Fluorophlogopite from Piano delle Concazze (Mt. Etna, Italy): Crystal chemistry and implications for the crystallization conditions
-
Fernando Scordari
,
Emanuela Schingaro
Abstract
Fluorine is an important proxy for magmatic differentiation processes in the shallow parts of volcanic plumbing systems. Fluorphlogopite is one of the more important fluorine carriers in magmatic rocks. In the present study, a full crystal chemical investigation of fluorophlogopite 1M from Piano delle Concazze, Mt. Etna volcano, Italy, is carried out. The fluorophlogopite occurs in a benmoreitic lava from prehistoric volcanic activity at Mt. Etna (post-caldera forming phase of the “Ellittico” eruptive center; ~15 ka BP). It is primarily associated with fluorapatite covered with amorphous SiO2 and crystallized during syn/post-eruption pneumatolytic stages. The mica sample studied here is among the most Fe- and Ti-rich fluorophlogopite found in nature. EPMA data yielded the following mean chemical formula for this mineral
(K0.83Na0.13)(Fe2+0.44Fe3+0.09Mg2.18Al0.05Ti0.23Mn0.01)(Al0.92Si3.08)O10.64(Cl0.01F1.35).
Structure refinements on four fluorophlogopite crystals, performed in space group C2/m, converged at R = 0.03-0.04, with cell parameters in the ranges a = 5.323-5.324, b = 9.219-9.222, c = 10.116- 10.119 Å, β = 100.1-100.3°. Major substitutions are OH- ↔ F-,M3+-oxy (VIM2++OH- ↔ VIM3++O2-) and Ti-oxy substitution: VIM2++2(OH)- ↔ VITi4++2O2-. The fluorophlogopite from Piano delle Concazze exhibits the shortest c-parameter with respect to other fluorophlogopites found in nature. The short c parameter is essentially due to the absence of the hydroxyl group in favor of F- and especially of O2- and to the thus increased attractive interaction between the interlayer cation and the anion content (F-, O2-) located at the O4 site. A comparison with other natural fluorophlogopites (namely from Biancavilla, Etna and Presidente Olegario, Brazil) show intermediate crystal-chemical features for the Piano delle Concazze fluorophlogopite. Particularly at Etna, differences in the chemical composition of the crystallized fluorophlogopites could be related to the various extent of enrichments by transfer of a gas phase achieved in specific parts of the volcanic plumbing system.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Review: Versatile Monazite: resolving geological records and solving challenges in materials science. Generalizations about monazite: Implications for geochronologic studies
- Versatile Monazite: Resolving geological records and solving challenges in materials science. Monazite as a promising long-term radioactive waste matrix: Benefits of high-structural flexibility and chemical durability
- Incorporation of Ge in ferrihydrite: Implications for the structure of ferrihydrite
- The pressures and temperatures of meteorite impact: Evidence from micro-Raman mapping of mineral phases in the strongly shocked Taiban ordinary chondrite
- Kangite, (Sc,Ti,Al,Zr,Mg,Ca,⃞)2O3, a new ultra-refractory scandia mineral from the Allende meteorite: Synchrotron micro-Laue diffraction and electron backscatter diffraction
- New insights into the formation of diagenetic illite from TEM studies
- Solidification of trapped liquid in rocks and crystals
- Using the chemical composition of carbonate rocks on Mars as a record of secondary interaction with liquid water
- Multinuclear NMR study of Cs-bearing geyserites of the Targejia hot spring cesium deposit in Tibet
- Clay minerals as geo-thermometer: A comparative study based on high spatial resolution analyses of illite and chlorite in Gulf Coast sandstones (Texas, U.S.A.)
