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Antarctica |
1 Department of Geography, University of Edinburgh, Edinburgh EH8 9XP, UK
2 Department of Geological Sciences and Institute for Quaternary Studies, University of Maine, Orono, Maine 04469, USA
3 Department of Earth Sciences, Boston University, 675 Commonwealth Avenue, Boston, Massachusetts 02215, USA
4 Isotope Geosciences Unit, Scottish Universities Research and Reactor Centre, East Kilbride, G75 0QF, UK
Quantitative estimates of denudation rates in different tectonic and climatic environments are of fundamental importance to an understanding of long-term landscape development. Little quantitative information is currently available on minimum denudation rates, although this is important in placing constraints on the maximum survival potential of individual landforms or erosion surfaces in terrestrial environments. The persistence for up to >15 Ma of a hyper-arid, polar climate in the ice-free Dry Valleys area of southern Victoria Land, Antarctica, makes this a highly probable environment for minimum terrestrial denudation rates. 40Ar/39Ar dating constraints on the mimimum formation ages of individual landforms indicates generally little modification of even minor features over the past few million years. Relatively, the highest rates of denudation occur at low elevations near the Ross Sea coast. By contrast, rates of landscape change are exceedingly slow at elevations above c. 1500 m in the western Dry Valleys where landforms with a relief of a only a few metres have survived with minimal modification since the mid-Miocene. Measurements of in situ-produced cosmogenic isotopes indicate that even on rectilinear slopes maximum denudation rates may be only c. 1 m Ma–1, with rates falling to <0.2m Ma–1 at some locations on low relief surfaces at high elevation.
