Petrology
sara shakiba; ali asghar sepahi; Mohammad reza Ghasempour; kazu nakashima
Abstract
Alvand plutonic body is one of the largest intrusive plutons in northern part of Sanandaj-Sirjan zone which is located in south of Hamadan city. It is composed of porphyroid and leucocratic granitoids, basic intrusive rocks, and abundant enclaves in various sizes and in a variety of forms. Biotites of ...
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Alvand plutonic body is one of the largest intrusive plutons in northern part of Sanandaj-Sirjan zone which is located in south of Hamadan city. It is composed of porphyroid and leucocratic granitoids, basic intrusive rocks, and abundant enclaves in various sizes and in a variety of forms. Biotites of porphyroid monzogranite, diorite, felsic microgranular enclave, mafic microgranular enclave and surmicaceous enclaves are located in magnesian biotites and biotites of norites in phlogopite field. Orthopyroxenes of norite are clinoenstatite and orthopyroxenes of mafic microgranular enclaves are clinofrosilite. Based on the Ti-in-biotite thermometer, temperature of monzogranite porphyroid is 662 to 734 oC, norite is 688 to 776 oC, diorite is 598 to 724 oC, surmicaceous enclaves temperature is 662 to 687 oC, felsic microgranular enclaves is 694 to 712 oC and mafic microgranolar enclaves is 635 to 737 oC. the enclaves of the Alvand plutonic body and their host rocks are located in the field of calc-alkaline suite. Orthopyroxenes in the norite and mafic microgranular enclaves indicate that rocks of the Alvand intrusive complex are located in the field of high oxygen fugacity rocks. It is in accordance with calc-alkaline property of rocks and is consistent with the subduction-related tectono-magmatic environment.
