Academic literature on the topic 'Olivine and pyroxene thermodynamics'
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Journal articles on the topic "Olivine and pyroxene thermodynamics"
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Matas, J., Y. Ricard, L. Lemelle, and F. Guyot. "An improved thermodynamic model of metal-olivine-pyroxene stability domains." Contributions to Mineralogy and Petrology 140, no. 1 (November 2000): 73–83. http://dx.doi.org/10.1007/s004100000177.
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Abdeyazdan, Hamed, Maksym Shevchenko, Peter C. Hayes, and Evgueni Jak. "Integrated Experimental and Thermodynamic Modeling Investigation of Phase Equilibria in the PbO–MgO–SiO2 System in Air." Metallurgical and Materials Transactions B 53, no. 2 (February 8, 2022): 954–67. http://dx.doi.org/10.1007/s11663-022-02440-6.
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AbstractMagnesium oxide-based refractory materials are used industrially to contain the chemically aggressive slags present in lead smelting systems. In the present study an integrated experimental and thermodynamic modeling approach was taken to provide fundamental information on the chemical reactions taking place in these systems. New experimental phase equilibria and liquidus data were obtained for the PbO–MgO–SiO2 system in air in the temperature range 750 °C to 1740 °C. In the MgO–SiO2 binary, new experimental results were obtained at 1550 °C to 1740 °C and compared to the available thermodynamic data in the literature. The experiments were carried out using the high-temperature equilibration of oxide powder mixtures followed by rapid quenching of the samples. Electron probe X-ray microanalysis (EPMA) was used to determine the compositions of the solid and liquid phases present at equilibrium conditions. Phase equilibria and liquidus isotherms in the cristobalite and tridymite (SiO2), pyroxene (protoenstatite MgSiO3), olivine (forsterite Mg2SiO4), barysilite (Pb8MgSi6O21), massicot (PbO) and periclase (MgO) primary phase fields were measured, and the extent of the high-silica two-liquid immiscibility gap in equilibrium with cristobalite was determined. The experimental results were used to optimize the parameters in a thermodynamic database that was subsequently used to describe this multi-component, multi-phase system and predict the liquidus for the PbO–MgO–SiO2 system. The new data were used to characterize the chemical interactions of magnesia-based refractory with PbO–MgO–SiO2 slags.
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Komatsu, Mutsumi, Timothy J. Fagan, Alexander N. Krot, Kazuhide Nagashima, Michail I. Petaev, Makoto Kimura, and Akira Yamaguchi. "First evidence for silica condensation within the solar protoplanetary disk." Proceedings of the National Academy of Sciences 115, no. 29 (July 2, 2018): 7497–502. http://dx.doi.org/10.1073/pnas.1722265115.
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Calcium-aluminum–rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs), a refractory component of chondritic meteorites, formed in a high-temperature region of the protoplanetary disk characterized by approximately solar chemical and oxygen isotopic (Δ17O ∼ −24‰) compositions, most likely near the protosun. Here we describe a 16O-rich (Δ17O ∼ −22 ± 2‰) AOA from the carbonaceous Renazzo-type (CR) chondrite Yamato-793261 containing both (i) an ultrarefractory CAI and (ii) forsterite, low-Ca pyroxene, and silica, indicating formation by gas–solid reactions over a wide temperature range from ∼1,800 to ∼1,150 K. This AOA provides direct evidence for gas–solid condensation of silica in a CAI/AOA-forming region. In a gas of solar composition, the Mg/Si ratio exceeds 1, and, therefore, silica is not predicted to condense under equilibrium conditions, suggesting that the AOA formed in a parcel of gas with fractionated Mg/Si ratio, most likely due to condensation of forsterite grains. Thermodynamic modeling suggests that silica formed by condensation of nebular gas depleted by ∼10× in H and He that cooled at 50 K/hour at total pressure of 10−4 bar. Condensation of silica from a hot, chemically fractionated gas could explain the origin of silica identified from infrared spectroscopy of remote protostellar disks.
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Murphy, William M., and Harold C. Helgeson. "Thermodynamic and kinetic constraints on reaction rates among minerals and aqueous solutions. III. Activated complexes and the pH-dependence of the rates of feldspar, pyroxene, wollastonite, and olivine hydrolysis." Geochimica et Cosmochimica Acta 51, no. 12 (December 1987): 3137–53. http://dx.doi.org/10.1016/0016-7037(87)90124-4.
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Murphy, W. M., and H. C. Helgeson. "Thermodynamic and kinetic constraints on reaction rates among minerals and aqueous solutions; IV, Retrieval of rate constants and activation parameters for the hydrolysis of pyroxene, wollastonite, olivine, andalusite, quartz, and nepheline." American Journal of Science 289, no. 1 (January 1, 1989): 17–101. http://dx.doi.org/10.2475/ajs.289.1.17.
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Huang, Ruifang, Xing Ding, Weidong Sun, and Xiuqi Shang. "Contrasted Effect of Spinel and Pyroxene on Molecular Hydrogen (H2) Production during Serpentinization of Olivine." Minerals 11, no. 8 (July 22, 2021): 794. http://dx.doi.org/10.3390/min11080794.
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Serpentinization produces molecular hydrogen (H2) and hydrocarbons that can feed the colonies of microbes in hydrothermal vent fields, and therefore serpentinization may be important for the origins of life. However, the mechanisms that control molecular hydrogen (H2) production during serpentinization remain poorly understood. Here the effect of pyroxene minerals and spinel on molecular hydrogen (H2) generation during serpentinization is experimentally studied at 311–500 °C and 3.0 kbar, where olivine, individually and in combinations with pyroxene and/or spinel, is reacted with saline solutions (0.5 M NaCl). The results show a contrasting influence of spinel and pyroxeneon molecular hydrogen (H2) production. At 311 °C and 3.0 kbar, spinel promotes H2 generation by around two times, and pyroxene minerals decrease molecular hydrogen (H2) production by around one order of magnitude. Spinel leaches aluminum (Al) and chromium (Cr) during hydrothermal alteration, and Al and Cr enhance molecular hydrogen (H2) production. This is confirmed by performing experiments on the serpentinization of olivine with the addition of Al2O3 or Cr2O3 powders, and an increase in molecular hydrogen (H2) production was observed. Pyroxene minerals, however, not only leach Al and Cr, but they also release silica (SiO2) during serpentinization. The sharp decline in molecular hydrogen (H2) production in experiments with a combination of olivine and pyroxene minerals may be attributed to releases of silica from pyroxene minerals. With increasing temperatures (e.g., 400–500 °C), the effect of spinel and pyroxene minerals on molecular hydrogen (H2) production is much less significant, which is possibly related tothe sluggish kinetics of olivine serpentinization under these T-P conditions. In natural geological settings, olivine is commonly associated with spinel and pyroxene, and molecular hydrogen (H2) during serpentinization can be greatly affected.
