Rutile inclusions in quartz crystals record decreasing temperature and pressure during the exhumation of the Su-Lu UHP metamorphic belt in Donghai, East China
-
Xiaofeng Li
,
Brian Rusk
Abstract
Donghai County in the Jiangsu Province of East China is known for its large-scale production of high-quality quartz crystals. The quartz crystals are hosted within the Su-Lu ultrahigh-pressure (UHP) metamorphic belt. They form in quartz veins hosted by eclogite and gneiss, or along contacts between eclogite and gneiss and are mined as placer deposits in the Quaternary sediments. Backscattered electron imaging of the rutile in rutile-bearing euhedral quartz crystals from this region reveal three compositionally and texturally distinct generations of rutile, encapsulated within the host quartz crystal. The earliest generation of rutile (R1) is brightest in BSE, reflecting enrichment in Fe2O3 (0.75-2.08 wt%), Nb2O5 (0.37-0.93 wt%), WO3 (0.48-2.99 wt%), and ZrO2 (0.005-0.105 wt%), relative to R2 and R3. R2 rutile overgrows R1 rutile and contains 0.66-1.11 wt% Fe2O3, 0.45-0.74 wt% Nb2O5, 0.09-0.20 wt% WO3, and <0.001-0.013 wt% ZrO2. R3 rutile, which is the only rutile generation in contact with the host quartz crystals is darkest in BSE and always overgrows R1 and rounded aggregates of R2. R3 rutile contains 0.40-0.68 wt% Fe2O3, 0.13-0.37 wt% Nb2O5, 0.03-0.12 wt% WO3, and <0.001 wt% ZrO2. Oxygen isotopes decrease progressively from 0.6 to -1.5‰ in R1 rutile to 0.1‰ in R2 rutile to -5.1 to -0.3‰ in R3 rutile, consistent with decreasing temperature of rutile crystallization.
Combined application of the Zr in rutile and Ti in quartz thermobarometers indicate that these rutile generations precipitated at progressively lower pressures and temperatures, consistent with previously determined retrograde metamorphic conditions of the Su-Lu UHP belt. R1 grew after peak metamorphism during retrograde eclogite facies metamorphism at temperatures between 720 and 800 °C and pressures between 21.7 and 26.6 kbar. During subsequent retrograde metamorphism, R1 was fractured and partially brecciated and overgrown by R2 during epidote-amphibolite facies retrograde metamorphism in the range of 400 to 500 °C and 5 kbar. Zirconium concentrations of <14 ppm in R3 rutile and Ti concentrations of <1 ppm in the co-precipitated host quartz suggest that they both grew at low temperatures of <300° and pressures <2 kbars. Oscillatory growth zones in quartz revealed by cathodoluminescence suggest that no subsequent metamorphism or hydrothermal activity occurred after the formation of the host euhedral quartz crystals and is consistent with a low temperature of quartz crystallization. The random distribution of rutile crystals in the quartz and the lack of evidence for rutile transport by hydrothermal fluids indicate that the host quartz formed by a dissolution-replacement process, whereby the original host mineral, likely omphacite or garnet, was replaced by quartz, but the rutile was not significantly replaced or dissolved due to the low solubility of Ti in low-temperature hydrothermal fluids.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Needs and opportunities in mineral evolution research
- Rutile inclusions in quartz crystals record decreasing temperature and pressure during the exhumation of the Su-Lu UHP metamorphic belt in Donghai, East China
- A first-principles study of the phase transition from Holl-I to Holl-II in the composition KAlSi3O8
- Sejkoraite-(Y), a new member of the zippeite group containing trivalent cations from Jáchymov (St. Joachimsthal), Czech Republic: Description and crystal structure refinement
- Thermoelastic and thermodynamic properties of plagioclase feldspars from thermal expansion measurements
- Quantitative determination of chrysotile in massive serpentinites using DTA: Implications for asbestos determinations
- In situ observation of the crystallization pressure induced by halite crystal growth in a microfluidic channel
- Microstructures of the larval shell of a pearl oyster, Pinctada fucata, investigated by FIB-TEM technique
- Magnesium quantification in calcites [(Ca,Mg)CO3] by Rietveld-based XRD analysis: Revisiting a well-established method
- The effect of Fe on olivine H2O storage capacity: Consequences for H2O in the martian mantle
- Kinetics of thermal transformation of partially dehydroxylated pyrophyllite
