F Sarjoughian; A Kananian; A Esna-Ashari; J Ahmadian
Abstract
The Kuh-e Dom intrusion with calc-alkaline nature, in the northeast of Ardestan is located in the central part of the Urumieh-Dokhtar Magmatic Arc and includes the felsic and intermediate-mafic units. The felsic unit consists of monzogranite, granodiorite, quartz monzonite and quartz monzodiorite, whereas ...
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The Kuh-e Dom intrusion with calc-alkaline nature, in the northeast of Ardestan is located in the central part of the Urumieh-Dokhtar Magmatic Arc and includes the felsic and intermediate-mafic units. The felsic unit consists of monzogranite, granodiorite, quartz monzonite and quartz monzodiorite, whereas the intermediate-basic rocks comprise gabbro, diorite, quartz diorite, monzodiorite and monzonite. The acidic dykes intruded this intrusion and its surrounding rocks. The various mafic microgranular enclaves of dioritic, quartz dioritic, monzodioritic and quartz monzodioritic composition exposed in the acidic rocks. The zircon U-Pb dating by the LA-ICP-MS method indicates that the ages of the felsic rocks, intermediate-mafic rocks, acidic dikes and enclaves are 51.1±0.4 Ma, 53.9±0.4 Ma, 49.95±0.64 Ma and 50.3±0.8 Ma respectively. These ages are in good agreement with the lower-middle Eocene age of the intrusive body, which is simultaneous with subduction of the Neotethys oceanic crust underneath the Central Iran. This result is in agreement with the previous geochemical result.
R Hendi; A.A Hassani pak
Abstract
This paper is part of the results of researches carried out on geochemical characteristics of sediment-hosted copper deposits in the Tabas-Ravar block trying to identify the mineralization host rock characteristics and the source rock of the sediments in the area. For this purpose, not only the common ...
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This paper is part of the results of researches carried out on geochemical characteristics of sediment-hosted copper deposits in the Tabas-Ravar block trying to identify the mineralization host rock characteristics and the source rock of the sediments in the area. For this purpose, not only the common geochemical samples but also a number of heavy mineral and rock samples were collected from the stream sediments and outcrops of the mineralization host rock, respectively. The clastic parts of minerals and components of sediments in this area have been determined based on the heavy mineral and thin section studies. After this stage, the spatial distribution map of included feldspar and metamorphic components of collected samples were prepared based on the sample sites, using “Indicator Kriging” estimation method. Through comparison made between the drawn map and the uniform geology of the neighbor blocks, the source rock supplying the clastic sediments was identified in the west margin of the Ravar – Tabas block in the area of Kalmard and Posht- e Badam Structural blocks. Zircon crystals were used in order to find out the range of age for the probable source rock from which the clastic contents of the host rock of sediment-hosted copper deposits were derived. Zircon was extracted from host rock and heavy mineral samples taken from the study area. The results for zircon crystals dating indicated the presence of four distinctive statistical populations while the principal population of dating results were in conformity with the range of age of the known source rock in the west margin of the basin source rocks and the frequency distribution of zircon crystal ages have a good coincidence with known orogenic processes in Central Iran. Another part of dating results with over 1Ga, suggests two orogenic phases: one in 1.7-2Ga and the other in more than 2.7Ga for basement mother rock of Central Iran.
M. H. Karimpour; G. L. Farmer; C. R. Stern
Abstract
Biotite-muscovite leucogranite and associated pegmatite intruded meta-ophiolite and meta-flysch (the remnants of Paleo-Tethys) during collision of Turan plate with Iran plate. Four types of pegmatite dykes, crosscutting biotite muscovite leucogranite, are identified. The results of U-Pb zircon ...
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Biotite-muscovite leucogranite and associated pegmatite intruded meta-ophiolite and meta-flysch (the remnants of Paleo-Tethys) during collision of Turan plate with Iran plate. Four types of pegmatite dykes, crosscutting biotite muscovite leucogranite, are identified. The results of U-Pb zircon age of Khajeh Mourad biotite muscovite leucogranite is 205.9 ± 4.1 Ma (Late Triassic, Rhaetian). Chemically, biotite muscovite leucogranite and aplite granite are peraluminous S-type pluton. Magnetic susceptibility of biotite muscovite leucogranite and aplite granite are between than 0-5 × 10-5 and the ratio of ferric to ferrous ratio (< 0.35),therefore they are classified as belonging to the ilmenite-series (reduced type). The total REE content of biotite muscovite leucogranite is between TREE = 130-176 and aplite is very low Total REE = 50.79. They have small negative Eu anomalies (Eu/Eu*= 0.52 to 0.76). The initial 87Sr/86Sr and (143Nd/144Nd)i was recalculated to an age of 205 Ma. Initial 87Sr/86Sr ratios for B-M leucogranite and aplite are 0.708161-0.709853. The (143Nd/144Nd)i isotope composition for B-M leucogranite 0.512214, aplite dykes 0.512024. Initial ε Nd isotope values for B-M leucogranite -6.48 and aplite dykes is -6.83. These values could beconsidered as representative of continental crust-derived magmas. The ratios of Rb/Sr = 1-1.3 and CaO/Na2O » 0.3 of biotite-muscovite leucogranite indicate that the source rock had a composition between meta-pelite and meta-psammite.
