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Dr Susan White: PhD Thesis

Karst and Landscape Evolution in parts of the Gambier Karst Province, Southeast South Australia and Western Victoria, Australia

Despite interest in the palaeontology, groundwater and tourist caves of the karst of the western Otway Basin, limited investigation of the karst landscape development and its processes has occurred. This study documents the overall features of the Gambier Karst Province and delineates its boundaries. The province comprises extensive area where cave and karst development is limited, interspersed with areas of atypical karst development. Two such karst sub regions are distinguished in the karst in the Tertiary limestones (Naracoorte and Glenelg River). These subregions contain karst assemblages with distinctive combinations of karst landform and process.

At Naracoorte the caves are concentrated and range from simple single passages to complex multi level caves. The cave passages trend northwest/southeast and contain a range of fossiliferous clastic sediments and dated speleothems. Cave walls retain evidence of solutional features. Dolines, uvalas and blind valleys characterise the surface karst. In the Glenelg area the karst, despite similarities such as the orientation of cave passages, the caves are smaller, less complex and more strongly associated with the main surface drainage (Glenelg River).

The syngenetic aeolianite karst is hosted within a different lithology; the Pleistocene dunes and their interdune swales that dominate the surface karst landscape. These shallow, predominantly horizontal caves vary from large maze type systems to short single caves, and have formed under a hardened cap rock in the dune. It is widespread across the province where favourable conditions occur.

This study includes the development of a model for the landscape history of the karst landscapes of Naracoorte, and Glenelg River areas of the western Otway Basin since the Pliocene. This model integrates the cave morphology and processes with groundwater and long term landscape data. This extends the current knowledge of the Gambier Karst Province and potentially contributes to more effective management of the karst of the province.