INSOLUBLE RESIDUE ANALYSIS OF LIMESTONE IN KOLHAN GROUP

The data from the insoluble residue analysis of nearly ninety eight samples collected from different horizons fully corroborate the petrogenetic evidences obtained from the petrographic and field features of the Kolhan Limestone. High grade limestones containing nearly 10% of insolubles constitute about half of the limestone samples. Only in ten samples, the silt - clay portion dominates over the sand portion and such very high grade pockets (containing at times about 95% CaCO 3 ) on chemical analysis should show almost equal distribution of SiO 2 and Al 2 O 3 , both together totaling to 5 to 10%. In the remaining forty samples the sand fraction clearly outweighs the silt - clay fraction and these varieties of equally high grade pockets should analyze SiO 2 content distinctly greater than the percentage of Al 2 O 3 .