Skip to main content
Article thumbnail
Location of Repository

A mesoproterozoic continental flood rhyolite province, the Gawler Ranges, Australia: the end member example of the Large Igneous Province clan

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

Abstract

Rhyolite and dacite lavas of the Mesoproterozoic upper Gawler Range Volcanics (GRV) (>30 000 km<sup>3</sup> 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

Topics: LCC:Geology, LCC:QE1-996.5, LCC:Science, LCC:Q, DOAJ:Earth Sciences, DOAJ:Earth and Environmental Sciences
Publisher: Copernicus GmbH
Year: 2010
DOI identifier: 10.5194/sed-2-251-2010
OAI identifier: oai:doaj.org/article:bed1ac0616704e13b12305f8f69149bc
Journal:
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://doaj.org/search?source=... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.