학술논문
A rapid sediment pulse induced by glacial melting during the MIS 8/7e transition buried well‐developed karst in the Railton Valley, Tasmania, Australia.
Document Type
Article
Source
Subject
*GLACIAL melting
*KARST
*BOULDERS
*SEDIMENTS
*ALLUVIAL fans
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Language
ISSN
0300-9483
Abstract
Recent catastrophic sinkhole collapse caused by regional water table lowering induced by quarrying has led to the partial exhumation and reactivation of a buried karst cave system in the floor of the Railton Valley in the lowlands of northern Tasmania, Australia, and widespread sinkhole development. Extensive silty sediments exposed in sinkholes, OSL dated to approximately 237 ka, are interpreted to be lacustrine deposits derived from rapidly deposited glacial outwash. The silty sediments have mineralogy consistent with derivation from a source in the upper Mersey catchment rather than locally and are interpreted to be the product of rapid melting of the Mersey Valley glacier during the MIS 8/7e transition. Thick Last Glacial alluvial fan and Holocene flood‐plain deposits mantle the lacustrine sediments. Exposures of glacial erratics and weathered till in streambeds provide further evidence that the valley was impacted by earlier Pleistocene glaciations. [ABSTRACT FROM AUTHOR]