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چکیده
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The aplites-pegmatites in the Qorveh region, NW Sanandaj-Sirjan zone, Zagros orogen, Iran, appear as dikes intruding various lithologies, such as granite, gabbro, diorite, and marble. These dikes have mostly granitic compositions, and their alumina saturation index (ASI) varies from metaluminous to peraluminous. Comparatively high amounts of incompatible trace elements, such as Nb (up to 109 ppm), Ba and Rb (up to 586 ppm), indicate an evolved composition of these dikes. The zircon U-Pb ages for an aplite sample from the Kangareh area are concordant, but scatter from c. 162 to 132 Ma, whereas allanite yields a 151.0 ± 4.3 Ma age (mean square of weighted deviates, MSWD = 1.4). Allanite of an aplitic dike from the Mayham area gave a U-Pb age of 150.3 ± 4.3 Ma (MSWD = 1.2). The ages obtained for aplite dikes indicate approximately the same ages as previously reported ages (140–160 Ma) for plutonic rocks of the region; therefore, Late Jurassic magmatic (plutonic) activities possibly in a continental arc setting could be an important feature in the region.
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