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The partial melting of basalt and its enclosed mineral-filled cavities at Scawt Hill, Co. Antrim

Published online by Cambridge University Press:  05 July 2018

D. E. Kitchen
D. E. Kitchen*
Affiliation:
Department of Environmental Studies, University of Ulster, Jordanstown, Co. Antrim, Northern Ireland BT37 0QB
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Abstract

Partially melted basalts enclosing amygdales which have been completely melted formed at Scawt Hill adjacent to a Tertiary dolerite plug. Melting of the basalts commenced in a clay-rich mesostasis to produce a feldspathic liquid which then crystallized to an assemblage of dendritic olivine, skeletal hypersthene, opaque oxide and Mg-hercynite in a microcrystalline plagioclase matrix. An original mineral assemblage of zeolite, calcite, and saponite-nontronite in the amygdales melted and quenched to a brown glass now containing complexly zoned pyroxenes with plagioclase and opaque oxide. Melting commenced between 700–800°C, reaching a maximum temperature of 1168°C, and was followed by rapid cooling. The assimilation of remelted basalt may alter the course of crystallization of contaminated magmas.

Keywords

basaltsmeltingamygdalesScawt HillCo. AntrimNorthern Ireland
Type
Research Article
Information
Mineralogical Magazine , Volume 49 , Issue 354 , December 1985 , pp. 655 - 662
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1985

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