Distribution patterns of heavy minerals from the Northern part of the Godavari Delta off Kakinada

Abstract

Heavy mineral studies of 31 samples along 4 traverses off the northern part of the Godavari delta off Kakinada are reported in this paper. The Godavari pro-delta region is characterised by the presence of clays and silty clays. The delta growth advances by the accretion of the spit and primarily by sedimentation at the river mouth and is strongly influenced by the northerly longshore current. The study area can be divided into 4 sedimentary petrologic provinces: Vokalpudi nearshore province-characterised by muscovite, biotite, opaques, tremolite/actinolite and clinopyroxene; Vokalpudi, offshore province-characterised by garnet, sillimanite, orthopyroxene, opaques and hornblende;Sand-spit offshore province-characterised by an elongated north south zone consisting of a mixed mineral assemblage like hornblende,opaques,muscovite,biotite,epidote,zircon,and Relict offshore province-characterised by a patch of tremolite/actinolite or zircon. The sediments have been derived mainly from the charnockite, khondalite and granite gneisses of the Eastern Ghats. Distribution of the minerals across the shore is difficult to generalise in terms of steady increase or decrease. The present mineralogical variations and products are influenced by basic parameters like river regime, longshore current, etc.