REVISED PERMIAN GLACIAL RECORD OF EASTERN AUSTRALIA

The timing, extent and duration of glaciation during the late Paleozoic Gondwanan Ice Age remain controversial. The notion of a single, protracted glacial epoch that has been championed by some authors has recently been challenged by the recognition in many parts of Gondwana of a multi-phase glacial history with events in both the Carboniferous and Permian. In the Permian of eastern Australia (New South Wales and Queensland), previous workers have proposed that the main phase of the Ice Age ended during the Sakmarian and was succeeded by a marine transgression of inter-regional extent (the Tastubian transgression). Our field work has isolated two discrete periods of glaciation during the Early Permian: 1. Asselian to early Sakmarian (represented by the shallow marine Wasp Head Formation in southern New South Wales, and the terrestrial Boonderoo Beds and marine Youlambie Conglomerate in Queensland), and 2. latest Sakmarian to Artinskian (represented by marine and coastal facies of the Cattle Creek Formation in central Queensland and of the Pebbley Beach Formation of the southern Sydney Basin). Discrete intervals of glacial, proglacial and periglacial strata are separated by terrestrial and marine facies that indicate cool climate but non-glacial conditions. We furthermore recognize several, large-amplitude sea-level fluctuations during the Ufimian (early Late Permian) recorded in the Wandrawandian Siltstone and equivalents in the Sydney Basin, and in the Freitag Formation of central Queensland. A picture of the late Paleozoic Gondwanan Ice Age is now emerging that involves several discrete, relatively short-lived (<5 m.y.) events separated by longer time intervals of less severe conditions, similar to the pattern in the late Cenozoic Icehouse period.