Mineralogical investigations of the phosphatic nodules from Warchha sandstone, salt range with emphasis on replacement process
Abstract
Discontinuous layers of phosphatic nodules are present within the upper part of Warchha Sandstone from Warrala area, in the east, to Katha Road Section in the west. The genesis of these phosphatic nodules, especially in Warchha sandstone, poses a big question mark. The interest in these phosphatic nodules is further increased, when they are found to be significantly radioactive, Along the strike, extension of the strata containing these phosphatic nodules is up to 35 km. Samples were collected from various localities including Nawabi Kass Warrala, Malot, Karuli, Simbal, Gahi, Marin and Nurpur. These samples were studied petrographically and on the average the P2O3 content is more than 19.5%. which qualifies them to be called "phosphorites". The radioactivity measured through Gamma spectrometer is up to 600 ppm eU3O8, while chemical analyses show concentration of U3O8 up to 787 ppm in one of the samples. The petrographic study, with especial emphasis on replacement process, indicates hydroxyl apatite replacing calcite.
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