The province is primarily under the jurisdiction of Australia. The boundary between Western Australia and the Northern Territory divides the Joseph Bonaparte Gulf (Fig. 2). The waters of the Territory of Ashmore and Cartier Islands, Australia, angle across the northwest corner of the province. The international boundary with Indonesia and East Timor runs near the northern province boundary. The Zone Of Cooperation (ZOC) was formed in 1991 between Australia and Indonesia to govern exploration in an area of approximately 61,000 km² south of the island of Timor toward the Bonaparte Gulf ending a dispute of more than a decade. The ZOC is further divided into A, B, and C each with different levels of control among the participating entities (Fig. 2). In February 2000 the United Nations Transitional Administration in East Timor replaced Indonesia as partner in the ZOC (Oil & Gas Journal, 2000).

The Paleozoic failed rift, initiated in the Devonian, trends northwest-southeast and includes the geologic provinces of the Kimberley Block to the west, and portions of the Londonderry high, the Plover-Lacrosse terrace, and Berkley platform, which are all faulted features bordering the Kimberley Block (Fig. 3). The basin continues northeast to the Darwin shelf and Money Shoal basin near Bathurst Island. The Carlton basin lies primarily onshore to the south (Fig. 3). The Paleozoic rift basin is intersected and overprinted by a basin trend that developed during the Mesozoic. 

Major geologic structural features of the Mesozoic trend include the Yampi shelf, Londonderry high, Vulcan graben sub-basin, Ashmore platform, Sahul trough or syncline, Sahul platform, Flamingo high and trough or syncline, Darwin shelf or platform, Malita graben, Calder graben and northern portions of the Goulburn graben (Fig. 3 and Fig. 4) (Edwards and others, 1997; Gunn, 1988a; Hocking and others, 1994; Mc Lennan and others, 1990). The Malita graben extends northeast between the eastern portion of the Sahul platform and the Darwin platform and Lynedoch Bank fault system and blends with the Calder graben of similar trend. The Malita graben ends at the Lynedoch Bank fault where the Goulburn graben begins (DPIE, 1998). Underlying the Goulburn graben in the easternmost portion of the province is another Paleozoic rift trending northwest-southeast. The Mesozoic portion of the Goulburn graben, the Money Shoal basin, is a sag basin that unconformably overlies and progressively oversteps the edges of the Paleozoic rift-faulted basin east of the province, the Arafura basin (DPIE, 1998). Numerous bitumen (tar) strandings on the shores of the northern coasts of the islands and peninsulas of Australia are reported in the Money Shoal Basin Province (Fig. 1) (Martin and Cawley, 1991; Summons and others, 1993; DPIE, 1998).

PALEOZOIC
The Paleozoic rift basin contains two petroleum systems, one that formed during Devonian to Early Carboniferous development of the rift (Milligans-Carboniferous, Permian, 391001), and one that formed later in the Late Carbonifeous to Permian stage (Keyling, Hyland Bay-Permian, 391002). The Paleozoic rift opened in a pivotal style from a pole at the southern end of the province and separated the Kimberley Block from the Sturt Block and Darwin shelf (Gunn, 1988a). Extension of 80 km with little displacement of continental crust by an axial intrusion occurred at the southern end (Fig. 4, G-H) (Gunn, 1988a). Extension at the northern end separated the rift margins by more than 250 km; the axial intrusion was split and oceanic crust more than 100 km wide was formed (Fig. 4, C-D and E-F). Gravity lows, indicating areas of thick sediments, alternate from the west side of the basin to the east and back again (Gunn, 1988a; O’Brien, 1993). Possible transform/transfer and bounding faults were mapped by Gunn (1988a). The alternating thick sediments and the mapped faults both suggest a rifting style of connected, alternating, asymmetrical half grabens (Bosworth, 1985). McConachie and others (1996) also describe transform faults that divide the rift into compartments (Barnett, Tern, and Curlew) that influenced deposition, maturation, and migration. 

