Stratigraphy, potential source rock and petroleum geochemistry of Western Georgina Basin, Northern Territory

Abstract

Between mid-1983 and early 1985, the Northern Territory Geological Survey (NTGS) carried out a diamond drilling program in the western portion of the Georgina Basin to elucidate the Lower and Middle Cambrian stratigraphy in areas of very poor outcrop. The program was carried out as an adjunct to the NTGS's mapping program in ELKEDRA and BARROW CREEK.

Two of the diamond drillholes, ELK6 and ELK7,7A intersected oil-stained dolostone over a number of intervals within the Middle Cambrian Chabalowe Formation (New Name, Stidolph and others, in preparation) and the Middle to Upper Cambrian Arrinthrunga Formation. Organic-rich Middle Cambrian sediments, assigned to the Arthur Creek Formation (Freeman, 1986), were intersected in drillholes ELK2, ELK3, and ELK7,7A. Organic geochemical data indicates that the Arthur Creek Formation is a good potential source for hydrocarbons.

The mapping and drilling programs carried out by the NTGS have significantly refined the Cambrian stratigraphy of the western portion of the Georgina Basin. It has been established that the Middle Cambrian sediments extend from the Dulcie Syncline NW into the 'Lander Trough' in the Wiso Basin (Bagas, 1985).

In the western portion of the Georgina Basin the Lower Palaeozoic sequence occurs over an area of approximately 3800 sq.km and reaches a thickness of at least 1500 min the axis of the Dulcie Syncline.