Paleozoic glacial sediments of Sri Lanka obliterated by neotectonic events? Weuda deposits revisited

Abstract

A sequence of rhythmic varve like sediments within the valley of Weuda and isolated sand and gravel deposits in the northwestern plains of Sri Lanka, were reinvestigated. Inter-bedded peaty clay and sand intercalating with un-weathered feldspar, striated and faceted pentagonal quartzite pebbles, “U” shaped valley flanked with large boulders, isolated occurrences of poorly sorted white angular sands, ferruginized gravels and Permo-Triassic plant microfossils all favored a glacial origin for these sediments. However, Paleozoic glacial features appear to be either obliterated or erased due to post-glacial neotectonic movements, large scale pluvial processes, effects of denudation and intense tropical weathering. Study on provenance indicates that Paleozoic glacial deposits may have mixed with or covered by subsequent sediments