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This paper summarizes fieldwork conducted in 2007 and presents results of petrographical analyses of basement rocks that occur along with fossil-rich Eocene sedimentary erratics in moraines along the north-east flank of Mount Discovery in southern McMurdo Sound. The Eocene rocks are significant as they provide a rare glimpse into greenhouse environments at high southern latitudes. Basement erratics recovered from the moraines are petrographically similar to metamorphic and igneous rocks exposed in the Transantarctic Mountains at locations between the Carlyon and Skelton glaciers and/or within the drainage catchments of Mulock and Skelton glaciers. These new clast provenance data imply that the Eocene sedimentary erratics are most likely derived from outcrops that are currently located beneath the Ross Ice Shelf south and/or immediately east of Minna Bluff. The suite of basement and sedimentary erratics were transported to their present location by ice that flowed north-eastwards from the Skelton-Mulock region and was pushed westwards into southern McMurdo Sound by grounded ice flowing north from West Antarctica. Results from this study support prior reconstructions of ice flow during peak glacial intervals during the Miocene-Pleistocene including the Last Glacial Maximum.

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A petrological investigation of amphibolebearing metamorphic clasts in the ANDRILL AND-2A core allows a detailed comparison with similar lithologies from potential source regions, leading to the identifi cation of three distinct provenance areas in the present-day segment of the Transantarctic Mountains between the Byrd Glacier and the Blue Glacier (Mulock-Skelton glacier area, the Britannia Range, and the Koettlitz-Blue glacier area in the Royal Society Range). A key role in the comparison is played by the wide range of Ca-amphibole compositions, type of intracrystalline zoning, mineral assemblages, and fabrics, which refl ect different bulk rocks and metamorphic conditions. Ca-amphibole compositions and zonations also offer the opportunity for the application of geothermobarometry methods, which, consistent with literature data, provide further evidence that the three provenance regions correspond to distinct metamorphic terrains with pervasive medium-pressure amphibolitegrade conditions restricted to the Britannia Range. The study contributes new insights into the depositional processes in a variety of glacial environments ranging from open marine with icebergs to distal, proximal, and subglacial settings. The results also highlight the record of two distinct glacial scenarios refl ecting either short-range (<100 km) fl uctuations of paleoglaciers in the Royal Society Range with dominant fl ows from W to E, or larger volume of ice sourced from southernmore outlet glaciers from the Skelton-Byrd glacier area with fl ow lines running N-S close to the Transantarctic Mountains front. Both scenarios demonstrate the importance of the AND-2A core to reveal a hitherto unavail-able, near-fi eld record of dynamic paleoenvironmental history through the Miocene. Amphibole-bearing metamorphic clasts in ANDRILL AND-2A coreGeosphere, August 2011 923