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Geochemical and isotopic data (Sr, Nd) are presented for the Khalkhab-Neshveh pluton, an E-W elon gated body of quartz monzogabbro, quartz monzodiorite, granodiorite and granite in the Urumieh Dokhtar magmatic arc of Central Iran. The plutonic rocks are medium-to high-K, metaluminous, and I-type, with 52-71 wt.% Si02_ The geochemistry shows smooth differentiation trends in which most major elements (except AlZ03, KzO and NazO) are negatively correlated with SiOz; I

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The Davarzan-Abbasabad Eocene Volcanics (DAEV) is located at the northeastern edge of the volcanic-plutonic belt of the Central Iran structural zone. DAEV start with continental to shallow marine sediments of the Paleocene-Eocene and then continue extensively with shallow submarine to sub-aerial basaltic and andesitic volcanics, related volcaniclastics and sedimentary rocks during the Middle-Upper Eocene. The volcanics are olivine basalts, basaltic andesites and andesites in composition and show porphyric, hyaloporphyritic, glomeroporphyric, fluidal, and seriate textures. The geochemistry of DAEV points to a fractional series from olivine basalt to andesite with transitional and medium to high K calc-alkaline nature. Their primitive mantle and chondrite-normalized trace element patterns show that these rocks have high light-and low heavy rare earth elements and are enriched in large-ion lithophile elements and depleted in high field strength elements (Nb, Ti, P, and Zr). Integration of geochemical and petrological data with regional studies indicates that the magma(s) forming the DAEV rocks were derived from 14 to 16 % partial melting of an enriched mantle source in 70-100 km depths during Middle-Upper Eocene time in an intra-arc extensional setting. This mantle source had been previously metasomatized by fluids derived from Sabzevar Neo-Tethyan-subducted slab during the Upper Cretaceous-Paleocene.

Neshveh intrusion is located in the NW of Saveh City and is a part of Orumieh-Dokhtar magmatic arc. This intrusion consists of quartz monzodiorite, granodiorite and granite that have intruded into the Eocene volcano-sedimentary rocks. This intrusion is high-K calk-alkaline and metaluminous and is classified as I-type granitoids. Field investigations along with petrographic and geochemical studies indicate that all phases of Neshveh intrusion are derived from a common magma source as a result of mineral differentiation. Different phases of this intrusion have low Mg#, Ni, Cr, Co and V which are indicative for higher evolution of magma during the magma ascent and before complete crystallization. All phases of Neshveh granitoid are characterized by LREE-rich patterns with high LREE/HREE ratio and negative Eu anomalies. Similarity of the mentioned patterns suggests a comagmatic source for these rocks and demonstrates the role of magmatic differentiation in their evolution. There are negative anomalies in the Nb and Ti along with positive anomalies of Rb, Ba, K and Pb on the spider diagrams. These anomalies are indicative for a subduction setting for magma source of these rocks. Geochemical studies indicate that the Neshveh granitoid is formed in a volcanic arc and active continental margin. In this base, it is assumed that this intrusion is formed as a result of Neo-Tethys oceanic lithosphere subduction beneath the Central Iran zone which is replaced in the Orumieh-Dokhtar magmatic arc.