Halogen-element (fluorine, chlorine, and bromine) behaviour in apatites, scapolite, and sodalite: An experimental investigation with field applications

Halogens (F, Cl, Br, and I) are common constituents in igneous, metamorphic, and sedimentary rocks, and are particularly important in the transport of many ore-forming metals. Detailed knowledge about the abundance of halogens in melts/fluids and minerals can help to interpret many geological processes. However, most hydrothermal fluids and melts cannot be directly sampled. Halogen-bearing minerals, such as apatites, scapolite and sodalite, can provide reliable information about the halogen concentrations in their parental fluids/melts provided that the partition coefficients between those minerals and fluids/melts are known.; This is the first systematic experimental investigation of partitioning of Br between apatites and coexisting melts and the uptake of Br by scapolite and sodalite. Twenty-nine partitioning experiments between fluorapatite (FAP)/chlorapatite (ClAP) and coexisting melts were conducted in the system of CaO-P2O 5-CaF2-CaCl2-NaBr at 1120°C to 1400°C and atmospheric pressure.; Seven exchange experiments at one atmospheric pressure and 800 to 1000°C yield the following distribution coefficients for Br-Cl exchanges between marialitic scapolite or sodalite and coexisting hydrous NaCl-NaBr melts: K Dmarialite-melt = 0.92 + 0.10 and KD sodalite-melt = 1.18 +/- 0.10. Therefore, the CI/Br values in marialitic scapolite and sodalite closely reflect the halogen proportions of their coexisting melts or fluids.; The second part of this thesis project analyzes the halogen (F, Cl, Br) contents in natural fluorapatite and scapolite by X-ray fluorescence microprobe (XRF) for Br and electron microprobe (EMPA) for other elements. All selected localities and environments are interesting, because the origins of the parental fluids/melts are controversial. The halogen compositions of 29 natural apatite grains from the Aoshan fluorapatite-magnetite deposit (China), the Oka carbonatite complex (Quebec), and Chinese mantle xenoliths and 36 scapolite samples from the Tieshan Fe-Cu skarn deposit (China), the Nickel Plate gold deposit (British Columbia), and the Grenville pegmatite/skarn/vein deposits (Ontario and Quebec) have been analyzed by electron microprobe (EMPA) and X-ray fluorescence microprobe (XRF). Twenty six whole-rock samples from the Aoshan deposit have also been analyzed by XRF for major and trace elements. (Abstract shortened by UMI.)...