A Case Study of Petrological Investigations o...

A Case Study of Petrological Investigations of Dolerites from Yadadri-Bhuvanagiri District of Telangana State

Author Name : Madgula Seenaiah, P. Swamy Sharan, K. David

ABSTRACT

Dolerite dyke sets are found distributed in the YadadriBhuvanagiri district of northern Telangana. These dykes havebeen emplaced in the older basement composed of peninsular gneissic complex. The dykesare composed of medium to fine-grained calcic-plagioclase and clinopyroxene withbiotite, amphibole, orthopyroxene, and anhedral quartz as accessories. Based on petrological characters, the olivine and quartz bearing dykes are identified with emplacement of these dykes was aided by crustal extension and associated fracturing todevelop a dyke swarm.The dolerite dykes (black granite) are occurring as intrusive bodies in the peninsular gneissic complex and the dykes are running from few meters to a few kilometers length and submerging into ground here and there and outcropping in the form of hillocks at some places and width is varying from few meters to 100 mts and these dykes are wide spread over in the most of YadadriBhuvanagiri district and striking NE-SW direction. 

The country rock is granite has been intruded by numerous dolerite dykes and quartz, plagioclase and pegmatitic veins at various places.  The dolerite dykes are commercially extracted under the name of black-granites, which are having good export market at present.  Number of quarries lease has been granted for black granites in these dolerite dykes.  The commercially important dolerite occur study area in YadadriBhuvanagiri district fall within a radious of 80 kms.

Keywords:Peninsular Gneissic Complex, Dolerite dyke, Petrography, Field setting, YadadriBhuvanagiri.