Dolines of the Pleistocene dune calcarenite terrain of western Eyre Peninsula, South Australia: a reflection of underprinting?

Abstract

A field of Middle and Late Pleistocene coastal foredunes occupies much of western Eyre Peninsula, South Australia. The rolling surface reflects the morphology of the stacks of calcarenite dunes that underlie the area. Hardpan calcrete is well developed in relation to the present, as well as to earlier dune surfaces. The region is a typical karst in that surface drainage is lacking. There are a few shallow and short caves but solution pipes and dolines are abundantly developed. Some dolines, including several of the larger forms occur high in the local topography and are also aligned in groups. They are attributed to underprinting, to the diversion of groundwaters into fractures in the pre-Pleistocene basement and the concentration of solution in the limestone above such zones. Low permeability calcrete horizons within the dune sequence have probably disturbed groundwater circulation and also form a stable framework preventing major collapse, and preserving both dolines and caves.