The existence of a large lake in central Australia is traceable to the middle Jurassic (150 million years before present (BP)) when freshwater Lake Walloon occupied the central eastern part of the continent: in the late Cretaceous (85-75 million years BP) it shrunk to a smaller, 5 x 105 km2 Lake Winton, which in the early Miocene (21 million years BP) assumed a position closely resembling the recent location of Lake Eyre. Lake Dieri, a Pleistocene greater Lake Eyre underwent large scale climatic variations, entering into the Recent epoch as a dry salt pan subject to occasional flooding. A longer period of constant filling of Lake Eyre occurred probably in the late Pleistocene, during a wetter climate in southern Australia, between about 45 000 and 25 000 BP. This was followed by a phase of lake contraction, dune building and desiccation. Since European occupation, the climate has been almost equivalent to that of the driest phases of the last 10 000 years.
Posted on: Sat, 09 Nov 2013 02:22:13 +0000