Physical Sciences and Mathematics Commons^™

Glaciochemical Investigations In Three Southern Hemisphere Mountain Sites, Mariusz Potocki

Electronic Theses and Dissertations

The research presented in this dissertation focuses on glaciochemical records of trace elements, major ions, and stable water isotopes from three mountain regions: the Antarctic Peninsula, the Central Chilean Andes, and South Georgia Island.

The first section reports a significant increase in U concentration over 27 years on Detroit Plateau, Antarctic Peninsula. U concentrations in the ice core increase by as much as 102 between the 1980s and 2000s, accompanied by increased variability in recent years. The U concentration increase coincides with expanded open pit mining in the Southern Hemisphere, most notably Australia. Since other land-source dust elements do not …

Miocene-Pleistocene Diatom Oxygen Isotope And Biogenic Silica Record From Iodp Site U1523, Ross Sea, Antarctica, Donald James Mclennan

Graduate Research Theses & Dissertations

The West Antarctic Ice Sheet (WAIS) plays a significant role in Earth’s climate. WAIS is currently retreating due to changes in wind-driven oceanic currents resulting in an increasing flux of warm waters to ice margins. Brine rejection in the Ross Sea is also major source of High Salinity Shelf water (HSSW) and Antarctica Bottom Waters (AABW), which creates a stratified ocean and plays a significant role in regulating Earth’s climate. Currently, there are very limited proxies that can quantify the variable input of HSSW formation on geologic time scales. Here we provide a 18Odiatom and biogenic silica (BSi) record which …

Model-Based Estimates Of The Timing Of Brine Flux Into The Victoria Land Basin From The Mcmurdo Dry Valleys, Antarctica, Valerie Nicole Voisin

Graduate Research Theses & Dissertations

Submarine groundwater discharge (SGD) at a continental scale is one of the least constrained components of the hydrologic cycle and may represent a significant flux of iron and silica waters to the global ocean. Quantifying SGD along the Antarctic margin is complicated by complex subglacial and subsurface hydrogeology and limited observational data. Airborne transient electromagnetic (AEM) surveys have identified extensive high-salinity subsurface brines in the McMurdo Dry Valleys (MDV) that are hydrologically connected to surface features in the MDV (e.g. Taylor Glacier, saline lakes) and are potentially a significant source of SGD to McMurdo Sound. A 2D numerical model was …

A Glacial History Of Roberts Massif, Central Transantarctic Mountains, Antarctica, Using Cosmogenic 3he, 10be, And 21ne Surface Exposure Ages, Alexandra M. Balter

Electronic Theses and Dissertations

Ice-free areas at high elevation in the central Transantarctic Mountains preserve moraines and drift deposits that delineate the former thickness and extent of the East Antarctic Ice Sheet (EAIS); cosmogenic exposure ages on these features indicate when the ice sheet was as or more extensive than today. Approximately 30 existing cosmogenic-nuclide exposure ages from scattered locations within these deposits suggest that some moraines and drift sheets are at least 5 Ma old. Those ages imply that the age range of these deposits may span warm periods during the Miocene and Pliocene, during which the EAIS is hypothesized to have been …

Ocean Forcing Of Quaternary East Antarctic Ice Sheet Evolution: An Ice-Proximal Sedimentary Perspective, Michelle E. Guitard

USF Tampa Graduate Theses and Dissertations

Antarctica and the Southern Ocean play a critical role in Earth’s climate system. Antarctica’s ice sheets contain enough ice to raise global sea level by ~58 m, and the Southern Ocean distributes climate signals and nutrients to the major ocean basins and the deep ocean. Antarctica’s largest ice sheet, the East Antarctic Ice Sheet (EAIS), was considered stable compared to those in West Antarctica and the Antarctic Peninsula because it was thought to be grounded above sea level. However, subglacial topography now reveals vast submarine basins and measurements of ice velocity in the Pacific sector indicate marine-terminating outlet glacier thinning …

Evolution With Depth From Detrital To Authigenic Smectites In Sediments From And-2a Drill Core (Mcmurdo Sound, Antarctica), Francesco Iacoviello, Giovanna Giorgetti, Fernando Nieto, Isabella Turbanti Memmi

ANDRILL Research and Publications

We have examined the nature and origin of smectites in glaciomarine sediments of the AND-2A drill core (McMurdo Sound, Antarctica) by means of X-ray diffraction (XRD) analyses on the clay fraction, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM) observations and SEM-EDS microanalyses on smectite particles. Relying on the smectite variation throughout the drill core it was possible to split the sequence into three units. Smectites throughout the core are either detrital or authigenic. Detrital smectites are close to montmorillonite-beidellite in composition while newly-formed smectites frequently have higher Fe-Mg contents and intermediate compositions between the saponite and nontronite …

Policy And Science Of Geothermal Heat Use At Mcmurdo Station, Antarcrtica, Joe Alvine

Department of Environmental Studies: Undergraduate Student Theses

My thesis research project deals with the use of geothermal heat in Antarctica. Currently it is not allowed due to article 7 of the 1991 Protocol on Environmental Protection that placed a 50 moratorium on the exploitation of mineral resources. The US main base in Antarctica, McMurdo Station is currently powered by diesel generators that are inefficient, cause environmental damage, and is expensive to run. By exploring alternative energy options, McMurdo Station can reduce its dependence on non-renewable energy sources. By determining the geothermal potential of McMurdo Station, this project explores the possibilities and benefits that would occur with the …