The Occurrence of Vanadiferous Titanomagnetite in Offshore Sediments, Gulf of Khambhat, West Coast of India

Abstract

Heavy mineral study of sediment samples collected from Gulf of Khambhat, off Alang, Gujarat, shows a predominance of opaque minerals represented by titanomagnetite, magnetite and ilmenite over non-opaque minerals like pyroxene and amphiboles and traces of sillimanite, zircon, garnet and monazite. The bulk sediments contain up to 28.5% of heavy minerals with an average of 12.5%. Within the heavy minerals, more than 50% are opaque in nature represented by titanomagnetite, magnetite and ilmenite. SEM–EDX studies on handpicked opaque grains indicated a higher concentration of vanadium up to 1.1%. The result of EDX studies was confirmed by AAS analysis of magnetic heavy mineral fraction that showed a concentration of vanadium up to 0.36%. Subsequently, XRD analysis of the heavy minerals of randomly selected samples revealed the presence of vanadium-bearing titanomagnetite as well as the vanadium mineral phase, melanovanadate. EPMA studies carried out in titanomagnetite grains that revealed V₂O₃ content of 0.36–1.7% with an average of 1.3%. Based on the analytical studies, it is inferred that the vanadiferous titanomagnetites in the Gulf of Khambhat are possibly drained from Deccan basalt mainly through the Rivers of Narmada and Tapti.