Abstract

Melting of basic to intermediate composition effusives enclosed in granitic magma forms a hybrid magma which subsequently can crystallize into granodiorite, quartz-diorite, and diorite. Crystallization of this hybrid magmatic melt proceeds along lines different from a normal differentiation of granitic magmas. Plagioclase in hybrid rocks is strongly zoned and dominantly andesine approaching, in places, the composition of labradorite. Outer zones of these crystals are andesine and oligoclase. In granitic rocks plagioclase is acid andesine to oligoclase. Outer zones get up to albite in composition. Pyriboles and biotite also show diagnostic optical features for crystallization of hybrid vs primary granitic magmas. Plagioclase composition that is coprecipitating with the crystallization of ferromagnesians, potassic feldspar, and quartz is of critical importance. Granitic and alaskitic magmas, in contrast to hybrid magmas, undergo anchieutectic crystallization. Changes in the alkali regimen of each of the two...

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.