Gravity survey and structure of the Forestier Peninsula, Southern Tasmania

Abstract

A gravity survey coupled with review of regional mapping has shown that the widespread exposure of Jurassic dolerite across the Foresrier 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.

Palaeozoic suturing of eastern and western Tasmania in the west Tamar region: Implications for the tectonic evolution of southeast Australia

“…In contrast, their geochemistry matches very closely that of basalts in the Port Sorell Formation approximately 12 km to the west. A correlation on this basis is consistent with geophysical (Leaman et al . 1973; Zengerer 1999) and structural evidence for the Badger Head Group being allochthonous and overlying both Andersons Creek Ultramafic Complex and Port Sorell Formation rocks.…”

“…The Badger Head Group has previously been considered allochthonous based on interpretations that a positive Bouguer anomaly is caused by dense, possibly Cambrian or Neoproterozoic sedimentary and volcanic rocks underlying the turbidites (Leaman et al . 1973).…”

“…The geology of the west Tamar region is complex. Gravity (Leaman et al . 1973; Zengerer 1999) and magnetic (Zengerer 1999) data indicate that Proterozoic turbidites of the Badger Head Group allochthonously overlie mafic–ultramafic rocks of the Lower Cambrian Andersons Creek Ultramafic Complex and probable Neoproterozoic to Lower Cambrian rift‐related sedimentary and igneous rocks of the Port Sorell Formation.…”

Efficient regional scale 3D potential field geophysical modelling to redefine the geometry of granite bodies beneath prospective, geologically complex, northwest Tasmania

“…Across western and northwestern Tasmania, several regional 2D and 3D models have been constructed by integrating geophysical data and geological observations (e.g. Leaman, 1990;Leaman, 2003;Leaman and Richardson, 1992;Leaman and Richardson, 1989;Murphy et al, 2004;Webster, 2003). The 3D model of Murphy et al (2004) has been distributed by Mineral…”

“…Resources Tasmania (MRT) and widely utilized to investigate major geological features at depth across Tasmania. The Devonian granites are modelled by Leaman (2003) and Murphy et al (2004) indicating the depth to the top of the Devonian Granites. These granite bodies mostly extend to depths of 9-12 km based on Black et al (2010).…”