Arid geomorphology

Geomorphic research in arid environments continues to attract a wide variety of researchers who employ a range of techniques to understand modem processes and landscape evolution in dry lands. A notable feature of much contemporary research is the collaboration between geomorphologists and those with specialized geochemical and geophysical knowledge, for example in the areas of exposure-age dating. Another significant development is the synergism (at least in the western USA) between environ mental and public policy concerns and fundamental geomorphic research. For example, the need to understand landform development and the history of climate in the region of the proposed high-level nuclear-waste storage facility at Yucca Mountain in southern Nevada has generated important fundamental research on soil-forming processes (Reheis et al., 1995), soil-landscape relations (Peterson et al., 1995), slope stability (Whitney and Harrington, 1993) and evidence for past groundwater discharge conditions (Quade et al., 1995). Similarly, concerns about the response of sensitive semi-arid areas to possible future climate change has stimulated research into the Holocene climatic history and aeolian environments of the Great Plains (Muhs and Maat, 1993; Forman et al., 1995; Loope et al., 1995; Madole, 1995; Muhs and Holliday, 1995; Wolfe et al., 1995) and the Negev Desert (Tsoar, 1995). Of particular importance is the realization that droughts and changes in sediment supply from fluvial systems within the past 150 yr have had effects on dune mobility that are comparable to some inferred Holocene climate changes (Muhs and Holliday, 1995).