Trachytes and Their Feldspar Phenocrysts

I. S. E. Carmichael
Department of Geology, Imperial College of Science, London, S.W. 7

Summary: The compositions of the groundmass and of the plagioclase and sanidine phenocrysts of a series of over- and under-saturated trachytes indicate that plagioclase will precipitate at some stage in the crystallization interval of all calcium-bearing potassic trachytes. Using this data obtained from natural salic liquids, a concept of crystallization within the system CaA2Si2O8-NaAlSiO4-KAlSiO4-SiO2 may be obtained.

Mineralogical Magazine; 1965 v. 34; no. 268; p. 107-125; DOI: 10.1180/minmag.1965.034.268.09
© 1965, The Mineralogical Society
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