Graphite thermometry in a low-pressure contact aureole, Halifax, Nova Scotia

Hilchie, Luke; Jamieson, Rebecca Anne

doi:10.1016/j.lithos.2014.08.015

Cited by 17 publications

(25 citation statements)

References 25 publications

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“…In very short time‐scale heating events (100–500 years), such as heating induced by a sill intrusion, graphitization may be limited by the duration of the thermal event (Mori, Mori, Wallis, Westaway, & Annen, ) but this is different from the time‐scale for contact metamorphism developed in contact aureoles due to the emplacement of igneous intrusions on the km scale, which is typically hundreds of thousands of years for rocks raised to >500°C, such as Nelson and Ballachulish (see references above). This point is further supported by a plot of RSCM temperature data in contact aureole versus reference temperature estimates from the same source paper (this study; Aoya et al., ; Delchini et al., ; Hilchie & Jamieson, ) presented in Figure . Reference temperature is an independent petrological estimate of temperature, except for the Halifax aureole in Nova Scotia, where it is quantified from thermal modelling with input from conventional petrology and RSCM thermometry (Hilchie & Jamieson, ).…”

Section: Implications For Rscm Thermometrysupporting

confidence: 81%

“…This point is further supported by a plot of RSCM temperature data in contact aureole versus reference temperature estimates from the same source paper (this study; Aoya et al., ; Delchini et al., ; Hilchie & Jamieson, ) presented in Figure . Reference temperature is an independent petrological estimate of temperature, except for the Halifax aureole in Nova Scotia, where it is quantified from thermal modelling with input from conventional petrology and RSCM thermometry (Hilchie & Jamieson, ). Apart from Ballachulish, the data mainly fall around the 1:1 line within an envelope of ±25°C except for a few outliers.…”

Section: Implications For Rscm Thermometrysupporting

confidence: 81%

“…Comparison of RSCM temperatures versus reference temperatures standing for temperatures quantified by conventional petrology and thermal modelling (Nelson and Ballachulish, this study), mineral assemblage and pseudosections (aureole in Morocco by Delchini et al., ), mineral assemblage and conventional geothermobarometry (aureoles in Japan by Aoya et al., ), thermal modelling with input from conventional petrology, and RSCM thermometry (aureole in Canada by Hilchie & Jamieson, ). The 1:1 line is depicted as well as lines representing 1:1 ± 25°C.…”

Section: Implications For Rscm Thermometrymentioning

confidence: 96%

“…In the studies by Aoya et al. (), Hilchie and Jamieson (), and Delchini et al. (), contact metamorphism was superposed on rocks that had already experienced greenschist facies regional metamorphism with temperature estimated in the range 300–400°C.…”

Section: Delayed Recrystallization Of Previously Metamorphosed CM At mentioning

confidence: 97%

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Contrasting degrees of recrystallization of carbonaceous material in the Nelson aureole, British Columbia and Ballachulish aureole, Scotland, with implications for thermometry based on Raman spectroscopy of carbonaceous material

Beyssac

Pattison

Bourdelle

2018

Journal Metamorphic Geology

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The degree of recrystallization of carbonaceous material (CM), as monitored by Raman microspectroscopy, was examined as a function of metamorphic grade in two well‐studied contact aureoles containing carbonaceous pelites: the Nelson aureole, British Columbia and the Ballachulish aureole, Scotland. Here, we use (a) the R2 ratio extracted from the Raman spectrum of CM as a proxy for the degree of graphitization (0.0 in perfect graphite then increasing with structural defects) and (b) the second‐order S1 band (~2,700 cm−1) as a marker for the tridimensional ordering of CM. The Nelson aureole (garnet–staurolite–andalusite–sillimanite–K‐feldspar sequence, ~550–650°C, 3.5–4.0 kbar) was developed in rocks that were unmetamorphosed prior to contact metamorphism, whereas the Ballachulish aureole (cordierite–andalusite–K‐feldspar–sillimanite sequence, ~550–700°C, ~3.0 kbar) was developed in rocks that had been metamorphosed to garnet grade conditions (~7 kbar, ~500°C) c. 45 Ma before contact metamorphism. Thirty‐one samples were examined from Nelson and 29 samples from Ballachulish. At Nelson, the R2 ratio steadily decreases from ~0.25 to 0.0 as the igneous contact is approached, whereas at Ballachulish, the R2 ratio remains largely unchanged from regional values (~0.20–0.25) until less than 100 m from the igneous contact. The second‐order S1 band reveals that carbonaceous material (CM) was transformed to highly “ordered” locally tridimensional graphitic carbon at Ballachulish by regional metamorphism prior to contact metamorphism, whereas CM was still a disordered turbostratic (bidimensional) material before contact metamorphism in the case of Nelson. Pretexturation of CM likely induced sluggish recrystallization of CM and delayed graphitization in the Ballachulish aureole. Temperatures of recrystallization of the CM in the two aureoles were estimated using different published calibrations of the thermometry based on Raman Spectroscopy of Carbonaceous Material (RSCM), with differences among the calibrations being minor. In the Nelson aureole, temperatures are in reasonable agreement with those indicated by the metapelitic phase equilibria (all within 50°C, most within 25°C). In the Ballachulish aureole, the retarded crystallization noted above results in increasing underestimates of temperatures compared to the metapelitic phase equilibria (up to ~75°C too low within 200 m of the igneous contact). Our study calls for careful attention when using RSCM thermometry in complexly polymetamorphosed rocks to assess properly the meaning of the calculated temperature.

