Showing 2 results for Northeast Iran
Zahra Rezaei, Mousa Noghreyan, Emilio Saccani,
Volume 27, Issue 3 (10-2019)
Abstract
Sabzevar ophiolitic pillow lavas contain variolitic, porphyritic with microlitic matrix, intersertal and amygdaloidal textures and include plagioclase, clinopyroxene (augite-diopside), olivine, amphibole (magnesiohastingsite) and opaque minerals. The chemical composition of clinopyroxenes show a calc-alkaline magmatic series and a tectonic environment within plate alkaline basalts. Geochemically, these rocks are divided into two groups. Group 1 is basically calc-alkaline andesite with low TiO2 and group 2 is alkali basalt with high TiO2. N-MORB normalized trace elements diagram shows that group 1 is enriched in Th, U, La and depletion in Ta, Nb, Ti and group 2 is enriched in Th, Ta and Nb. Calc-alkaline rocks have produced in a subducted tectonic environment by a continental crust and erupted southwards on the Turan plate. In contrast, alkaline rocks formed within plate oceanic and then tectonically accreted in the forearc setting.
Somayeh Durani, Mohammad Poosti, Gholamreza Ghadami, Asma Nazarinia,
Volume 3100, Issue 1000 (1-2023)
Abstract
The Yakhāb intrusive complex, located in the north Tabas region of central Iran, is characterized by a series of granitic stocks intruding into mica schist host rocks. This study combines petrographic, geochemical, and tectonic analyses to elucidate the complex's petrogenesis and tectonic setting. Petrographic studies reveal a granular texture with major minerals including quartz, alkali feldspar, plagioclase, and biotite. Geochemical data indicates a calc-alkaline affinity, with the rocks ranging from metaluminous to peraluminous and showing enrichment in LILE and LREE relative to HFSE. Spider diagrams normalized to primitive mantle, MORB and chondrites, highlight the influence of magmatic differentiation and crustal contamination. Tectonic discrimination diagrams suggest that the granites formed in a syn-collisional to volcanic arc environment are classified as fractionated granites (FG). The geochronology data suggests a prolonged magmatic evolution, with the syn-collisional and volcanic arc granitoids formed in separate episodes. The petrographic and geochemical signature confirms a crustal origin for the studied granitoids. This study provides a comprehensive understanding of the magmatic evolution and geodynamic setting of the Yakhāb intrusive complex and its associated magmatic systems within the Iranian Central Zone.
