Abstract

The Dry Valleys are subdivided into three microclimate zones on the basis of summertime measurements of atmospheric temperature, soil moisture, relative humidity and wind-speed/ direction. Subtle variations in these climate parameters result in considerable differences in process geomorphology and in the development of unique landforms within each zone. The mapped zones include a coastal thaw zone, an inland mixed zone and a stable upland zone. Landforms within each zone are subdivided into macroscale features (e.g. valleys, slopes and gullies), mesoscale features (e.g. polygons and viscous-flow features) and microscale features (e.g. rock and near-surface soil features, including the effects of salt weathering, wind erosion and pitting). We present a review of landscape development in the Dry Valleys with implications for long-term climate change and ice-sheet stability. Chronological control is afforded by ⁴⁰Ar/³⁹Ar dating of volcanic ash-fall deposits and cosmogenic nuclide analyses of surface boulders. Collectively, the data call for persistent cold and dry conditions in the stable upland zone for approximately the last 14 Ma, although some level of climatic amelioration and landform modification may have occurred within low-lying regions and in the inland mixed zone.