In the Paleozoic rift basin, Devonian to Tertiary sedimentary rocks reach a total thickness in excess of 17 km (Mory, 1988). These strata comprise the Milligans-Carboniferous, Permian (391001) and the Keyling, Hyland Bay-Permian (391002) petroleum systems (Fig. 5). In the Petrel sub-basin, strata overlie oceanic crust and thicken northward from onshore to where the Paleozoic Petrel sub-basin is intersected by the Mesozoic Malita graben (Fig. 4, C-D) (DPIE, 1998). Paleozoic strata thin gradually to the northeast onto the Darwin shelf (Fig. 4, E-F) (Miyazaki, 1997). An extensive period of non-deposition or erosion occurred between Cambrian and Devonian times, and Devonian salt deposits directly overlie basement rocks, which consist of Cambrian volcanics and sandstones (Edwards and others, 1997; Gunn, 1988a; McLennan and others, 1990). Deposition of evaporites and rift-fill sediments proceeded marine to nearshore clastic and carbonate sedimentation that continued through the Carboniferous and Permian (Fig. 5). Upper Devonian carbonate reefs developed on structurally high fault blocks. Other syn-rift deposits include shallow marine clastics, shelf carbonates and clastics, and basinal clastics. During the Carboniferous through Early Triassic sag phase of the Paleozoic rift basin development, shallow marine, deltaic, and coastal plain sediments were deposited. A tectonic compressional event during Middle Triassic and Early Jurassic time uplifted and eroded the flanks of the Paleozoic rift basin and produced faulted inverted structures (DPIE, 1998). Fault-drape anticlines and monoclines developed at this time primarily in the southwestern and central portions of the Paleozoic basin. As tectonic activity focused on the outer Mesozoic basin trend, Jurassic-Cretaceous deposition in the Paleozoic rift basin consisted of fluvial, deltaic, and shallow marine sands (Gunn, 1988b). Paleozoic structural trends remain prominent in the basin and salt diapirs are scattered throughout (Fig 3). The salt contains Middle to Late Devonian palynomorphs suggesting either a pre-rift, Late Ordovician to Early Silurian age or a syn-rift, Middle Devonian age for the salt (DPIE, 1998; Gunn, 1988b; Jefferies, 1988; Warris, 1993). 

The presence of the Keyling, Hyland Bay-Permian system beneath the Vulcan graben is implied by evidence of the presence of the Paleozoic rift. This northward extension of the rift is suggested by salt diapirs that occur in the Vulcan graben sub-basin sourced by salt from the same Devonian section that is the origin of diapirs in the Petrel sub-basin (DPIE, 1998; Gunn, 1988a,b; Jefferies, 1988; Warris, 1993).

MESOZOIC
Tectonic activity and subsidence shifted in the Mesozoic to the northwest margin of the Bonaparte Gulf Basin Province resulting from continental breakup along the entire northern and western margins of Australia and the formation of faulted platforms of continental crust and abyssal plains of oceanic crust. The Mesozoic trend includes the Vulcan graben sub-basin with tilted fault blocks and grabens, confined to the east by the Permo-Triassic Londonderry high and to the west by the Ashmore platform, and the Malita graben sub-basin, bounded to the north by the Sahul platform and to the south by the Darwin shelf (Fig. 3). Sedimentary rocks are as much as 10 km thick in the sub-basins and 4 km thick over the highs (Fig. 4). Deposition of a thick sequence of shallow marine and fluvial deltaic clastics during Triassic to Middle Jurassic in the Vulcan graben sub-basin consisted of 2.5 km of deltaic sands, deep marine muds, and deep-water fans during Late Jurassic-Early Cretaceous time (DPIE, 1998; Pattillo and Nicholls, 1990; Baxter and others, 1999). Subsidence of the Malita sub-basin occurred primarily during the Cretaceous. Jurassic sediments are thin or absent on the Ashmore platform (DPIE, 1998). The sub-basins are offset and connected by the Sahul and Flamingo synclines or troughs that trend roughly north-south (Fig. 3). These features may be related to Paleozoic rifting in as much as they originated during the Permian and are aligned with the Paleozoic rift trend (DPIE, 1998; Robinson and others, 1994). Fluvial deposits to deep-water fans and restricted marine shales accumulated in the Sahul syncline from Late Jurassic to Early Cretaceous time, when sediment supply was greater than subsidence and the syncline was filled and no longer a topographic low (Robinson and others, 1994). These sub-basin strata are overlain by 1.5-3 km of passive margin ramp deposits of Early Cretaceous to Tertiary age consisting of fine-grained clastics and carbonates forming the modern continental shelf (Fig. 5) (DPIE, 1998). Salt diapirs of Late Ordovician to Early Silurian or Middle Devonian age are also present in the Vulcan graben sub-basin (Fig. 4) (Pattillo and Nicholls, 1990; Woods, 1994; DPIE, 1998). Structural style differs in the Vulcan graben sub-basin across the Paqualin Transfer Zone (Smith and Sutherland, 1991; Woods, 1994). This difference, and the occurrence of salt along the transfer zone, may be due to the underlying presence of the Paleozoic rift. The Paqualin Transfer Zone may be a structural element of the Paleozoic rift, perhaps the rift margin.

Collision of the Australian and Asian plates during the Tertiary Timorese orogeny resulted in fault rejuvenation and compression of the outer Timor Sea area from Miocene to Holocene (Mildren and others, 1994; Nelson, 1993). Subsequent strong east-trending compressional faulting has modified some of the earlier Mesozoic structural grain (Mildren and others, 1994; Nelson, 1993).