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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 …

Interglacial Expansion Of Alpine Glaciers In Garwood Valley, Antarctica, Laura Mattas

Honors College

It is important to understand the response of the Antarctic Ice Sheet (AIS) to ongoing global atmospheric and oceanic warming to anticipate future sea-level change. There are several contrasting views in this regard. Harig and Simons (2015) concur with the IPCC (2013) conclusion that, in recent decades, outflow across the peripheral grounding lines of the ice sheet has exceeded increased accumulation on the interior surface of the ice sheet. In contrast, Zwally et al. (2015) suggest that recent surface accumulation in the interior East and West Antarctica has outpaced peripheral losses. They further suggest that this recent positive imbalance adds …

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 …

Antarctic Climate Change And The Environment, Peter Convey, R. Bindschadler, G. Di Prisco, E. Fahrbach, J. Gutt, D. A. Hodgson, Paul Andrew Mayewski, C. P. Summerhayes, J. Turner, Acce Consortium

Earth Science Faculty Scholarship

The Antarctic climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system. We review these variations from the perspective of the geological and glaciological records and the recent historical period from which we have instrumental data (similar to the last 50 years). We consider their consequences for the biosphere, and show how the latest numerical models project changes into the future, taking into account human actions in the form of the release of greenhouse gases and chlorofluorocarbons into the atmosphere. In doing so, we provide an essential …

Chevkinite-Group Minerals From Granulite-Facies Metamorphic Rocks And Associated Pegmatites Of East Antarctica And South India, H. E. Belkin, R. Macdonald, Edward S. Grew

Earth Science Faculty Scholarship

Electron microprobe data are presented for chevkinite-group minerals from granulite-facies rocks and associated pegmatities of the Napier Complex and Mawson Station charnockite in East Antarctica and from the Eastern Ghats, South India. Their compositions conform to the general formula for this group, viz. A(4)BC(2)D(2)Si(4)O(22) where, in the analysed specimens A = (rare-earth elements (REE), Ca, Y, Th), B = Fe(2+) Mg, C = (Al, Mg, Ti, Fe(2+), Fe(3+), Zr) and D = Ti and plot within the perrierite field oftlic total Fe (as FeO) (wt.%) vs. CaO (wt.%) discriminator diagram of Macdonald and Belkin (2002). In contrast to most chevkinite-group …

Variations In Ice Rafted Detritus On Beaches In The South Shetland Islands: A Possible Climate Proxy, Brenda L. Hall, Ethan R. Perry

Earth Science Faculty Scholarship

Raised beach ridges on Livingston Island of the South Shetland Islands display variations in both quantity and source of ice rafted detritus (IRD) received over time. Whereas the modem beach exhibits little IRD, all of which is of local origin, the next highest beach (similar to250 C-14 yr BP) has large amounts, some of which comes from as far away as the Antarctic Peninsula. Significant quantities of IRD also were deposited similar to 1750 C-14 yr BP. Both time periods coincide with generally cooler regional conditions and, at least in the case of the similar to250 yr old beach, local …

Distribution Of Patterned Ground And Surficial Deposits On A Debris-Covered Glacier Surface In Mullins Valley And Upper Beacon Valley, Antarctica, Andrew M. Lorrey

Electronic Theses and Dissertations

Beacon Valley is located in the western Dry Valleys, Antarctica, adjacent to the East Antarctic Ice Sheet (EAIS). The surficial material on the floor of Beacon Valley is segmented into large polygonal landforms separated by trenches. Buried beneath the polygons and surficial material is massive ground ice. One hypothesis is that the buried ice in upper Beacon Valley is glacier ice originating from local debris-covered glaciers. The networks of polygons and trenches form as the buried ice undergoes thermal contraction and sublimation. Contraction cracks that penetrate the surficial material and buried ice in Beacon Valley contain Late Miocene age volcanic …

Glacial Lake Wright, A High-Level Antarctic Lake During The Lgm And Early Holocene, Brenda L. Hall, George H. Denton, B. Overturf

Earth Science Faculty Scholarship

We report evidence of a large proglacial lake (Glacial Lake Wright) that existed in Wright Valley in the McMurdo Dry Valleys region of Antarctica at the last glacial maximum (LGM) and in the early Holocene. At its highstands, Glacial Lake Wright would have stretched 50 km and covered c. 210 km(2). Chronology for lake-level changes comes from 30 AMS radiocarbon dates of lacustrine algae preserved in deltas, shorelines, and glaciolacustrine deposits that extend up to 480 m above present-day lakes. Emerging evidence suggests that Glacial Lake Wright was only one of a series of large lakes to occupy the McMurdo …

Antarctic Glacial History Since The Last Glacial Maximum: An Overview Of The Record On Land, Ólafur Ingólfsson, Christian Hjort, Paul A. Berkman, Svante Björck, Eric Colhoun, Ian D. Goodwin, Brenda Hall, Kazuomi Hirakawa, Martin Melles, Per Möller, Michael L. Prentice

Earth Science Faculty Scholarship

This overview examines available circum-Antarctic glacial history archives on land, related to developments after the Last Glacial Maximum (LGM). It considers the glacial-stratigraphic and morphologic records and also biostratigraphical information from moss banks, lake sediments and penguin rookeries, with some reference to relevant glacial marine records. It is concluded that Holocene environmental development in Antarctica differed from that in the Northern Hemisphere. The initial deglaciation of the shelf areas surrounding Antarctica took place before 10000 C-14 yrs before present(sp), and was controlled by rising global sea level. This was followed by the deglaciation of some presently ice-free inner shelf and …