Mid Silurian-Carboniferous tectonic and depositional history of the Darling Basin Conjugate Fault System, western New South Wales: Overview

• Published in: Australian journal of earth sciences Vol. 59; no. 1; pp. 91 - 117
• Main Author: Neef, G.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.02.2012
• Subjects: biostratigraphy; Darling Basin; Darling Fault; fluvial deposition; Koonenberry Fault; Mid Silurian-Mid Carboniferous Conjugate Fault System
• ISSN: 0812-0099; 1440-0952
• DOI: 10.1080/08120099.2012.624124

Mid Silurian-Late Devonian sandstone-rich strata, largely fluvial and several kilometres thick, were deposited in the Darling Basin while the strata were deformed largely by strike-slip and thrust faulting within and adjacent to the basin. This study describes the history of strata exposed in eight areas where strata were mostly deposited from braided streams on braid-plains and streams flowing on alluvial fans, with minor lacustrine and marine deposition. At the centre of the basin, the 1000 km-long, northeast-trending, slightly convex to the northwest Darling Lineament (Fault), intersects the south-southeast-trending ∼80 km-long Lake Wintlow Line (Fault) and the ∼300 km-long north-northwest-trending Koonenberry Fault (which is partly exposed in the study area for ∼50 km). Together these faults form the Darling Basin Conjugate Fault System. The history of the basin suggests that principal stresses switched twice from north-northeast-south-southwest to west-northwest-east-southeast and then back to north-northeast-south-southwest during Mid Silurian-Late Devonian time. Sectors of the DBCFS under greater compression during these orogenic phases tended to be uplifted and eroded, whereas sectors with less compression tended to subside, to accumulate fluvial and shallow marine sediments. The model's recognition indicates that there has been little deformation in the Darling Basin since Mid Carboniferous time.