Arid geomorphology: Changing perspectives on timescales of change

作者：Tooth Stephen^*

来源：Progress in Physical Geography, 2012, 36(2): 262-284.

DOI：10.1177/0309133311417943

• arid geomorphology
• biological evolution
• geoarchaeology
• geochronology
• landscape development
• palaeontology

Arid geomorphological research continues apace with publications appearing in a diverse range of outlets. Themes common to several recent (2008-2009) books include greater emphasis on the global diversity of arid environments, the improved temporal framework for research findings, and the growing contribution of arid geomorphology to interdisciplinary research fields. Building on previous progress reports, this article touches on all three themes, but particularly highlights how applications of geochronology (e. g. cosmogenic isotope analysis, luminescence dating, and radiocarbon dating) are challenging or revolutionizing understanding of the timing and rates of arid geomorphological change. Four case studies from %26apos;iconic%26apos; arid landscapes illustrate changes over different timescales: (1) canyons of the Colorado Plateau region, southwest USA (last similar to 5-6 Ma); (2) aeolian dunefields in central Australia (last similar to 1 Ma); (3) palaeolakes in the Kalahari, central southern Africa (last similar to 300 ka); and (4) alluvial and bedrock-controlled rivers in the southwest USA (last similar to 12 ka). Other developments across the suite of geochronological techniques are also contributing to improved understanding of arid landscape dynamics and the links with late Cenozoic environmental changes, biological (including hominin) evolution and cultural developments, but many outstanding issues remain. These include: (1) compiling large geochronological data sets to enable rigorous hypothesis testing; (2) establishing guiding conceptual frameworks to aid the selection and interpretation of geochronological data; (3) using multiple chronometers; (4) combining geochronology with other investigative techniques such as computational modelling; and (5) clarifying the causal links between events in different palaeorecords, even when temporal correlation can be established with a high degree of certainty. Despite recent rapid advances, today%26apos;s understanding of the antiquity and tempo of landscape development in Earth%26apos;s arid environments undoubtedly will be challenged and extended by further research, with particularly valuable perspectives likely to be provided by arid geomorphological research on other planetary bodies.

• 出版日期2012-4