Basin inversion and structural architecture as constraints on fluid flow and Pb–Zn mineralization in the Paleo–Mesoproterozoic sedimentary sequences of northern Australia

Abstract

<jats:p>Abstract. As host to several world-class sediment-hosted Pb–Zn deposits and unknown quantities of conventional and unconventional gas, the variably inverted 1730–1640 Ma Calvert and 1640–1575 Ma Isa superbasins of northern Australia have been the subject of numerous seismic reflection studies with a view to better understanding basin architecture and fluid migration pathways. These studies reveal a structural architecture common to inverted sedimentary basins the world over, including much younger examples known to be prospective for oil and gas in the North Sea and elsewhere, with which they might be usefully compared. Such comparisons lend themselves to suggestions that the mineral and petroleum systems in Paleo–Mesoproterozoic northern Australia may have spatially, if not temporally overlapped and shared a common tectonic driver, consistent with the observation that basinal sequences hosting Pb–Zn mineralization in northern Australia are bituminous or abnormally enriched in hydrocarbons. Sediment-hosted Pb–Zn mineralization coeval with basin inversion first occurred during the 1650–1640 Ma Riversleigh Tectonic Event towards the close of the Calvert Superbasin with further pulses taking place during and subsequent to the onset of the 1620–1580 Ma Isa Orogeny and final closure of the Isa Superbasin. Mineralization is typically hosted by the post-rift or syn-inversion fraction of basin fill, contrary to existing interpretations of Pb–Zn ore genesis where the ore-forming fluids are introduced during the rifting or syn-extensional phase of basin development. Mineralizing fluids were instead expelled upwards during times of crustal shortening into structural and/or chemical traps developing in the hangingwalls of inverted normal faults. Inverted normal faults predominantly strike NNW and ENE, giving rise to a complex architecture of compartmentalized sub-basins whose individual uplifted basement blocks and doubly plunging periclinal folds exerted a strong control not only on the distribution and preservation of potential trap rocks but the direction of fluid flow, culminating in the co-location and trapping of mineralizing and hydrocarbon fluids in the same carbonaceous rocks. An important case study is the 1575 Ma Century Pb–Zn deposit where the carbonaceous host rocks served as both a reductant and basin seal during the influx of more oxidized mineralizing fluids, forcing the latter to give up their Pb and Zn metal. A transpressive tectonic regime in which basin inversion and mineralization were paired to folding, uplift, and erosion during arc–continent or continent–continent collision, and accompanied by orogen-parallel extensional collapse and strike-slip faulting best accounts for the observed relationships. </jats:p>

Selective inversion of rift basins in lithospheric-scale analogue experiments

“…This polydeformed terrane has been affected by multiple extensional and compressional episodes due to its interaction with Laurentia to the east between ∼ 1800 and 1500 Ma (Betts et al, , 2008Gibson et al, 2018;Korsch et al, 2012;Olierook et al, 2022). The Leichhardt superbasin is the oldest exposed basin in the region, cropping out throughout the entire Mount Isa terrane (Gibson and Edwards, 2020;Neumann et al, 2006). A ∼ 20 Myr period of extensional activity was followed by a compressional event known as the Wonga Orogeny (Spence et al, 2022), possibly related to the accretion of the seismically imaged Numil province to the east (Blaikie et al, 2017).…”

“…Early models of Pb-Zn ore formation at Mount Isa suggested that mineralisation occurred during basin formation and was facilitated by fluid transport along active normal faults (Betts et al, 2003;Betts and Lister, 2001). How-ever, more recent interpretations suggest that basin inversion strongly controlled the emplacement of Pb-Zn mineral systems as well as the development of petroleum systems in Mount Isa (Gibson and Edwards, 2020;Gibson et al, 2017). For the ca.…”

“…Our experimental setup is inspired by the Proterozoic basins of the North Australian Craton (northern Australia; , which have long drawn the interest of the petroleum and mineral exploration industries. The mineralrich lithologies of these basins and their multistage history have been associated with the formation of world class mineral deposits, including the world's single largest source of sediment-hosted Pb-Zn deposits (Mount Isa, Queensland; Betts et al, 2003;Large et al, 2005;Gibson et al, 2016;Gibson and Edwards, 2020), the planet's oldest oil deposits (northern Mount Isa Basin, Queensland; Jackson et al, 1986), and conventional and unconventional gas (greater McArthur Basin, Northern Territory;Cox et al, 2022). This distributed system of intra-cratonic basins in the North Australian Craton underwent multiple phases of extensional and compressional deformation driven by far-field plate boundary processes (Giles et al, 2002;Cawood and Korsch, 2008;Betts et al, 2008Betts et al, , 2011Scott et al, 2000;Gibson et al, 2008).…”

Analogue modelling of basin inversion: a review and future perspectives

“…Inverted basins are very common geological features and are found in multiple locations, for instance the North Sea area (Lamplugh, 1919;Glennie and Boegner, 1981;Nalpas et al, 1995;Evans et al, 2003;De Jager, 2003;Hansen et al, 2021), the Pyrenees and European Alps (Pfiffner, 1993;Ziegler et al, 1995;Kiss et al, 2020;Mencos et al, 2015;Lescoutre and Manatschal, 2020;Musso Piantelli et al, 2022), the Atlas Mountains (Vially et al, 1994), Iran (Boutoux et al, 2021), the Araripe Basin in northeastern Brazil (Marques et al, 2014), the Andes (Ferrer et al, 2022b, and references therein), offshore of Korea (Park et al, 2021), and China (Yu et al, 2021), as well as many other places around the globe (Letouzey, 1990;Lowell, 1995;Iaffa et al, 2011;Gibson and Edwards, 2020;Bosworth and Tari, 2021;Dooley and Hudec, 2020).…”

“…Fourth, basin inversion processes and related fluid flow may furthermore lead to the development of economical mineral resources and ore deposits (e.g. Pb-Z mineralizations and Fe-Cu-Au deposits, Sibson and Scott, 1998;Groves and Bierlein, 2007;Hageman et al, 2016;Gibson et al, 2017;Gibson and Edwards, 2020;Liang et al, 2021). Finally, a thorough understanding of basin evolution, including basin inversion, is also of great interest for geothermal energy projects since tectonic displacements can strongly affect the thermal profile of the subsurface (Sandiford, 1999;Edwards et al, 2015;Vidal and Genter, 2018;Doornenbal et al, 2019;Békési et al, 2020;Weibel et al, 2020;Willems et al, 2020).…”