Petrography of volcanic rocks of south Kahrizak (south Tehran) with an overview to Analcime genesis
Category | Petrology |
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Group | GSI.IR |
Location | 23th symposium on geosciences |
Holding Date | 05 May 2008 |
Abstract:
Tertiary Zeolite bearing volcanic series in south Kahrizak(south Tehran) vary greatly in chemical composition from basic to acid with a silica content between % 45 to %69 . These rocks are consisting of basalt, trachy-andesite to dacite and are mainly located in the calc-alkaline domain. Petrographic evidences show the nonequilibrium condition between melt and crystal during magma cooling and crystallization. Moreover, andesitic rocks are highly altered and contain Zeolite, Analcime, and a few other hydrothermal and secondary minerals. The source and genesis of these minerals are a controversial issue, whereas, the SEM study of some analcime crystals reveals a hydrothermal source for them.