Geology and mineral resources of the Northern Territory Ahmad M and Munson TJ (compilers) Northern Territory Geological Survey Special Publication 5 Chapter 36: Bonaparte Basin BIBLIOGRAPHIC REFERENCE: Ahmad M and Munson TJ, 2013. Chapter 36: Bonaparte Basin: in Ahmad M and Munson TJ (compilers). ‘Geology and mineral resources of the Northern Territory’. Northern Territory Geological Survey, Special Publication 5. Disclaimer While all care has been taken to ensure that information contained in this publication is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of its information. The Northern Territory of Australia gives no warranty or assurance, and makes no representation as to the accuracy of any information or advice contained in this publication, or that it is suitable for your intended use. You should not rely upon information in this publication for the purpose of making any serious business or investment decisions without obtaining independent and/or professional advice in relation to your particular situation. The Northern Territory of Australia disclaims any liability or responsibility or duty of care towards any person for loss or damage caused by any use of, or reliance on the information contained in this publication. Bonaparte Basin Current as of November 2012 Chapter 36: BONAPARTE BASIN M Ahmad and TJ Munson INTRODUCTION onshore coastal areas along the NT–Western Australia border northward into the Timor Sea across Australia’s The Bonaparte Basin (previously referred to as Bonaparte continental margin. The basin covers an area of Gulf Basin, Figure 36.1) is a large, predominantly offshore, approximately 270 000 km2, with the onshore portion being composite polyphase sedimentary basin, extending from about 20 000 km2. It contains up to 15 km of Phanerozoic, 125° 127° 129° 131° Calder TIMOR-LESTE 9° Graben lt u a F k n a Goulburn TIMOR TROUGH Troubadour B h Graben INDONESIA High c o d n y Laminaria Sahul Platform L High Kelp High MONEY SHOAL Flamingo High Flamingo BASIN A Syncline Malita GrabenDarwin Shelf Sahul Ashmore Syncline Platform Vulcan 12° Sub-basin D Londonderry High DARWIN Paqualin Transfer Zone BONAPARTE BASIN Daly Basin Pine Creek Petrel Sub-basin Orogen BROWSE BASIN BerkeleyC Platform Moyle Kulshill Platform Birrindudu Terrace Basin Daly Basin Yampi Shelf Keep Inlet Carlton Sub-basin Sub-basin Fitzmaurice 15° Kimberley Basin Pincombe Basin NT Inlier WA Victoria Basin Bastian Basin Wyndham B Burt Range Sub-basin Carlton Sub-basin Kununurra Wolfe Basin 0 100 km Halls Carr-Boyd Creek Basin Orogen Birrindudu Basin Halls Speewah Creek Basin Orogen Ord Basin Offshore Petrel Sub-basin Mesozoic–Cenozoic road platform/high Neoproterozoic– fault Palaeozoic offshore basin boundary location Figure 36.2 early Cambrian Kalkarindji Province syncline location Figure 36.18 Palaeo–Mesoproterozoic state boundary CDsections in Figure 36.3 basins WESTERN NORTHERN DARWIN Palaeo–Mesoproterozoic locality AUSTRALIA TERRITORY orogens Archaean onshore Bonaparte Basin A11-253.ai Figure 36.1. Regional setting of Bonaparte Basin showing major structural elements. NT geological regions from NTGS 1:2.5M GIS GDWDEDVH:$JHRORJLFDOUHJLRQVVLPSOL¿HGDQGVOLJKWO\PRGL¿HGIURP7\OHUDQG+RFNLQJ VRPHVPDOORXWOLHUVLQOLHUVRPLWWHG Geology and mineral resources of the Northern Territory 36:1 Special publication 5 Bonaparte Basin PDULQHDQGÀXYLDOVLOLFLFODVWLFDQGFDUERQDWHVHGLPHQWDU\ The middle Cambrian to Early Carboniferous Carlton rocks. Along with the Browse, Roebuck and Carnarvon Sub-basin occurs to the south of an east–west fault zone basins in Western Australia, the Bonaparte Basin forms part in onshore areas of the basin, mostly in Western Australia. of the Late Paleozoic to Cenozoic Westralian Superbasin The Proterozoic Pincombe Inlier separates the Carlton Sub- (Bradshaw et al 1988), which extends along the northwestern basin to the west from a northerly plunging syncline to continental margin of Australia from the Arafura Sea in the the east that forms the Late Devonian–Carboniferous Burt north to the Exmouth Plateau in the south. Range Sub-basin (Sweet 1977). The Pincombe Inlier was a The boundaries of the Bonaparte Basin are not well probable emergent palaeohigh through the Late Devonian to GH¿QHG2QVKRUHDUHDVLQWKHVRXWKDUHIDXOWHGDJDLQVWWKH Early Carboniferous (Jorgensen et al 1990). 