The dynamics of a very large intra-plate continental basaltic volcanic province, the Newer Volcanics Province, SE Australia, and implications for other provinces
01 Jan 2017-Geological Society, London, Special Publications (Geological Society of London)-Vol. 446, Iss: 1, pp 123-172
TL;DR: 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.
Abstract: Abstract 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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TL;DR: Small-scale volcanic systems are commonly monogenetic in the sense that they are represented at the Earth's surface by fields of small volcanoes, each the product of a temporally restricted eruption of a compositionally distinct batch of magma, and this is in contrast to relatively large edifices built by multiple eruptions over longer periods of time involving magmas with diverse origins.
Abstract: Abstract Small-scale volcanic systems are the most widespread type of volcanism on Earth and occur in all of the main tectonic settings. Most commonly, these systems erupt basaltic magmas within a wide compositional range from strongly silica undersaturated to saturated and oversaturated; less commonly, the spectrum includes more siliceous compositions. Small-scale volcanic systems are commonly monogenetic in the sense that they are represented at the Earth's surface by fields of small volcanoes, each the product of a temporally restricted eruption of a compositionally distinct batch of magma, and this is in contrast to polygenetic systems characterized by relatively large edifices built by multiple eruptions over longer periods of time involving magmas with diverse origins. Eruption styles of small-scale volcanoes range from pyroclastic to effusive, and are strongly controlled by the relative influence of the characteristics of the magmatic system and the surface environment.
115 citations
Cites background from "The dynamics of a very large intra-..."
...Cas et al. (2016) and Murcia et al. (2016) describe regional-scale studies of the western Victorian (Australia) province and the northern part of Harrat Rahat in Saudi Arabia....
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TL;DR: In this article, the authors use results from seismic tomography to demonstrate a clear link between lithospheric thickness and the occurrence, composition and volume of volcanic outcrop, and find that non age-progressive lava fields overlie significant cavities in the base of the lithosphere.
Abstract: Cenozoic intraplate volcanism is widespread throughout much of eastern Australia, and manifests as both age-progressive volcanic tracks and non-age progressive lava-fields. Various mechanisms have been invoked to explain the origin and distribution of the volcanism, but a broad consensus remains elusive. We use results from seismic tomography to demonstrate a clear link between lithospheric thickness and the occurrence, composition and volume of volcanic outcrop. Furthermore, we find that non age-progressive lava-fields overlie significant cavities in the base of the lithosphere. Based on numerical simulations of mantle flow, we show that these cavities generate vigorous mantle upwellings, which likely promote decompression melting. However, due to the intermittent nature of the lava-field volcanics over the last 50 Ma, it is probable that transient mechanisms also operate to induce or enhance melting. In the case of the Newer Volcanics Province, the passage of a nearby plume appears to be a likely candidate. Our results demonstrate why detailed 3-D variations in lithospheric thickness, plate motion and transient sources of mantle heterogeneity need to be considered when studying the origin of non age-progressive volcanism in continental interiors.
41 citations
TL;DR: In this paper, the authors used 3D seismic data to describe the magma plumbing system of the Bight Basin Igneous Complex; a volcanic province located along the Magma-poor southern Australian margin.
37 citations
TL;DR: In this article, the authors analyzed a natural analogue of CO2 storage, migration and leakage to the atmosphere, using noble gas and stable isotopes to constrain the effect of these processes on the geochemical fingerprint of the CO2.
23 citations
Cites background from "The dynamics of a very large intra-..."
...Many of 142 the oldest eruptive centres are found in the eastern side of the province and near the CVH (4.6 - 2.6 143 Ma) (Price et al., 1997), but no systematic pattern of eruptions ages exists (Cas et al., 2017)....
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...Elements of the figure adapted from 173 (Cartwright et al., 2002; Bernecker and Moore, 2003; Watson et al., 2003; Cayley et al., 2011; Cas et al., 2017)....
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...The 139 province is a well preserved intra-plate basaltic lava field with more than 400 eruptive centres 140 (Boyce, 2013), active between 5 Ma and 4.5 ka (Cas et al., 2017)....
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TL;DR: In this paper, a part of the Great Australian Bight Deepwater Marine Program (GABDMP) for funding this project is described, where 3D seismic data was gratefully provided by TGS.
Abstract: This work comprises a part of the Great Australian Bight Deepwater Marine Program (GABDMP) for funding this project. The GABDMP is a CSIRO research program, sponsored by Chevron Australia the results of which will be made publicly available. 3D seismic data was gratefully provided by TGS. IHS are thanked for access to seismic interpretation software. Spectral decomposition was carried out using Foster-Findlay Associates Geoteric Software. Sverre Planke and Tracy Gregg are thanked for constructive reviews.
21 citations
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