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The weathering of a suite of basalt clasts, that have been transported by mass wasting downslope in the Cumulus Hills region of the Queen Maud Mountains, Antarctica, is examined from both geochemical and glacio-geomorphic viewpoints. Chemical weathering, predominantly oxidation and hydration, increases in severity from clast core to rim for the suite. These weathering processes and concomitant formation of a weathering rind are suggested to be an accumulative process, culminating in the disaggregation of the rock due in part both to the chemical breakdown of the interstitial and intersertal basaltic glass and to physical weathering processes.Mass wasting rates in the range of 1.4 x 10~3-1.13 x 10" 1 cm. y" 1 are estimated, assuming that the style of transport is dry creep. These transport rates suggest that the rock-surface/air-temperature differences in the study area may have been as little as 0.5 °C and heating and cooling cycles as few as 1 cy. y" 1 for the last 4.2 Ma. Downloaded: 05 Apr 2015 IP address: 128.6.218.72 554 R. W. TALKINGTON, P. A. MAYEWSKI & H. E. GAUDETTECumulus Hills including Halfmoon Bluff is currently ice-free. Shackleton Glacier, two of its tributary glaciers and highland ice, flank the borders of this ice-free area. Local climate and geomorphic settingThe climate of the Halfmoon Bluff area is largely dominated by the intense katabatic winds that descend from the Polar Plateau northwestward down Shackleton Glacier and towards the coast. Mean annual snow balance for the area is approximately 10-20 g. cm" 2 . y" 1 (Bull, 1971). Most of this precipitation is derived from the coast, though small amounts of wind-blown snow are also carried into the area from the southeast by katabatic winds. Although mean annual temperature is approximately -30 to -35 °C (Weyant, 1967) and meltwater not common, there are usually several days during each summer season when small streams can be observed at the contact between ice and bedrock. Although local climatic conditions play an important role in the development of geomorphic features in Antarctica, the Halfmoon Bluff study site has been chosen so as to minimize microclimate effects. The site is small (60 m x 3 m), vertical relief of the slope is small (16.3 m), all segments of the slope face the same direction (N 7° E) and the clasts examined are all of similar size and lithology.Weathering rates differ primarily as a function of lithology (Behling, 1971, Ph.D. Thesis, Ohio State University;Birkeland, 1974). In the study area, basalt clasts comprise the most resistant lithology, and sandstones and mudstones the least resistant lithologies. Due to their high relative resistance to weathering and disaggregation the basalt clasts record a long history of exposure. The source dike for the basalt clasts is relatively free of weathering effects, as evidenced by fresh surfaces along columnar joint planes of the dike.The basalt clasts in this study have been dispersed throughout the study slope by mass wasting. Slope angles in the study area range from 9° to 23°...