A NEW MODEL FOR THE MID-CRETACEOUS STRUCTURAL HISTORY OF THE NORTHERN GIPPSLAND BASIN

Abstract

The tectonic history of the northern flank of the offshore Gippsland Basin can be divided into three phases:

an Early Cretaceous rift phase (120-98 Ma) with deposition of the Strzelecki Group and extension in a northeast-southwest direction.

a mid-Cretaceous phase (98-80 Ma) with deposition of the Golden Beach Group and extension in a northwest- southeast direction and

a Late Cretaceous to Tertiary sag phase with intermittent compression or wrenching.

Previous workers have described the first and third phases. This paper argues for a distinctive second phase with extension at right angles to the first phase. The complex Cretaceous structure in the Kipper-Hammerhead area is interpreted in terms of a model in which transfer faults of the first phase became domino faults of the second phase.