Geology of the Mundubbera district

In the Mundubbera district Upper Palaeozoic sediments of the .southern portion of the Yarrol Basin are exposed in a broad syncline. The sequence has been divided into two Devonian and six Carboniferous formations. Consideration of fossil zones and stratigraphic and structural relations infers that the Carboniferous rocks are of Tournaisian, Visean, and possibly Namurian age. Lithologic variation throughout the Carboniferous indicates a single strong vertical movement of the Gogango High at the end of Tournaisian time. Evidence is presented showing that this vertical movement of the high may be related to orogenic movements within the Yarrol Basin. Various lines of evidence suggest that the eastern margin of the basin is here marked by a thrust sheet of Lower Palaeozoic rocks. Faulting along the western margin of the basin is also discussed. The structural and stratigraphic history of the district is outlined.