Geochemia uranu, toru i cyny w procesach pomagmowych

Abstract

GEOCHEMISTRY OF URANIUM, THORIUM, AND TIN IN POSTMAGMATIC PROCESSES Summary Measurements of distribution of uranium and thorium in rocks markedly contribute to the knowledge of mechanisms of postmagmatic processes as well as segregation of products of differentiation. The Th/U index appears highly useful in search for tin ores as an differentiation index, making possible identification of products of individual segregation stages and tracing directions of increase in concentration of this metal. Biotites present in granites are able to accumulate tin from intrusions even poor in that metal. The presence of uranium and thorium, even in trace amounts, is found to be significant from the point of view of geochemistry as it well defines metallogenic environment.