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Radomsky, Patrick M., and Roger H. Hewins. "Formation conditions of pyroxene-olivine and magnesian olivine chondrules." Geochimica et Cosmochimica Acta 54, no. 12 (December 1990): 3475–90. http://dx.doi.org/10.1016/0016-7037(90)90299-z.
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Bradley, J. P. "Physical and Mineralogical Properties of Anhydrous Interplanetary Dust Particles in the Analytical Electron Microscope." International Astronomical Union Colloquium 126 (1991): 63–70. http://dx.doi.org/10.1017/s0252921100066495.
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AbstractThe fine grained mineralogy and petrography of anhydrous “pyroxene” and “olivine” classes of chondritic interplanetary dust have been investigated by numerous electron microscopic studies. The “pyroxene” interplanetary dust particles (IDPs) are porous, unequilibrated assemblages of mineral grains, metal, glass, and carbonaceous material. They contain enstatite whiskers, FeNi carbides, and high-Mn olivines and pyroxenes, all of which are likely to be well preserved products of nebular gas reactions. Solar flare tracks are prominent in most “pyroxene” IDPs, indicating that they were not strongly heated during atmospheric entry. The “olivine” IDPs are coarse grained, equilibrated mineral assemblages that have probably experienced strong heating. Since most “olivine” IDPs do not contain tracks, it is possible that this heating occurred during atmospheric entry.
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Morse, S. A., Brent E. Owens, and Alan R. Butcher. "Origin of finger structures in the Rhum Complex: phase equilibrium and heat effects." Geological Magazine 124, no. 3 (May 1987): 205–10. http://dx.doi.org/10.1017/s0016756800016241.
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AbstractThe finger structures described earlier by Brown and later by Butcher, Young & Faithfull involve dissolution of troctolite during crystallization of olivine, followed by crystallization of pyroxene around olivine grains in the fingers. However, the ingestion of troctolite takes the liquid away from pyroxene saturation rather than toward it. The pyroxene field can be encountered metastably, and pyroxene caused to crystallize, by supercooling the olivine-rich liquid against the troctolite. The melt corrosion represented by the fingers, and other field relations, suggest that the mafic layers were emplaced as sills of mafic magma into nearly solid troctolites. Melting at the base of mafic liquid layers was impeded by a bed of olivine crystals releasing light solute upward, causing compositional convention and rapid heat transfer to the top of the layer, where melting demonstrably occurred. Recognition of this process introduces the novel concept of a magmatic heat pump driven by compositional convection. The crystallization path ol–px–pl(–sp) is also found next to xenoliths in the Kiglapait Intrusion where the magma was normally saturated only in ol+pl, directly demonstrating the effect of supercooling on the crystallization sequence.
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Kretz, Ralph, Peter Jones, and Ron Hartree. "Grenville metagabbro complexes of the Otter Lake area, Quebec." Canadian Journal of Earth Sciences 26, no. 2 (February 1, 1989): 215–30. http://dx.doi.org/10.1139/e89-018.
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Metagabbro complexes in a portion of the Grenville Province lying northwest of Ottawa occur as sheets, cylinders, and irregular bodies within a medium- to high-grade marble–gneiss–amphibolite terrane. The largest bodies (0.5–10 km in greatest dimension) consist principally of felsic metagabbro, mafic metagabbro, and minor metapyroxenite. Major-element and select trace-element analyses show that different complexes contain distinctly different amounts of K and other elements resulting in different interelement trends.Microstructure and microprobe mineral analyses provide evidence that the following metamorphic changes have occurred: (i) recrystallization of Ca pyroxene, orthopyroxene, and plagioclase; (ii) reaction of Mg-rich olivine with plagioclase to produce reaction zones consisting of orthopyroxene and a hornblende–spinel intergrowth; (iii) reaction of Mg–Fe olivine with plagioclase to produce garnet and hornblende; (iv) production of anthophyllite and hornblende from orthopyroxene and plagioclase; (v) production of hornblende (locally as rims about Ca pyroxene) from Ca pyroxene and plagioclase; (vi) crystallization of biotite, possibly by reaction between orthopyroxene and K-feldspar; and (vii) crystallization of small inclusions of spinel and ilmenite in Ca pyroxene and of spinel and biotite in plagioclase.With regard to the reaction olivine + plagioclase = orthopyroxene + hornblende + spinel, the anorthite and locally the forsterite components were extracted preferentially from plagioclase and olivine; K and Ti (for hornblende) and Zn (for spinel) were evidently obtained from the surrounding minerals; and H, F, and Cl (for hornblende) were obtained from beyond the gabbro bobies. Locally the reaction occurred within large crystals of Ca pyroxene where embedded olivine and plagioclase crystals were in contact.The production of hornblende rims about Ca pyroxene evidently involved plagioclase as a reactant, but the rims formed regardless of the contacting minerals. For example, rims were locally produced where Ca-pyroxene crystals were embedded in large crystals of orthopyroxene.Application of five geothermometers to crystals of both igneous and metamorphic origin yield temperatures of about 700 °C, similar to temperatures recorded for the enclosing marble and gneiss.
Dissertations / Theses on the topic "Olivine and pyroxene thermodynamics"
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Sommacal, Silvano, and silvano sommacal@anu edu au. "Computational petrology: Subsolidus equilibria in the upper mantle." The Australian National University. Research School of Earth Sciences, 2004. http://thesis.anu.edu.au./public/adt-ANU20050415.151025.
