The Nature, Distribution and Genesis of Calcite Cements Within Sandstones of the Western Cooper Basin Region in South Australia
Munasinghe, Binuki N.
Geoscience Honours Degree, 2010
University of Adelaide
This study focuses on the Cooper-Eromanga Basin which is currently one of the most highly economic basins in Australia contains most of South Australia’s and Queensland’s oil and gas reserves. The basin’s structural architect is relatively well understood and the key horizons have already been interpreted throughout the basin. However commonly encountered in this basin are calcite accumulations that appear to directly overlie Permian fault sets.
The study focuses on the Jurassic sediments of the Eromanga section. The calcite is found to be commonly associated with the Adori Sandstone and Westbourne Formations in sections overlying Permian fault sets. These calcite cemented zones within the sand units are not regionally extensive and vary in thickness over the area of interest.
It appears that the faults located in the Permian age sequences, that were reactivated in the Cretaceous, have some relation to the calcite accumulations as do the migration pathways through the sediments in the Cretaceous. The calcite was found to be sourced through Jurassic to Cretaceous processes and accumulation appears to be controlled by structural features of the Permian.