Phosphorus in regionally metamorphosed skarns of the Bohemian Massif and its genetic meaning

Abstract

Concentrations of phosphorus have been determined in 130 specimens o regionally metamorphosed skarn rocks, including their enclosing rocks Average P2O5-values found were 0.11% in the pyroxene skarns from the Core of the Bohemian Massif and 0.07% in those of the Krusne hory Mountains, which correspond to those commonly present in primary, i.e. contact metamorphic skarns, but are quite different from the high P2O5-values usually found in sedimentary iron ores. The P-contents of the rocks from the cores of the skarn bodies studied equal those determined in relic carbonate rocks, from which they probably originated, whereas the P-contents of the rocks from the outer parts of the skarn bodies correspond to those found in the enclosing rocks. The distribution of P in migmatites surrounding the skarn bodies suggests that P did not migrate during the regional metamorphism, so that the P-contents in the skarns may be considered as primary (premetamorphic). Thus, a study of P-percentages in regionally metamorphosed skarns may be useful in the investigation of skarn genesis.