STRONTIUM ISOTOPIC COMPOSITION OF LOWER RIPHEAN CARBONATE ROCKS IN THE MAGNESITE-BEARING SATKA FORMATION, SOUTHERN URALS

Abstract

Great interest in the genesis of stratiform deposits of sparry magnesite has been stimulated by a number of convergent attributes that admit a sedimentary, infiltration, hydrothermal metasomatic, and even metamorphic origin of magnesite bodies. The analysis of Sr isotopic composition of magnesites and other carbonates is a tool that makes it possible to estimate the geochemical characteristics of the sedimentary medium and specific features of postsedimentary transformations of rocks. Despite long-term interest in the issue of magnesite formation, the Rb–Sr systematics of magnesite and host carbonate rocks has been considered only in a few publications, and all they deal with the Veitsch-type sparry magnesites hosted in the Paleozoic rocks of the Alpine Foldbelt.