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Processes that take place in the Earths mantle are not accessible to direct observation. Natural samples of mantle material that have been transported to the surface as xenoliths provide useful information on phase relations and compositions of phases at the pressure and temperature conditions of each rock fragment. In the past, considerable effort has been devoted by petrologists to investigate upper mantle processes experimentally. Results of high temperatures, high pressure experiments have provided insight into lower crust-upper mantle phase relations as a function of temperature, pressure and composition. However, the attainment of equilibrium in these experiments, especially in complex systems, may be very difficult to test rigorously. Furthermore, experimental results may also require extrapolation to different pressures, temperatures or bulk compositions. More recently, thermodynamic modeling has proved to be a very powerful approach to this problem, allowing the deciphering the physicochemical conditions at which mantle processes occur. On the other hand, a comprehensive thermodynamic model to investigate lower crust-upper mantle phase assemblages in complex systems does not exist. ¶
In this study, a new thermodynamic model to describe phase equilibria between silicate and/or oxide crystalline phases has been derived. For every solution phase the molar Gibbs free energy is given by the sum of contributions from the energy of the end-members, ideal mixing on sites, and excess site mixing terms. It is here argued that the end-member term of the Gibbs free energy for complex solid solution phases (e.g. pyroxene, spinel) has not previously been treated in the most appropriate manner. As an example, the correct expression of this term for a pyroxene solution in a general (Na-Ca-Mg-Fe2+-Al-Cr-Fe3+-Si-Ti) system is presented and the principle underlying its formulation for any complex solution phase is elucidated.¶
Based on the thermodynamic model an algorithm to compute lower crust-upper mantle phase equilibria for subsolidus mineral assemblages as a function of composition, temperature and pressure has been developed. Included in the algorithm is a new way to represent the total Gibbs free energy for any multi-phase complex system. At any given temperature and pressure a closed multi-phase system is at its equilibrium condition when the chemical composition of the phases present in the system and the number of moles of each are such that the Gibbs free energy of the system reaches its minimum value. From a mathematical point of view, the determination of equilibrium phase assemblages can, in short, be defined as a constrained minimization problem. To solve the Gibbs free energy minimization problem a Feasible Iterate Sequential Quadratic Programming method (FSQP) is employed. The systems Gibbs free energy is minimized under several different linear and non-linear constraints. The algorithm, coded as a highly flexible FORTRAN computer program (named Gib), has been set up, at the moment, to perform equilibrium calculations in NaO-CaO-MgO-FeO-Al2O3-Cr2O3-Fe2O3- SiO2-TiO2 systems. However, the program is designed in a way that any other oxide component could be easily added.¶
To accurately forward model phase equilibria compositions using Gib, a precise estimation of the thermodynamic data for mineral end-members and of the solution parameters that will be adopted in the computation is needed. As a result, the value of these parameters had to be derived/refined for every solution phase in the investigated systems. A computer program (called GibInv) has been set up, and its implementation is here described in detail, that allows the simultaneous refinement of any of the end-member and mixing parameters. Derivation of internally consistent thermodynamic data is obtained by making use of the Bayesian technique. The program, after being successfully tested in a synthetic case, is initially applied to pyroxene assemblages in the system CaO-MgO-FeO-Al2O3-SiO2 (i.e. CMFAS) and in its constituent subsystems. Preliminary results are presented.¶
The new thermodynamic model is then applied to assemblages of Ca-Mg-Fe olivines and to assemblages of coexisting pyroxenes (orthopyroxene, low Ca- and high Ca clinopyroxene; two or three depending on T-P-bulk composition conditions), in CMFAS system and subsystems. Olivine and pyroxene solid solution and end-member parameters are refined, in part using GibInv and in part on a trial and error basis, and, when necessary, new parameters are derived. Olivine/pyroxene phase relations within such systems and their subsystems are calculated over a wide range of temperatures and pressures and compare very favorably with experimental constraints.
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Derenne, Sylvie. "Contribution a l'etude des proprietes physiques de mineraux du manteau inferieur." Paris 6, 1988. http://www.theses.fr/1988PA066281.
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Etude de petrologie experimentale sur les transformations a hautes pressions et hautes temperatures, de silicates et de germanates a structure olicine et pyroxene. Il a ete determine en fonction de la pression et de la temperature, la distribution du magnesium, du fer et du calcium entre mineraux mantelliques. Un modele thermodynamique coherent est construit et a permis de determiner le champ de stabilite de la perovskite silicatee et de proposer une interpretation de la discontinuite sismique des 670 km. Des mecanismes microscopiques de transformations de phase de l'olivine sont proposes. De quelques composes etudies par spectroscopie raman, a ete tire des parametres thermodynamiques harmoniques et anharmoniques de ces phases
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Harrell, Michael D. "Anisotropic lattice thermal diffusivity in olivines and pyroxenes to high temperatures /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/6725.
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Storm, Shaye Perry. "Distribution of olivine and pyroxene in S-type asteroids throughout the inner main belt." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/117446.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.Cataloged from PDF version of thesis. "May 5, 2008." "This thesis was submitted to the Institute Archives without all the required signatures"--Disclaimer Notice page.
Includes bibliographical references (page 33).
The mineralogical composition of asteroids can be constrained using visible and near-infrared (VNIR) spectroscopy. The most prominent spectral features observed over this wavelength range are due to olivine and pyroxene, the two most abundant minerals in both chondritic and achondritic meteorites. The observed ratio of these two minerals is highly dependent on the amount of heating that an asteroid has undergone. The 1-micron band center wavelength and the band area ratio (BAR) between the 2- and 1-micron bands reveal relative abundances of olivine and/or pyroxene on an asteroid surface (Gaffey, 1993). A large sample of S-, A-, V-, and R-type asteroid spectra was collected over the visible and near-IR wavelengths during the second phase of the Small Main-belt Asteroid Spectroscopic Survey (Bus and Binzel, 2002) and using the low-resolution SpeX spectrograph (Rayner, 2003) at NASA's Infrared Telescope Facility (IRTF). Here we present a methodology for calculating the location of the 1-micron band center wavelength and BAR with appropriate 1- sigma uncertainties. This method was used to characterize 188 S-type asteroids throughout the inner main belt. We will also present the distribution of olivine / pyroxene throughout the main belt by measuring how the S-type mineralogy varies with heliocentric distance. This will provide a better understanding of both the thermal processing across the main belt and subsequent mixing of asteroids through collisional and dynamical processes.
by Shaye Perry Storm.
S.B.
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Burness, Sara. "Pyroxene stability within kimberlite magma in the upper mantle : an experimental investigation." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96837.
