The volcano-tectonic setting of the intraplate, Pliocene-Holocene, Newer Volcanic Province (SE Australia): the role of crustal fracture zones

摘要

The Pliocene-Holocene Newer Volcanic Province in Victoria, southeast Australia, \udis a wide volcanic field site of the most recent volcanic activity of Australia. The intraplate \udsignature and the localization on the northern side of the Southern Ocean have been \udused in the past to ascribe the volcanic activity either to the presence of a mantle \udhot spot or to thermal anomalies inherited from the seafloor spreading that separated \udAustralia from Antarctica during the Gondwana breakup. The spacing and distribution \udof groups of eruption points suggests the presence of a 32 km deep mantle thermal \udanomaly. Alignments of eruption points indicate a strong tectonic control on magma \udemplacement mainly along NW-SE Mesozoic-Cenozoic structures and along N-S \udPalaeozoic and E-W Late Cretaceous structures. This volcano tectonic setting relates \udto the interference of the left-lateral kinematics of the major N-S trending faults associated \udwith the Tasman Fracture Zone and the extensional structures of the Otway basin. \udThis interpretation is also coherent with stress in situ data and focal mechanisms \udof earthquakes (SHmax oriented N150