Hillsborough Basin

Last updated:7 June 2023

Basin Details and Geological Overview

The Hillsborough Basin straddles the east coast of Queensland, north of Mackay. The basin covers 2 700 km2, most of which lies offshore in water depths up to 20 metres. The Hillsborough Basin contains up to 1 250 metres of Paleogene sediments overlying Late Devonian to Early Carboniferous sediments and volcanics onshore, but on seismic evidence may reach a thickness of up to 3000 metres offshore. The Hillsborough Basin is one of four structural blocks in the Proserpine area, along with the Midgeton Block to the west and possibly southeast, the Airlie Block in the northeast and the Whitsunday Block in the east.

The Hillsborough Basin developed as a narrow southeast trending asymmetrical graben on the eastern side of the Midgeton Block during a phase of Late Cretaceous or Paleogene faulting. Sediments accumulated in the graben during the Paleogene: and the thickest known section is offshore along the northeast margin of the basin. The sedimentary fill (Cape Hillsborough beds) is largely composed of sandstone, mudstone and minor conglomerate: the depositional environment was probably entirely non-marine. Oligocene volcanic flows and intrusions are present in the south of the basin at Cape Hillsborough, an onshore horst feature. The stratigraphy of the offshore Hillsborough Basin is largely unknown as there are no wells and only poor quality seismic data. Oil shale and lignite are present within the Cape Hillsborough beds, including the Condor Oil Shale deposit, located to the south of Proserpine in the northwestern part of the basin. The offshore part of the Hillsborough Basin lies entirely within the Great Barrier Reef Marine Park, in which petroleum exploration is prohibited.

Basin Summary Table

State(s) Queensland
Area (km2) Offshore 2350
Onshore 250
Maximum thickness (m) 3000 (but generally < 900)
Age Range Paleogene
Basin Overlies Late Devonian to Early Carboniferous sediments and volcanics: Late Cretaceous volcanics in the north.
Underlies Neogene alluvium: shelf sands and carbonates.
Subdivisions -
Other -
Indicators Knowledge Detailed outcrop and well data and regional geophysical data onshore: regional geophysical data only offshore.
Basin type Asymmetric intramontane graben.
System(s) Capricorn.
Water Depth (m) 0 - 20
Exploration Status Frontier.
Wells 3 onshore petroleum exploration, plus shallow bores into the Condor Oil Shale.
Seismic line-km > 1000 2D onshore, one small survey offshore.
Discoveries Nil
Shows Minor gas shows in Proserpine-1.
HC evidence Onshore basin contains the Condor Oil Shale deposit.
Geology Source(s) Lacustrine oil shale facies if present and mature in the deepest parts of the basin.
Reservoirs Sands are poorly sorted and of poor reservoir quality.
Seals Intraformational shales.
Trap types Fault traps most likely.
Palaeogeographic summary Intramontane basin, with no known marine influence: alluvial, fluvial and lacustrine facies.
Timing Oil generation No evidence of generation: Neogene if it occurred.
Gas generation No evidence of generation: Neogene if it occurred.
Trap formation Neogene.
Other key times Repeated Neogene faulting of the basin fill.
Other important information The offshore Hillsborough Basin lies entirely within the Great Barrier Reef Marine Park, in which petroleum exploration activity is prohibited.
Geoscience Australia products available -

Key references

Author(s) Year Title
Benbow, D.D. 1980 The petroleum prospects of the Great Barrier Reef region. The Australian Petroleum Production & Exploration Association (APEA) Journal, 20 (1), 159-175
Brown, L.N. 1981 Geology and hydrocarbon potential of authority to prospect 287P, Queensland. Unpublished report held by the Queensland Department of Mines as CR 9250
CSIRO 1977 Source rock analyses on samples from thirteen sedimentary basins. A report to the Bureau of Mineral Resources, Canberra by Saxby. Unpublished report held by the Queensland Department of Mines as CR 6358
Clarke, D.E., Paine, A.G.L., & Jensen, A.R. 1971 Geology of the Proserpine 1:250,000 Sheet area, Queensland. Bureau of Mineral Resources, Geology & Geophysics, Report 144. 1968/022
Department of Resource Industries, Queensland 1989 Petroleum Resources of Queensland: Review to June 30, 1989). Petroleum Resources Assessment and Development Subprogram, Department of Resource Industries, Queensland. Pages, 145-147
Forman, D.J., Kurylowicz, L.E., Mayne, S.J., Paine, A.G.L., Passmore, V.L., Robertson, C.S., and Wyborn 1974 Summary of Phanerozoic sedimentary basins of Australia and adjacent regions. Bureau of Mineral Resources, Geology & Geophysics, Record 1974/178
Gannon, A.J., and Wright, B.C. 1987 Progress in continuing oil shale project studies. In Proceedings Fourth Australian Workshop on Oil Shale, Brisbane, December 1987
Gray, A.R.G. 1976 Hillsborough 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, 460-464.
Green, P.M., and Bateman, R.J. 1981 The geology of the Condor Oil Shale deposit – onshore Hillsborough Basin. The APEA Journal, 21 (1), 24-32.