Heavy minerals of modern and relict sediments of the Nizampatnam bay, east coast of India

Abstract

Heavy minerals of the beach, sand-spit and palaeastrandline sediments of Nizampatnam bay are dominated by opaques, amphibiles and pyroxenes (70% of the total). Garnet, epidote and monazite are present in significant quantities (20%), whereas rutile, zircon and tourmaline are in appreciable amounts. Multiple regression analysis indicates that heavy mineral variations in each sedimentary environment have been significantly influenced by hydraulic fractionation by size, shape, density and by a selective chemical decomposition of unstable heavy minerals. A comparison of heavy mineral suites of the modern and relict sediments, derived from a common provenance, also shows mineral variations resulting from factors other than provenance.