| Summary: | Much debate surrounds the history of Pliocene marine diatoms emplaced in the Sirius Group, a diamictite found at the peaks of the Transantarctic Mountains, Antarctica. Hypotheses as to their origin include a retreat of the East Antarctic ice sheet 2-3 million years ago and flooding of interior continental basins to deposit the diatoms, eolian transport of diatoms from marine and terrestrial sources across a stable East Antarctic ice sheet from at least 8-11 million years ago, and an impact event large enough to cause displacement and rainfall of marine debris ca. 2 million years ago. I present chemical analyses of samples of the Cenozoic (specific age unknown) Sirius Group collected from Mt. Sirius in the Transantarctic Mountains, Antarctica, in search of impact glass potentially created from a large impact event. Weight percent oxide totals range from 102% - 60%. From the usable chemical analyses of 122 points across 76 grains, I identified the following: calcite or aragonite (38.5%), pyroxene (36.1%), plagioclase (18.0%), quartz (5.7%) and apatite (1.6%). The pyroxene grains are chiefly augite and ferroaugite. The plagioclase is mostly Ca-rich (bytownite and labradorite). The remaining analyses not identified could be impact glass, crystallinity could not be determined.
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