3LQH&UHHN2URJHQDQG9LFWRULDDQG.LPEHUOH\EDVLQV7R The regional geology and stratigraphic succession of the the northwest, the basin extends across the Timor Sea to Bonaparte Basin has been described by many authors over the the Timor Trough, where water depths exceed 3000 m. To last half century. Regional studies of the onshore succession the east the basin is bounded by the Lynedoch Bank Fault include Traves (1955), Brady et al 9HHYHUV DQG System, which separates it from the Money Shoal Basin, Roberts (1968), Dickins et al (1972), Laws (1981), Whitehead and to the southwest, it adjoins the offshore Browse Basin and Fahey (1985), Beere and Mory (1986), Mory (1988, (Figure 36.1). Elements of the stratigraphic succession are 0RU\DQG%HHUH /DYHULQJDQG2]LPLF continuous with those of adjacent offshore basins. Petroconsultants (1990), McConachie et al (1996) and Dunster The Bonaparte Basin is structurally complex and et al 6LJQL¿FDQWVWXGLHVRIWKHRIIVKRUHVXFFHVVLRQV consists of a number of Palaeozoic and Mesozoic platform LQFOXGH/DZVDQG.UDXV *XQQ /HHDQG*XQQ areas and sub-basins (Mory 1991, Figures 36.1, 36.2). The (1988), Gunn and Ly (1989), MacDaniel (1988), Mory (1988, Vulcan Sub-basin is a major northeast-trending Late Jurassic 1991), Botten and Wulff (1990), Petroconsultants (1990), rift depocentre in the western part of the Bonaparte Basin. +RFNLQJet al :RRGV *RUWHU DQXPEHU It is separated from the Ashmore Platform to the west and of papers in Ellis et al *RUWHUet al (2005, 2008, 2009) WKH/RQGRQGHUU\+LJKWRWKHHDVWE\WZRHQHFKHORQIDXOW and Bourget et al6LJQL¿FDQWVXPPDULHVRIWKHEDVLQ systems. The Ashmore Platform is a large elevated block include Longley et al &DGPDQDQG7HPSOH DQG ORFDWHG WR WKH ZHVW RI WKH9XOFDQ VXEEDVLQ ,W FRQWDLQV D Geoscience Australia (2009, 2011). UHODWLYHO\ WKLQ VXFFHVVLRQ RI ÀDWO\LQJ &UHWDFHRXV VWUDWD 7KH %RQDSDUWH %DVLQ FRQWDLQV VLJQL¿FDQW RLO DQG JDV overlying Permian–Triassic rocks which were faulted and accumulations and is an important petroleum producer. eroded during the Jurassic. The Londonderry High comprises 2QVKRUHSRUWLRQVRIWKHEDVLQLQWKH17DQG:$FRQWDLQDQ elevated Permian–Triassic rocks with thin Late Jurassic and H[WHQVLYH0LVVLVVLSSL9DOOH\W\SHEDVHPHWDOVSURYLQFH Cretaceous cover. The Sahul Platform is also an elevated This chapter focuses on the onshore sedimentary basement area overlain by less than 5000 m of Late Permian VXFFHVVLRQVRIWKH3HWUHODQG.HHS,QOHWVXEEDVLQVLQWKH17 to Cenozoic rocks. It was uplifted to form a structural high A full discussion of the other components of the Bonaparte during Jurassic extension of the adjacent Malita and Calder %DVLQLVEH\RQGWKHVFRSHRIWKLVYROXPH+RZHYHUEULHI grabens. The Malita Graben is a northeast-trending trough VXPPDULHV RI WKH PLGGOH &DPEULDQ±(DUO\ 2UGRYLFLDQ between the Sahul Platform and Darwin Shelf. Its eastward Carlton Group, which only outcrops in the Carlton Sub- extension is known as the Calder Graben. Both grabens basin in Western Australia, and of the offshore successions contain a thick succession of late Palaeozoic, Triassic, of the Petrel Sub-basin are also included. Jurassic and Early Cretaceous sedimentary rocks. They were developed during the Middle Jurassic as a result of rifting Southeastern Bonaparte Basin prior to the break-up of Gondwana. The northwest-trending Sahul and Flamingo synclines are depocentres that link and 7KHVRXWKHDVWHUQ%RQDSDUWH%DVLQLQFOXGHVWKH3HWUHO.HHS RIIVHWWKHQRUWKHDVWWUHQGLQJ9XOFDQ6XEEDVLQDQG0DOLWD Inlet and Carlton sub-basins. The Petrel Sub-basin is located and Calder grabens. They are separated by the Laminaria mostly offshore in the Joseph Bonaparte Gulf, but extends and Flamingo highs. The Petrel Sub-basin Figure 36.2) is a onshore into coastal areas of the NT (Figure 36.2). The sub- broad northwest-trending Palaeozoic rift in the southeastern basin is an northwest-trending Palaeozoic rift (Figure 36.3) Bonaparte Basin that extends into onshore areas of the that contains a succession of thick Palaeozoic and thinner NT and Western Australia. It contains a thick Palaeozoic Mesozoic sedimentary rocks. The eastern and western succession overlain by thinner Mesozoic sedimentary rocks. margins of the sub-basin are both faulted and converge to the 2IIVKRUHWKH3HWUHO6XEEDVLQH[SHULHQFHG/DWH3DODHR]RLF south. To the east, the onshore Petrel Sub-basin and poorly and Mesozoic rifting that has resulted in a northeast-trending GH¿QHG.HHS,QOHW6XEEDVLQDUHERUGHUHGE\WKH3URWHUR]RLF structural overprint. The Darwin Shelf, to the northeast of the 3LQH&UHHN2URJHQ)LW]PDXULFH%DVLQDQG+DOOV&UHHN Petrel Sub-basin, represents a thin succession of Jurassic to 2URJHQZKHUHDVWRWKHVRXWKZHVWDQGVRXWKWKH3HWUHODQG Cenozoic sedimentary rocks. The Keep Inlet Sub-basin refers onshore Carlton and Burt Range sub-basins abut Proterozoic to a poorly developed depocentre to the east and southeast URFNV RI WKH .LPEHUOH\ 6SHHZDK DQG &DUU%R\G EDVLQV RI WKH 7XUWOH%DUQHWW +LJK ZKLFK H[WHQGV RQVKRUH WR WKH Proterozoic basement rocks form extensive shelves around QRUWKRIGULOOKROH.HHS5LYHULQQRUWKHDVW$89(5*1(1 the eastern, western and southern margins of the southeastern DQG SRVVLEO\ WR WKH HDVW DV SDUW RI WKH .XOVKLOO