Landforms Ancient and Recent: the Paradox |
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| Authors: | C R Twidale |
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| Institution: | Department of Geology and Geophysics, University of Adelaide, Adelaide, Australia |
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| Abstract: | Very old etchforms of Cretaceous age or older (Pangaean surfaces) are preserved in many parts of the world. Some have been exposed to the elements for periods of 108 years and their persistence poses problems per se . Moroever, landforms are actively developing within or immediately adjacent to these palaeosurface remnants. Unconsolidated materials, whether occurring as regolith on palaeosurfaces or as deposits in valleys and basins, are readily eroded, but coherent rocks are resistant, particularly in well drained situations. A model involving unequal erosion and positive feedback provides optimal conditions for survival. |
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| Keywords: | palaeosurface survival epigene surface etch surface exhumed surface regolith accelerated soil erosion |
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