Stratigraphic results of diamond drilling of the Hunterston Dome, Tasmania: implications for palaeogeography and hydrocarbon potential

The structure known as the Hunterston Dome, in central Tasmania, was drilled to a depth of 1324 m, through Jurassic dolerite, Lower Parmeener Supergroup and into Precambrian dolomite basement. The base of the Lower Parmeener Supergroup does not outcrop in the area, and drilling revealed the absence of the extensive glacial diamictites present elsewhere in the Tasmania Basin. A conglomeratic facies is found in place of the Bundella Mudstone and Woody Island Siltstone. Basement to the Lower Parmeener Supergroup is shown to be deformed Precambrian dolomite, of similar lithology to the relatively undeformed Black River Dolomite of northwestern Tasmania.
Significant hydrocarbons were not encountered during drilling, but stratigraphic drilling proved the maturity of potential source beds in the region and the nature of potential reservoir rocks, where they are found in close association with a dolerite intrusion.