T24 Glaciogeological and Geomorphological Evidence of Ancient Ice Streams and Outlet Glaciers (Posters)

PALEOZOIC GLACIAL VALLEY-SYSTEMS IN NAMIBIA? NEW ASPECTS: MORPHOGENETC CONTREDICTIONS AND MORPHOTECTONIC RELATIONS

Paper number: T24-13
Program: Technical Sessions
Time: 1:30 PM – 4:30 PM

Authors

Abstract

Geomorphological investigations on palaeosurfaces and their tectonic deformations lead to a critical review of palaeo-landforms hitherto interpreted as glacially shaped Palaeozoic valleys. Such an age has proven as inconsistent with the known surface development considering the effects of valley superimposition and of post-Karoo tectonics. Tillites in situ as convincing Palaeozoic sediments are widely missing. Glacial striae of differing directions plead for overriding ice sheets but nor for valley glaciers. Some of the features in question must be interpreted as products of gravity flow processes. Several valley sections are structurally controlled and have been formed as rupture valleys. Only a minimum of valley remnants can be attributed to Palaeozoic times.