The use of plural really confused me. What little I knew of this previously, always seemed to talk in the singular. One place (Gabon) this happened to our knowl

The use of plural really confused me. What little I knew of this previously, always seemed to talk in the singular. One place (Gabon) this happened to our knowledge. But, it happened more than once I find. I suppose for geological effects, time causes change, and sufficient change both physically (location) and pressure/temperature, and radiology, means the thing can happen again and again. Or, dispersed foci can react in shorter time, close to each other, until entropy sets in.