Talc rock weathering (Nikolayev Massif,Ukrainian SSR)

Thermal analysis, optical determinations, and comparisons of mineral and chemical composition of samples from an ocher type section, 25-60 m thick, preserved on the ultrabasics in which the talc of the lower part is replaced by hypergenetic minerals in the upper horizons. Characterized by indistinct zonation, all the rocks are identified in the section and a generalization of the sequence of mineral replacement as shown by the analyses is given.—IGR Staff.