A STUDY OF ROCK DENSITIES IN THE ENGLISH MIDLANDS

Abstract

A knowledge of the densities of rock formations is important in the interpretation of gravity anomalies. This paper describes the results of field and laboratory experiments made on the rocks in the Midlands of England. Density measurements were made on nine geological formations from the Silurian to the Cretaceous and also on Metamorphic rocks from the Malvern area. A catalogue of densities has been prepared for general use based on the assumption that rocks in the field are saturated with water. A table of densities and porosities for a large number of rocks is also given. Among the conclusions drawn about the observed sampling variances, the most significant is that rock formations in the West Midlands do not appear to show any “regional variation” of density. The results of the field and laboratory methods are consistent within the experimental errors of each, in marked contrast to the results reported by S. Hammer from observations in some American mines, from somewhat different data.