric development on Antarctica; and 2) the abrupt climate shift across the Eocene/Oligocene transition. The first step for this project is to collect the requisite seismic and gravity data for identifying future drilling targets for the ANDRILL Program. ANDRILL is a multinational program, with the aim to recover stratigraphic intervals for interpreting Antarctica’s climate and glacial history over the past 50 million years. Offshore New …

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Fracture Logging Of The And-1b Core, Mcmurdo Ice Shelf Project, Antarctica, Terry J. Wilson, T. Paulsen, A. L. Läufer, C. Millan Jan 2007

Fracture Logging Of The And-1b Core, Mcmurdo Ice Shelf Project, Antarctica, Terry J. Wilson, T. Paulsen, A. L. Läufer, C. Millan

ANDRILL Research and Publications

Over 4300 natural and induced fractures were logged in AND-1B drill core. Induced fractures include steeply dipping, petal, petal-centreline, and core-edge induced fractures (n=421) which reach a maximum density of 5 fractures/metre. Subhorizontal induced extension fractures are also abundant. Natural fractures (n=1485) occur in Miocene to Pleistocene age strata and include faults, brecciated zones, veins and sedimentary intrusions. Kinematic indicators document dominant normal faulting, although reverse faults are also present. Vein types include slickenfiber veins along faults, opening-mode fibrous veins, pressure shadows on clast margins, and complex microvein webs within fault zones.

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Enhancing The Detection And Classification Of Coral Reef And Associated Benthic Habitats: A Hyperspectral Remote Sensing Approach, Deepak R. Mishra, Sunil Narumalani, Donald Rundquist, Merlin P. Lawson, R. Perk Jan 2007

Enhancing The Detection And Classification Of Coral Reef And Associated Benthic Habitats: A Hyperspectral Remote Sensing Approach, Deepak R. Mishra, Sunil Narumalani, Donald Rundquist, Merlin P. Lawson, R. Perk

Center for Advanced Land Management Information Technologies: Publications

Coral reefs and associated benthic habitats are heterogeneous in nature. A remote sensor designed to discriminate these environments requires a high number of narrow, properly placed bands which are not currently available in existing satellite sensors. Optical hyperspectral sensors mounted on aerial platforms seem to be appropriate for overcoming the lack of both high spectral and spatial resolution of satellite sensors. This research presents results of an innovative coral reef application by such a sensor. Using hyperspectral Airborne Imaging Spectroradiometer for Applications (AISA) Eagle data, the approach presented solves the confounding influence of water column attenuation on substrate reflectance on …

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Palaeomagnetism Of The And-1b Core, Andrill Mcmurdo Ice Shelf Project, Antarctica, G. S. Wilson, F. Florindo, L. Sagnotti, C. Ohneiser, Andrill-Mis Sceince Team Jan 2007

Palaeomagnetism Of The And-1b Core, Andrill Mcmurdo Ice Shelf Project, Antarctica, G. S. Wilson, F. Florindo, L. Sagnotti, C. Ohneiser, Andrill-Mis Sceince Team

ANDRILL Research and Publications

Preliminary palaeomagnetic data are presented for the AND-1B drill core. A total of 1309 samples were collected from the drill core immediately following recovery and splitting. Natural remanent magnetisation (NRM) and bulk magnetic susceptibility data were determined for all samples using a Molspin spinner magnetometer and Bartington Instruments susceptibility bridge, respectively, immediately after collection. Polarity was determined for the upper 700 m of the drill core from 615 stepwise alternating field (AF) and thermally demagnetized samples with an average sample spacing of ~80 cm between 32 and 240 mbsf and ~2 m between 240 and 700 mbsf. Stepwise demagnetised samples …

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Clast Provenance And Variability In Mis (And-1b) Core And Their Implications For The Paleoclimatic Evolution Recorded In The Windless Bight - Southern Mcmurdo Sound Area (Antarctica), F. Talarico, Andrill-Mis Science Team Jan 2007

