3D seismic reflection constraints on the emplacement of mafic laccoliths and their role in shallow crustal magma transport: A case study from the ceduna sub-basin, Great Australian Bight

Abstract Magma plumbing systems transport and store magma in the subsurface, as well as playing an important role in feeding eruptions and inducing overburden deformation. Whilst the important role of sills and dikes in these systems is well documented, the three-dimensional (3D) morphology of mafic laccoliths and their role in magma transport and eruption is less well understood. This is due to a paucity of well-documented examples from 3D seismic reflection data, and the limited exposure provided by field examples. Here we use 3D seismic reflection data to document for the morphology and emplacement of a multi-lobed laccolith of inferred mafic composition (the Hammerhead Laccolith (HHL)). This middle Eocene-age intrusion was emplaced at