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Thesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Entrainment and assimilation of xenolithic material during kimberlite ascent is considered to be important in shaping the chemistry of the magma and fuelling magma ascent by driving CO2 exsolution. Previous, but as yet unpublished experimental work from Stellenbosch University has demonstrated that orthopyroxene has a key role in this. Orthopyroxene is a very rare xenocrystic constituent of kimberlite but makes up a considerable fraction of the entrained xenolithic material. The initial study used a natural kimberlite composition (ADF1) doped with a peridotite mineral suite (by weight); 88 % ADF1 5% olivine, 5% orthopyroxene and 2% garnet-spinel intergrowth as a starting composition. The subsequent high PT experiments (1100 to 1300°C and 2.0 to 3.5GPa) established that equilibrium orthopyroxene is stable at 1100°C above 2.5GPa, at 1200°C above 2.5GPa and at 1300°C between 2.0 and 3.5GPa. At lower pressures orthopyroxene is completely digested by the experimental melt by the reaction; Mg2Si2O6 (opx) = Mg2SiO4 (ol) + SiO2 (in liquid). In contrast, clinopyroxene is a common phase in kimberlite and often occurs as more than one generation of crystals. Xenocrystic clinopyroxene is dominated by diopside compositions. However, rare omphacite is sometimes also inherited from an eclogite source. The Omphacite, like orthopyroxene, displays textural evidence of severe disequilibrium and may also contribute to the evolution of kimberlitic melt. Thus, a second study produced experiments on the ADF1 kimberlite material at upper mantle PT conditions (1100 to 1300°C and 2.0 to 4.0GPa) as well as an omphacite doped starting material (ADF1+O). These experiments examine the behaviour of pyroxene in kimberlite magma including the influence this may have on magma buoyancy. Within this PT range omphacitic clinopyroxene breaks-down via complex multipart reactions. At 1100°C and 2.0GPa reaction textures around remnant omphacite suggest that omphacite melts incongruently in a complex reaction similar to: Omp + Melt = Ap + Cr-diop + SiO2-enriched Melt. At 1300°C omphacite melts completely and is perceived to produce peritectic Cr-diopside, calcium-rich olivine, carbonate in the melt as well as enrich the melt in SiO2. The melts produced by both the ADF1+O and ADF1 compositions at 1300°C and 4.0GPa are reduced in SiO2 content and have increased TiO2, Cr2O3, Al2O3, MnO, CaO, K2O and P2O5 compared to their respective starting compositions. However, significantly higher proportions of Ca, Na and Fe observed within the ADF1+O melt is a direct consequence of omphacite melting. The ADF1+O starting composition produced equilibrium orthopyroxene above 1100°C and 4.0GPa as well as at 1300°C above 2.0GPa. At lower pressure the orthopyroxene melts incongruently to form peritectic olivine and more silica-rich melt compositions. This digestion favours CO2 exsolution. The effect of orthopyroxene melting can be seen in the melt compositions produced by the peridotite doped starting material (ADF1+P) of the initial study. At 1300°C and 2.0GPa, ADF1+P produced a siliceous melt (37.0 wt.% SiO2) enriched in Al and alkalis compared to the starting ADF1+P composition. This behaviour is directly attributed to xenocrystic orthopyroxene melting at high temperature. In contrast, at the same PT the original kimberlite (ADF1) composition produces a melt with 28.9 wt.% SiO2 and high Ca and Mg contents. Overall, with an increase in pressure the melts become enriched in alkalis and Al2O3 as a direct result of xenocrystic pyroxene melting. In addition, increased pressure allows for a greater solubility of CO2 within the melt. This results in a lower SiO2 melt content and the increased stabilization of equilibrium silica-rich mineral phases (i.e. olivine and equilibrium orthopyroxene). Within the peridotite doped static system (unpublished) the mineral separates with an average crystal size of 115μm ±10μm were all effectively digested in less than 48hours. Similarly, the omphacite doped experiments consumed the 150μm (±10μm) xenocrysts in under 24 hours. Thus, it is suggested that xenocrystic pyroxene is unstable in these experimental kimberlitic melt compositions and is likely to be efficiently assimilated in less than 24 hours. These experimental melts most likely resemble those of natural systems under upper mantle PT conditions. Therefore, pyroxene melting increases the silica content of the melt which in turn drives CO2 exsolution and ascent.
AFRIKAANSE OPSOMMING: Meevoering en assimilasie van xenolitiese materiaal gedurenende kimberliet bestyging is beskou as belangrik in verband met die vorming van die chemie van die magma, en bevorder magma bestyging deur die aandrywing van CO2 ontmenging. Vorige, maar ongepubliseerde eksperimentele werk vanaf Stellenbosch Universiteit het gedemonstreer dat ortopirokseen ‘n sleutelrol hierin het, omrede ortopirokseen ‘n baie skaars xenokristiese bestanddeel van kimberliet is maar ‘n aansienlike fraksie van die meevoerde xenolitiese materiaal moet opmaak. Hierdie studie het ‘n natuurlike primere kimberliet komposisie (ADFI) gedoop met ‘n peridotiet mineraal reeks (per gewig); 88 % ADF1 5% olivien, 5% ortopirokseen en 2% granaat-spinel ingroeiing as begin komposisie gebruik. Die daaropvolgende hoë DT eksperimente (1100 tot 1300°C en 2.0 tot 3.5GPa) het vasgestel dat ewewigsortopirokseen stabiel is teen 1100°C bo 2.5GPa, 1200°C bo 2.5GPa en teen 1300°C vanaf 2.0 tot 3.5Gpa. Teen laer druk word ortopirokseen geheel verteer deur die eksperimentele smelting volgens die reaksie Mg2Si2O6 (opx) = Mg2SiO4 (ol) + SiO2 (in vloeistof). In kontras hiermee is clinopirokseen algemeen in kiemberliet en kom dikwels voor as meer as een generasie se kristalle. Diopsiet komposisies domineer xenokristiese klinopirokseen. Seldsame omfasiet is tog somtyds ook geërf vanaf ‘n eklogiet bron. Die omfasiet, soos ortopirokseen, vertoon teksturuele bewys van ernstige disekwilibrium en mag ook bydra tot die evolusie van kimberlitiese smelt. Dus was daar addisionele eksperimente uitgevoer op die ADF1 kimberliet material teen hoër mantel DT kondisies (1100 tot 1300°C en 2.0 tot 4.0GPa), asook ‘n begin materiaal gedoop met omfasiet (ADF1+O). Hierdie eksperimente ondersoek die gedrag van pirokseen in kiemberliet magma, asook die invloed wat dit sal hê op die dryfvermoë van die magma. Binne hierdie DT reeks breek omfasitiese klinopirokseen af via komplekse multideel reaksie prosesse. Teen 1100°C en 2.0Gpa stel reaksie teksture rondom die oorblywende omfasiet voor dat omfasiet ongelykvormig smelt deur ‘n komplekse reaksie soortgelyk aan: Omp + Smelt = Ap + Cr-diop + SiO2-verrykde Smelt. Teen 1300°C smelt omfasiet volkome en is waargeneem om peritektiese Cr-diopsiet, kalsiumryke olivien en kalsiet te produseer, sowel as dat dit die smelt verryk in SiO2. Die smeltings geprodiseer deur die ADF1+O en ADF1 massa komposisies teen 1300°C en 4.0GPa is verlaag in SiO2 inhoud en bevat verhoogde TiO2, Cr2O3, Al2O3, MnO, CaO, K2O en P2O5 in vergelyking met die onderskeie begin komposisies. Aansienlike hoër proporsies van Ca, Na en Fe is egter waargeneem in die ADF1+O smelt en is ‘n direkte gevolg van die smelting van omfasiet. Die ADF1+O begin samestelling het ewewigsortopirokseen bo 1100°C en 4.0Gpa geproduseer en massa teen 1300°C en 2.0 tot 4.0GPa. Teen laer druk smelt hierdie pirokseen inkongruent om peritektiese olivien en meer silika-ryke smelt samestellings te vorm, en ontmeng CO2. Die effek van ortopirokseen smelting kan aanskou word in die smelt samestellings wat produseer is deur die begin materiaal wat gedoop is in peridotiet (ADF1+P), in die oorspronklike studie. Teen 1300°C en 2.0GPa het ADF1+P ‘n silikahoudende smelt (37.0 wt.% SiO2) produseer wat verryk is in Al en alkalies in vergelyking met die ADF1+P massa samestelling. Hierdie gedrag is direk toegeskryf aan die xenokristiese ortopirokseen wat smelt teen hoë temperatuur. In kontras hiermee, teen dieselfde DT kondisies produseer die oorspronklike kiemberliet (ADF1) massa ‘n smelt met 28.86 gewigspersentasie SiO2 en hoë Ca en Mg inhoud. In die algeheel word die smeltings verryk in alkalies en Al2O3 teen verhoogde druk as ‘n derekte gevolg van xenokristiese pirokseen smelting. Verder laat verhoogde druk toe vir hoër oplosbaarheid van CO2 in die smelt, wat lei tot laer SiO2 inhoud en ‘n toename in stabilisering van ewewigs silika-ryke mineraal fases (dws. olivien en ewewigsortopirokseen). In die peridotiet gedoopde statiese sisteem (ongepubliseerd), was die mineraal skeiding met ‘n gemiddelde kristal grootte van 115μm ±10μm almal effektief verteer in minder as 48 ure. Soortgelyk hieraan het die omfasiet gedoopde eksperimente die 150μm (±10μm) sade onder 24 ure verteer. Dus stel dit voor dat xenokristiese pirokseen in naatuurlike sisteme onstabiel is in kiemberlietiese smelt samestellings en sal waarskynlik geassimileer wees in miner as 24 ure en ‘n meer silica-ryke kiemberlietiese smelt samestelling produseer terwyl dit CO2, ontmenging en bestyging aandryf.
