Mantle-derived K-rich melts had intrigued most of the founders of petrology and many of the later experts in field and experimental geology, because they are sometimes associated with carbonatites and even diamond. They tend to contain anomalous concentrations of many such elements as K, Rb, Sr, U.F.P. etc. along with Ni, Co, and Cr indicating a mixture of crust and mantle. For key isotopic indicators like Sr86/Sr87, O16/O18, they show great variability. In ...
