L178 Central Victoria (Stawell / Bendigo / Melbourne Zones) Seismic Transect, VIC, 2006 Stacked and Migrated Seismic data and images for line 06GA-V1, 06GA-V2, 06GA-V3, and 06GA-V4

A ~400 km long deep crustal reflection seismic survey was acquired in central Victoria, Australia, in2006. It has provided information on crustal architecture across the western Lachlan Orogen and hasgreatly added to the understanding of the tectonic evolution. The east-dipping Moyston Fault isconfirmed as the suture between the Delamerian and western Lachlan Orogens, and is shown toextend down to the Moho. The Avoca Fault, the boundary between the Stawell and Bendigo Zones, isa west-dipping listric reverse fault that intersects the Moyston Fault at a depth of about 22 km, forming aV-shaped geometry. Both the Stawell and Bendigo Zones can be divided broadly into a lower crustalregion of interlayered and imbricated metavolcanic and metasedimentary rocks and an upper crustalregion of tightly folded metasedimentary rocks. The Stawell Zone was probably part of a Cambrianaccretionary system along the eastern Gondwanaland margin, and mafic rocks may have been partlyconsumed by Cambrian subduction. Much of the Early Cambrian oceanic crust beneath the BendigoZone was not subducted, and is preserved as a crustal-scale imbricate thrust stack. The seismic datahave shown that a thin-skinned structural model appears to be valid for much of the Melbourne Zone,whereas the Stawell and Bendigo Zones have a thick-skinned structural style. Internal faults in theStawell and Bendigo Zones are mostly west-dipping listric faults, which extend from the surface to nearthe base of the crust. The Heathcote Fault Zone, the boundary between the Bendigo and MelbourneZones, extends to at least 20 km, and possibly to the Moho. A striking feature in the seismic data is themarkedly different seismic character of the mid to lower crust of the Melbourne Zone. The deep seismicreflection data for the Melbourne Zone have revealed a multilayered crustal structure that supports theSelwyn Block model.Raw data for this survey are available on request from [e-mail]