Clast Provenance And Variability In Mis (And-1b) Core And Their Implications For The Paleoclimatic Evolution Recorded In The Windless Bight - Southern Mcmurdo Sound Area (Antarctica), F. Talarico, Andrill-Mis Science Team

ANDRILL Research and Publications

Granule- to cobble-grade clasts in the uppermost 575 m of the MIS drill-core (AND-1B) highlight significant downcore modal and compositional variations, which provide direct information about the potential source regions and evidence of an evolving provenance, most likely as results of variable ice conditions and ice-flow directions during the deposition of recovered diamictites. In addition to a significant contribution from the McMurdo Volcanic Group, the dataset indicates a compositionally varied clast assemblage including several basement rock types which are comparable to the main geological units exposed in the area SW of the drillsite, between the Skelton and Byrd Glaciers. Based …

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The Volcanic Record In The Andrill Mcmurdo Ice Shelf And-1b Drill Core, M. Pompilio, P. Kyle, T. Wilch, N. Dunbar, Andrill-Mis Project Science Team Jan 2007

The Volcanic Record In The Andrill Mcmurdo Ice Shelf And-1b Drill Core, M. Pompilio, P. Kyle, T. Wilch, N. Dunbar, Andrill-Mis Project Science Team

ANDRILL Research and Publications

The 1285 m thick MIS core offers an invaluable opportunity to obtain a detailed record of volcanism in McMurdo Sound. Volcanic stratigraphy and preliminary petrologic data on volcanic rocks in the AND-1B core are reported here. Remarkable volcanic deposits include: a) a phonolitic pumice layer found at ≈85 mbsf which is not correlated to any known vent onshore; b) a black well sorted volcanic sands succession (132.83 to 146.79 mbsf) interpreted as being derived mainly from subaerial Hawaiian/Strombolian eruptions; c) a thick volcanic succession in the middle part of the core with an interbedded submarine lava flow. The flow may …

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Future Antarctic Geological Drilling: Discussion Paper On Andrill And Beyond, P. J. Barrett, P.-N. Webb, D. Futterer, C. Ghezzo, M. R. A. Thomson, A. R. Pyne, F. R. Rack Jan 2007

Future Antarctic Geological Drilling: Discussion Paper On Andrill And Beyond, P. J. Barrett, P.-N. Webb, D. Futterer, C. Ghezzo, M. R. A. Thomson, A. R. Pyne, F. R. Rack

ANDRILL Research and Publications

Geological drilling technology developed over the last quarter century has provided access to critical knowledge on the climatic and tectonic history of the Victoria Land margin of Antarctica, giving us a new understanding of the history and behaviour of the Antarctic ice sheet in this region over the last 34 million years. The challenge now is to develop a framework within the Antarctic science and logistics communities and other relevant groups for further projects to extend this technology to other areas both around the Antarctic margin and into the interior. This paper reviews some of the issues and offers a …

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Operations Overview For The Andrill Mcmurdo Ice Shelf Project, Antarctica, T. Falconer, A. Pyne, M. Olney, M. Curren, Andrill-Mis Science Team Jan 2007

Operations Overview For The Andrill Mcmurdo Ice Shelf Project, Antarctica, T. Falconer, A. Pyne, M. Olney, M. Curren, Andrill-Mis Science Team

ANDRILL Research and Publications

During the austral summer of 2006, a record-setting 1 284.87 metre (m)-long rock and sediment core (ANDRILL [AND]-1B) was recovered from beneath the McMurdo Ice Shelf (MIS) in 917m of water. A custom built drilling system comprising a UDR-1200 rig, jack-up platform, hot water drill, sea riser, and diamond-bit wireline coring string was set up on the McMurdo Ice Shelf approximately 9 kilometres (km) from Scott Base (NZ). The drilling sytem employed technology developed to handle challenging environmental conditions including an 85 m-thick ice shelf ‘platform’ that moved both laterally and vertically, strong tidal currents, and high winds. Drill site …

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Geochemical Variations Detected With Continuous Xrf Measurements On Andrill And-1b Core - Preliminary Results, D. Helling, G. Kuhn, Andrill-Mis Science Team Jan 2007

