TiO2 activity in metamorphosed pelitic and basic rocks: principles and applications to metamorphism in southeastern Canadian Cordillera

Ghent, Edward D.; Stout, Mavis Z.

doi:10.1007/bf00373670

Cited by 114 publications

(75 citation statements)

References 17 publications

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“…Results presented in bold were considered the most reliable for each sample (as explained in the text). 1a: Ferry and Spear (1978), corrected by Hodges and Spear (1982); 1b: Ferry and Spear (1978), corrected by Hodges and Spear (1982) for biotite inclusions in garnet; 2: Lal (1993); 3: Lee and Gangully (1988); 4: Holland and Blundy (1994); 5: Ellis and Green (1979); 6: Andersen and Lindsley (1988);7: Krogh Ravna (2000); 8: Stormer (1975); 10: Kohn and Spear (1990); 11 and 12: Eckert et al (1991);13: Moecher et al (1988); 9a and 9b: Combined GRIPS and GRAIL (Ghent and Stout, 1984) …”

Section: Discussionmentioning

confidence: 96%

“…Table 8. Fe-Mg geothermometry between garnet and biotite (Hodges and Spear, 1982) for sillimanite-bearing and sillimanite-free metatexites and GRIPS and GRAIL (Ghent and Stout, 1984) results. All temperature results are in °C Metatexites Sample g c -bi mat g c -bi inc a g contact -bi inc b g r -bi mat GRIPS-GRAIL Sillimanite-free 13a 819 730 562 519 -12b 880 691 538 680 -Sillimanite-bearing 26A2a 815 655 511 520 801 26B1d 770 --509 842 35Aa 1025 --656 869 35Ba 1001 --769 -35Bc 920 600 478 609 -35C 961 -- cooling or that matrix biotite was not available in significant amounts to react.…”

Section: P-t Estimates For Metatexitesmentioning

confidence: 98%

“…of selected amphibole analyses are presented (less than 1% of the total obtained amphibole chemical data). Structural formula of amphiboles is based in 13 cations (except Ca, Na and K) and the A 0-1 B 2 C 5 T 8 q-pl (GASP) barometer of Newton and Haselton (1981), the g-ru-ilm-pl-q (GRIPS) and g-ru-pl-ilm-q (GRAIL) barometers of Ghent and Stout (1984) and the g-amph-pl-q (GAmphPS) barometer of Kohn and Spear (1990). Summarized P-T estimates are presented in Table 7 and the entire range of determined temperatures and pressures is presented in Appendix 1.…”

Section: Geothermobarometrymentioning

confidence: 99%

“…Qualitative and quantitative constrains of metamorphic peak conditions of the studied metatexites (GRIPS and GRAIL (Ghent and Stout, 1984) geothermobarometry and biotite dehydration-melting reaction curve from sample Pl (C/6-45) used in the pseudosection section are used). Mineral abbreviations are presented as in THERMOCALC 3.31 (Holland and Powell, 1998;Powell and Holland, 1999).…”

Section: Figmentioning

confidence: 99%

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Metamorphic P-T evolution of granulites in the central Ribeira Fold Belt, SE Brazil

et al. 2011

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Pseudosections, geothermobarometric estimates and careful petrographic observations of gneissic migmatites and granulites from Neoproterozoic central Ribeira Fold Belt (SE Brazil)were performed in order to quantify the metamorphic P-T conditions during prograde and retrograde evolution of the Brasiliano Orogeny. Results establish a prograde metamorphic trajectory from amphibolite facies conditions to metamorphic peak (T = 850 ± 50°C; P = 8 ± 1 kbar) that promoted widespread dehydrationmelting of 30 to 40% of the gneisses and high-grade granitization. After the metamorphic peak, migmatites evolved with cooling and decompression to T ≈ 500°C and P ≈ 5 kbar coupled with a H2O increase, replacing the high-grade paragenesis plagioclase-quartz-K-feldspar-garnet by quartz-biotite-sillimanite-(muscovite). Cordierite absence, microtextural observations and P-T results constrain the migmatite metamorphic evolution in the pseudosections as a clockwise P-T path with retrograde cooling and decompression. Hightemperature conditions further dehydrated the lower crust with biotite and amphibole-dehydration melting and granulite formation coupled with 10% melt generation. Granulites can thus be envisaged as middle to lower crust dehydrated restites. Granulites were slowly (nearly isobarically) cooled, followed by late exhumation/ retrograde rapid decompression and cooling, reflecting a two step P-T path. This retrograde evolution, coupled with water influx, chemically reequilibrated the rocks from granulite to amphibolite/ greenschist facies, promoting the replacement of the plagioclasequartz-garnet-hypersthene peak assemblage by quartz-biotite-K-feldspar symplectites.

