Combining geophysical data and calcite twin stress inversion to refine the tectonic history of subsurface and offshore provinces: A case study on the Cooper-Eromanga Basin, Australia

Abstract

The use of core samples, borehole image logs, and seismic data is common practice for obtaining valuable structural data; however, these data are often obtained in isolation from other methods and not usually used for paleostress inversion processes. Therefore, for the first time, we present a new approach for constraining paleoprincipal stress orientations and regimes by integrating geophysical data (seismic and well data) with calcite twin principal stress orientation inversion analysis to refine the evolution of entirely subsurface or offshore basins; a case study on the subsurface Cooper-Eromanga Basin, Australia. Calcite samples were collected from oriented core, natural fracture data collected from borehole image logs, and fault data interpreted from three-dimensional seismic surveys. The analysis of microscale, mesoscale and macroscale data constrained the paleoprincipal stress orientations and regimes of six successive tectonic events: (1) NNW-SSE oriented strike-slip Carboniferous Alice Springs event; (2) SE-NW oriented compressional Mid-Permian event; (3) NE-SW oriented strike-slip Late Permian Daralingie event; (4) E-W compressional Late Triassic Hunter-Bowen event; (5) E-W compressional Late Cretaceous event; and (6) N-S compressional Paleogene event. This study shows the applicability of integrating geophysics with calcite twin stress inversion to decipher the tectonic evolution of entirely subsurface and offshore provinces.