Mineral chemistry and geothermobarometry of Moshirabad pluton, Qorveh, Kurdistan, western Iran

Abstract

The Moshirabad pluton is located southwest of the Sanandaj–Sirjan Metamorphic Belt, Qorveh, western Iran. The pluton is composed of diorite, monzodiorite, quartz diorite, quartz monzodiorite, tonalite, granodiorite, granite, aplite, and pegmatite. In this study 31 samples from various rocks were chosen for whole‐rock analyses and 15 samples from different lithologies were chosen for mineral chemical studies. The compositions of minerals are used to describe the nature of magma and estimate the pressure and temperature at which the Moshirabad pluton was emplaced. Feldspar compositions are near the binary systems in which plagioclase compositions range from An5 to An53 and alkali‐feldspar compositions range from Or91 to Or97. Mafic minerals in the plutonic rocks are biotite and hornblende. Based on the composition of biotites and whole‐rock chemistry, the Moshirabad pluton formed from a calc‐alkaline magma. Amphiboles are calcic amphiboles (magnesio‐hornblende or edenite). Temperatures of crystallization, calculated with the hornblende–plagioclase thermometer, range 550–750°C. These temperatures indicate that plutonic rocks have undergone some retrogressive changes in their mineral compositions. Aluminum‐in‐hornblende geobarometry indicates that the Moshirabad pluton was emplaced at pressures of 2.3–6.0 kbar, equal to depths of 7–20 km, but with consideration of regional geology, lower pressures than the above pressure range are more probable. Alteration of amphiboles can be the reason for some overestimation of pressures.

Mineral chemistry and crystallization conditions of the Late Cretaceous Mamba pluton from the eastern Gangdese, Southern Tibetan Plateau

“…Equilibrium temperatures of K-feldspar megacrysts vary from 565 to 594 °C via the method as proposed by Ma (1988). This estimated temperature spectrum suggests that sub-solidus re-equilibrium may have occurred (e.g., Sepahi et al, 2012). Additionally, the percentage of orthoclase ranges from 93.01 to 95.23 (Table 6).…”

Characterization of the Petrographic and Physicomechanical Properties of Rocks from Otanmäki, Finland

“…The compositions and structures of the various mineral phases (feldspar, amphibole, pyroxene, etc.) can give an idea of the physicomechanical parameters of igneous rocks (Honarmand et al 2012;Sepahi et al 2012;Ayati et al 2013;Sarjoughian et al 2015).…”