Lorne Basin

Location Map

Lorne Basin in relation to Australia

Location Map of Lorne Basin in relation to Australia

Basin Details and Geological Overview

The Lorne Basin is a small, intramontane, Triassic basin, surrounded by the New England Fold Belt. Located between Taree and Port Macquarie, the basin is composed of northern and southern segments separated by an outcrop of basement forming a faulted ridge. The overall dimensions of the basin are approximately 20km in an east-west direction and 35km in a north-south direction. It probably extends offshore under the continental shelf, but this is speculative. Although situated between two major sedimentary basins (the Sydney Basin and Clarence-Moreton Basins), the Lorne Basin has no direct connection with either of them.

The basin is filled with Early Triassic continental sediments of the Camden Haven Group. Terrestrial sedimentation into this basin was probably initiated by tectonic activity along surrounding major faults and serpentinite belts. The sediments include alluvial fan deposits of the Laurieton Conglomerate, associated desert plain or playa deposits of the Camden Head Siltstone and overlying fluvial sediments of the Grants Head Formation. Lorne Basin rocks are overlain by minor Cainozoic volcanics and intruded by Cainozoic microgranites.

The thin sedimentary section of terrestrial lithologies has no potential source rocks and is intruded by Cainozoic microgranites. Fluvial channel sandstones within the Grants Head Formation could be considered as potential reservoir rocks, but the sealing quality of associated intraformational siltstone is dubious. The onshore basin has no petroleum prospectivity. The thickness of any possible offshore extension is unknown, but on the available onshore evidence its prospectivity is probably very low.

Basin Summary Table

LORNE BASIN
State(s) New South Wales
Area (km2) Offshore ? (unknown if the basin extends offshore)
Onshore 500
Maximum thickness (m) 300
Age Range Triassic
Basin Overlies Palaeozoic basement of the New England Fold Belt.
Underlies Neogene coastal fluvio-lacustrine facies.
Subdivisions There are no formal subdivisions, but northern and southern lobes of the basin are recognised.
Other -
Indicators Knowledge Moderate geophysical and outcrop data onshore; no data at all if the basin extends offshore.
Basin type Intramontane.
System(s) Nil
Water Depth (m) 0 - (?) < 200
Exploration Status Frontier
Wells 0
Seismic line-km 0
Discoveries Nil
Shows Nil
HC evidence Nil
Geology Source(s) No source identified
Reservoirs Triassic sandstone and conglomerate facies.
Seals No seal identified.
Trap types Complex faulting and facies variations could in theory form traps.
Palaeogeographic summary Initially alluvial fan and desert plain/playa complex; later wetter with meandering fluvial streams.
Timing Oil generation No evidence of generation
Gas generation No evidence of generation.
Trap formation Triassic
Other key times -
Other important information Any offshore extension of the basin will lie under whale migration paths for several months of the year.
Geoscience Australia products available -

Stratigraphy

Stratigraphy

Image Pratt and Herbert, 1973

Key References

Author(s) Year Title
Bembrick, C.S. 1976 Lorne Basin. In R.B. Leslie, H.J. Evans and C.L. Knight, (Editors), Economic geology of Australia and Papua New Guinea. Volume 3. Petroleum. Australasian Institute of Mining and Metallurgy, Monograph Series, 7, 457-458
Herbert, C. and Burg, R.A. 1972 Reconnaissance survey of the ceramic potential of the Lorne Basin. Geological Survey of New South Wales Department of Mines, Report 1972/294
Herbert, C. 1975 Lorne Basin. In The mineral deposits of New South Wales, Markham, N.L. & Basden, H., (Editors). Geological Survey of New South Wales Department of Mines, 505-509
Packman, G.H. 1969 The New England region; Triassic system. In the geology of New South Wales. Journal of the Geological Society of Australia, 16, Part 1, 270-271
Pratt, G.W. and Herbert, C. 1973 A reappraisal of the Lorne Basin. NSW Geological Survey Record, 15, 205-212

Topic contact: petroleum@ga.gov.au Last updated: December 3, 2012