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Soustelle, Vincent. "Interactions entre déformation et percolation de magma ou de fluide dans le manteau à l'aplomb des zones de subduction." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20151/document.
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Ce travail apporte de nouvelles contraintes sur les interactions entre déformation et processus d'hydratation et de percolation de magma ou de fluides et leurs implications sur les propriétés sismiques dans le coin mantellique. Il se base sur l'analyse de péridotites à spinelle provenant du massif de Ronda (Espagne) et deux séries de xénolites issues de zones de subduction actives (Kamchatka, Papouasie-Nouvelle-Guinée). L'étude structurale, pétrologique et géochimique de ces échantillons montrent qu'ils ont subi une percolation réactive de magma ou de fluide synchrone d'une déformation de haute température basse contrainte cohérente avec les condition PT de la base de la lithosphère ou de l'asthénosphère. Cette percolation réactive est responsable d'un enrichissement en pyroxènes localisés dans des bandes parallèles aux structures de déformation. Cet enrichissement est associé à la décroissance et à la désorientation des cristaux d'olivine. Le système de glissement dominant dans l'olivine est {0kl}[100], cela implique que la direction de polarisation rapide des ondes S dans la partie supérieure du coin mantellique est parallèle à la direction d'écoulement du manteau. L'enrichissement en pyroxène associé à une décroissance de l'intensité des OPR de l'olivine a pour conséquence une baisse non négligeable de l'anisotropie qui peut induire jusqu'à 33% d'erreur sur l'interprétation de la couche anisotrope. Un enrichissement en orthopyroxène peut entraîner une baisse du rapport Vp/Vs, mais ne peut expliquer des Vp/Vs <1,7 cartés dans certains avant-arcs. Cependant de telles valeurs peuvent être expliquées si l'anisotropie des péridotites du coin mantellique est prise en compteThis work provides new constraints on the interactions between deformation and hydration process and the percolation of melt or fluids, and their implications for seismic properties of the mantle wedge. It is based on the analysis of spinel peridotites from the massif of Ronda (Spain) and two xenolith suites from active subduction zones (Kamchatka, Papua New Guinea). The structural, petrological and geochemical of these samples show that they underwent a reactive percolation of melt or fluid, which was synchronous to a deformation event occuring under high temperature and low stress consistent with the PT conditions of the base of the lithosphere or in the asthenosphere. This reactive percolation is responsible for pyroxenes enrichment localized in bands parallel to the deformation structures. This enrichment is associated with the grain size recuction and the disorientation of the crystals of olivine. The dominant slip system in olivine is {0 kl}[100], which results in fast S-wave polarization parallel to the flow direction in the mantle. The enrichment in pyroxene, associated with a decrease in the intensity of the olivine crystal preferred orientations, results in a significant decrease of the anisotropy that may induce error on the interpretation of the anisotropic layer (up to 33%). The observed orthopyroxene enrichment also lowers the Vp/Vs ratio, but cannot explain Vp/Vs < 1.7 mapped in some fore-arc mantles. Such low Vp/Vs ratios may however be explained by considering the intrinsic anisotropy of the peridotites, which is generally ignored in large-scale Vp/Vs ratio mapping of the mantle wedge
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Demouchy, Sylvie. "Water in the earth's interior thermodynamics and kinetics of hydrogen incorporation in olivine and wadsleyite /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972106057.
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Davis, Jimmy Allen. "FREQUENCY DISTRIBUTION OF PYROXENE TYPES AND A METHOD TO SEPARATE THE COMPOSITION OF MULTIPLE PYROXENES IN A SAMPLE." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3145.
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Determining mafic mineral composition of asteroid bodies is a topic reviewed by M.J. Gaffey et al. (2002). The iterative procedure discussed can be implemented as an algorithm, and such efforts revealed weaknesses that are examined in this work. We seek to illustrate the limits of this method and graphically determine its predictions. There are boundaries in the formulae given where the equations break down. In ranges where mafic mixtures are predicted, a method is illustrated that allows a decoupling of these mixtures into the constituents.M.S.
Department of Physics
Sciences
Physics MS
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Pens, Maria. "Etude expérimentale de l’altération hydrothermale des roches ultrabasiques." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1107/document.
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Les péridotites, roches du manteau terrestre, sont instables en présence d'eau et peuvent se transformer en un minéral hydraté la serpentine, qui a la capacité remarquable de générer de l'hydrogène H2; cette réaction s'appelle la serpentinisation. Au niveau des dorsales médio-océaniques, la circulation d'eau dans ces roches conduit à la formation de larges systèmes hydrothermaux. Ils montrent différentes conditions de température et de pH des fluides, bien qu'ils conduisent tous à la formation abiotique d'H2, de méthane CH4 et possiblement d'autres hydrocarbures légers.Cette thèse est dédiée à l'étude du rôle de la composition chimique du fluide hydrothermal sur la cinétique et les mécanismes de serpentinisation des roches ultrabasiques à différentes conditions de P-T. L'interaction entre l'olivine et/ou l'orthopyroxène a été analysée avec une solution aqueuse simulant une eau de mer enrichie en aluminium et/ou en ions bicarbonates, à différents pH. Une première série d'expériences a été réalisée à 200, 340 °C et 200 MPa en lp-DAC à l'ESRF en France. Elle a permis de quantifier les paramètres cinétiques de réaction, de déterminer un effet opposé de l'aluminium sur la cinétique de ces deux minéraux et l'accélération de la réaction en conditions alcalins. Autres expériences ont été réalisée à Pamb et 80 °C en flacons de verre. Elles ont conduit, pour la première fois, à la formation de serpentine ainsi qu'à la formation d'H2 et de CH4. Ces résultats montrent qu'une chimie plus complexe du fluide hydrothermal peut avoir un impact majeur sur la cinétique de la serpentinisation pour l'accélérer et la rendre plus accessible à une échelle de temps industriellePeridotites, Earth's mantle rocks, are unstable in the presence of water and can be transformed into a hydrated mineral, serpentine, which has the remarkable ability to generate hydrogen H2; this reaction is called serpentinization. At the mid-ocean ridges, the circulation of water in these rocks leads to the formation of large hydrothermal systems. They show great variability of temperature and fluids’pH conditions, although they all lead to the abiotic formation of H2, methane CH4 and eventually other light hydrocarbons. This PhD thesis is dedicated to the study of the chemical composition role of the hydrothermal fluid on the kinetics and mechanisms of serpentinization of ultramafic rocks to different conditions of P-T. The interaction between olivine and/or orthopyroxene was analyzed with an aqueous solution to simulate sea water which is rich in aluminum and/or bicarbonate ions, with different pH values. A first series of experiments was carried out at 200, 340 °C and 200 MPa in lp-DAC at the ESRF in France. It was used to quantify the kinetic parameters of the reaction, to determine an opposite effect of aluminum on the kinetics these two minerals and the acceleration of the reaction under alkaline conditions. Other experiments were performed in glass bottles at Pamb and 80 °C. They led, for the first time, to the formation of serpentine, as well as to the formation of H2 and CH4. These results show that the slightly more complex chemistry of the hydrothermal fluid can have a major impact on the kinetics of serpentinization to speed and make it more accessible to industrial time scale
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Ancellin, Marie-Anne. "Origine de la diversité géochimique des magmas équatoriens : de l'arc au minéral." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC083/document.
