We present the first quantitative attempt at reconciling the source and emplacement of granite erratics in Beacon Valley. The erratics are enigmatic because granite does not crop out in the valley and its nearest subaerial exposure is at least 10 km downstream to the east of the valley. Detailed mapping of the valley shows three types of granite erratics, which are not present in equal amounts and do not show spatial patterns. Pb isotopic and elemental compositions of the erratics eliminate the Metschel Tillite as a source and indicate they derive from the Dry Valley plutons. Our limited study tentatively ties the erratics to suites of plutons, but it does not allow a direct tie of the erratics to specific plutons because of i) the geochemical variability of the plutons and ii) the limited number of erratics that were analysed. Published data suggest the erratics provide evidence of wet-based glaciation, which covered the Dry Valleys and much of Antarctica during the mid-Miocene. Our paper also explains the problems associated with the emplacement of these erratics and the age of the massive ice in Beacon Valley.

Ice exposed in ablation zones of ice sheets can be a valuable source of samples for paleoclimate studies and information about long-term ice dynamics. We report a 28-km long stable isotope sampling transect along a flowline on lower Taylor Glacier, Antarctica, and show that ice from the last glacial period is exposed here over tens of kilometers. Gas isotope analyses on a small number of samples confirm our age hypothesis. These chronostratigraphic data contain information about past ice dynamics and in particular should be sensitive to the longitudinal strain rate on the north flank of Taylor Dome, averaged over millennia. The imprint of climatic changes on ice dynamics may be discernible in these data.