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Showing 1 to 20 of 24 for “"West Antarctica"”.
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Airborne geophysical investigations of subglacial structure of West Antarctica
… on geology, structure and tectonic evolution of West Antarctica. An airborne geophysical survey in West Antarctica comprising simultaneous Radio Echo Sounding (RES) and magnetics was carried out over -1 M km$^{2}$ of the ice covered area. The collection and reduction of large volumes of RES and …
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Sea-ice and ice-shelf variability in the Amundsen Sea Embayment, West Antarctica
… dominated by the Amundsen Sea Embayment (ASE) in West Antarctica. Ice shelves in the ASE influence the ice-mass-loss rates of the Antarctic Ice Sheet through their ability to buttress the grounded ice and modulate ice-flow speed. Ice shelves reduce ice flow and retreat by buttressing grounded ice. …
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New ice core records from West Antarctica and their spatial context: from 1000 to 100,000 years
The West Antarctic Ice Sheet (WAIS) is vulnerable to warming as a result of anthropogenic climate change, with the potential to contribute several metres to global sea level rise over the coming centuries. The Thwaites and Pine Island glaciers are already undergoing acceleration due to climate …
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Implementing a new method to measure δ³⁴SSO₄ in ice cores to assess sulfate sources in West Antarctica
Sulfate sources in Antarctica can reveal information about the interconnection of climate systems and past climate events. The major sulfate sources in Antarctica are sea salt, biogenic activity, and volcanic activity, though volcanic events have a limited ~1–2 year deposition period. Each source …
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Radio-echo sounding of Pine Island Glacier, West Antarctica : understanding the past from observations, analysis and modelling of internal layering
… one of the fastest and most dynamic glaciers in West Antarctica. The stability of the glacier may thus have profound impact on the overall stability of the West Antarctic Ice Sheet and its contribution to global sea-level rise. This thesis addresses questions concerning the past dynamics of the …
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GEOPHYSICAL INVESTIGATION OF GLACIER GEOMETRY AND SUBGLACIAL GEOLOGY, AND THEIR INFLUENCE ON GLACIER DYNAMICS: CASE STUDIES OF TAKU GLACIER, ALASKA AND THWAITES GLACIER, WEST ANTARCTICA
… Taku Glacier in Alaska and Thwaites Glacier in West Antarctica, and improve on observations of their subglacial environments that are currently poorly constrained. We employ a multi-modal geophysical technique, utilizing a combination of seismic and gravity- and magnetic-anomaly data. Taku …
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Surface Wave Derived Shear Velocity Structure of the Gamburtsev Subglacial Mountains, Transantarctic Mountains, and West Antarctica and Shallow Seismicity of the Mariana and Tonga Subduction Zones
… is particularly important in regions such as Antarctica and the ocean bottom where more traditional tools such as geologic mapping and sampling are difficult, if not currently impossible. This volume utilizes information garnered from several temporary deployments to such locations. In chapter …
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Amundsen Sea sea-ice variability, atmospheric circulation, and spatial variations in snow isotopic composition from new West Antarctic firn cores
… work has documented dramatic changes in the West Antarctic Ice Sheet (WAIS) over the past 30 years (e.g., mass loss, glacier acceleration, surface warming) due largely to the influence of the marine environment. WAIS is particularly vulnerable to largescale atmospheric dynamics that remotely …
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Amundsen Sea sea-ice variability, atmospheric circulation, and spatial variations in snow isotopic composition from new West Antarctic firn cores
… work has documented dramatic changes in the West Antarctic Ice Sheet (WAIS) over the past 30 years (e.g., mass loss, glacier acceleration, surface warming) due largely to the influence of the marine environment. WAIS is particularly vulnerable to large-scale atmospheric dynamics that remotely …
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Studies of Seismic Sources in Antarctica Using an Extensive Deployment of Broadband Seismographs
… comprehensive study reporting the seismicity of Antarctica utilizing year-round recordings from autonomous instruments installed on the continent itself. I first examine the general seismic nature of the continent using locally deployed seismographs in both East Antarctica and West Antarctica. I …
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ANTARCTIC GLACIAL CHRONOLOGY REFLECTED IN THE OLIGOCENE THROUGH PLIOCENE SEDIMENTARY SECTION IN THE ROSS SEA
… 24% of the ice surface area covering East and West Antarctica drains into the Ross Sea and supplies the Ross Ice Shelf. The dominant proportion of this ice originates from the West Antarctic subcontinent. Thus, any change in the glacial regime in West Antarctica, and to a lesser extent East …
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Diatoms in Antarctic ice cores, a novel proxy for reconstructing past wind variability in the Pacific sector of the Southern Hemisphere Westerly Wind belt
The Southern Hemisphere Westerly Winds play a critical role in the global climate system by modulating the upwelling and the transfer of heat and carbon between the atmosphere and the ocean. Since observations started, the core of the westerly wind belt has increased in strength and has contracted …
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Surface Wave Inversion of the Upper Mantle Velocity Structure in the Ross Sea Region, Western Antarctica
<p>The Ross Sea in Western Antarctica is the locale of several extensional basins formed during Cretaceous to Paleogene rifting. Several seismic studies along the Transantarctic Mountains and Victoria Land Basin’s Terror Rift have shown a general pattern of fast seismic velocities in East …
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RECONSTRUCTING PAST ANTARCTIC ICE FLOW PATHS IN THE ROSS EMBAYMENT, ANTARCTICA USING SAND PETROGRAPHY, PARTICLE SIZE AND DETRITAL ZIRCON PROVENANCE
… for this study were analyzed from sites in East Antarctica (EA), West Antarctica (WA) and along a transect in the Ross Sea. Particle size, sand petrography, and detrital zircons were used to provide new information on the subglacial geology of Antarctica, as well as assisting in the …
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Monitoring the Antarctic Ice Sheet From Space
… much of the Antarctic continent, especially in West Antarctica and along much of the coasts. Less drastic changes, including regular seasonal variations, are observed over much of the ice shelf. Possible scattering mechanisms are proposed and discussed. A secondary result is the demonstration of …
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The tectonic evolution of Antarctica
… attempt to illustrate the tectonic evolution of Antarctica. Evidence is presented for at least three structural stages in the development of the Precambrian shield, though it is not as yet possible to delineate individual tectonic provinces within the shield area. From the late Proterozoic until …
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Detrital Zircon Analysis of Permian Victoria Group Sandstones, Transantarctic Mountains, Antarctica
… Mountains, the Gondwana sequence of Antarctica, comprises Devonian (inferred) and Permian-Triassic strata. The latter were deposited in an intracratonic basin which evolved into a foreland basin in mid Permian time. Sedimentary petrology and paleocurrent data indicate that this basin …
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The influence of subglacial hydrology on the flow of West Antarctic ice streams
… of subglacial hydrology on the flow of the West Antarctic ice streams. This is achieved through development of a numerical flowline model, the Hydrology, Ice and Till (HIT) model. Ice thermodynamics are coupled to a till layer of Coulomb plastic rheology. The porosity of the till changes …
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Antarctic Station-based Pressure Reconstructions from 1905-2011 using Principal Component Regression
<p>In Antarctica, most weather stations did not start collecting meteorological observations until the late 1950s. To extend these records and provide a more complete picture of the pressure variability at each station, this thesis reconstructs the pressure records at 18 different Antarctic …
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