Palaeoenvironment of the Darlington Limestone (Early Permian)Tasmania

Abstract

The Early Permian Darlington Limestone in the Tasmania Basin consists of fossiliferous mudstone, siltstone and impure limestone. It was deposited in a somewhat restricted basin with uplands on the northeast and east, the northwest, and probably the southwest. Icebergs from glaciers on the uplands or sea-ice may have transported erratic lonestones into the basin. Cold, low salinity water is indicated by a foramol fauna which contained many individuals but relatively tew genera and which is rich in foraminifera, bryozoans, spiriferids, and pelecypods. Hydraulic energy was generally low. Little sorting and few sedimentary structures were observed. Evidence of current action is mainly on the periphery of the basin and suggests currents from the southwest. Such evidence is mostly the orientation of fossils. Islands such as the Beaconsfield-Frankford island, and shallows probably impeded current action in the basin.