Document Type : Original Paper
Authors
1 Assistant Professor, Department of Geology, University of Hormozgan, Bandar abbas, Hormozgan, Iran
2 Department of Geology, Faculty of Sciences, University of Hormozgan, Iran
3 Department of Geology, Faculty of Sciences, University of Hormozgan, Hormozgan, Iran
4 Department of Geology, Payame Noor University, Tehran, Iran
Abstract
The study area is near Goloumak village, 30 km south of Kerman city. These rock units consist of acidic rhyolite and dacite, as well as intermediate andesite, basalt, and trachy-andesite. Basic igneous rocks are alkaline and intermediate rocks are calc-alkaline to transition range. Volcanic rocks show depletion in Ba, Ti, Nb, and Ta and enrichment of K, Rb, and Th. Basaltic rocks were formed by partial melting of the mantle, based on 87Sr/86Sr and 144Nd/143Nd isotopic ratios. Samples show relative enrichment of 87Sr/86Sr in the mantle array on the Sr-Nd isotope correlation diagram. Basic rocks are affected by subduction of lithospheric slab or mantle crust metasomatism, as per the comparison of studied samples in the 143Nd/144Nd isotope correlation diagram versus 87Sr/86Sr. Based on Sr-Nd geochronological data, the rocks were formed at 12.5 ±2.0 Ma, corresponding to the Miocene for the basaltic rocks. All samples are in a continental arc margin and post-collision volcanic arc. The magma source is from low to intermediate partial melting of the mantle, as indicated by the LREE/HREE ratio of the basic and intermediate. LREE enrichment is due to low partial melting of mantle source and magma contamination by crust materials. Basalts show a low melting degree of the mantle for magma formation. Depletion of these rocks of HREE in the source shows garnet in genesis. La and Sm abundance in the studied composition is similar to magma derived from the enriched mantle, comprising about 1-5% of lherzolitic garnet.
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