Abstract
The Cobar Basin formed by sinistral transtension in the latest Silurian to late Early Devonian and evolved through a syn-rift phase of brittle upper crustal faulting and subsidence followed by a post-rift sag phase of passive subsidence which can also be recognised in other Early Devonian stratotectonic elements in western New South Wales. Basin evolution was controlled by regional faults splaying off the Gilmore Suture and the Kiewa Fault. The Cobar Basin was largely inverted ~400 Ma ago with reversal of movement (dextral transpression) on synsedimentary N-NW trending strike-slip/oblique-slip faults and on W-NW trending dip-slip faults. These faults controlled the partitioning of deformation in surface rocks into a high-strain Zone 1 developed above the half positive flower structure in the eastern part of the basin, and a lower strain Zone 2 developed above a flat detachment in the central part of the basin. Shortcut faults developed during inversion are the most likely structural targets for sulphide and gold accumulation which is structurally controlled and syntectonic metahydrothermal in origin. Some of these faults have experienced strike-slip faulting as well as contractional movement. -Author
| Original language | English |
|---|---|
| Pages (from-to) | 13-24 |
| Number of pages | 12 |
| Journal | BMR Journal of Australian Geology & Geophysics |
| Volume | 12 |
| Issue number | 1 |
| Publication status | Published - 1991 |