No description available.

Apatite is a common accessory mineral in the source rocks for the glacial debris supplying recent sediments to many Canadian lakes. Chemical analyses of sediments in Kamloops Lake, British Columbia suggest that this apatite may comprise a significant portion of the total phosphorus load to the lake, thereby overestimating the trophic state that would be predicted by the relationship between total phosphorus load and the ratio of mean depth to flushing time. A method has been developed which uses scanning electron microscopy and energy dispersive X-ray spectrometry for direct identification of apatite. This method has been used to examine the apatite content of various size fractions in Kamloops Lake sediments. Apatite concentrations obtained by this direct examination correlate well with the apatite concentrations of the indirect chemical analyses and indicate that, in addition to comprising as much as 70% of the total phosphorus load, apatite may comprise as much as 20% of the "dissolved" (<0.45 μm) inorganic phosphorus load. Therefore, estimates of lake productivity could be erroneous even if dissolved rather than total phosphorus values are used for the estimation. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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-P2O5-CaF2-CaCl2NaBr at 1120 degree C to 1400 degree C and atmospheric pressure. The partition coefficients (D) with errors of 1 sigma in parentheses are as follow: <p>DF (ClAP/melt) 3.59(64) at 1120 degree C to 4.13(22) at 1330 degree C <p> DF (FAP/melt) 1.05(4) at 1220 degree C to 1.07 at 1400 degree C <p> DCl (ClAP/melt) 1.07(1) at 1120 degree C to 0.83 at 1330 degree C <p> DCl (FAP/melt) 0.127(2) at 1250 degree C to 0.115 at 1400 degree C <p> DBr (ClAP/melt) 0.32(9) at 1120 degree C to 0.42(5) at 1330 degree C <p> DBr (FAP/melt) 0.020(3) at 1220 degree C to 0.016 at 1400 degree C <p> Seven exchange experiments at one atmospheric pressure and 800 to 1000 degree C yield the following distribution coefficients for Br-Cl exchanges between marialitic scapolite or sodalite and coexisting hydrous NaCl-NaBr melts: KD (marialite-melt) = 0.92 +/- 0.10 and KD (sodalite-melt) = 1.18 +/- 0.10. Therefore, the Cl/Br values in marialitic scapolite and sodalite closely reflect the halogen proportions of their coexisting melts or fluids. <p> 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. <p> Fluorapatite from the Aoshan fluorapatite-magnetite deposit is Cl-bearing with 0.38-0.98 wt% Cl, 1.83-3.45 wt% F, and 0-52 ppm Br. Fluorapatite from Chinese mantle xenoliths has similar halogen compositions to the Aoshan fluorapatite. Fluorapatite from the Oka carbonatite has trace amounts of chlorine (up to 0.052 wt%) and bromine (from 9 to 57 ppm). Applications for the experimental results suggest that the Aoshan Fe-Cu deposit has Cl/Br values comparable to those of mantle sources and that the anomalously low Cl/Br values in Oka fluorapatite require Br-enriched sources. <p> The Cl/Br values (weight) of marialitic scapolite from the Tieshan Fe-Cu deposit cluster around 626 +/- 92, supporting an origin involving hydrothermal brines from associated evaporites. Scapolite-group minerals in the exoskarns of the Nickel Plate Au skarn deposit have Cl/Br from 560 to 570, higher than those (110 to 180) of their counterparts in the endoskarns and vuggy cavities. This variation is attributable to an increased involvement of magmatic water from distal to proximal zones. Similarly, scapolite-group minerals in the Grenvillian U-Th-Mo-REE pegmatite-skarn-vein deposits vary widely in Cl/Br from 80 to 380, indicative of mixed sources of hydrothermal fluids from magmatic sources and from associated sedimentary rocks. <p> The experimentally determined partition coefficients of halogens between minerals (apatites, scapolite, and sodalite) and fluids/melts of this study have wide applications in the interpretation of source and evolution of hydrothermal fluids in mineralization processes and other geological systems. Applications of those partition coefficients to selected mineral deposits and mantle xenoliths confirm their significance.