Geochemical Variations Detected With Continuous Xrf Measurements On Andrill And-1b Core - Preliminary Results, D. Helling, G. Kuhn, Andrill-Mis Science Team

ANDRILL Research and Publications

Antarctica and especially its ice sheets play a major role in both the global ocean current system and climate. The ANDRILL (Antarctic Geological Drilling) MIS deep drilling project (McMurdo Sound, NE Ross Ice Shelf, drilled core AND-1B during austral summer 2006/2007) is located in a flexural moat basin filled with glaciomarine, terrigenous, volcanic, and biogenic sediments (Horgan et al., 2005). This basin contains a well-preserved outstanding record of paleoclimate history. During the drilling phase, some major and minor chemical elements were measured directly using a non-destructive X-Ray Fluorescence Core Scanner (XRF-CS) method. For the first time, sediments beneath an ice …

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Sedimentology And Stratigraphy Of The Andrill Mcmurdo Ice Shelf (And-1b) Core, L. A. Krissek, G. Browne, L. Carter, E. A. Cowan, G. Dunbar, R. Mckay, T. Naish, R. D. Powell, J. Reed, T. Wilch, Andrill-Mis Science Team Jan 2007

Sedimentology And Stratigraphy Of The Andrill Mcmurdo Ice Shelf (And-1b) Core, L. A. Krissek, G. Browne, L. Carter, E. A. Cowan, G. Dunbar, R. Mckay, T. Naish, R. D. Powell, J. Reed, T. Wilch, Andrill-Mis Science Team

ANDRILL Research and Publications

During the 2006-2007 austral summer, the ANDRILL McMurdo Ice Shelf Project recovered a core 1285 m long (AND-1B) from Windless Bight in McMurdo Sound. This core contains a range of lithologies, including both siliciclastic and volcanic diamictites, sandstones and mudstones; diatomites; and volcanic ash/tuff and one phonolitic lava flow. This sequence has been subdivided into eight lithostratigraphic units and 25 subunits, based on lithological abundances. Eleven lithofacies have been identified, ranging from open marine diatomites and mudstones to turbidites to ice-proximal massive and stratified diamictites. More than 50 glacimarine sequences have been recognized, bounded by glacial surfaces of erosion. Three …

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Determination Of And Preliminary Results From The High-Resolution Physical Properties Record Of The And-1b Sediment Core From Beneath Ross Ice Shelf, Antarctica, D. Magens, F. Niessen Jan 2007

Determination Of And Preliminary Results From The High-Resolution Physical Properties Record Of The And-1b Sediment Core From Beneath Ross Ice Shelf, Antarctica, D. Magens, F. Niessen

ANDRILL Research and Publications

A more than 1200 m long sediment core was drilled beneath McMurdo Ice Shelf near Ross Island (Antarctica) in austral summer 2006/07 (ANDRILL-MIS Project). High-resolution whole-core physical properties were determined as one set of parameters to describe changes in the depositional system over the sedimentation period of about 12 myrs incorporated in the core. Four parameters were measured using a multi-sensor core logger: acoustic velocity, wet-bulk density, non-contact electrical resistivity and magnetic susceptibility. Data quality was routinely controlled by measurement of standards. Deviations from the reference values are minimal with regard to the whole spectrum of sediment data points and …

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Sedimentology And Stratigraphy Of The And-1b Core, Andrill Mcmurdo Ice Shelf Project, Antarctica, L. Krissek, G. Browne, L. Carter, E. A. Cowan, G. Dunbar, R. Mckay, T. Naish, R. D. Powell, J. Reed, T. Wilch, Andrill-Mis Science Team Jan 2007

Sedimentology And Stratigraphy Of The And-1b Core, Andrill Mcmurdo Ice Shelf Project, Antarctica, L. Krissek, G. Browne, L. Carter, E. A. Cowan, G. Dunbar, R. Mckay, T. Naish, R. D. Powell, J. Reed, T. Wilch, Andrill-Mis Science Team

