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Coexisting glasses occurring as inclusions in leucite from lamproites: examples of silicate liquid immiscibility in ultrapotassic magmas

Published online by Cambridge University Press:  05 July 2018

Roger H. Mitchell*
Affiliation:
Department of Geology, Lakehead University, Thunder Bay, Ontario, Canada P7B 5E1

Abstract

Inclusions occurring in leucites from the Oscar and Zirkel Mesa leucite lamproites consist of high (>10 wt.%) and low (<4 wt.%) K2O discrete glass phases which are interpreted to have resulted from silicate liquid immiscibility. Both glasses are quartz-normative and rich in Ti, Fe, Mg, Ca and Ba and poor in Al. The high-K glass is strongly peralkaline. Neither of the glasses have compositions representative of any known lamproites. These inclusions represent the first described examples of silicate-silicate immiscibility shown by glass in alkaline rocks.

Type
Mineralogy and Geochemistry
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1991

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