A Mesoproterozoic continental flood rhyolite province, the Gawler Ranges, Australia

the end member example of the Large Igneous Province clan

M. J. Pankhurst*, B. F. Schaefer, P. G. Betts, N. Phillips, M. Hand

*Corresponding author for this work

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Rhyolite and dacite lavas of the Mesoproterozoic upper Gawler Range Volcanics (GRV) (>30000 km3preserved), 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 (∼1600ppm fluorine, ∼400ppm chlorine). These depolymerised the magma such that temperature-composition-volatile non-Arrhenian melt viscosity modelling suggests they had viscosities of <3.51og η (Pas). 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.

Original languageEnglish
Pages (from-to)25-33
Number of pages9
JournalSolid Earth
Volume2
Issue number1
DOIs
Publication statusPublished - 2011

Fingerprint Dive into the research topics of 'A Mesoproterozoic continental flood rhyolite province, the Gawler Ranges, Australia: the end member example of the Large Igneous Province clan'. Together they form a unique fingerprint.

  • Cite this