New evidence of Tasmania's tectonic history from a novel seismic experiment

In March 1995, 44 land-based recorders were deployed throughout Tasmania, S E Australia, to record seismic energy from an encircling array of marine no rmal-incidence reflection shot lines. We invert refraction and wide-angle r eflection traveltimes for crustal structure, with the principal outcome bei ng a map of the Tasmanian Moho. Key tectonic inferences from this map inclu de: (1) the Arthur Lineament metamorphic belt in NW Tasmania overlies a maj or change in crustal thickness (over 5 km) and probably represents the NW l imit of deformation in Tasmania during the Mid-Late Cambrian Tyennan Orogen y, (2) thickening of the crust beneath central northern Tasmania may be ass ociated with the juxtaposition of the Eastern and Western Tasmania Terranes during the Mid-Devonian Tabberabberan Orogeny, and (3) the difference in c rustal thickness between the east and west coasts reflects the presence of differing strain regimes during the Cretaceous break-up of Gondwana.