Petrogenetic evolution of the torfajökull volcanic complex, Iceland II. The role of magma mixing

Journal of Petrology
By: , and 

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Abstract

In southern Iceland, tholeiitic basalt magmas propagating laterally from the active Eastern Rift Zone into the older cmstal segment of the South Eastern Zone have been injected into Torfajökull, a mature volcanic centre dominated by rhyolites. Eruptions of complex suites of mixed and hybrid rocks have been triggered, involving tholeiites of the rift zone and transitional basalts and rhyolites of the Torfajökull centre. Three-component hybrids are an unusual feature of the activity. The distribution of various magma mixing and hybrid types is related to the periodic injection of tholeiite into a magma chamber, or chambers, where rhyolite overlies parental transitional basalts.Pre-postglacial rhyolites (>10000 y) at Torfajokull are predominantly peralkaline, whereas later rhyolites are, with few exceptions, subalkaline. Furthermore, the injection of rift zone magmas, and the consequent abundance of rhyolite-basalt mixing, have been important features of magmatism at the centre only in postglacial times. Reduced repose times in the magma reservoirs have prevented the production of peralkaline rhyolites. These trends are interpreted in terms of the southerly migration of the Eastern Rift Zone. © 1990 Oxford University Press.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Petrogenetic evolution of the torfajökull volcanic complex, Iceland II. The role of magma mixing
Series title Journal of Petrology
DOI 10.1093/petrology/31.2.461
Volume 31
Issue 2
Year Published 1990
Language English
Publisher Oxford University Press
Description 21 p.
First page 461
Last page 481
Country Iceland
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