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Section: Discussionmentioning

confidence: 96%

Section: P-t Estimates For Metatexitesmentioning

confidence: 98%

Section: Geothermobarometrymentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

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Metamorphic P-T evolution of granulites in the central Ribeira Fold Belt, SE Brazil

et al. 2011

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“…While a TiO 2 in crustal rocks are generally 0.6 or higher (Hayden and Watson, 2007), use of a TiO 2 = 0.6-0.74 obtained from metabasic and gabbroic rocks (Ghent and Stout, 1984;Ickert et al, 2011) would increase temperatures by 40-70 • C relative to a TiO 2 = 1. On the other hand, low pressure conditions in Vesta's crust would require corrections of −50 to −100 • C as compared to the estimates at ca.…”

Section: Genesis and Crystallization Conditions Of The Agoult Zirconmentioning

confidence: 98%

Timing of global crustal metamorphism on Vesta as revealed by high-precision U–Pb dating and trace element chemistry of eucrite zircon

Iizuka

Yamaguchi

Haba

et al. 2015

Earth and Planetary Science Letters

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Non-cumulate eucrites represent basaltic crust that experienced a complex thermal history involving multistage metamorphism and metasomatism, probably on asteroid Vesta. To better constrain the thermal history of these rocks and their parent body, we have integrated high-precision U-Pb age and trace element data for zircon grains with sizes up to 80 μm in the eucrite Agoult. All analyzed zircon grains yielded concordant U-Pb dates that correspond to the precise 207 Pb/ 206 Pb age of 4554.5 ± 2.0 Ma.The Ti contents in these zircon grains indicate their crystallization at subsolidus temperatures of ca. 900 • C, which are similar to the inferred conditions of pyroxene exsolution in most basaltic eucrites that occurred during protracted thermal metamorphism. The zircon crystallization temperatures, together with the presence of baddeleyite needles and variable Zr concentration in Agoult ilmenite grains, indicate metamorphic origin of the Agoult zircon through Zr release from ilmenite followed by reaction with silica. We therefore consider the zircon 207 Pb/ 206 Pb age as the timing of the widespread thermal metamorphism in Vesta's crust. The metamorphic age is coincident with the oldest Mn-Cr date for cumulate eucrites, supporting the view that the thermal metamorphism is a result of burial of basaltic crust and subsequent heating from the hot interior rather than collision of asteroids. The zircon rare earth element patterns with restricted Ce positive anomalies suggest that the metamorphism occurred at an oxygen fugacity below the iron-wüstite buffer, implying the absence of oxidizing agents such as aqueous fluid within the crust at that time.

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Titanium concentration in quartz as a record of multiple deformation mechanisms in an extensional shear zone

Nachlas

Teyssier

Bagley

et al. 2014

Geochem. Geophys. Geosyst.

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Results of high precision analysis of Ti concentration ([Ti]) in quartz representing different recrystallization microstructures in a suite of progressively deformed quartzite mylonites show the effect of recrystallization on distribution of Ti in quartz. Petrographic observations and ion microprobe analysis reveals three texturally and geochemically distinct quartz microstructures in mylonites: (1) cores of recrystallized quartz ribbons preserve the highest [Ti] and are interpreted to have recrystallized via grain boundary migration recrystallization, (2) recrystallized rims and grain margins preserve a lower and more variable [Ti] and are interpreted to reflect the combined influence of subgrain rotation and bulging recrystallization, and (3) neocrystallized quartz precipitated in dilatancy sites has low ( 1 ppm) [Ti], reflecting the Ti content of the syndeformational fluid. Muscovite in nonmylonitic quartzite (at the base of the sampling traverse) is compositionally zoned, whereas muscovite in mylonitic quartzite shows a progressive decreasing in zoning in higher strain samples. Threedimensional phase distribution mapping using X-ray computed tomography analysis of rock hand samples reveals that Ti-bearing accessory phases are less abundant and more dispersed in higher strained mylonites compared to nonmylonitic quartzite. This study demonstrates the influence of dynamic recrystallization on Ti substitution in quartz and evaluates the Ti buffering capacity of aqueous fluids (meteoric versus metamorphic/ magmatic) as well as the distribution and reactivity of Ti-bearing accessory phases in a deforming quartzite. Results of this study suggest that Ti-in-quartz thermobarometry of deformed quartz is a sensitive technique for resolving the multistage history of quartz deformation and recrystallization in crustal shear zones.

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TiO2 activity in metamorphosed pelitic and basic rocks: principles and applications to metamorphism in southeastern Canadian Cordillera

Cited by 114 publications

References 17 publications

Metamorphic P-T evolution of granulites in the central Ribeira Fold Belt, SE Brazil

Metamorphic P-T evolution of granulites in the central Ribeira Fold Belt, SE Brazil

Timing of global crustal metamorphism on Vesta as revealed by high-precision U–Pb dating and trace element chemistry of eucrite zircon

Titanium concentration in quartz as a record of multiple deformation mechanisms in an extensional shear zone

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