CHEMICAL VARIATION OF CHROMITE IN THE CENTRAL SECTOR OF XEROLIVADO CHROME MINE OF VOURINOS, WESTERN MACEDONIA, GREECE

The serpentinite (originally dunite) of the central sector of Xeroliva do chrome mine, which hosts seven schlieren chromite bodies, contains on average 1 % by volume, disseminated chromite grains. Modal analyses showed that the chromite-bands of the schlieren ore, contain on avera ge 70 % chromite (concentrated chromite), while the serpentinite-bands of the schlieren contain on average 5 % chromite. All chromite types are intensely fractured and show no optical or chemical zonation. The main silicate mineral in contact with chromite is serpentine. Concentr ated chromite within the chromite-bands of the schlieren, is richer in Mg and poorer in Fe2+, compared to the disseminated chromite within t he serpentinite. The chromite, disseminated within the serpentinite-ba nds of the schlieren, showed an intermediate composition. The dissemin ated chromite within the serpentinite showed, on average, a slight dif ference from the other two types of chromite, concerning the Al and Cr contents. These chemical variations of chromite are mainly due to sub solidus process, involving chromite, silicates and fluids, but also re flect initial differences in conditions of crystallization at the magm atic stage.