Implications of cross-bedding data from the upper part of the Cambrian succession, Arrowie Basin, South Australia

Abstract

The Cambrian succession in the Arrowie Basin, Flinders Ranges, South Australia comprises the carbonate-dominated Hawker Group overlain by the sandstones and siltstones of the Billy Creek Formation, Wirrealpa Limestone and the clastic-dominated Lake Frome Group. Cross-bedding and other current data indicate a change in provenance for the clastic sediments at about the level of the Wirrealpa Limestone. It is suggested that the clastics of the Hawker Group and the Billy Creek Formation were derived from the Curnamona Craton to the east and southeast whereas those of the Lake Frome Group were derived from the Gawler Craton. This change occurred at approximately the same time as a change in provenance within the upper Backstairs Passage Formation of the Kanmantoo Group on Fleurieu Peninsula and may indicate that the top part of the Backstairs Passage Formation would correlate approximately with the Billy Creek Formation. The provenance change suggests that the Delamerian Orogeny caused uplift of the Curnamona Craton prior to that of the Gawler Craton.