| Abstract: | Kerogen from terrestrial plant debris (type III) has commonly been considered to be a good source for hydrocarbon gas, but not for oil, compared with types I and II kerogen from marine and lacustrine sediments. The Gippsland Basin, Australia, contains giant oil fields producing from organic matter of land plant origin. Clearly some terrestrial paleodepositional environments have produced organic matter of land plant origin with the potential to generate large volumes of oil. An attempt has been made here to identify some environments that contain organic matter of terrestrial origin with the potential to generate oil.The dispersed organic matter (DOM) in sediments from various paleodepositional environments in the Northern Carnarvon, Clarence-Moreton, Simpson Desert, Bowen and Gunnedah Basins of Australia has been analysed petrographically. To reduce variations in organic matter type due to differences in geological age, examples of Triassic age only have been compared. DOM with relatively high contents of liptinite, which is widely accepted as having a better potential to generate oil than vitrinite and inertinite, was found in the following environments: fluvio-deltaic (Bowen Basin), proximal lacustrine (Gunnedah Basin) and fluvio-deltaic (Northern Carnarvon).Relationships between Triassic DOM types and paleodepositional environments found in one basin did not necessarily hold true for other basins. It is not valid to infer a unique paleodepositional environment from DOM type, but within a given basin, DOM type may be predicted from environment. |