ANDRILL Research and Publications

During the 2006–2007 austral season, the ANDRILL McMurdo Ice Shelf Project recovered a core 1285 m-long (AND-1B) from Windless Bight in the McMurdo Sound region. This core contains a range of lithologies, including both siliciclastic and volcanic diamictites, sandstones and mudstones; diatomites; and volcanic ash/tuff and one phonolitic lava flow. The succession has been subdivided into eight lithostratigraphic units and 25 subunits, based on lithological abundances. Eleven lithofacies have been recognized, ranging from open marine diatomites and mudstones to turbidites to ice-proximal massive and stratified diamictites. More than 60 glacimarine sequences have been recognised, bounded by glacial surfaces of erosion. …

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Downhole Measurements In The And-1b Borehole, Andrill Mcmurdo Ice Shelf Project, Antarctica, Roger H. Morin, T. Williams, S. Henrys, T. Crosby, D. Hansaraj, Andrill- Mis Science Team Jan 2007

Downhole Measurements In The And-1b Borehole, Andrill Mcmurdo Ice Shelf Project, Antarctica, Roger H. Morin, T. Williams, S. Henrys, T. Crosby, D. Hansaraj, Andrill- Mis Science Team

ANDRILL Research and Publications

A comprehensive set of downhole measurements was collected in the AND-1B drillhole as part of the on-ice scientific programme defined for the McMurdo Ice Shelf (MIS) Project. Geophysical logs were recorded over two operation phases and consisted of calliper, temperature, fluid conductivity, induction resistivity, magnetic susceptibility, natural gamma activity, acoustic televiewer, borehole deviation, and dipmeter. In addition, two standard vertical seismic profiles (VSP) and one walk-away VSP were obtained. Radioactive logs (porosity and density) were not run because of unstable borehole conditions. Although the total depth of the hole is 1285 metres below seafloor (mbsf), the depth range for in …

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A Record Of Antarctic Climate And Ice Sheet History Recovered, T. R. Naish, R. D. Powell, R. H. Levy, F. Florindo, D. M. Harwood, G. Kuhn, F. Niessen, F. Talarico, G. S. Wilson Jan 2007

A Record Of Antarctic Climate And Ice Sheet History Recovered, T. R. Naish, R. D. Powell, R. H. Levy, F. Florindo, D. M. Harwood, G. Kuhn, F. Niessen, F. Talarico, G. S. Wilson

ANDRILL Research and Publications

Antarctica’s late Cenozoic (the past ~15 million years) climate history is poorly known from direct evidence, owing to its remoteness, an extensive sea ice apron, and an ice sheet cover over the region for the past 34 million years. Consequently, knowledge about the role of Antarctica’s ice sheets in global sea level and climate has relied heavily upon interpretations of oxygen isotope records from deep-sea cores. Whereas these isotopic records have revolutionized our understanding of climate-ice-ocean interactions, questions still remain about the specific role of Antarctic ice sheets in global climate. Such questions can be addressed from geological records at …

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Examining Antarctica: A Geological Record Of The Last 14 Million Years Of Antarctic Climate And Tectonic History From Andrill Mcmurdo Ice Shelf Project, T. R. Naish, R. D. Powell, R. H. Levy, Andrill-Mis Science Team Jan 2007

Examining Antarctica: A Geological Record Of The Last 14 Million Years Of Antarctic Climate And Tectonic History From Andrill Mcmurdo Ice Shelf Project, T. R. Naish, R. D. Powell, R. H. Levy, Andrill-Mis Science Team

ANDRILL Research and Publications

During the Southern Hemisphere's last summer, between October 29 and December 26, about 80 researchers, drillers, educators and support staff from four nations met in Antarctica to drill deeper than ever before into the Antarctic continental margin. With a recovery of 98 percent, the new core represents the longest and most complete geological record from the seafloor just off Antarctica. Researchers working on the project hope the core will help them understand Antarctica's storied past.

