پترولوژی (Nov 2017)
Petrology and Geochemistry of Shakh Sefid Granitoid and related skarn in the North of Rayen (southeastern of Kerman)
Abstract
The Shakh Sefid Granitoid pluton and related Skarn are located 80 Km in the southeastern of Kerman and 20 Km north of Rayen. This area is geologically located in the southeastern of the Lut block in the Central Iran. The Shakh Sefid Granitoid with Eocene-Oligocene age cuts the Cretaceous sedimentary rocks and led to the formation of Skarn. The granitoids are granite and granodiorite in composition composing of quartz, plagioclase, orthoclase, as primary minerals, biotite as minor and chlorite and sericite as secondary minerals. The sedimentary rocks are shale, sandstone, siltstone and limestone. Metamorphic rocks are marble and Skarns. The Skarn is calcic type. Garnet (grossular-andradite), tremolite and magnetite are the main minerals that are often accompanied with hematite, goethite and limonite. Pyrite, chalcopyrite and copper carbonate (malachite and azurite) are the other minerals in Skarn. Geochemical studies show that the amount of major and minor elements of granitoid with increasing SiO2 content do not change due to the uniform mass, low dispersion of elements which result from heterogeneous textures and low alteration zone. Spider diagrams from minor elements normalized to Chondrite and primitive mantle show enrichment of all elements except for Ti, positive anomalies of Th, Pb and negative anomalies of Ti, P and Sr for the Sakh Sefid granitoids are probably due to crustal contamination. They are enriched in light rare earth elements (LREE) between 10 to 100 times and heavy elements (HREE) enrichment between 1 to 10 times compared to the reference (chondrite) and regular pattern with approximately the same slope , the parallel trends indicate that the granitoid rocks share a common source rock . The Shakh Sefid granitoid is I-type, metaluminous to peraluminous belonging to an active continental margin. Mineral and Mineralization in Kuh Shakh Sefid skarn is remarkably similar to iron skarn deposits. Minerals such as garnet and magnetite were formed in an anhydrous prograde stage at T
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