Silicate liquid immiscibility in tholeiitic basalt

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• Bernard Charlier, MIT
• Tuesday 29 November 2011, 16:30-17:30
• Harker 1 seminar room, Department of Earth Sciences.

If you have a question about this talk, please contact John Maclennan.

Liquid-liquid unmixing and the separation of Fe- and Si-rich liquids occur during the evolution of tholeiitic basalt to rhyolite. We will report evidence from plutonic and volcanic settings to revive the initial idea by Daly to explain the dearth of intermediate magmatic compositions at the Earth’s surface. New crystallization experiments on evolved tholeiitic basalts are used to define the compositional space for the development of silicate liquid immiscibility on liquid lines of descent relevant for typical fractionated MORB , Iceland, Deccan, Mull and Snake River Plain lavas and for the Sept Iles layered intrusion where large- scale immiscibility has been recognized. Crystallization conditions favouring or inhibiting the development of immiscibility will be discussed, as well as implications for magma chamber processes and tholeiitic liquid trends.

Charlier B, Namur O, Toplis MJ, Schiano P, Cluzel N, Higgins MD, Vander Auwera J (2011) Large-scale silicate liquid immiscibility during differentiation of tholeiitic basalt to granite and the origin of the Daly gap. Geology 39, 907-910. Holness MB, Stripp G, Humphreys MCS , Veksler IV, Nielsen TFD , Tegner C (2011) Silicate liquid immiscibility within the crystal mush: late-stage magmatic microstructures in the Skaergaard intrusion, East Greenland. Journal of Petrology 52, 175-222. Philpotts AR (1982) Compositions of immiscible liquids in volcanic rocks. Contributions to Mineralogy and Petrology 80, 201-218.

This talk is part of the Department of Earth Sciences Seminars (downtown) series.

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• Department of Earth Sciences Seminars (downtown)
• Department of Earth Sciences seminars
• Harker 1 seminar room, Department of Earth Sciences
• ps635

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