Heavy Mineral distribution studies in different micro- environments of Bhimunipatnam coast, Andhra Pradesh, India

The study of heavy mineral placer deposits of the coastal sediments in Bhimunipatnam stretch for 12 km from Chapala Uppada to Annavaram in the south was carried out, the surface sediments samples from eighteen locations of different micro-environments along the coast are collected. The main framework of this paper is to study the distribution of various heavy minerals in different coastal micro- environments of a part of an eastern coast in India. Different sizes of sieves are used to make the samples into three (+60, +120, and +230) fractions. The data sets reveal that the heavy minerals are associated with fine (+230) fractions and only three minerals viz., opaque, sillimanite and garnet are more than 85% and other minerals constitute only 15%. The concentration of heavy minerals is more in dunes (new and old) than in beach sediments. The heavy mineral concentration shows an increasing trend from south to north. The observed variations in the distribution of heavy minerals in the area are found to be due to differences in the sediment supply, their sorting and oceanographic processes all of which result in a selective sorting of the sediments. The observed mineral assemblages of transparent heavy minerals (pyroxene, amphibole, tourmaline, kyanite, garnet, zircon and silliminate) are suggestive of their derivation from a heterogeneous provenance comprising of igneous rocks, high grade metamorphic rocks, characterize the Precambrian gneissic, granitic and basic rocks and has been derived from the Eastern Ghats and the river Gosthani. In some samples rounded zircon is also present which indicates the sediments that are formed from reworked sediments. In economical point of view a considerable amount of heavy minerals are present in the dunes of the northern side of the Gosthani river mouth.