Complex evolution of volcanic arcs: The lithofacies and palaeogeography of the Cambrian Stavely Arc, Delamerian Fold Belt, Western Victoria

The Mount Stavely Volcanic Complex is a Cambrian greenstone belt in western Victoria (Australia), which formed as a continental arc during subduction of the proto-Pacific plate under Gondwana. While the MSVC has been broadly described in literature, its lithofacies and palaeogeography remains unconstrained. The lithofacies that occur throughout the MSVC were characterised using field work, and diamond drill core from the Geological Survey of Victoria. The majority of the MSVC consists of fragmental facies that were deposited in a deep-marine environment. These deposits were subsequently intruded by melts, which formed the coherent facies; some became either shallow-intrusive or even extrusive. The volcanic processes that formed the Mount Stavely Volcanic Complex are similar to those currently occurring in the present-day Kermadec Arc. Furthermore the submarine nature of these volcanic facies is similar to the Cambrian Mount Read Volcanics in Tasmania. However, in timing and cause of volcanic activity, not all of these ancient volcanic terranes are related. These findings help constrain the depositional environment in which the Mount Stavely Volcanic Complex was emplaced, which in turn provides important constraints for the tectonic reconstruction of Gondwana.