CORRELATION OF ROCK DENSITY DETERMINATIONS FOR GRAVITY SURVEY INTERPRETATION*

Abstract

ABSTRACT The results of field and laboratory methods of density determination on a series of Coal Measure, Permian and Triassic rooks are presented and the different methods compared. It is concluded that the most satisfactory method is that of measuring the vertical change of gravity in a mine shaft. Nettleton's method is unsatisfactory to us, due to weathering of the rocks (particularly Magnesian Limestone) and possible effects from drift. Laboratory measurements are of variable value depending on the lithology and source of the samples. A method adopted to solve the problem of finding the true densities for use in a local gravity survey in N.E. England is given.