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-P2O5-CaF2-CaCl2NaBr at 1120 degree C to 1400 degree C and atmospheric pressure. The partition coefficients (D) with errors of 1 sigma in parentheses are as follow: <p>DF (ClAP/melt) 3.59(64) at 1120 degree C to 4.13(22) at 1330 degree C <p> DF (FAP/melt) 1.05(4) at 1220 degree C to 1.07 at 1400 degree C <p> DCl (ClAP/melt) 1.07(1) at 1120 degree C to 0.83 at 1330 degree C <p> DCl (FAP/melt) 0.127(2) at 1250 degree C to 0.115 at 1400 degree C <p> DBr (ClAP/melt) 0.32(9) at 1120 degree C to 0.42(5) at 1330 degree C <p> DBr (FAP/melt) 0.020(3) at 1220 degree C to 0.016 at 1400 degree C <p> Seven exchange experiments at one atmospheric pressure and 800 to 1000 degree C yield the following distribution coefficients for Br-Cl exchanges between marialitic scapolite or sodalite and coexisting hydrous NaCl-NaBr melts: KD (marialite-melt) = 0.92 +/- 0.10 and KD (sodalite-melt) = 1.18 +/- 0.10. Therefore, the Cl/Br values in marialitic scapolite and sodalite closely reflect the halogen proportions of their coexisting melts or fluids. <p> 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. <p> Fluorapatite from the Aoshan fluorapatite-magnetite deposit is Cl-bearing with 0.38-0.98 wt% Cl, 1.83-3.45 wt% F, and 0-52 ppm Br. Fluorapatite from Chinese mantle xenoliths has similar halogen compositions to the Aoshan fluorapatite. Fluorapatite from the Oka carbonatite has trace amounts of chlorine (up to 0.052 wt%) and bromine (from 9 to 57 ppm). Applications for the experimental results suggest that the Aoshan Fe-Cu deposit has Cl/Br values comparable to those of mantle sources and that the anomalously low Cl/Br values in Oka fluorapatite require Br-enriched sources. <p> The Cl/Br values (weight) of marialitic scapolite from the Tieshan Fe-Cu deposit cluster around 626 +/- 92, supporting an origin involving hydrothermal brines from associated evaporites. Scapolite-group minerals in the exoskarns of the Nickel Plate Au skarn deposit have Cl/Br from 560 to 570, higher than those (110 to 180) of their counterparts in the endoskarns and vuggy cavities. This variation is attributable to an increased involvement of magmatic water from distal to proximal zones. Similarly, scapolite-group minerals in the Grenvillian U-Th-Mo-REE pegmatite-skarn-vein deposits vary widely in Cl/Br from 80 to 380, indicative of mixed sources of hydrothermal fluids from magmatic sources and from associated sedimentary rocks. <p> The experimentally determined partition coefficients of halogens between minerals (apatites, scapolite, and sodalite) and fluids/melts of this study have wide applications in the interpretation of source and evolution of hydrothermal fluids in mineralization processes and other geological systems. Applications of those partition coefficients to selected mineral deposits and mantle xenoliths confirm their significance.

No description available.

Authigenic growths of heavy minerals, crystallised under relatively low temperature diagenetic conditions have been recognised in a number of sedimentary sequence. A range of microbeam techniques have revealed trace element geochemical variations on several scales in authigenic titanites and apatites. These variations occur, within individual cement grains and patches, within a single sedimentary sequence, and between different sedimentary sequences. Mixed fluvial-aeolian, Permian, sediments at the Cock of Arran (Isle of Arran, Scotland) contain pore filling titanite cements. The titanites show a range of zoning patterns, dominated by compositional sector zones. The sector zones are defined by large (order of magnitude) differences in rare earth element (REE) and high field strength element (HFSE) concentrations between titanite grown at different crystal faces. The mechanism responsible for sector zone formation is considered to relate to differences in the surface structure of titanite at different crystal faces. Faces of the forms { 100 } and { 001 } are likely to have surface configurations more amenable for impurity element incorporation than faces of the form { 161 }. This evidence for disequlibirium titanite growth, and the large differences which must exist between effective partition coefficients at different titanite crystal faces, makes models of equilibrium trace element partitioning effectively meaningless. Minor growth zones are also present and relate to subtle differences in the REE composition of the titanite. These variations have been used to construct a model of titanite-fluid REE partitioning which suggests that the HREE have higher effective titanite-fluid partition coefficients than the LREE. In the continental Statfjord Formation (Jurassic, North Viking Graben) authigenic apatite occurs as overgrowths on variably corroded detrital cores. The authigenic apatite is chemically very distinct from the detrital apatite and contains high concentrations of Sr, REE, F, and probable concentrations of C.

Thesis (Ph. D.)--Dept. of Physics and School of Computing and Engineering. University of Missouri--Kansas City, 2005. / "A dissertation in physics and computer networking." Advisor: Wai-Yim Ching. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed March 12, 2007. Includes bibliographical references (leaves 256-267). Online version of the print edition.

Reproduction de : Thèse de doctorat : Science et génie des matériaux : Toulouse, INPT : 2005. / Titre provenant de l'écran-titre. Bibliogr. 189 réf.

Th. doct.-ing.--Toulouse 3, 1978. N°: 615.

Th.--Sci. phys.--Toulouse--I.N.P., 1984. N°: 82.