Sedimentary facies analysis and paleogeographic significance of the latest Silurian to Early Devonian Winduck Interval in the Darling Basin, western New South Wales, Australia
This work presents the first detailed sedimentary facies analysis of the subsurface latest Silurian to Early Devonian Winduck Interval, based on four wells in the Blantyre and western Neckarboo sub-basins in the central part of the Darling Basin. The study integrates wireline logs, cores, cuttings and limited biostratigraphic data to determine the sedimentary sequence subdivision in the study area. Sedimentological analysis was applied, using characteristic wireline-log responses, and core and cuttings descriptions, to aid in the development of a depositional environment model for the Winduck Interval. Twenty-nine sedimentary facies are defined, forming five facies associations. These associations are characterised as distributary channel sandstone complex, distributary mouth bar, tidal channel sand, proximal delta front associated with mouth bars complex, and distal delta front to prodelta sediments. Tectonism influenced the paleogeography, although fault zones (a complex of normal and reverse faults) were important in determining sedimentary sequence thicknesses obtained from the wells. Tectonic subsidence was moderate, and accumulation rates were low. The results of sedimentary facies analysis of the Winduck Interval have implications for evaluating the hydrocarbon potential, and may assist extensive exploration efforts that are currently occurring in the Darling Basin within western New South Wales.