Structural transect and forward modelling of geophysical data across the St Arnaud Group, Victoria

Abstract

The integration of detailed field mapping with 2.75D forward modelling and worming of potential-field datasets has constrained the 3D geometry of regionally significant faults and allowed a detailed understanding of the crustal-scale architecture of the St Arnaud Group in the Stawell Zone to be developed. The forward modelling has also highlighted the existence of a major west-dipping, non-outcropping fault, the Burrom Fault, between the Concongella and Landsborough Faults. The structure of the upper crust is characterised by major reverse faults. These faults originate from a basal décollement that is located within mafic volcanics underlying the St Arnaud Group. Deformation has resulted in slices of these mafic volcanics being ramped up along the traces of the major faults.

Key words:

• geophysics
• gravity
• magnetics
• St Arnaud Group
• structure

Acknowledgements

This project was supported by a pmd * CRC Honours scholarship and by Leviathan Resources. This paper has benefited from discussions with Barry Murphy, who provided the wormed data across the study area. Reviews by David Moore and Peter Betts have improved this paper.