The Neogene tectonic history of the North West Shelf, Australia

Geomorphological evidence of neotectonic deformation in the Carnarvon Basin, Western Australia

“…Reactivation of Gondwana era rift-related structures is well documented in the Carnarvon basin (cf, Clark et al, 2012). The most recent structural reactivation is widely attributed to the reorganization of the northern Australian plate boundary that initiated during the Neogene (Densley et al, 2000;Kaiko and Tait, 2001;Audley-Charles, 2004, 2011Cathro and Karner, 2006;Keep et al, 2007;Hengesh et al, 2011) when the horizontal stress field in the Carnarvon basin realigned to east-west compression Reynolds, 2000, 2003;Hillis et al, 2008;Müller et al, 2012).…”

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“…The postbreakup sedimentary succession forms an ~2000 m thick, relatively uniform blanket over the Scott Plateau and the northeastern margin of Browse Basin. Site U1483 is located south of the Sunda arc, where ongoing collision between Australia and the Eurasia/Pacific arc system has occurred since the Miocene (Keep et al, 2007;Hall, 2012). However, intense Neogene faulting is mainly observed in the southernmost parts of Browse Basin (Barcoo Subbasin), whereas the northern parts are relatively devoid of intense Neogene deformation (Keep et al, 2007).…”

“…This region, which is adjacent to some of the oldest ocean crust still in the world's ocean (Argo Abyssal Plain), has remained a stable passive margin since the breakup of Gondwanaland and the separation of northwest Australia from the Tethyan landmass (Gradstein et al, 1992). As a result of the northward movement of the Australian plate, continuous Neogene deformation along the normal faults that bound the Scott Plateau led to the amplification of relief between the Browse Basin and Scott Plateau and may have resulted in some of the downslope sediment transport seen in the seismic profiles (Keep et al, 2007) and sediment deformation in the cores recovered at this site.…”

“…The top of the first prominent reflector, originally interpreted as the middle Miocene sequence boundary 13.8 Ma), is 0.55 s two-way traveltime (TWT) below the seafloor, equivalent to ~500 mbsf (Rosenthal et al, 2016). Site U1482 is on the Scott Plateau, which corresponds to a subsided platform area that forms the northwestern flank of the northeasttrending Browse Basin (Keep et al, 2007). This region, which is adjacent to some of the oldest ocean crust still in the world's ocean (Argo Abyssal Plain), has remained a stable passive margin since the breakup of Gondwanaland and the separation of northwest Australia from the Tethyan landmass (Gradstein et al, 1992).…”

The geometry, kinematics, and reactivation history of major fault systems in eastern Australia: implications for deformation phases from the Permian to Cenozoic

“…The Australian continent, for example, is situated far from the plate boundaries (Figure 6.1a) and is commonly assumed to be a relatively stable continent. Nonetheless, there is widespread evidence that late Cenozoic intraplate transpressional deformation affected different parts of Australia, mainly through the reactivation of earlier faults (Keep et al, 2000;Dickinson et al, 2001;Sandiford, 2003b, a;Keep et al, 2007;Hillis et al, 2008). This intraplate deformation has been interpreted to result from the far-field stresses, which were transmitted from the Australian plate boundaries (Hillis et al, 2008;Muller et al, 2012).…”