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Section: Implications For Rscm Thermometrysupporting

confidence: 81%

Section: Implications For Rscm Thermometrysupporting

confidence: 81%

Section: Implications For Rscm Thermometrymentioning

confidence: 96%

Section: Delayed Recrystallization Of Previously Metamorphosed CM At mentioning

confidence: 97%

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Contrasting degrees of recrystallization of carbonaceous material in the Nelson aureole, British Columbia and Ballachulish aureole, Scotland, with implications for thermometry based on Raman spectroscopy of carbonaceous material

Beyssac

Pattison

Bourdelle

2018

Journal Metamorphic Geology

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“…No obstante, es necesario tomar en cuenta detalles propios de la técnica, como el ángulo del láser, heterogeneidad de las partículas, aplicabilidad a diferentes temperaturas, y la preparación de la muestra para el ensayo (Aoya et al, 2010;Hilchie & Jamieson, 2014).…”

Section: Introductionunclassified

Correlación entre parámetros químicos, cristalográficos y espectroscópicos en la termometría de grafito aplicada a una aureola de contacto del monzogranito de La Soledad (Andes venezolanos)

Reategui

Martínez

2017

Estud. geol.

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Muestras de grafito provenientes de una aureola de contacto entre filitas de la Asociación Cerro Azul (Paleozoico) y el Monzogranito de La Soledad en Los Andes venezolanos, fueron estudiadas mediante técnicas químicas (% Carbono inorgánico y distribución isotópica), cristalográficas (DRX) y espectroscópicas (Raman) con el fin de evaluar los cambios en las características del grafito en las cercanías del contacto, correlacionar los diferentes parámetros entre sí, y estimar la temperatura máxima alcanzada por la roca caja durante la intrusión ígnea. La cristalografía del grafito exhibe cambios notables, y tiene lugar una disminución en el contenido del mineral en las inmediaciones del contacto. El δ13C alcanzó valores menos negativos en las cercanías al monzogranito, ocasionado por devolatilización; el grafito presente exactamente en el contacto con el plutón pudo experimentar recristalización posterior al evento térmico, con puntual desplazamiento isotópico hacia valores más negativos. El intervalo de valores de grado de grafitización calculados (GD=53–80) corresponde a un mineral bien estructurado y con empaquetamiento ordenado. La temperatura máxima durante el evento intrusivo en el contacto fue calculada a través de los parámetros cristalográficos (DRX) como espectroscópicos (Raman) con gran concordancia en ambas técnicas, registrando 528 ± 16 y 526 ± 20 ºC respectivamente. El nivel metamórfico alcanzado por las rocas metapelíticas en la aureola de contacto comprende la Zona de la Cordierita (cordierita + biotita + muscovita) donde el grafito se halla bien cristalizado y en microtextura hexagonal. Factores como la actividad de fluidos y la recristalización posterior de mineral grafitoso inciden en redistribuciones isotópicas posteriores al evento intrusivo, al igual que en la tasa de cambio de cristalinidad del grafito con la temperatura lo que determina una ausencia clara de correlación entre las variaciones isotópicas de 13C en el grafito y la temperatura.

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Pressure dependence of graphitization: implications for rapid recrystallization of carbonaceous material in a subduction zone

Nakamura

Yoshino

Satish-Kumar

2020

Contrib Mineral Petrol

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We report the results of kinetic experiments of graphitization at various pressures (0.5-8.0 GPa) and durations (1 s to 24 h) at 1200 °C. The natural carbonaceous material in sedimentary rocks from the Shimanto accretionary complex and the Hidaka metamorphic belt, Japan, underwent systematic changes in crystallinity and morphology with increasing pressure. To assess the pressure dependence of graphitization, we adopted three approaches to formulating the graphitization kinetics using a power law rate model, a Johnson-Mehl-Avrami-Kolmogorov model, and a superposition method. Activation volumes of − 21.7 ± 3.0 to − 45.7 ± 4.5 cm 3 mol −1 and − 0.7 ± 0.2 to − 16.8 ± 1.8 cm 3 mol −1 were obtained for pressures from 0.5 to 2.0 GPa and 2.0 to 8.0 GPa, respectively. Such large negative activation volumes might arise from structural modification and compression in the primary carbonaceous material. We applied the experimental data to the Arrhenius-type equation of graphitization, extrapolated to geological P-T-t conditions. Our model predicts that carbonaceous material undergoing metamorphism for ~ 10 Myr at pressures of 0.5-3.0 GPa will begin to crystallize at around 350-420 °C and transform fully to ordered graphite at around 450-600 °C, depending on the peak pressure. Thus, natural graphitization might proceed much more rapidly than previously estimated, owing to the large negative activation volumes for the reaction rate. This indicates that subducted carbonaceous materials will completely convert to fully ordered graphite by rapid recrystallization and metamorphic devolatilization before reaching sub-arc depths (< 100 km).

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Graphite thermometry in a low-pressure contact aureole, Halifax, Nova Scotia

Cited by 17 publications

References 25 publications

Contrasting degrees of recrystallization of carbonaceous material in the Nelson aureole, British Columbia and Ballachulish aureole, Scotland, with implications for thermometry based on Raman spectroscopy of carbonaceous material

Contrasting degrees of recrystallization of carbonaceous material in the Nelson aureole, British Columbia and Ballachulish aureole, Scotland, with implications for thermometry based on Raman spectroscopy of carbonaceous material

Correlación entre parámetros químicos, cristalográficos y espectroscópicos en la termometría de grafito aplicada a una aureola de contacto del monzogranito de La Soledad (Andes venezolanos)

Pressure dependence of graphitization: implications for rapid recrystallization of carbonaceous material in a subduction zone

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