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Les laves d'arc ont une géochimie complexe du fait de l'hétérogénéité des magmas primitifs et de leur transformation dans la croûte. L'identification des magmas primitifs dans les arcs continentaux est difficile du fait de l'épaisseur de la croûte continentale, qui constitue un filtre mécanique et chimique à l'ascension des magmas. En Équateur, cette problématique est particulièrement critique du fait de la grande épaisseur de la croûte (≈ 50-60 km) et de la rareté des magmas primitifs arrivant en surface. Cette thèse a pour but de déterminer la composition des liquides primitifs dans l'arc équatorien, à l'échelle de l'arc entier, et à celle de deux édifices volcaniques : le Pichincha et le Tungurahua. Elle vise également à mieux comprendre comment ces liquides primitifs évoluent à travers la croûte continentale. En Équateur, le pendage, le relief et l'âge de la plaque plongeante varient du nord au sud de l'arc. Ainsi, la première partie de la thèse aborde la question de l'influence de ces paramètres sur la géochimie des magmas, via une étude sur roches totales couvrant la totalité de l'arc. Elle confirme les variations géochimiques décrites à travers l'arc par les études précédentes : augmentation de la teneur en éléments incompatibles et diminution de l'enrichissement en éléments "mobiles" d'est en ouest. L'étude identifie des variations géochimiques le long du front volcanique (e.g., rapport Ba/Th), liées au changement de nature des fluides métasomatiques, qui sont aqueux au centre de l'arc (environ 0,5°S) et silicatés au Nord et possiblement au Sud. Ce changement est attribué à la jeunesse du plancher océanique dans le nord de l'arc, qui pourrait promouvoir la fusion de la plaque plongeante. Enfin, il semble que la contamination par la croûte inférieure augmente vers le sud du front volcanique. Dans un deuxième temps, les produits émis par le Tungurahua lors de ses derniers 3000 ans d'activité sont étudiés. À cette échelle de temps, les paramètres tectoniques de la première étude sont constants. Ce travail détaille le rôle de la croûte dans la production des magmas différenciés, qui sont systématiquement associés à des éruptions plus explosives. Elle conclut que les andésites ont des compositions isotopiques hétérogènes (206Pb/204Pb = 18,834 - 19,038), acquises en profondeur (manteau ou croûte inférieure), qui se restreignent lors de la différenciation des andésites en dacites (206Pb/204Pb = 18,965 - 19,030), par cristallisation fractionnée et assimilation de la croûte supérieure locale (7-9 %). Enfin, la troisième partie de la thèse se focalise sur l'hétérogénéité des magmas primitifs. Des études sur minéraux individuels ont été effectuées au Pichincha et au Tungurahua, et montrent que la majorité des minéraux sont en déséquilibre avec la roche hôte (jusqu'à 8600 ppm en 206Pb/204Pb). Au Pichincha, la diversité des minéraux échantillonnés permet d'identifier la diversité des liquides mantelliques (206Pb/204Pb = 18,816 - 19,007), qui s'alignent dans les espaces Pb-Pb. Comme dans le cas des roches totales du Tungurahua, l'assimilation crustale écrase cette diversité isotopique lors de la différenciation des liquides primitifs, dont la signature n'est pas préservée dans les roches. Au Tungurahua, les minéraux individuels montrent que l'hétérogénéité des signatures est acquise en profondeur. L'analyse de deux lots d'olivines met en évidence une signature radiogénique dans les liquides primitifs du Tungurahua, interprétée comme la présence de croûte délaminée dans la source mantellique du Tungurahua. Enfin, l'étude de lots d'olivines provenant de sept volcans équatoriens montre qu'il n'existe pas de signature primitive unique dans l'arc. La totalité de l'hétérogénéité isotopique des magmas est héritée du manteau (206Pb/204Pb = 18,583 - 19,000). Les compositions des liquides primitifs sont ensuite déviées par la contamination crustale, dans la majorité des cas, vers des signatures plus radiogéniquesArc lavas display a complex geochemistry resulting from the heterogeneity of primitive magmas and their transformation within the crust. Identifying primitive magma compositions in continental arcs is challenging because continental crust is thick and acts as a mechanical and chemical filter for ascending magmas. This issue is particularly criticial in Ecuador owing to the great thickness of the continental crust (≈ 50-60 km) and the scarcity of erupted primitive magmas. This thesis aims to determine the composition of primitive silicate melts in the Ecuadorian arc, on the scale of the whole arc, as well as on the scale of two volcanic edifices: the Pichincha and the Tungurahua. This study also intends to better understand how those primitive melts evolve during their journey through the continental crust. In Ecuador, slab dip, relief and age change from north to south. Hence, the first part of the PhD focuses on the influence of those parameters on magma geochemistry, through a whole rock study covering the entire arc. It confirms the across-arc geochemical variations described by previous studies: an increase of incompatible element contents and a decrease of fluid-mobile over fluid-immobile element ratios from west to east. We identify along-arc geochemical variations in the volcanic front (e.g. Ba/Th), related to the changing nature of metasomatic fluids, which are aqueous fluids at the centre of the arc (around 0.5°S) and silicate melts to the north and probably to the south. This change may be due to the subduction of a younger and warmer oceanic crust to the north, which might promote slab melting. Lastly, it seems that deep crustal contamination increases towards the south of the volcanic front. Secondly, volcanic products emitted for the last 3,000 years at Tungurahua are studied. On this timescale, the tectonic parameters of the first study are constant. This work details the role of continental crust in the production of differentiated magmas, which are systematically associated with more explosive eruptions. We conclude that andesites have heterogeneous isotopic compositions (206Pb/204Pb = 18.834 - 19.038), acquired at depth (mantle or deep crust), that homogeneize through andesite differentiation to dacite (206Pb/204Pb = 18.965 - 19.030) by fractional crystallization and assimilation of the local upper crust (7-9 %). Lastly, the third part of the PhD focuses on the heterogeneity of primitive magmas. We study individual minerals from Pichincha and Tungurahua volcanoes and show that most minerals are in disequilibrium with their host rock (up to 8,600 ppm for 206Pb/204Pb). The diversity of Pichincha minerals allows the identification of mantle melt diversity (206Pb/204Pb = 18.816 - 19.007), with compositions forming a tight trend in Pb-Pb isotope spaces. As for Tungurahua whole rocks, crustal assimilation erases the diversity of primitive melt isotope signatures through differentiation, so that primitive melt signatures are not preserved in whole rock samples. At Tungurahua, individual minerals show that the heterogeneity of isotope compositions is acquired at depth. The analysis of two olivine fractions reveals the existence of a radiogenic signature in the mantle source of Tungurahua volcano, interpreted as the presence of delaminated crust within the mantle beneath its edifice. Finally, olivine fractions from seven Ecuadorian volcanoes highlight the fact that no unique primitive signature exists in the arc. Isotopic heterogeneity is entirely inherited from the mantle (206Pb/204Pb = 18.583 - 19.000). Primitive melt compositions are then shifted by continental crust contamination which, in most cases, results in more radiogenic signatures
Books on the topic "Olivine and pyroxene thermodynamics"
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Ellam, Rob. 10. Probing the Earth with isotopes. Oxford University Press, 2016. http://dx.doi.org/10.1093/actrade/9780198723622.003.0010.
