GSA talk: Crustal architecture and geological evolution of the Central Lachlan Orogen - new insights from deep crustal seismic

Crustal architecture and geological evolution of the Central Lachlan Orogen: Insights from new deep crustal seismic imaging of the Yathong-Cobar-Hermidale region

The Geological Survey of NSW recently acquired and processed over 500 km of deep crustal seismic reflection data across the Yathong-Cobar-Hermidale areas to constrain the subsurface architecture and better understand the metallogeny of the region. The use of a high-density vibroseis-source and best-practice data processing workflows yielded unprecedented subsurface imaging quality for a hard rock setting. Seismic interpretation reveals that the Hermidale Terrane is an archetypical thick-skinned fold and thrust belt, characterised by west-vergent faulting and folding indicative of very significant (> 40%) east-to-west crustal shortening. Geological and geophysical observations distinguish multiple phases of deformation providing important temporal constraints on the geological evolution of the region. Cross-cutting relationships indicate that most of the shortening and major structures within the Hermidale Terrane formed prior to the late Silurian to Devonian Cobar and Yathong basins, highlighting the importance of the late Ordovician to early Silurian Benambran Orogeny in this region.

You're invited to dinner at The Bank Hotel after the talk. 

Speaker Dr Luke Mahoney is a Senior Geoscientist at GSNSW, specialising in geological and geophysical data interpretation and 3D modelling. He holds a PhD in structural geology and tectonics from The University of Melbourne, and prior to joining the Geological Survey early last year, spent the previous decade working on resource exploration projects throughout Australia and Papua New Guinea.