Tourmaline is an aluminoborocyclosilicate mineral with a complex arrangement of atoms. With highly variable chemistry and multiple cation sites, tourmaline is one of the last complex minerals whose structure was unraveled, and its response to changes in Pressure-Temperature-Time (P-T-X) are not well understood. Due to its stability at high temperature and pressure, tourmaline has the potential to be an informative mineral in terms of petrogenetic indicators and could be used in assessing provenance, thermobarometry and geochronology. Three reactions were proposed to understand the cation exchange and disordering between the Y- and Z-sites in the tourmaline structure. These reactions include: 1. YFe2+ + ZAl + OH ; ZFe3+ + YAl + O + H ; in two samples with varying Fe2+ content. 2. YMg + ZAl ; ZMg + YAl. 3. YFe3+ + ZAl ; ZFe3+ + YAl. Using single crystal X-ray diffraction and stepwise heating, the extent and effect of the exchange between the Y- and Z-sites in response to changes in temperature was described. In response to increased temperature, equivalent amounts of Fe2+, Fe3+, Mg2+ of the Y-sites exchange with Al of the Z-sites. This leads to decreases in Y-site average bond length, increases in Z-site average bond length, shortening of a lattice parameters, lengthening of c lattice parameters and decreases in quadratic elongation. Additionally, the T-site experienced an increased in tetrahedral rotation and ditrigonality and changes to the crimping of the tetrahedral ring upon heating. The cation exchange and disordering in these samples relates to the stability of tourmaline at elevated temperatures in that tourmaline will undergo cation exchange and disordering to maintain the stability of the mineral. This has implications on the conditions in which tourmaline is formed as well as stability of tourmaline and other minerals and materials in different P-T-X conditions.

The early Cretaceous anorogenic Erongo Granite of Namibia is known to host abundant boron mineralization in rounded, quartz-tourmaline clusters and in NYF-type miarolitic, pegmatitic cavities. Rock and mineral samples were taken from the bulk granite, tourmaline nests, and miarolitic cavities and analyzed using a variety of modern analytical techniques. Geochemical and mineralogical data suggest substantial input from the metasedimentary rocks of the Damara orogen was important in the genesis of the Erongo Granite magma. The geochemical signature of the Damara orogen is most evident in the tourmaline clusters and miarolitic cavities, where fractional crystallization accumulated volatile and incompatible elements enough to exsolve a second fluid phase and induce drastic textural and mineralogical changes. As a result, the geochemical character of the pegmatitic cavities is far removed from that of classic NYF-type systems, where boron mineralization is usually not observed.

<p> The Buffalo Mine, located in Heyson Township, Red Lake, consists of quartz-tourmaline veins in a grandiorite. An alteration halo, consisting of andesine feldspar, quartz, calcite, with minor tourmaline, zircon, and opaques, is seen surrounding the veins. Opaque minerals consists of pyrite and hematite. Possible Na - overgrowths of the Plagioclase are seen , as well as complete destruction of the mafic minerals. </p> <p> Geochemistry shows that the wall-rock alteration involves the breakdown of Si, Al, Fe, Mg, Na, and K . Si and Al remain fairly constant, while Na and Ca increase and Fe, Mg, and K decrease in abundance. There has been a sufficient input of CO2 to precipitate calcite, as well as Enough sulfur to form pyrite. </p> <p> The initial hydrothermal solutions were high temperature NaCl solutions, enriched in boron and containing some CO2 . The fluids were likely oxidizing and had a neutral pH. </p> / Thesis / Bachelor of Science (BSc)

