PETROGRAPHIC STUDIES OF LIMESTONE IN DUKAMAJE FORMATION AT GILBEDI, GADA, SOKOTO BASIN, NIGERIA

The study was conducted in and around Gilbedi village its environs the Iullemmeden Basin, Sheet 4 SW, Gada local government area, Sokoto, North-West Nigeria. research area is located Sokoto which part of Basin. bounded by latitudes 13046'05"N to 13043'22"N longitudes 5045'00"E 5040'45"E covering 25 Km2. mapping exercise carried out using a topographic base map on scale 1:25,000. observed Dukamaje Formation derived from marginal marine depositional setting primarily composed shales, limestones, mudstone with gypsum intercalation. Shales are consolidated mudstones fine-grained texture greyish. Limestone medium coarse-grained. It pale yellow greyish color. Petrographic observation showed grains be equigranular, having interstitial quartz cement. occurs as colorless anhedral crystal no alteration but wavy extinction without cleavage. Other minerals present include muscovite. Based Folk’s classification for limestone, limestone called “extramicrite” because allochems extraclasts. also lime mud supported less than 10% Dunham’s schemes studied “mudstone”.