نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشگاه صنعتی شاهرود
2 گروه پژوهشی ماگمازایی و کانی زایی در ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The Lower Jurassic Abshour gabbro intruded the Upper Paleozoic-Upper Triassic amphibolites of the Sargaz-Abshour metamorphic complexes, resulting in contact metamorphism under sanidinite facies conditions, partial melting of the amphibolites, and generation of quartz diorite-tonalite migmatites (plagiogranite) with pegmatoid structure composed predominantly of amphibole and plagioclase. Chemical composition of feldspar in the gabbros, host amphibolites, and migmatitic pegmatoids fall within the bytownite-anorthite, labradorite and andesine range, respectively. Also, the amphiboles are of calcic-type and include magnesio-hornblende and tschermakite in the gabbros, tschermakite in the host amphibolites, and magnesio-hornblende and tschermakite in the pegmatoid migmatites. Field observations, petrographic studies, and thermobarometric estimates indicate that partial melting of the amphibolites occurred within the contact aureole of the gabbroic intrusion at 508–977 °C and 0.19–6.57 kbar, which are consistent with the metamorphic conditions of the sanidinite facies for partial melting of amphibolites and generation of plagiogranitic melt forming the pegmatoids.
کلیدواژهها [English]
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