[1] Four specimens of zoned tourmaline from granitic pegmatites are characterised in detail, each having unusual compositional and/or morphologic features: (1) a crystal from Black Rapids Glacier, Alaska, showing a central pink zone of elbaite mantled by a thin rim of green liddicoatite; (2) a large (~25 cm) slab of Madagascar liddicoatite cut along (001) showing complex patterns of oscillatory zoning; and (3) a wheatsheaf and (4) a mushroom elbaite from Mogok, Myanmar, both showing extensive bifurcation of fibrous crystals originating from a central core crystal, and showing pronounced discontinuous colour zoning. Crystal chemistry and crystal structure of these samples are characterised by SREF, EMPA, and 11B and 27Al MAS NMR and Mössbauer spectroscopies. For each sample, compositional change, as a function of crystal growth, is characterised by EMPA traverses, and the total chemical variation is reduced to a series of linear substitution mechanisms. Of particular interest are substitutions accommodating the variation in [4]B: (1) TB + YAl ↔ TSi + Y(Fe, Mn)2+, where transition metals are present, and (2) TB2 + YAl ↔ TSi2 + YLi, where transition metals are absent. Integration of all data sets delineates constraints on melt evolution and crystal growth mechanisms. [2] Uncertainty has surrounded the occurrence of [4]Al and [4]B at the T-site in tourmaline, because B is difficult to quantify by EMPA and Al is typically assigned to the octahedral Y- and Z-sites. Although both [4]Al and [4]B have been shown to occur in natural tourmalines, it is not currently known how common these substituents are. Using 11B and 27Al MAS NMR spectroscopy, the presence of [4]B and [4]Al is determined in fifty inclusion-free tourmalines of low transition-metal content with compositions corresponding to five different species. Chemical shifts of [4]B and [3]B in 11B spectra, and [4]Al and [6]Al in 27Al spectra, are well-resolved, allowing detection of very small (< ~0.1 apfu) amounts of T-site constituents. Results show that contents of 0.0 < [4]B, [4]Al < 0.5 apfu are common in tourmalines containing low amounts of paramagnetic species, and that all combinations of Si, Al and B occur in natural tourmalines.

[1] Four specimens of zoned tourmaline from granitic pegmatites are characterised in detail, each having unusual compositional and/or morphologic features: (1) a crystal from Black Rapids Glacier, Alaska, showing a central pink zone of elbaite mantled by a thin rim of green liddicoatite; (2) a large (~25 cm) slab of Madagascar liddicoatite cut along (001) showing complex patterns of oscillatory zoning; and (3) a wheatsheaf and (4) a mushroom elbaite from Mogok, Myanmar, both showing extensive bifurcation of fibrous crystals originating from a central core crystal, and showing pronounced discontinuous colour zoning. Crystal chemistry and crystal structure of these samples are characterised by SREF, EMPA, and 11B and 27Al MAS NMR and Mössbauer spectroscopies. For each sample, compositional change, as a function of crystal growth, is characterised by EMPA traverses, and the total chemical variation is reduced to a series of linear substitution mechanisms. Of particular interest are substitutions accommodating the variation in [4]B: (1) TB + YAl ↔ TSi + Y(Fe, Mn)2+, where transition metals are present, and (2) TB2 + YAl ↔ TSi2 + YLi, where transition metals are absent. Integration of all data sets delineates constraints on melt evolution and crystal growth mechanisms. [2] Uncertainty has surrounded the occurrence of [4]Al and [4]B at the T-site in tourmaline, because B is difficult to quantify by EMPA and Al is typically assigned to the octahedral Y- and Z-sites. Although both [4]Al and [4]B have been shown to occur in natural tourmalines, it is not currently known how common these substituents are. Using 11B and 27Al MAS NMR spectroscopy, the presence of [4]B and [4]Al is determined in fifty inclusion-free tourmalines of low transition-metal content with compositions corresponding to five different species. Chemical shifts of [4]B and [3]B in 11B spectra, and [4]Al and [6]Al in 27Al spectra, are well-resolved, allowing detection of very small (< ~0.1 apfu) amounts of T-site constituents. Results show that contents of 0.0 < [4]B, [4]Al < 0.5 apfu are common in tourmalines containing low amounts of paramagnetic species, and that all combinations of Si, Al and B occur in natural tourmalines.

Coal mine impoundment failures have been well documented to occur due to an increase in excess pore pressure from sustained monotonic loads. Very few failures have ever occurred from dynamic loading events, such as earthquakes, and research has been done regarding the stability of these impoundment structures under such natural seismic loading events. To date no failures or damage have been reported from dynamic loading events caused by near-by production blasting, however little research has been done considering these conditions. Taking into account that current environmental restrictions oblige to increase the capacity of coal impoundments, thus increasing the hazard of such structures, it is necessary to evaluate the effects of near-by blasting on the stability of the impoundment structures. To study the behavior of excess pore pressure under blasting conditions, scaled simulations of blasting events were set inside a controlled sand tank. Simulated blasts were duplicated in both saturated and unsaturated conditions. Explosive charges were detonated within the sand tank at various distances to simulate different scaled distances. Information was collected from geophones for dry and saturated scenarios and additionally from pressure sensors under saturated conditions to assess the behavior of the material under blasting conditions.

