gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1986.050.358.13 Pyroxenes and Coexisting Minerals in the Cheviot Granite Haslam H. W. British Geological Survey, 154 Clerkenwell Road, London EC1R 5DU 12 1986 50 358 671 674 31 1 1986 Copyright © 1986, The Mineralogical Society 1986 Abstract

Orthopyroxene and clinopyroxene, with biotite, are widespread in the high-level Cheviot granite, while amphibole is rare. The pyroxene compositions are very close to (Mg,Fe)2Si2O6 and Ca(Mg,Fe)Si2O6. Biotite compositions, with low Si and Al, are characteristic of biotites coexisting with pyroxenes. Geothermometric estimates based on oxide and pyroxene compositions show that present mineral compositions result from post-consolidation equilibration.

 Keywords granite Cheviot rare earth elements pyroxene biotite geothermometry