THE EFFECT OF VARIATIONS IN CHEMICAL COMPOSITION ON THE VELOCITY OF SEISMIC WAVES IN CARBONATE ROCKS
The variations of velocity in limestones have not fallen into as definite a pattern as have those in sandstones and shales. Although it is conceded generally that textural characteristics are more important than mineral content in determining the velocity in sandstones and shales, the possibility that the concentration of magnesium carbonate may appreciably alter the velocity in a limestone is investigated. It is found that dolomitization can be expected to have an effect on the velocity, but that effect is not certain, in that it depends on the nature of the dolomitization process. A volume for volume replacement of calcite by dolomite tends to increase the velocity, but dolomitization giving rise to local porosity, whether the resulting interstices are empty or filled by non‐carbonate material, tends to decrease the velocity.