Petrography and classification of the arenites of the Chari Series in the Jurassic rocks of Central Kutch,Gujarat (India)

The Chari arenites of the Jurassic rocks of Central Kutch form a real transition in the orthoquartzite—carbonate facies. The arenites pose a classificatory problem due to the presence of a good amount of reworked biogenic constituents. In order to get a correct picture, a new classification is proposed to classify these arenites in a meaningful manner, with quartz + rock fragments, felspar, and biogenic constituents as the three poles of the triangle.The petrographic characteristics of the arenites with a brief account of heavy-mineral and mechanical composition, is given. It is concluded that these arenites form a part of the orthoquartzite—carbonate facies.