Paleostress field evolution of the Australian continent since the Eocene

Abstract

[1] Although the low-order present stress field of most continents is fairly well established, information on paleostress fields is generally sparse. Knowledge of paleostresses is crucial for understanding brittle tectonic reactivation through time. The Indian-Australian plate lends itself well to a reconstruction of paleostresses, as it has undergone enormous changes in plate-driving forces through the Tertiary, and there is a rich record of fault reactivation from sedimentary basins. We reconstruct the plate boundary configuration and age-area distribution of ocean crust around Australia through time to obtain estimates for ridge push, slab pull, and collisional forces acting on the Indian-Australian plate since the Eocene. Other model parameters we explore are the effects of the Australian-Antarctic discordance and the mechanical strength of the Australian continental margin. We apply these constraints to model the orientation of the maximum horizontal compressive stress (S Hmax ) regime for the present, early Miocene, and early Eocene using the commercial software ABAQUS 2 along with the optimization software Nimrod/O. We use an elastic two-dimensional plane stress finite element model with a resolution of $0.2°in both longitude and latitude. Realistic elastic parameters representing different rock types and geologic provinces for the Australian continent have been included to model the stress field of a heterogeneous plate. We show that spatially significant rotations of S Hmax directions can be modeled as a consequence of perturbations of S Hmax in areas of juxtaposed rigid and compliant rheologies. The absence of the collisional Papua New Guinea boundary in the Miocene and reduced ridge push force from the south result in stress directions considerably different from the present. Stress directions over the northern Australian continent in the early Miocene in particular show large disparity with present stress directions. Stress orientations for the Australian plate during the early Eocene are controlled predominantly by ridge push forces arising from spreading in the Wharton Basin in the Indian Ocean and vary substantially with stress directions in the early Miocene and the present because of the drastically different plate geometry and boundary configurations. Fault reactivation histories observed on the northwest shelf of Australia and in the Bass Strait region are consistent with modeled changes in stress directions through time.

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“…Subsequent rifting episodes occurred during the Late Triassic-Early Jurassic and Late Jurassic (von Rad, Haq, et al, 1992;Driscoll and Karner, 1998) with the final rifting in the latest Jurassic also culminating in earliest Cretaceous separation of greater India from Australia (Boote and Kirk, 1989;von Rad, Haq, et al, 1992;Heine and Müller, 2005). The postrift thermal subsidence history of the margin has been affected by mild shortening, generally attributed to plate boundary forces resulting from plate reorganization (Romine et al, 1997;Driscoll and Karner, 1998;Sayers et al, 2001;Cathro et al, 2003;Dyksterhuis et al, 2005). The most recent major nearby tectonic event was the late Miocene collision between northern Australia and the Banda arc (Audley-Charles et al, 1988;Lee and Lawver, 1995;Richardson and Blundell, 1996).…”

Subsurface architecture of the Texas Orocline and its influence on in situ stresses in the overlying Surat Basin

“…Stress deviations associated with changes in the mechanical properties of rocks have been well documented on a local (Teufel 1991, Aleksandrowski et al 1992, Martin & Chandler 1993, Bell 1996b) and regional (Bell 1996b, Zhao & Müller 2003, Dyksterhuis et al 2005a, Dyksterhuis et al 2005b, Dyksterhuis & Müller 2008, Müller et al 2012 scale. consequently be attributed to the dampening of tectonic stress within the geomechanically "softer" trough, acting as a regional control on in situ stress.…”

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

“…However, the timing of faulting can be constrained indirectly by considering the age of displaced rocks, the deformation history of Mesozoic-Cenozoic sedimentary basins in the region, and the comparison of the results with modeled paleostress maps (Dyksterhuis et al, 2005a;Dyksterhuis and Müller, 2008;Muller et al, 2012). In the following sections, I discuss the deformation and fault reactivation in the NPFS in the context of the three major stages in the Mesozoic and Cenozoic tectonic evolution of eastern Australia.…”

“…The latter interpretation seems to be more reasonable, as most of other NW-striking sinistral faults are younger than early Mesozoic as discussed above. show the average horizontal tensional stress direction during the Late Cretaceous to Eocene (Gaina et al, 1998a;Gaina et al, 1998b;Dyksterhuis et al, 2005b), blue and red arrows show the maximum horizontal compressive stress (Dyksterhuis et al, 2005b;Muller et al, 2012;Babaahmadi and Rosenbaum, 2014a). Note that a component of dextral movement could occur along the Demon Fault during the Miocene (Babaahmadi and Rosenbaum, 2013) in response to ENE-trending maximum horizontal compressive stress (Muller et al, 2012) displacing some NWstriking sinistral faults.…”

“…Ma) (Weissel and Watts, 1979;Gaina et al, 1998a;Gaina et al, 1998b;Dyksterhuis et al, 2005b) ( Figure 2.14a); and (2) compressional far-field stresses transmitted from the northeastern, eastern, and southeastern boundaries of the Australian Plate during the late Eocene-early Oligocene, late…”