In situ elemental and isotopic analysis of fluorapatite from the Taocun magnetite-apatite deposit, Eastern China: Constraints on fluid metasomatism

Abstract

Metasomatic alteration of fluorapatite has been reported in several iron-oxide apatite (IOA) deposits, but its effect on elemental and isotopic variations has not been well understood. In this study, we present integrated elemental, U-Pb, Sr, and O isotopic microanalytical data on fresh and altered domains in fluorapatite from the Taocun IOA deposit, Eastern China, to evaluate the timing and nature of the metasomatism and its effects on the ore-forming event. Orebodies of the Taocun deposit are spatially associated with a subvolcanic, intermediate intrusion, which displays zonal alteration patterns with albite in the center and increasing actinolite, chlorite, epidote, and carbonate toward the margin. Both disseminated and vein-type ores are present in the Taocun deposit, and fluorapatite commonly occurs with magnetite and actinolite in most ores.