Trace Elements in Minerals and Rocks of the Precambrian Group of the Yellandlapad Area, Andhra Pradesh

Abstract

Eight trace elements Co, Cu, Ga, Ge, Li, Ni, Pb and V have been determined semi-quantitatively with the Hilger spectrograph in 14 minerals and 18 rocks belonging to the Singareni series and the Gneissic complex of the early Precambrian and the Pakhals of the late Precambrian. The Pakhal phyllite is higher in Co, Ga, Ge, Li and Ni and Lower in Cu, Pb and V than the average shale. The pelitic schist of the Singareni Series broadly shows the same order of trace element distribution as that of the Pakhal phyllite. Metamorphism (amphibolite facies) of the Pakhals has not affected any redistribution of the trace elements in them. The granite-gneisses which are the granitised derivatives of the Singareni series show a decrease in Co, Ni and V. The trace elements Co, Cu, Li and Ni follow the major elements Fe, Mg and are preferentially fixed in the ferromagnesian minerals forming the essential constituents of the rock.