Compositional variation in apatite from various host rocks: clues with regards to source composition and crystallization conditions

Electron microprobe (EPMA) and total reflection X-ray fluorescence (TXRF) analyses were used to investigate the composition of 17 apatite samples of magmatic to hydrothermal origin, including six carbonatites, two ijolites, and each one phoscorite and pyroxenite (Russia/Kola Peninsula), one apatitite (Brazil/Ipanema), three silico-carbonatic pegmatites (Madagascar/Ampandrandava and Russia/Slyudyanka), one Kiruna-type deposit (Iran/Esfordi), as well as the Otter and Emerald Lake apatites (Canada). Their composition is compared to a compilation of literature data for apatite from carbonatites, gabbros, diorites, biotite (amphibole) -bearing granitoids, muscovite-bearing granites, felsic pegmatites and the widely known Durango apatite. The results of EPMA in this study reveal that the composition of apatite tends to be distinctive for specific rock-types (e.g. relative high SrO and/or Ce2O3 contents in apatites from carbonatites or high MnO contents in apatites from muscovite-bearing granites). However, source composition, temperature and redox conditions during crystallization or composition of a coexisting fluid can influence the apatite composition, for example, so that a broad overlap of various element contents exists between apatites from different rock-types. In addition, we present TXRF data for barely investigated trace elements in apatite (As, Tl and Br) that appear to be promising elements for future petrological and geochemical investigations.