The history of movement on the Henty Fault Zone, western Tasmania: An analysis of fault striations

The Henty Fault Zone is a major west‐dipping structure in the economically important Mount Read Volcanics of western Tasmania. It has been active from the Early Palaeozoic to the Tertiary. Detailed investigations of this fault history were carried out using numerical analysis of fault striations. Five generations of fault movement were recognized. The first generation of movement was east‐directed thrusting, which pre‐dates Devonian folding. This phase may correlate with Early Ordovician thrusting on the Great Lyell Fault. High angle reverse faulting took place after the Devonian folding and synchronous with granite intrusion. The last Devonian movement was a sinistral displacement of less than 5 km. The structure was reactivated as a sinistral wrench fault, possibly in the Mesozoic, and a normal fault in the Tertiary.