Gravity survey and structure of the Forestier Peninsula, Southern Tasmania

A gravity survey coupled with review of regional mapping has shown that the widespread expusure of Jurassic dolerite across the Forestier Peninsula is due largely to repetition of a thick sheet by gently ramped Tertiary fault-blocks. Feeders for the sheet appear to be located near the centre of the peninsula and to be related to concealed pre-Permian structures, such as granitoid margins. At least two major fault zones were eroded during the mid Tertiary and these, as well as the peninsula ties to mainland Tasmania and the Tasman Peninsula, now consist of Tertiary materials covered by Recent sands. The western edge of the East Tasmanian batholith extends approximately north-south beneath the centre of the peninsula.