Chlorite in the Barail Siliciclastic Rock of the Imphal Valley, Indo-Myanmar Ranges

Chlorite in the Barail siliciclastic rock of the Imphal valley, Indo-Myanmar Ranges has been studied to determine the type, its source, transportation, depositional environment and climate that had prevailed during its deposition. Chlorite occurs as grain coating, dispersed in the siliciclastic rocks. Mafic and metamorphic rocks are the dominant source for the siliciclastic rocks. Serpentine is derived from peridotites and ultramafic-mafic rocks. Plagioclase and albite indicate a felsic igneous rock source and low-grade metamorphic rocks where plagioclase has been altered to albite. Chlorite was formed at the transitional river-seawater mixing zone and marine depositional environment with low to moderate salinity under an oxic condition. The chlorite bearing Barail siliciclastic rock was deposited under a semi-arid to semi-humid climate. Chlorite grain coatings in the Barail siliciclastic rocks have inhibited quartz cementation and hence have good reservoir quality. Barail Group of rocks of Upper Assam Basin was the hydrocarbon source for the reservoir rocks.