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‘Probing the Earth with isotopes’ shows how, using isotopes, we have come to understand the structure and behaviour of the Earth. The outer few tens of kilometres are divided into continental and oceanic crust. Below the crust, the sub-surface is divided into the mantle and the core. From the base of the crust to about 2,800 km depth, the Earth is rocky and composed of minerals like olivine and pyroxene that are rich in magnesium, iron, and calcium. From about 2,800 km to about 5,100 km depth the outer core is liquid. The remaining 1,200 km or so to the centre of the Earth is solid metal.
Book chapters on the topic "Olivine and pyroxene thermodynamics"
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Koike, Chiyoe, and Akira Tsuchiyama. "The Infrared Spectra of Synthesized Amorphous Silicates with Compositions of Olivine and Pyroxene." In Origin and Evolution of Interplanetary Dust, 95–98. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3640-2_19.
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Papike, James J. "Chapter 7. COMPARATIVE PLANETARY MINERALOGY: CHEMISTRY OF MELT-DERIYED PYROXENE, FELDSPAR, AND OLIVINE." In Planetary Materials, edited by James J. Papike, 1007–18. Berlin, Boston: De Gruyter, 1998. http://dx.doi.org/10.1515/9781501508806-022.
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Agresti, David G. "Temperature dependence of the quadrupole splitting of olivine and pyroxene from the Plains of Gusev Crater on Mars." In ICAME 2011, 697–701. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-4762-3_121.
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Oshtrakh, M. I., E. V. Petrova, V. I. Grokhovsky, and V. A. Semionkin. "Determination of quadrupole splitting for 57Fe in M1 and M2 sites of both olivine and pyroxene in ordinary chondrites using Mössbauer spectroscopy with high velocity resolution." In HFI/NQI 2007, 193–99. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-85320-6_30.
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Sa\'ad ZA Kader, Al-Mashaikie. "Abnormal Ophiolite (Olivine/Pyroxene Rich) Sandstone NE Iraq: An Approach to the Origin and Tectonosedimentary Evolution of Zagros Foreland Basin." In New Insights in Sedimentary Rocks [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.108333.
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Unusual Paleocene ophiolite sandstone rich in olivine/pyroxene identified in Zagros Thrust Belt (NZTB) in NE Iraq. NZTB is regionally extended from Iran to Alpen Belt. Kolosh sandstones are controlled by progressive thrusting during late Cretaceous-Paleocene. Zagros thrust sheets composed of ophiolites, oceanic crust, basaltic flows, and ash sequences. Kolosh sandstones reveal high percentages of fresh olivine-pyroxene grains accompanied by igneous intrusive and volcanic ultrabasic-basic fragments, which are reported for the first time in NE Iraq and along ZTB. Olivine, pyroxene, ultrabasic igneous altered, serpentine and chlorite fragments, heavy minerals (includes chrome spinal), anorthite, and labradorite all together composed about 70% of the mineralogical composition. Sanidine, anorthoclase, quartz and cristobalite, argillaceous, carbonate and chert fragments all together composed (12.25%), supported by argillaceous matrix (16.53%), which are derived from mantle and oceanic crust/ophiolite sequences from NE Iraq, emplaced during late Cretaceous with arc volcanism, which subjected to rapid submarine erosion and deposition. Intense wave action accelerated the erosion of beach rocks, and concentrate the heavy minerals insitue that slumped to deeper margins. Identified lithofacies types, grouped in four associations, slope/submarine channel, inner, outer fan, and hemipelagic/pelagic, respectively, represented progressive upward transgression from slope to basin plain systems controlled by progressive thrusting.
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Dai, Lidong, Haiying Hu, Yu He, and Wenqing Sun. "Some New Progress in the Experimental Measurements on Electrical Property of Main Minerals in the Upper Mantle at High Temperatures and High Pressures." In Mineralogy [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101876.
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In this chapter, we present the recent progress in the experimental studies of the electrical conductivity of dominant nominally anhydrous minerals in the upper mantle of the deep Earth interior, namely, olivine, pyroxene, and garnet. The influences from pressure, oxygen partial pressure, and anisotropic orientation on hydrous and anhydrous electrical conductivities of minerals and rocks have been already explored detailedly. There are two main electric conduction mechanisms in Fe-bearing mantle minerals, for example, small proton and proton hopping conditions, which are well distinguished by the magnitude of activation enthalpy at high temperature and high pressure. Likewise, the conduction mechanisms are efficiently characterized by these obtained positive and negative effects from the oxygen fugacity on electrical conductivities of corresponding dry and wet Fe-bearing silicate minerals at the regions of the upper mantle under conditions of different oxygen partial pressures. On the base of high-pressure laboratory-based conductivity measurements for these nominally anhydrous minerals (e.g., olivine, pyroxene, and garnet), the water content will be estimated within the depth range of the upper mantle. In comprehensive considerations of filed geophysical magnetotelluric results, the electrical conductivity measurements of dominant upper-mantle minerals can thoroughly disclose the distribution, storage state, and migration conduction in the deep Earth interior.
