Marion Bay shoreline morphology

At Marion Bay, a well marked line of high abandoned cliffs cut in basalt, sandstone and dolerite is found. In front of these cliffs is a wide sandy platform. A compact 1coffee rock' B horizon is a characteristic feature of the deposit. Elsewhere, a deposit of weathered basalt gravels occurs. The age of the deposits is thought to be Pleistocene but their origin is controversial. A spit almost closes off a shallow lagoon behind which extensive development of salt marshes has taken place. The morphology of the spit is thought not to require a Postglacial fall in sea level. Trend-surface mapping of sedimentary parameters of the beach sand reveals the pattern of spatial variation to be complex and temporal variation to be minimal., The pattern of variation appears to be predominantly caused by the carbonate fraction.