The 3D structure and growth of dykes and dyke-induced faults - EGU 2018 poster

Dyke intrusion can accommodate extension during continental rifting through to seafloor spreading. To track dykes in active rifts, seismicity and ground deformation data is used to detect faults driven by dyke intrusion. It has particularly been recorded that graben-bounding normal faults develop above dykes that open as the host rock extends. Such dyke-induced normal faults have been observed along active continental rifts and oceanic spreading centres, as well as on volcanoes in various tectonic settings and on other planets. We have identified a suite of dykes and dyke-induced faults, which extend for >100 km, in 3D seismic reflection data from offshore NW Australia. These data present a unique opportunity to quantify fault displacement patterns and thereby test hypotheses concerning fault growth above dykes. Associated with the dykes and dyke-induced faults are a series of pit chain craters, similar to structure observed in modern rifts and on other planetary bodies, allowing us to examine their 3D morphology.