Characterization of Opaques off Konkan Coast Maharashtra, Central West Coast of India

Abstract

Characterisation of opaques, comprising of ilmenites and magnetites, separated from the sediment samples off Konkan coast, has been attempted. On the basis of dominance of intergrowth of the exsolved or replaced phases, magnetites of Vijayudurg and Wada vetye are grouped together while the magnetites of Ambolgarh and Rajapur are showing similar characteristics. Ilmenites display intergrowths with hematite and rutile. In Ambolgarh and Rajapur, ilmenites of exsolved and replacement phases are abundant with alterations along the borders. On the basis of intergrown lamellae width, the source rock for the ilmenites is attributed to the distant metamorphic rocks The presence of altered ilmenites testify a higher percentage of TiO 2 in Ambolgarh and Rajapur. A higher amount of FeO (35.79 % - 36.25 %) in Wada Vetye and Vijaydurg is ascribed to higher percentage of ilmenite – hematite phase in the exsolved ilmenites. REE pattern of ilmenites, magnetites and non-magnetics show an enrichment of LREE over HREE. Ilmenite, magnetite and non-magnetics show a negative Eu anomaly which is ascribed to the individual or combination of the following conditions: 1) Melt effect, 2) Crystallo-Chemical effect, and 3) Competing mineral effect. A higher enrichment of TiO 2 in the ilmenites reflects the possibility of establishing down-stream industries as well as the suitability for converting ilmenites into synthetic rutile.