Maps of the thickness of Cenozoic deposits and the isostatic residual gravity over basement for Nevada

Abstract

This study of gravity data from Nevada is part of a statewide analysis of mineral resources. The main objectives of the gravity study were: 1) to infer the structure and composition of the basement; and 2) to determine the thickness of Cenozoic deposits. An iterative procedure based on the gravity data, a knowledge of the surface geology/ and an estimate of the density of Cenozoic deposits was used to separate the isostatic residual gravity field into two component parts/ a "basement" component and a "cover thickness" component. The former component contains information about the basement whereas the latter yields an estimate of the thickness of Cenozoic deposits. All computations were performed with a rectangular grid having intersections spaced at 2 km. The results are presented as contours on two maps at a scale of 1:1 f OOO f OOO. Sheet 1 represents the basement gravity and sheet 2 represents the inferred thickness of Cenozoic cover.