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Rogers, John J. W., and M. Santosh. "Creation, Destruction, and Changes in Volume of Continental Crust Through Time." In Continents and Supercontinents. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195165890.003.0005.
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The low density of continental crust creates areas of land that cover about 25% of the world’s surface. The ultimate source of this crust must have been the mantle, but the mechanisms and times of extraction are not well known. Because the rate at which continental crust has been destroyed and incorporated back into the mantle is also uncertain, the volume of continental crust that existed in the earth throughout its history is highly controversial. We investigate these problems in this chapter, beginning with a discussion of how the wide variety of rocks that constitute the crust may have evolved from the mantle. The next section summarizes information on the rates of destruction of crust, which leads to the issue of changes in the volume of continental crust through time. We leave to chapter 4 the discussion of “cratons,” which are large areas of continental crust that became stable at different times in the past 3 billion years and then moved around the earth as relatively undeformed continental blocks. Cratons are commonly referred to as “shields” where their crystalline basement rocks are exposed. The discussion in this chapter and several later chapters requires some knowledge of the significance of isotopic information, and we provide a brief summary in appendix D. In order to describe continental crust and its relationships to other parts of the earth, we must start with several definitions. “Sialic” (Si + Al) refers to rocks, such as granite, that are particularly rich in SiO2, with Al2O3 as the second most abundant oxide; they are commonly referred to as “felsic.” “Simatic” (Si + Mg) similarly designates basalts and other low-silica “mafic” rocks. “Ultrasimatic” and “ultramafic” refer to rocks extremely rich in olivine, mostly different varieties of peridotite. Some sialic (felsic) rocks have high concentrations of large-ion-lithophile (LIL) elements, which are ions that are “incompatible” with (do not fit into) typical minerals in the mantle, including olivine, pyroxene, and calcic plagioclase. LIL elements include K, Rb, Ba, and U, which is coordinated with oxygen to form the low-density uranyl complex (UO2+2).
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Moll, M., H. Paulick, G. Suhr, and W. Bach. "Data Report: Microprobe Analyses of Primary Phases (Olivine, Pyroxene, and Spinel) and Alteration Products (Serpentine, Iowaite, Talc, Magnetite, and Sulfides) in Holes 1268A, 1272A, and 1274A." In Proceedings of the Ocean Drilling Program. Ocean Drilling Program, 2007. http://dx.doi.org/10.2973/odp.proc.sr.209.003.2007.
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Alexander, Earl B., Roger G. Coleman, Todd Keeler-Wolfe, and Susan P. Harrison. "Nature of Ultramafics." In Serpentine Geoecology of Western North America. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195165081.003.0005.
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The earth is divided into three layers: the crust, the mantle, and the core. There are two principle regions within the crust: continents and ocean basins. The rocks that make up these layers differ from one another in chemical composition and density. The mantle is composed of dense ultramafic rocks, rich in magnesium-iron silicate minerals such as olivine and pyroxene. Ultramafic rock is the main source of serpentine soil in the continental crust. Most of the lighter crustal rocks are made up of silicate minerals that are enriched in the lighter elements sodium, calcium, and potassium, which have large cations, rather than magnesium (also a light element) and iron, which have smaller cations (table 2-1, appendix A). Over geological time living organisms have evolved on continents or in oceans with elemental concentrations dependent more on the crust than on the mantle. In the oceanic realm, new oceanic crust forms at spreading centers between active plates where hot, decompressed mantle rock rising toward the surface partially melts to form basaltic magma. The spreading centers develop at mid-ocean ridges, behind volcanic arcs (back-arc basins), in front of volcanic arcs (forearc basins), or as continents rift apart, as with the Red Sea. Cracks formed between the spreading plates are intruded by basaltic magma that forms thin vertical sheets (sheeted dikes). New cracks and dikes are continually forming as the plates spread apart. Some of the magma rising into the cracks reaches the ocean floor and, as the hot lava is quenched by ocean water, it solidifies to form distinctive rounded, pillowlike structures. As magma above the partially melted mantle cools, some of the first crystals to form settle to the bottoms of liquid magma chambers, producing layered gabbros—a process called differentiation. The layered sequence of pillow lava, diabase dikes, and gabbro built upon the ultramafic mantle is typical of new ocean crust. New crust formed at spreading centers slowly migrates away from the spreading center and cools into a rigid oceanic crust that ranges in thickness from 6 to 12 km.
Conference papers on the topic "Olivine and pyroxene thermodynamics"
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Zolensky, Michael, and Ruth Barrett. "Olivine and pyroxene compositions of chondritic interplanetary dust particles." In Analysis of interplanetary dust: NASA/LPI workshop. AIP, 1994. http://dx.doi.org/10.1063/1.46526.
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Li, Yaozhu, Phil J. A. McCausland, Phil J. A. McCausland, Roberta L. Flemming, and Roberta L. Flemming. "COMPARATIVE MICRO-X-RAY DIFFRACTION STUDY OF SHOCK METAMORPHOSED OLIVINE AND PYROXENE IN UREILITE METEORITES." In GSA Annual Meeting in Phoenix, Arizona, USA - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019am-333895.
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Duccini, Kalie M., and Diane Clemens-Knott. "OLIVINE-PLAGIOCLASE-PYROXENE CUMULATES ASSOCIATED WITH THE HORNBLENDE-RICH SUMMIT GABBRO: EARLY STAGES OF DIFFERENTIATION WITHIN THE LATE JURASSIC SIERRA NEVADA ARC." In 112th Annual GSA Cordilleran Section Meeting. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016cd-274734.
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Duccini, Kalie M., and Diane Clemens-Knott. "OLIVINE-PLAGIOCLASE-PYROXENE CUMULATES ASSOCIATED WITH THE HORNBLENDE-RICH SUMMIT GABBRO: EARLY STAGES OF DIFFERENTIATION WITHIN THE LATE JURASSIC SIERRA NEVADA ARC." In GSA Annual Meeting in Denver, Colorado, USA - 2016. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016am-282044.
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Duccini, Kalie M. "OLIVINE-PLAGIOCLASE-PYROXENE CUMULATES ASSOCIATED WITH THE HORNBLENDE-RICH SUMMIT GABBRO: EARLY STAGES OF DIFFERENTIATION WITHIN THE LATE JURASSIC SIERRA NEVADA ARC." In 113th Annual GSA Cordilleran Section Meeting - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017cd-292982.
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Fenton, Cassandra, Samuel Niedermann, Steven Binnie, and Tibor Dunai. "The SPICE Project: Cross-calibration of six terrestrial cosmogenic nuclide production rates in quartz, olivine, and pyroxene from the 72 ka SP lava flow, AZ, USA." In Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.12933.
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Saper, Lee, Michael Baker, Ery Hughes, Maryjo Brounce, and Edward Stolper. "Experimental use of olivine-hosted melt inclusions to explore the thermodynamics and kinetics of Fe and S redox equilibria in silicate melts." In Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.10323.
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