| CLARENCE-MORETON BASIN | ||
|---|---|---|
| State(s) | New South Wales, Queensland | |
| Area (km2) | Offshore | 1,000 + (offshore extent poorly known) |
| Onshore | 26,000 | |
| Maximum thickness (m) | 3,000+ | |
| Age Range | Late Triassic to Late Jurassic. | |
| Basin | Overlies | Ipswich Basin, New England Fold Belt. |
| Underlies | Cainozoic volcanics; alluvium and coastal facies. | |
| Subdivisions | Cecil Plains, Laidley, Logan Sub-basins. | |
| Other | Yamba Trough (of Logan SB) is mainly offshore. | |
| Indicators | Knowledge | Moderate geophysical and well data onshore; sparse geophysical data only offshore. |
| Basin type | Intracratonic sag following crustal transtension. | |
| System(s) | Murta. | |
| Water Depth (m) | 0 - 90 (mainly 20 - 70). | |
| Exploration | Status | Frontier offshore; Immature onshore. |
| Wells | Over 50 deep exploration, all onshore. | |
| Seismic line-km | > 1,000 2D onshore, one small survey offshore. | |
| Discoveries | Horgarth (uneconomic gas). | |
| Shows | Numerous gas shows, minor oil shows. | |
| HC evidence | Appears to be an operating gas-prone petroleum system; an oil-prone system is also possible. | |
| Geology | Source(s) | Middle Jurassic Walloon Coal Measures has best potential as an oil source; older section is gas prone. |
| Reservoirs | Several sandstone units within the Late Triassic to Early Jurassic Bundamba Group. | |
| Seals | Intraformational flood plain shales in several units. | |
| Trap types | 1) Drape over; or 2) pinchout against sub-Clarence-Moreton topography; 3) hanging wall anticlines on minor thrusts; 4) stratigraphic traps. |
|
| Palaeogeographic summary | Mainly fluvial throughout, with coal swamp and lacustrine facies at various times and places. | |
| Timing | Oil generation | Late Cretaceous. |
| Gas generation | Late Cretaceous to Neogene | |
| Trap formation | 1 and 2 - Late Triassic; 3 - Late Triassic to Early Cretaceous; 4 - Late Triassic to Late Jurassic. | |
| Other key times | Early Cretaceous folding; Late Cretaceous to Palaeogene erosion. | |
| Other important information | 1) The Solitary Islands Marine National Park and Reserve are both near a
possible offshore extension of the basin. 2) The offshore basin lies under a whale migration path for several months of the year. 3) A detailed Southeast Queensland dataset that includes the onshore basin is available from the Queensland Department of Natural Resources and Mines. |
|
| Geoscience Australia products available | 1) Wells and O'Brien, 1994. Bulletin 241. 2) Cadman and others, 1998. APA Report 11. |
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