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Background To The Andrill Mcmurdo Ice Shelf Project (Antarctica) And Initial Science Volume, T. R. Naish, R. D. Powell, R. H. Levy, Andrill-Mis Science Team Jan 2007

Background To The Andrill Mcmurdo Ice Shelf Project (Antarctica) And Initial Science Volume, T. R. Naish, R. D. Powell, R. H. Levy, Andrill-Mis Science Team

ANDRILL Research and Publications

The aim of the McMurdo Ice Shelf (MIS) Project was to obtain a continuous sediment core through approximately ~1 200 metres (m) of Neogene (~0-10 Ma) glacimarine, terrigenous, volcanic, and biogenic sediment that has accumulated in the Windless Bight region of the McMurdo Ice Shelf (Fig. 1). The present-day MIS forms the northwest part of Ross Ice Shelf where it has been pinned by Ross Island for the last ~10 k.y., and is nourished by ice sourced from East Antarctic Ice Sheet (EAIS) outlet glaciers in the southern Transantarctic Mountains (TAM). The drill site was situated above a flexural moat …

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Synthesis Of The Initial Scientifi C Results Of The Mis Project (And-1b Core), Victoria Land Basin, Antarctica, T. R. Naish, R. D. Powell, R. H. Levy, S. Henrys, L. Krissek, F. Niessen, M. Pompilio, R. Scherer, G. S. Wilson Jan 2007

Synthesis Of The Initial Scientifi C Results Of The Mis Project (And-1b Core), Victoria Land Basin, Antarctica, T. R. Naish, R. D. Powell, R. H. Levy, S. Henrys, L. Krissek, F. Niessen, M. Pompilio, R. Scherer, G. S. Wilson

ANDRILL Research and Publications

The ANDRILL Program successfully recovered a 1285 m-long succession of cyclic glacimarine sediment with interbedded volcanic deposits in its first season of drilling from the McMurdo Ice Shelf (MIS). The MIS AND-1B drill core represents the longest and most complete (98% recovery) geological record from the Antarctic continental margin to date, and will provide a key reference record of climate and ice-sheet variability through the Late Cenozoic. Here we present a synopsis of this Initial Science Report with emphasis on the potential of the record for improving our knowledge of Antarctica’s influence on global climate.

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Physical Properties Of The And-1b Core, Andrill Mcmurdo Ice Shelf Project, Antarctica, F. Niessen, D. Magens, A. C. Gebhardt Jan 2007

Physical Properties Of The And-1b Core, Andrill Mcmurdo Ice Shelf Project, Antarctica, F. Niessen, D. Magens, A. C. Gebhardt

ANDRILL Research and Publications

Whole-core physical properties of the AND-1B sediment core were determined on site for initial core characterisation and correlation with seismic modelling to predict target-reflector depth. This was accomplished by the application of a GEOTEK MSCL (multisensor core logger) from which detected parameters were converted to wet bulk density (WBD), P-wave velocity (Vp), and magnetic susceptibility (MS). Due to difficulties in terms of sensor drift, non-contact resistivity (NCR) data were not processed on site. Standards were logged together with the cores throughout the entire depth range to monitor data quality and demonstrate that no systematic offsets occurred between different core diameters …

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Petrology And Geochemistry Of The And-1b Core, Andrill Mcmurdo Ice Shelf Project, Antarctica, M. Pompilio, N. Dunbar, A. C. Gebhardt, D. Helling, G. Kuhn, P. Kyle, R. Mckay, F. Talarico, S. Tulaczyk, S. Vogel, T. Wilch, Andrill-Mis Science Team Jan 2007

Petrology And Geochemistry Of The And-1b Core, Andrill Mcmurdo Ice Shelf Project, Antarctica, M. Pompilio, N. Dunbar, A. C. Gebhardt, D. Helling, G. Kuhn, P. Kyle, R. Mckay, F. Talarico, S. Tulaczyk, S. Vogel, T. Wilch, Andrill-Mis Science Team

ANDRILL Research and Publications

This section reports preliminary data and results on petrology and geochemistry of AND-1B core.

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