Petrographic, mineralogical and microstructural studies in the mafic dyke occurred in the area of Mettur, Salem District, Tamil Nadu, India

Abstract

A mafic dyke is a mass of rock generated in either sedimentary or igneous terrain and intrudes in pre-existing cracks. It was common to see many enormous dyke swarms in the southern granulitic landscape made up of archean rocks. Dykes tend to be younger than the surrounding rock body. Generally, mafic dolerite dyke has an ophitic texture and is medium to fine grained. In the study area country rock and dolerite dyke rocks petrographical microscope, XRD, and FE-SEM techniques were analysed. Plagioclase feldspar, augite, biotite, hornblende, and quartz minerals presented in the study area rocks. Alternating wedges, augite/labradorite grain boundaries are shown in the microstructure as a white rectangle. Two augite wedges were observed with rounded ends. The mineral percentage of quartz is rich in dolerite rock because of its intergrowth texture and low cooling temperature and pressure. So, the magma crystallized rapidly on the surface thus, the crystallizing temperature of the quartz is low. Thus, the rock mineral shows a high percentage of quartz. The rock is quartz-dolerite.