Geophysical and geochemical evidence for a new mafic magmatic province within the Northwest Shelf of Australia: Supplementary material

Buried magmatic provinces are rarely identified and difficult to classify. The Northwest Shelf of Australia contains large volumes of potentially interconnected mafic igneous material across several sedimentary basins. However, limited study and a lack of surface exposure have prevented detailed description and classification of these rocks. In this study, the distribution and composition of these mafic igneous rocks is described using an integrated geophysical and geochemical approach, which included over 10,000 km of 2D historical seismic data, well log data and chemical analysis of samples from 14 wells across the Browse, Roebuck, Canning and North Carnarvon basins. Using this combined dataset, we demonstrate interconnectivity of buried mafic igneous rocks across the Northwest Shelf and calculate for these mafic rocks a total surface area exceeding 280,000 km2 and a cumulative minimum volume of ~140,000 km3. Petrology and geochemistry of samples indicate they are basaltic and dolerit...