Field Geology and Petrography of Granitoid rocks in southeastern part of Nanded district, Maharashtra State

This paper presents field geological and petrographic aspects of various granitoid units occurring around Khatgaon area in the southeastern part of Nanded district of Maharashtra. The study area is bestowed with granitoids of Archaean to Proterozoic age overlain by Deccan basalts of Cretaceous age. Three main types of granitoids were identified in the study area viz., older granites, gneissic/foliated granites and younger granites. These granitoid rocks are traversed by dykes, veins and veinlets of felsic and mafic composition. Although these granitoids are similar in mineralogy, they exhibit differences in petrographic characteristics. The granitoids of the study area, especially the gneissic granitoids, comprise felsic and mafic lenticular enclaves of different sizes. Petrographically older and younger granitoids show medium to fine-grained, porphyritic and inequigranular textures. The gneissic rocks show foliation. At the contact of mafic enclaves and gneissic zones, conspicuous variation in mineralogy is observed in thin-sections. Presence of enclaves indicates coexistence and mixing of both felsic and mafic magmas at the source. The typical textures like perthitic, graphics and lamellar twinning indicate a direct magmatic origin for these granitoid rocks. The presence of pyrite mineralization at Khatgaon indicates late stage hydrothermal activity associated with felsic veins. P. R.C.Phani | N. Ningam | M. Srinivas"Field Geology and Petrography of Granitoid rocks in southeastern part of Nanded district, Maharashtra State" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-6 , October 2017, URL: http://www.ijtsrd.com/papers/ijtsrd4710.pdf http://www.ijtsrd.com/other-scientific-research-area/geology/4710/field-geology-and-petrography-of-granitoid-rocks-in-southeastern-part-of-nanded-district-maharashtra-state/p-rcphani