Inelastic yielding and forebulge shape across a modern foreland basin: North West Shelf of Australia, Timor Sea

Abstract

Abstract.The

Mesozoic/Cenozoic tectonic events around Australia

“…Recent collision along the Banda Orogen has created a foreland basin including the Timor Trough and the outer North West Shelf [Lorenzo et al, 1998]. Sea floor faulting due to foreland basin formation occurs within a 300 km radius south of the axis of the Timor Trough and modelled values of the elastic plate thickness suggest that plate flexure due to thrust loading should not affect the North West Shelf south of latitude -14-15°S.…”

“…In the last 10 Ma the Vitiaz Trench became inactive, and subduction was transferred to the New Hebrides Trench, which began a clockwise rotation ( Figure 5b [Scholl, 1995] between the LauColville and Tonga-Kermadec volcanic arcs. Collision along the Banda Orogen northwest of Australia created a foreland basin including the Timor Trough and the outer North West Shelf post-5 Ma [Lorenzo et al, 1998] ( Figure 5 b). Widespread tectonic reactivation occurred on Australia's northwest shelf in the Late Miocene-Pliocene.…”

“…Including a falling eustatic sea level would increase the backstripped tectonic subsidence. Anomalous subsidence and/or uplift has been linked to wrench and inversion tectonics and foreland basin formation [Etheridge et al, 1991 ;Lorenzo et al , 1998;Shuster et al, 1998]. Miocene to recent anomalous subsidence in the Cartier Trough and the Malita Graben has likely been caused by reactivation of rift structures by sinistral shear, as a consequence of oblique collision north of Australia [Shuster et al, 1998].…”

“…This means that the crust at ODP site 765d is at least 500 m too deep if it has subsided according to the plate model. accelerated subsidence, which started at least at 20 Ma, cannot be accounted for by simple foreland basin modelling, as the wavelength of the elastic deformation caused by thrust loading along the Banda Arc does not exceed a few 100 km [Lorenzo et al, 1998]. …”

Structural style in a young flexure-induced oblique extensional system, north-western Bonaparte Basin, Australia

“…At present, the forebulge hinge is located at the shelf margin. Londoño and Lorenzo, 2004;Langhi et al, 2011), as well as sediment and sub-surface loading (Lorenzo et al, 1998). Neogene flexure of the North West Shelf has been variably interpreted to as asymmetric (Bradley and Kidd, 1991;Lorenzo et al, 1998;Shuster et al, 1998) or symmetric as a true orogenic forebulge (Etheridge et al, 1991).…”