modern research physics

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The Javaherdasht basalts have considerable outcrops in the north part of Alborz mountains in the east of Guilan province.The petrographical, geochemical and isotopical evidence is indicative of the contamination of the basalts with continental crust. The petrographical evidence such as corosion gulf and crenated margins in pyroxene phenocrysts and chemical composition difference between clinopyroxene phenocrysts margins with matrix clinopyroxenes suggest of crustal contamination and nonequilibrium due to the change of matrix composition as compared with pre-existed phenocrysts in rock .The depletion in elements such as Zr, Nb,TiO2 ,P2O5 and enrichment of LIL elements,high ratios of Pb/Nd and Ba/Nd,low content of Zr/Nb,Y/Nb,Ce/Pb, positive correlation between SiO2 and 87 Sr/86Sr and positive correlatian between MgO and Nd are geochemical and isotopical evidences of crustal contamination of these basalts. Our studies show that these basalts have a clear elemental equilibrium with lower and middle crust rocks and that they have been contaminated with them.

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Malayer granitoid rocks, as a part of Sanandaj-Sirjan plutonism, are located at latitude 34°00´-34°18´ and longitude 48°30´-48°52´. Tectono-‌‌magmatic investigation on the history of Sanandaj-Sirjan Zone attributed the formation of these plutonic rocks to convergence of Iranian and Arabian plates in conjunction with subduction of Neo-Tethys in the western part of Sanandaj-Sirjan Zone. Geochemical studies of Major and Trace elements on Malayer granitic rocks reveal that these granitic plutons are formed in a compressive environment, such as active continental margin in the convergent zone of oceanic crust and continental plate at the magmatic arc of continental margin. High ratio of LILEs/HFSEs and negative anomaly of Sr, Nb, Ba and Ta confirm the relation of these granitoids to subduction zone. These, also point out the role of shallow continental crust in formation and evolution of granitoidic magma. Broad range of mineral composition in petrographical observations and large variations in field studies, high-K calc-alkaline affinity and assessment of trends observed in AFM, K2O-SiO2, FeO-MgO diagrams versus those of plutons of known tectonic setting accentuate the similarities between Malayer granitic rocks and Andian type Magmatic Arc of Active Continental Margins and as a result highlights the role of upper mantle mafic magmas and tectonic movement in formation of their parental magma.

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Jahagh anticline in south of Kashan is host to the Silurian volcanic rocks at the base of Niure formation (with sandstone lithology).This area is located in the western edge of Central Iran zone. The volcanic rocks under study involved basalt until trachy basalt and contain Plagioclase. These rocks belong to alkali basalt to sub- alkali basalt field on the geochemical diagrams.The investigation of rare earth elements indicate garnet presence in the source with low partial melting degree. High Ti and Zr content in these rocks show that the magmatic series is alkaline- transitional. The geotectonic setting is intracontinental rift that follow the extension phases after Caledonian orogeny and creatie the deep faults in Iran cratonic crust. In all probability, Isfahan fault activation that is one of the old and basal faults in this area cause the eruption and volcanism at Silurian in this part of Iran.

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Productive and non-productive intrusive of Oligocene-Miocene age with similar mineralogical composition in Kerman porphyry copper belt exhibited important geochemical differences in terms of trace and rare earth element geochemistry. The productive intrusives are best characterized by low contents of MnO (&le0.1 wt.%), Y(&le18ppm), &SigmaHFSE (&le۱۰۰ppm), heavy rare earth elements (Yb&le1.9 ppm), high Sr content(&ge406-1015ppm), high (Sr/Y&ge30), significant REE fractionation (La/Yb&ge20), as well as positive Eu anomalies(Eu/Eu&ge1), when compared with non-productive intrusives(MnO&ge0.1wt.%,Sr=184-576ppm,Y=12-50ppm, Sr/Y<30, La/Yb<15,Eu/Eu*<1).These signatures are indicative of hydrous and oxidized magmas that formed in a condition which has been different from that of the non-productive intrusives. Based on the present study, the discrimination diagrams which can be used as a tool for identification of productive intrusives, where they are accompanied by nonproductive intrusives, in other copper provinces in Iran, are as follows: MnO-Y, &SigmaHFSE-Y, Sr/Y-Y, Sr/Y-SiO2 , La/Yb-SiO2, La/Yb-Yb, Eu/Eu*-SiO2.

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The granitoid intrusion trending NW-SE, is expose in the East of Zanjan, structurally located in the Alborz - Azarbaijan zone and Tarom sub-zone. Petrographic composition of the intrusion includes a range of monzogranite, quartz-monzonite, quartz-monzodiorite to monzodiorite and in fact shows monzonite series composition. The major rock forming minerals consist of K-feldspar, plagioclase, pyroxene (augite-diopside) and quartz. They show granular, intergranular, microgranular to porphyrytic-microgranular textures. The intrusion has metaliminus high-K calc-alkaline to shoshonitic and I-type affinity. Enclaves of the intrusion have micro-granular mafic and monzodiorite, quartz monzodiorite composition, which are fine-grained than their host rock and have micro-granular porphyritic texture. According to the petrographical and geochemical studies, the magma has originated from partial melting of metasomitised sub-continental lithospheric mantle due to fluids and/or partial melts that originated from subduction edge. According to Harker Diagrams seems that monzodiorite magmas differentiation Leads to monzonite Formation And finally the Crystallization and differentiation are monzogranite. Therefore Crystallization and differentiation are the most important processes controlling rock types in the monzonite series intrusion. Tectonic diagrams indicate a continental margin magmatic arc and syn-to-post collisional intra-arc extensional environment.