Crust (geology) depth, reaching values typically in the range from about to at the boundary with the underlying mantle. The temperature increases by as much as for every kilometer locally in the upper part of the crust, but the geothermal gradient is smaller in deeper crust. The continental crust has an average composition similar to that of andesite. The most abundant minerals in Earth's continental crust are feldspars, which make up about 41% of the crust by weight, followed by quartz at 12%, and pyroxenes at 11%. Continental crust is enriched in incompatible elements compared to the basaltic ocean crust and much
The Clay Minerals Society The Clay Minerals Society The Clay Minerals Society is an international non-profit organization devoted to the study of clays and clay minerals. The Clay Minerals Society began as the Clay Minerals Committee of the National Academy of Sciences—National Research Council in 1952, in response to the need for a formal way to hold national clay conferences. By 1962, the Clay Minerals Committee had become strong enough to stand on its own, and The Clay Minerals Society was incorporated. From 1952 to 1964, Proceedings of the annual conferences were published. The journal Clays and Clay Minerals was first published in 1964.