List of Articles Tectonic setting

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  1 - Geochemistry and petrology of Qareh-Dash rhyolites from Shahindej- NW Iran: Geochemical features of post- collision volcanism
  Masoumeh Ahangari معصومه  نظری Mohsen Moazzen
  Qareh-Dash rhyolites from the Shahindej area are peraluminous rocks with high SiO2 and K2O contents. These rocks are mainly composed of quartz, K- feldspar and rare plagioclase phenocrysts in a fine-grained K-feldspar rich matrix. Geochemically, Qareh-Dash rhyolites sho More

  Qareh-Dash rhyolites from the Shahindej area are peraluminous rocks with high SiO2 and K2O contents. These rocks are mainly composed of quartz, K- feldspar and rare plagioclase phenocrysts in a fine-grained K-feldspar rich matrix. Geochemically, Qareh-Dash rhyolites show enrichment in LREEs and LILEs and depletion in HREEs. Field studies, textural and petrographical relations, along with whole rock geochemistry, demonstrate that the parental magma of the Qareh-Dash rhyolites was originated from the crust. The composition of the parental magma was modified due to fractional crystallization of plagioclase and titanomagnetite evidenced by negative Eu, Sr and Ti anomalies in multielement diagrams. The chemical characteristics of Qareh- Dash rhyolites such as Rb/Nb, K/Rb, Rb/Sr, Rb/Ba and Ga/Al ratios are similar to A-Type granites/ rhyolites associated with post- collision tectonic settings. According to Precambrian age for the Qareh-Dash rhyolites, formation of these rocks might be related to extensional phases which were probably taken place after closure of proto- Thetys Ocean. Manuscript profile
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  2 - Geochemical study of the soils provenance of The Gysian-Silvana-Urmia ophiolitic region
  zainab sadeghi Hossein Pirkharrati monir modjarrad Reza dehbandi
  Gysian ophiolite is a remnant of the Neotethys, located in the north-west Iran at the intersection of the ophiolite belts of south-eastern Turkey, north-eastern Iraq and north-western Iran. The geochemical comparison of the soils with the average of global rocks and the More

  Gysian ophiolite is a remnant of the Neotethys, located in the north-west Iran at the intersection of the ophiolite belts of south-eastern Turkey, north-eastern Iraq and north-western Iran. The geochemical comparison of the soils with the average of global rocks and the study area led to determination of the composition group of the region soils. The geochemical evidence of the first group of soil samples with low silica percentage by Harker and triangular diagrams is close to the position of ultramafic rocks of the region (serpentenites) and primary mantle and expresses their compositional similarity. The second group of soils ranges in the area between the earth's crust and basalt, and they show more distribution near basalt. The normalized pattern of REE rare earth elements in this group of soils is similar to the mafic rocks pattern in the region, also in the minor elements chart, they classified in the mafic group. Soils with high percentage of silica in the diagram of major and minor element oxides are located near the positiion of meta-plates rocks in the region, in the range between the earth's crust and global shale. So, this suggests the intermediate composition of their origin. Most likely, the tectonic setting of the three soil groups is based on the oxides of the main elements of the active continental margin. Manuscript profile