چكيده لاتين
The Kahiyeh region is located 175 kilometers northeast of Isfahan and southeast of Ardestan. The volcanic rocks in this area are from the Eocene age and include tuff units and andesitic lava breccias, which have been studied. Additionally, granodiorite masses with an east-west trend have intruded the Eocene volcanic rocks and have been investigated. Alteration in this area is of low-grade types, including chloritization and epidotization. Andesite-diorite rocks with Si content ranging from 39% to 65% by weight are present, and their magmatic series are calc-alkaline and shoshonitic. The magmatism is associated with subduction, and crustal contamination has occurred during the magmatic process. The petrogenesis is related to volcanic arc regions and mid-ocean ridge basalts (MORB). Based on field studies, hand samples, and microscopic analysis, the regionʹs rocks are broadly divided into two main groups according to the abundance and importance of their minerals: 1) extrusive igneous rocks and 2) intrusive igneous rocks. In this study, both groups of igneous rocks were examined through field sampling, optical (microscopic) studies, and geochemical analysis. Optical characteristics of the two igneous rock types reveal that the primary minerals include plagioclase, feldspar, hornblende, and pyroxene. One of the main alterations observed in optical studies is the pervasive sericitization in both types of igneous rocks, which occurred after their formation. Although the geochemical studies are limited by the number of analyzed samples, the results suggest that both groups of rocks belong to an alkaline magmatic series. Based on the microscopic observations, one of the primary minerals in the rocks is plagioclase, indicating a significantly high percentage of aluminum oxide, which is consistent with the geochemical analysis results.
