Provenance rock, weathering conditions and tectonic setting determination of quartzofeldspathic schists from the Sovordydosha valley, the NW of Zayandeh-Rud lake, Sanandaj-Sirjan Zone

doi:10.29252/gnf.4.1.89

Provenance rock, weathering conditions and tectonic setting determination of quartzofeldspathic schists from the Sovordydosha valley, the NW of Zayandeh-Rud lake, Sanandaj-Sirjan Zone

10.29252/gnf.4.1.89

Abstract

Quartzofeldspathic schists of the valley of Sovordydosha are situated in the shear zone of the north Shahrekord, in the central part of Sanandaj-Sirjan Zone. The metamorphic rocks show lepido-granoblastic texture. The most important of minerals are quartz, feldspar, and biotite. The samples indicate nature of greywacke to shale on the log (Na₂O/K₂O) versus log (SiO₂/A1₂O₃) diagram for their protolith. According to the geochemical characteristics, the source material of the rocks is the result of erosion, transportation, and deposition of evolved felsic igneous rocks and granitoid rocks. The average of the chemical index of alteration (CIA) and chemical index of weathering (CIW), as well as the binary diagram of Al/Na versus CIA show moderate weathering in during formation of the sedimentary protolith of the rocks. Moreover, based on SiO₂ versus (Al₂O₃+K₂O+Na₂O) diagram, the paleoclimate of the region was dry at the time of the formation of the source material. The Mn* index and U/Th ratio determine oxidant conditions of the sedimentary basin in past time. Geochemical data indicate that tectonic setting of the protolith of the schists has been an active continental margin and continental arc.

Keywords

Quartz-feldspatic schist

Provenance rock

Weather condition

Continental arc

Sovordydosha

North of the Shahrekord

Sanandaj-Sirjan Zone

Subjects