The garnet line is a planar fabric occuring within the intermediate and core zone in many of the Oxford County, Maine pegmatites. This study focuses primarily on the textural and chemical characteristics of the garnet line within the Mt. Mica and western Mt. Apatite quarries. Smaller, but similarly textured garnet line analogs from the Bennett, Emmons, Havey and Tamminen quarries are also investigated. All of these textures represent specific fractionation events within their respective dikes. In some of these locations, multiple stages of crystallization occur and appear to be post-magmatic, related to late stage metasomatism. These late stage fluids are believed to have migrated from localized and highly evolved regions within these pegmatites. The garnet line at Mt. Mica has the greatest diversity of secondary mineral assemblages, e.g. tourmaline and/or muscovite rims around garnets and ferric pollucite. None of these late stage textures have ever been described before.

Cette thèse présente un modèle numérique 3D par différences finies capable de simuler la diffusion atomique dans les monocristaux. Ce nouvel outil permet : de prendre en compte l'anisotropie de diffusion, de générer un large choix de forme de cristal, de considérer n'importe quelle distribution initiale de concentration, de faire évoluer la concentration de surface en fonction du temps et de choisir, sans restriction, la variation de température en fonction du temps.<br />Le modèle 3D créé a été appliqué à quatre cas d'étude : trois portent sur des expériences de diffusion de l'hydrogène réalisées en laboratoire dans le diopside, la lawsonite et la tourmaline, le quatrième sur des profils de diffusion naturels (Al-Si et O) dans des diopsides des Adirondacks. Ces études illustrent le potentiel du modèle numérique 3D développé pour la description et l'interprétation des profils de diffusion dans les minéraux. Ce nouvel outil sera très utile pour interpréter les zonations de plus en plus fines obtenues à l'échelle du grain à l'aide des techniques analytiques modernes.

The aim of this study is to investigate the petrography, geochemistry and evolution of quartz-tourmaline-rich rocks occurring in a wide breccia zone within the Late Cretaceous Kerkenez Granitoid (Central Anatolian Crystalline Complex (CACC), Turkey). The approximately 40-m wide main breccia zone has a NE-SW trend and is characterized by intense cataclastic deformation. The breccia zone can be traced several kilometers towards the west and generally occurs as tourmaline-filled faults and 1mm-30cm-thick veins within the granitoid. On the basis of mineralogical and textural features, rocks within this zone are defined as tourmaline veins, tourmaline-breccias and quartz-tourmaline rocks. These rocks are generally composed of quartz, tourmaline and granitic fragments. Petrographical investigations and electron-microprobe analyses indicate that, there are three optically and chemically different tourmaline generations. From oldest to youngest, the tourmalines are classified as blue pleochroic feruvites, blue-green pleochroic schorls and green-light green pleochroic schorls. The chemistry of the tourmalines suggests that these tourmalines crystallized from boron rich fluids derived from an evolving magma. Consequently, the quartz tourmaline-breccia zone is considered to have formed by the injection of overpressured boron rich fluids into faults and fractures present within the Kerkenez Granitoid. Fluid-filled faults and fractures were sealed by quartz-tourmaline crystallization. This led to further fractionation in the magma, new fluid pressure accumulations, reactivation of faults and crystallization of different tourmaline generations. Tourmaline-breccia zones are scarce in the literature and the presence of such rocks within the CACC is first reported in this study.

