The stratigraphy of the Sturtian glacigene and ferruginous sediments, southeast of Mattawarrangala Station, central Flinders Ranges, South Australia

Abstract

Detailed stratigraphic mapping of sediments of the Sturtian Glacial Sequence was carried out in an area in the Central Flinders Ranges. These sediments are unconformable on the Burra Group and are represented by the Pualco Tillite, the Holowilena Ironstone and the Wilyerpa Formation. The Pualco Tillite consists of lenticular diamictites, siltstones and sandstones and passes conformably into the Holowilena Ironstone which is composed of a mixture of chemical and detrital components. Minor erosion after the deposition of the Holowilena Ironstone is explained to be a result of post-Holowilena Ironstone faulting, which is responsible for a deepening of the basin of deposition. Evidence for ice-rafting in sediments of the Wilyerpa Formation is provided by the common occurrence of dropstones. The time gap between the Pualco Tillite, the Holowilena Ironstone and the Wilyerpa Formation is insignificant, based on the presence of a sandstone dyke which cuts the boundary between the Pualco Tillite and the Wilyerpa Formation (in absence of the Holowilena Ironstone).