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| Titel |
A Mesoproterozoic continental flood rhyolite province, the Gawler Ranges, Australia: the end member example of the Large Igneous Province clan |
| VerfasserIn |
M. J. Pankhurst, B. F. Schaefer, P. G. Betts, N. Phillips, M. Hand |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 2, no. 1 ; Nr. 2, no. 1 (2011-03-31), S.25-33 |
| Datensatznummer |
250000450
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| Publikation (Nr.) |
 copernicus.org/se-2-25-2011.pdf |
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| Zusammenfassung |
| Rhyolite and dacite lavas of the Mesoproterozoic upper Gawler Range
Volcanics (GRV) (>30 000 km3 preserved), South Australia, represent
the remnants of one of the most voluminous felsic magmatic events preserved
on Earth. Geophysical interpretation suggests eruption from a central
cluster of feeder vents which supplied large-scale lobate flows >100 km in
length. Pigeonite inversion thermometers indicate eruption temperatures of
950–1100 °C. The lavas are A-type in composition (e.g. high Ga/Al
ratios) and characterised by elevated primary halogen concentrations (~1600 ppm fluorine, ~400 ppm chlorine). These depolymerised the
magma such that temperature-composition-volatile non-Arrhenian melt
viscosity modelling suggests they had viscosities of <3.5 log η (Pa s). These physicochemical properties have led to the emplacement of a Large
Rhyolite Province, which has affinities in emplacement style to Large
Basaltic Provinces. The low viscosity of these felsic magmas has produced a
unique igneous system on a scale which is either not present or poorly
preserved elsewhere on the planet. The Gawler Range Volcanic Province
represents the erupted portion of the felsic end member of the family of
voluminous, rapidly emplaced terrestrial magmatic provinces. |
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