- Dehydration of the natural zeolite goosecreekite CaAl2Si6O16·5H2O upon stepwise heating: A single-crystal and powder X-ray study
- Incorporation mechanisms of Ta and Nb in zircon and implications for pegmatitic systems
- Variable-temperature 27Al and 29Si NMR studies of synthetic forsterite and Fe-bearing Dora Maira pyrope garnet: Temperature dependence and mechanisms of paramagnetically shifted peaks
- Calibrating Ti concentrations in quartz for SIMS determinations using NIST silicate glasses and application to the TitaniQ geothermobarometer
- Crystal structure of Na3Fe(SO4)3: A high-temperature product (∼400 °C) of sideronatrite [Na2Fe(SO4)2OH⋅3H2O]
- Evidence for boron incorporation into the serpentine crystal structure
- Structure refinement of Ag-free heyrovskýite from Vulcano (Aeolian Islands, Italy)
- Microtextures, microchemistry, and mineralogy of basaltic glass alteration, Jeju Island, Korea, with implications for elemental behavior
- Orientation of channel carbonate ions in apatite: Effect of pressure and composition
- Thermoelastic property and high-pressure stability of Fe7C3: Implication for iron-carbide in the Earth’s core
- Yttriaite-(Y): The natural occurrence of Y2O3 from the Bol’shaya Pol’ya River, Subpolar Urals, Russia
- Identification and characterization of nanosized tripuhyite in soil near Sb mine tailings
- Letter. High-pressure I2/c-P21/c phase transformation in SrAl2Si2O8 feldspar
- Letter. Crystal structure of uchucchacuaite, AgMnPb3Sb5S12, and its relationship with ramdohrite and fizélyite
Articles in the same Issue
- Needs and opportunities in mineral evolution research
- Rutile inclusions in quartz crystals record decreasing temperature and pressure during the exhumation of the Su-Lu UHP metamorphic belt in Donghai, East China
- A first-principles study of the phase transition from Holl-I to Holl-II in the composition KAlSi3O8
- Sejkoraite-(Y), a new member of the zippeite group containing trivalent cations from Jáchymov (St. Joachimsthal), Czech Republic: Description and crystal structure refinement
- Thermoelastic and thermodynamic properties of plagioclase feldspars from thermal expansion measurements
- Quantitative determination of chrysotile in massive serpentinites using DTA: Implications for asbestos determinations
- In situ observation of the crystallization pressure induced by halite crystal growth in a microfluidic channel
- Microstructures of the larval shell of a pearl oyster, Pinctada fucata, investigated by FIB-TEM technique
- Magnesium quantification in calcites [(Ca,Mg)CO3] by Rietveld-based XRD analysis: Revisiting a well-established method
- The effect of Fe on olivine H2O storage capacity: Consequences for H2O in the martian mantle
- Kinetics of thermal transformation of partially dehydroxylated pyrophyllite
- Dehydration of the natural zeolite goosecreekite CaAl2Si6O16·5H2O upon stepwise heating: A single-crystal and powder X-ray study
- Incorporation mechanisms of Ta and Nb in zircon and implications for pegmatitic systems
- Variable-temperature 27Al and 29Si NMR studies of synthetic forsterite and Fe-bearing Dora Maira pyrope garnet: Temperature dependence and mechanisms of paramagnetically shifted peaks
- Calibrating Ti concentrations in quartz for SIMS determinations using NIST silicate glasses and application to the TitaniQ geothermobarometer
- Crystal structure of Na3Fe(SO4)3: A high-temperature product (∼400 °C) of sideronatrite [Na2Fe(SO4)2OH⋅3H2O]
- Evidence for boron incorporation into the serpentine crystal structure
- Structure refinement of Ag-free heyrovskýite from Vulcano (Aeolian Islands, Italy)
- Microtextures, microchemistry, and mineralogy of basaltic glass alteration, Jeju Island, Korea, with implications for elemental behavior
- Orientation of channel carbonate ions in apatite: Effect of pressure and composition
- Thermoelastic property and high-pressure stability of Fe7C3: Implication for iron-carbide in the Earth’s core
- Yttriaite-(Y): The natural occurrence of Y2O3 from the Bol’shaya Pol’ya River, Subpolar Urals, Russia
- Identification and characterization of nanosized tripuhyite in soil near Sb mine tailings
- Letter. High-pressure I2/c-P21/c phase transformation in SrAl2Si2O8 feldspar
- Letter. Crystal structure of uchucchacuaite, AgMnPb3Sb5S12, and its relationship with ramdohrite and fizélyite
