Abstract
High-temperature, ammonium-rich white mica has been identified for the first time in deep Paleozoic (and probably older) polymetamorphic schists from the Internal Zone of the Betic Cordillera (Spain). Ammonium-rich white mica has been characterized by optical microscopy, X-ray diffraction, infrared spectroscopy, elemental analysis, electron microprobe, and scanning and transmission electron microscopy. High-temperature, ammonium-rich white mica shows some significant chemical differences with tobelite formed in hydrothermal and low-temperature metamorphic rocks. Although the average formula, Ca0.09Na0.01K0.15(NH4)0.75(Al1.70Ti0.01Fe0.26Mg0.13)(Si2.99Al1.01)O10(OH)2, is typical of a dioctahedral mica, the chemical plots reveal a clear deviation toward the trioctahedral field. Thus, the increase in Fe + Mg contents is not accompanied by the parallel increase of Si contents, characteristic of the phengitic substitution, which is characteristic of low-pressure conditions of formation. Chemical differences are also accompanied by notable differences in the optical properties, both features suggesting that the term tobelite is not appropriate for this mica. Ammonium-rich white mica relics only persist in some graphite-rich microdomains, defining the first schistosity. Textural relations indicate that this mica formed during an older pre-Alpine metamorphic episode.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Rietveld structure refinement of MgGeO3 post-perovskite phase to 1 Mbar
- High-temperature ammonium white mica from the Betic Cordillera (Spain)
- Synthesis and crystal structure of the feldspathoid CsAlSiO4: An open-framework silicate and potential nuclear waste disposal phase
- The crystal chemistry of Li in gadolinite
- The effect of the hedenbergitic substitution on the compressibility of jadeite
- The structure of monohydrocalcite and the phase composition of the beachrock deposits of Lake Butler and Lake Fellmongery, South Australia
- First-principles calculation of the infrared spectrum of hematite
- In situ observations of muscovite dissolution under alkaline conditions at 25–50 °C by AFM with an air/fluid heater system
- Ramanite-(Cs) and ramanite-(Rb): New cesium and rubidium pentaborate tetrahydrate minerals identified with Raman spectroscopy
- Pressure-temperature studies of talc plus water using X-ray diffraction
- Hematite and magnetite precipitates in olivine from the Sulu peridotite: A result of dehydrogenation-oxidation reaction of mantle olivine?
- Arsenide in a metasomatized peridotite xenolith as a constraint on arsenic behavior in the mantle wedge
- Multiple oxygen sites in synthetic phyllosilicates with expandable layers: 17O solid-state NMR study
- On the existence of a Na-deficient monoclinic trinepheline with composition Na7.85Al7.85Si8.15O32
- Chlorite and biotite weathering, Fe2+-rich corrensite formation, and Fe behavior under low Po₂ conditions and their implication for Precambrian weathering
- Structural characterization of natural UO2 at pressures up to 82 GPa and temperatures up to 2200 K
- Dense hydrous magnesium silicates, phase D, and superhydrous B: New structural constraints from one- and two-dimensional 29Si and 1H NMR
- Mid-IR bands of synthetic calcic amphiboles of tremolite-pargasite series and of natural calcic amphiboles
- Probing the site occupancies of Co-, Ni-, and Mn-substituted biogenic magnetite using XAS and XMCD
- Origin of titanite in metarodingite from the Zagros Thrust Zone, Iraq
- Experimental calibration of aluminum partitioning between olivine and spinel as a geothermometer
- Single-crystal X-ray diffraction study of CaIrO3
- Orthorhombic polymorph of rengeite from Ohmi region, central Japan
- New insights into the crystal chemistry of epididymite and eudidymite from Malosa, Malawi: A single-crystal neutron diffraction study
- Mechanisms of rhyolitic glass hydration below the glass transition
- Heat capacity and entropy of melanophlogite: Molecule-containing porosils in nature
- Crystal structure of glaucodot, (Co,Fe)AsS, and its relationships to marcasite and arsenopyrite
- Modification of gas speciation in quartz-hosted fluid inclusions by stray laser radiation during LA-ICPMS analysis
- A PH₂O-dependent structural phase transition in the zeolite natrolite
Articles in the same Issue
- Rietveld structure refinement of MgGeO3 post-perovskite phase to 1 Mbar
- High-temperature ammonium white mica from the Betic Cordillera (Spain)
- Synthesis and crystal structure of the feldspathoid CsAlSiO4: An open-framework silicate and potential nuclear waste disposal phase
- The crystal chemistry of Li in gadolinite
- The effect of the hedenbergitic substitution on the compressibility of jadeite
- The structure of monohydrocalcite and the phase composition of the beachrock deposits of Lake Butler and Lake Fellmongery, South Australia
- First-principles calculation of the infrared spectrum of hematite
- In situ observations of muscovite dissolution under alkaline conditions at 25–50 °C by AFM with an air/fluid heater system
- Ramanite-(Cs) and ramanite-(Rb): New cesium and rubidium pentaborate tetrahydrate minerals identified with Raman spectroscopy
- Pressure-temperature studies of talc plus water using X-ray diffraction
- Hematite and magnetite precipitates in olivine from the Sulu peridotite: A result of dehydrogenation-oxidation reaction of mantle olivine?
- Arsenide in a metasomatized peridotite xenolith as a constraint on arsenic behavior in the mantle wedge
- Multiple oxygen sites in synthetic phyllosilicates with expandable layers: 17O solid-state NMR study
- On the existence of a Na-deficient monoclinic trinepheline with composition Na7.85Al7.85Si8.15O32
- Chlorite and biotite weathering, Fe2+-rich corrensite formation, and Fe behavior under low Po₂ conditions and their implication for Precambrian weathering
- Structural characterization of natural UO2 at pressures up to 82 GPa and temperatures up to 2200 K
- Dense hydrous magnesium silicates, phase D, and superhydrous B: New structural constraints from one- and two-dimensional 29Si and 1H NMR
- Mid-IR bands of synthetic calcic amphiboles of tremolite-pargasite series and of natural calcic amphiboles
- Probing the site occupancies of Co-, Ni-, and Mn-substituted biogenic magnetite using XAS and XMCD
- Origin of titanite in metarodingite from the Zagros Thrust Zone, Iraq
- Experimental calibration of aluminum partitioning between olivine and spinel as a geothermometer
- Single-crystal X-ray diffraction study of CaIrO3
- Orthorhombic polymorph of rengeite from Ohmi region, central Japan
- New insights into the crystal chemistry of epididymite and eudidymite from Malosa, Malawi: A single-crystal neutron diffraction study
- Mechanisms of rhyolitic glass hydration below the glass transition
- Heat capacity and entropy of melanophlogite: Molecule-containing porosils in nature
- Crystal structure of glaucodot, (Co,Fe)AsS, and its relationships to marcasite and arsenopyrite
- Modification of gas speciation in quartz-hosted fluid inclusions by stray laser radiation during LA-ICPMS analysis
- A PH₂O-dependent structural phase transition in the zeolite natrolite