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چکیده
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The Nasrand pluton of Oligo-Miocen age, which is located in south-east of Ardestan, intruded into Eocene volcanic rocks of the Urumieh-Dokhtar magmatic belt. This pluton consists mainly of granite and granodiorite, and has been intruded by a series diabase dikes. The nasrand plutonic rocks are metaluminous, with mineralogical and geochemical characteristics of I-type calc-alkaline to high-K calc-alkaline granite. They are characterized by enrichment of LREE and LILE, depletion of HREE and HFSE, negative anomalies of Ti, Nb, P, Ba, and positive anomalies of U, K, Th, Rb, Ba, associated with high Ba/Nb ratio and interpreted to reflect emplacement of the plutonic rocks in an active continental margin. The Nasrand granitic pluton and its diabase dikes were all derived from partial melting of the lower continental crust, but it seems that the granitic rocks are slightly more fractionated than diabase dikes and may be modified by assimilation of upper crustal materials.
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