P-T-X relationships during metamorphism of manganese-rich sediments: current status and future studies

This paper aims at reviewing the mineralogy, mineral chemistry and petrology of metamorphosed manganese-rich sediments from occurrences described since 1988. It presents a summary of new experimental data and evaluates the merits and shortcomings of the petrogenetic grids so far proposed for Mn-rich metamorphic rocks. The paper focuses on the inadequacies of experimental data on Mn-rich systems and discusses the problems associated with further quantification of the petrogenetic grids. Finally, a few suggestions for future research on Mn-rich systems are put forward