Mineralogy, Chemical Characters and Genesis of the Chromite Deposits of Moulabhanja Area, Dhenkanal District, Orissa

Pockets of 'sack-form' chromite deposit occur at the intersection of dykes of olivine gabbro near Moulabhanja hills in the Dhenkanal district of Orissa. The dykes intruded the Precambrian granite-gneiss belonging to the Eastern Ghat orogenic belt. Chromite also occurs as minor accessory in olivine gabbro; and in this respect differs in its mode of occurrence from chromite deposits associated with the dunite-peridotite of the Iron ore orogenic cycle. The close association of chromite with olivine gabbro, the paragenetic sequence of the minerals in the rock, and the mineralogy, texture and chemical nature of the ore, suggest that the chromite melt was separated from the basic (olivine gabbro) magma as an immiscible liquid fraction and crystallized earlier than the silicate minerals.