Rutile Mineral Chemistry as a Guide to Provenance of Red Sediments and Modern Sands of Bhimunipatnam–Konada Coast, Andhra Pradesh, East Coast of India

Abstract

Rutile is the most stable and widely distributed TiO2 polymorph in rocks of low- to high-grade metamorphic facies and is also an accessory mineral in igneous rocks. Rutile is commonly available in modern to ancient placer mineral deposits in the coastal sediments. Mineral chemistry of rutile from red sediments and modern sands along Bhimunipatnam–Konada coast were used in the present study to know its provenance. Iron (Fe), chromium (Cr), niobium (Nb) content and their distribution pattern in rutile and also their relationships with aluminum (Al) and magnesium (Mg) concentrations provide information on its provenance. These study reveals that the Fe–Cr and Cr–Nb systematics indicates majority of rutiles were derived from metapelitic rocks mainly khondalites and leptynites of the Eastern Ghats Granulite Belt (EGGB) and minor contribution is from magmatic charnockites, pegmatites and granites. The Al and Mg behavioral pattern in rutile from both zones clearly depicts that the most of the rutiles are derived from crustal rocks. The rutile contribution to late quaternary red sediments and modern coastal sands is also from same provenance.