Petrogenesis and Tectonomagmatic pattern of Shahvali Leucogranite (North of Azna-Sanandaj-Sirjan zone)

Articles in Press

Authors

1 Department of Geology, Aligudarz Branch, Islamic Azad University, Aligudarz, Iran

2 Department of Geology, Khoramabad Branch, Islamic Azad University, Khoramabad, Iran

Abstract

The Shahvali granitic pluton is one of the numerous intrusive bodies in the Sanandaj-Sirjan zone. The pluton is dominated by leucogranite and small volume of granite and granodiorite. The major minerals include quartz, plagioclase, K-feldspar, biotite as well as muscovite, tourmaline, garnet and rarely sillimanite. The medium to high amount of potassium, calc-alkali series and peraluminous S-type nature of these rocks is verified by their high content of normative corundum (average=2.1), and high molar A/CNK>1.1 ratio. Low CaO amounts, CaO/Na2O ratios (0.10-0.36), negative Eu anomalies imply that the melts originated under vapour-absent conditions from a metapelitic source. Depletion in Sr, Ba, HFSE and enrichment in LILE are remarkable characteristics of the rocks under discussion. The geochemical data and petrogenesis of the Shahvali granite mass indicate similar to the impact environment granites such as the Himalayas, which were formed from the partial melting of metapellites and muscovite dehydration in the absence of fluids. Therefore, the mentioned mass was most likely formed in connection with the collision of the Afro-Arabian continental crust with Central Iran during the Laramide orogeny phase and during the Late Cretaceous-Eocene, and the presence of shear zones played a very important role in its formation and uplift. Therefore, their whole rock geochemical features are broadly consistent with partial melting of middle to upper crustal metasedimentary rocks in an active continental margin related to collision between the Afro-Arabian continental plate and the Central Iranian microplate.

Keywords

Main Subjects

Advanced Applied Geology

Articles in Press, Accepted Manuscript
Available Online from 13 October 2024

Files

Share

How to cite

Statistics