Les tourmalines, les scheelites et les magnétites provenant des gisements aurifères de type orogénique (n=22) et des sédiments glaciaires (n=5) du district minier de Val-d’Or (Québec, Canada) ont été investiguées à la microsonde électronique (EPMA) et par ablation laser et spectrométrie de masse à plasma à couplage inductif (LA-ICP-MS) afin de déterminer leur signature chimique et d’évaluer leur potentiel en tant que minéraux indicateurs pour l’exploration aurifère. Les tourmalines de Type I provenant de dépôts aurifères de type orogénique encaissés dans des roches felsiques et intermédiaires calco-alcalines montrent de faibles teneurs en V, Cr, Mn, Fe, Co, Ni, Zn et Sn et une teneur élevée en Mg par rapport aux tourmalines de Type II provenant de dépôts aurifères de type orogénique encaissés dans des roches mafiques tholéiitiques. Les tourmalines de Type III provenant de dépôts aurifères de type orogénique situés au contact entre des roches mafiques volcaniques et métasédimentaires montrent une chimie similaire aux tourmalines de Type I avec des teneurs en Li, Mn et Pb légèrement plus élevées. Les tourmalines des gisements aurifères de type orogénique sont caractérisées par des teneurs en Zn, Cu, Sn et Pb plus faibles que les tourmalines associées aux miniéralisations de type Cu-Zn, Pb-Zn-Cu et Sn. Les tourmalines récupérées dans le till portent la signature chimique des tourmalines provenant des gisements aurifères de type orogénique avec une majorité portant la signature des tourmalines de Type I. Les scheelites provenant de dépôts aurifères de type orogénique encaissés dans des intrusions calco-alcalines de composition intermédiaire sont caractérisées par des teneurs en Na, ÉTR et Y plus élevées que les scheelites provenant de dépôts aurifères encaissés dans des roches sédimentaires ou mafiques. Les scheelites récupérées dans le till portent la signature chimique des scheelites provenant des gisements aurifères de type orogénique. Les magnétites sont rare dans les dépôts aurifères de type orogénique du district de Val-d’Or. Les magnétites d’origine hydrothermale provenant des veines aurifères sont caractérisées par des teneurs plus élevées en Cr, Zn, Mn, K, Ca, Ti et Al que les magnétites d’origine magmatique retrouvées dans les roches encaissantes de composition dioritique ou gabbroique. Les magnétites associées à la minéralisation aurifère forment des grains fins disséminés (&lt; 0,05 mm), ce qui suggère que les magnétites grossières récupérées dans le till ne proviennent probablement pas des veines de quartz aurifères. / Tourmalines, scheelites and magnetites from orogenic gold deposits (n=22) and glacial sediments (n=5) of the Val-d’Or mining district (Québec, Canada) were investigated by Electron Probe Micro-Analyzer (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) in order to determine their chemical signature and to assess their potential as indicator minerals for gold exploration. Type I tourmalines from orogenic gold deposits hosted in felsic and intermediate calc-alkaline rocks have low contents of V, Cr, Mn, Fe, Co, Ni, Zn, and Sn and a high content of Mg compared to Type II tourmalines from orogenic gold deposits hosted in mafic tholeiitic rocks. Type III tourmalines from orogenic gold deposits located at the contact between mafic volcanic and metasedimentary rocks show a chemistry similar to Type I tourmalines with slightly higher Li, Mn, and Pb contents. Tourmalines from orogenic gold deposits are characterized by lower contents of Zn, Cu, Sn, and Pb than tourmalines associated to Cu-Zn, Pb-Zn-Cu, and Sn mineralizations. Till tourmalines carry the chemical signature of tourmalines from orogenic gold deposits with a majority carrying the signature of Type I tourmalines. Scheelites from orogenic gold deposits of the Val-d’Or district hosted in calc-alkaline intrusions of intermediate composition are characterized by high Na, REE, and Y contents compared to scheelites from sediment- or mafic-hosted gold deposits. Till scheelites carry the chemical signature of scheelites from orogenic gold deposits. Magnetites are rare in orogenic gold deposits of the Val-d’Or district. Magnetites of hydrothermal origin occuring in gold veins are characterized by higher contents of Cr, Zn, Mn, K, Ca, Ti, and Al than magnetites of magmatic origin found in the dioritic or gabbroic host rocks. Magnetites associated to the gold mineralization form fine disseminated grains (&lt; 0.05 mm), which suggests that the coarse magnetites recovered in the till probably do not originate from the gold-bearing quartz veins.