- Incorporation of Zn in the destabilization products of muscovite at 1175 °C under disequilibrium conditions, and implications for heavy metal sequestration
- H/D methane isotopologues dissolved in magmatic fluids: Stable hydrogen isotope fractionations in the Earth’s interior
- Ca-Sr fractionation between zoisite, lawsonite, and aqueous fluids: An experimental study at 2.0 and 4.0 GPa/400 to 800 °C
- The infrared vibrational spectrum of andradite-grossular solid solutions: A quantum mechanical simulation
- Occurrence of silica polymorphs nanocrystals in tuffaceous rocks, Province of the Mesa Central, Mexico, and their formation from subcritical Si-rich fluids
- Pressure-induced Pbca-P21/c phase transition of natural orthoenstatite: Compositional effect and its geophysical implications
- High-pressure and high-temperature equation of state of cobalt oxide: Implications for redox relations in Earth’s mantle
- Synthesis and characterization of kanemite from fluoride-containing media: Influence of the alkali cation
- Structure of prismatic halloysite
- Fluorophlogopite from Piano delle Concazze (Mt. Etna, Italy): Crystal chemistry and implications for the crystallization conditions
- Analysis of hydrogen and fluorine in pyroxenes: I. Orthopyroxene
- Analysis of hydrogen and fluorine in pyroxenes: II. Clinopyroxene
- Letter. A carbonate-fluoride defect model for carbonate-rich fluorapatite
- Letter. Kumdykolite, a high-temperature feldspar from an enstatite chondrite
- Letter. High-pressure aragonite phenocrysts in carbonatite and carbonated syenite xenoliths within an alkali basalt
Articles in the same Issue
- Review: Versatile Monazite: resolving geological records and solving challenges in materials science. Generalizations about monazite: Implications for geochronologic studies
- Versatile Monazite: Resolving geological records and solving challenges in materials science. Monazite as a promising long-term radioactive waste matrix: Benefits of high-structural flexibility and chemical durability
- Incorporation of Ge in ferrihydrite: Implications for the structure of ferrihydrite
- The pressures and temperatures of meteorite impact: Evidence from micro-Raman mapping of mineral phases in the strongly shocked Taiban ordinary chondrite
- Kangite, (Sc,Ti,Al,Zr,Mg,Ca,⃞)2O3, a new ultra-refractory scandia mineral from the Allende meteorite: Synchrotron micro-Laue diffraction and electron backscatter diffraction
- New insights into the formation of diagenetic illite from TEM studies
- Solidification of trapped liquid in rocks and crystals
- Using the chemical composition of carbonate rocks on Mars as a record of secondary interaction with liquid water
- Multinuclear NMR study of Cs-bearing geyserites of the Targejia hot spring cesium deposit in Tibet
- Clay minerals as geo-thermometer: A comparative study based on high spatial resolution analyses of illite and chlorite in Gulf Coast sandstones (Texas, U.S.A.)
- Incorporation of Zn in the destabilization products of muscovite at 1175 °C under disequilibrium conditions, and implications for heavy metal sequestration
- H/D methane isotopologues dissolved in magmatic fluids: Stable hydrogen isotope fractionations in the Earth’s interior
- Ca-Sr fractionation between zoisite, lawsonite, and aqueous fluids: An experimental study at 2.0 and 4.0 GPa/400 to 800 °C
- The infrared vibrational spectrum of andradite-grossular solid solutions: A quantum mechanical simulation
- Occurrence of silica polymorphs nanocrystals in tuffaceous rocks, Province of the Mesa Central, Mexico, and their formation from subcritical Si-rich fluids
- Pressure-induced Pbca-P21/c phase transition of natural orthoenstatite: Compositional effect and its geophysical implications
- High-pressure and high-temperature equation of state of cobalt oxide: Implications for redox relations in Earth’s mantle
- Synthesis and characterization of kanemite from fluoride-containing media: Influence of the alkali cation
- Structure of prismatic halloysite
- Fluorophlogopite from Piano delle Concazze (Mt. Etna, Italy): Crystal chemistry and implications for the crystallization conditions
- Analysis of hydrogen and fluorine in pyroxenes: I. Orthopyroxene
- Analysis of hydrogen and fluorine in pyroxenes: II. Clinopyroxene
- Letter. A carbonate-fluoride defect model for carbonate-rich fluorapatite
- Letter. Kumdykolite, a high-temperature feldspar from an enstatite chondrite
- Letter. High-pressure aragonite phenocrysts in carbonatite and carbonated syenite xenoliths within an alkali basalt
