A Mesoproterozoic continental flood rhyolite province, the Gawler Ranges, Australia: the end member example of the Large Igneous Province clan
A Mesoproterozoic continental flood rhyolite province, the Gawler Ranges, Australia: the end member example of the Large Igneous Province clan
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DOI：
10.5194/se-2-25-2011
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发表时间：
2010-09
期刊：
影响因子：
3.4
通讯作者：
M. Pankhurst;B. Schaefer;P. Betts;N. Phillips;M. Hand
中科院分区：
文献类型：
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作者：
M. Pankhurst;B. Schaefer;P. Betts;N. Phillips;M. Hand
摘要。南澳大利亚中元古代高勒山脉（GRV）上部的流纹岩和英安岩熔岩（保存了约30万km3）是地球上保存的最大量的长英质岩浆事件之一的遗迹。地球物理解释表明，火山喷发来自一个中央的支线喷口群，这些喷口提供了长约100公里的大规模叶状流。鸽子反演温度计显示喷发温度为950-1100℃。熔岩在组成上为a型（例如高Ga/Al比率），其特征是原生卤素浓度升高（氟~1600 ppm，氯~400 ppm）。这些岩浆解聚，使得温度-成分-挥发性非阿仑熔体粘度模型表明它们的粘度为
Abstract. 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