The dynamics of a very large intra-plate continental basaltic volcanic province, the Newer Volcanics Province, SE Australia, and implications for other provinces
R. A. F. Cas, J. van Otterloo, T. N. Blaikie, J. van den Hove, 2017. "The dynamics of a very large intra-plate continental basaltic volcanic province, the Newer Volcanics Province, SE Australia, and implications for other provinces", Monogenetic Volcanism, K. Németh, G. Carrasco-Núñez, J. J. Aranda-Gómez, I. E. M. Smith
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The Newer Volcanics Province of SE Australia is a very large continental basaltic province, with an area of >23 000 km2, a dense rock equivalent volume of <900 km3 and >400 monogenetic volcanoes; it has been active since c. 8 Ma. Lava fields, shields, scoria cones are common, and there are >40 maars and volcanic complexes. Maars occur dominantly in the south where magmas erupted through Tertiary sedimentary aquifers, whereas in the north, over Palaeozoic crust, there are few. Complex interactions of the magma volatile content, magma ascent rates, conduit characteristics and the availability and depth of aquifers caused diverse eruption styles. Volcanoes commonly occur close to major crustal faults, which acted as magma conduits. There is no simple age pattern of volcanism across the province. Volcanism was probably triggered by transtensional decompression in the crust where fault sets intersect, affecting hot, hydrated mantle that had welled up through edge-driven convection where the base of the lithosphere thins abruptly at the edge of the continent. Rock compositions range from picritic to basaltic andesitic. Some volcanoes are polymagmatic. Regional geophysical datasets have clarified the regional characteristics of the province, whereas detailed ground magnetic and gravity surveys resulted in new insights into the subsurface structure of maar-diatremes.
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The nature and origin of the small-scale volcanic systems, generally referred to as “monogenetic”, have enjoyed an elevated level of interest during the past decade. There has been recognition that their ostensibly simple volcano types are a window into the nature of explosive volcanism, landscape evolution and the processes of magma generation in the Earth’s upper mantle. In the past few years, major conferences have offered specialized technical sessions dealing with monogenetic volcanism and there have been thematic conferences, such as the IAVCEI International Maar Conference series, which have provided a focus for discussion of volcanological and geochemical aspects of small-scale basaltic volcanism. Many new aspects of monogenetic volcanism have emerged and have clearly demonstrated that this volcanism can be very complex on a fine scale. This book is a collection of papers arising from two recent Maar Conferences (the fifth in Queretaro Mexico and the sixth in Changchun, China) and serves as a snapshot of current research on monogenetic volcanism.