Graphitization of carbonaceous matter during metamorphism with references to carbonate and pelitic rocks of contact and regional metamorphisms, Japan

Wada, Hideki; Tomita, Toshihiro; Matsuura, Kazuhiro; Tuchi, Keisuke; Ito, Masahiro; Morikiyo, Toshiro

doi:10.1007/bf00306643

Cited by 113 publications

(123 citation statements)

References 31 publications

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“…This is because the formation temperature for the granite is generally close to or higher than the temperature values listed above. On the basis of the investigation into the mechanism for the graphitization of CM in regionally metamorphosed rocks (Grew, 1974;Wintsch et al, 1981;Wada et al, 1994), it is known that the graphitization of CM is affected by temperature and pressure, the fugacity of O-, H-, S-and N-bearing gases, permeability of the host rock, the duration of metamorphism and metamorphic fluid, and even the lithology and texture of the original organic tissues. Obviously, lower temperatures, higher pressures, high fugacity of volatile components, and low rock permeability might prolong the graphitization of CM.…”

Section: Discussionmentioning

confidence: 99%

“…The isolation and identification of CM in metamorphic rocks are of great petrologic importance in view of the ability of graphite to control the partial pressure of oxygen in the coexisting gaseous phase (French, 1964). As the graphitization of CM in rocks is believed to be irreversible, the extent of graphitization may be a useful indicator of the maximum metamorphic grade attained (Wada et al, 1994), so that many petrologists working at metamorphism have paid attention to the chemical composition and structural state of CM in metamorphic rocks and its geological applications. On the basis of previous works (e.g., Swain et al, 1958;French, 1964;Izawa, 1968;Landis, 1971;Grew, 1974;Itaya,…”

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confidence: 99%

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Carbonaceous material in S-type Xihuashan granite.

2001

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In order to verify the presence of residual organic matter in some S-type granites, a method used conventionally in petroleum geochemistry for isolation of kerogen was employed to separate carbonaceous material (CM) from the Xihuashan granite, Jiangxi Prov., China. Optical, XRD and SEM/EDAX analyses identified the acid-insoluble residue as mainly composed of various mineral debris, with a minor carbonaceous fraction found in the residue. LMR and micro-FTIR studies showed that the residue contained a small amount of CM, which is heterogeneous in composition and structural state. The occurrence of CM in the granite implies that this granitic magma originated from sediments and crystallized at relatively lower temperatures and high pressures. This deduction is consistent with geological and geochemical studies of the Xihuashan granite. A tentative model was suggested which connects CM in S-type granite with organic matter in sedimentary rocks. The conditions under which CM can be preserved in S-type granite are discussed. The occurrence of some heavy hydrocarbons is expected in the Xihuashan granite.gradually converted to increasingly crystalline and pure carbonaceous material (CM), with graphite as the end product.CM is a common constituent of metamorphosed sedimentary rocks. The isolation and identification of CM in metamorphic rocks are of great petrologic importance in view of the ability of graphite to control the partial pressure of oxygen in the coexisting gaseous phase (French, 1964). As the graphitization of CM in rocks is believed to be irreversible, the extent of graphitization may be a useful indicator of the maximum metamorphic grade attained (Wada et al., 1994), so that many petrologists working at metamorphism have paid attention to the chemical composition and structural state of CM in metamorphic rocks and its geological applications. On the basis of previous works (e.g., Swain et al.,

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Carbonaceous material in S-type Xihuashan granite.

2001

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“…The presence of two types of optically different 'graphite' in the rocks of the La Umbría series suggests that detrital graphite derived from the continent drainage system was incorporated into the sediments. Such highly crystalline, detrital graphite in association with 'in situ'-formed graphite of lower crystallinity has been recognized by different techniques in samples from many low-grade metamorphic terranes (Diessel, Brothers & Black, 1978;Buseck & Bo-Jun, 1985;Okuyama-Kusunose & Itaya, 1987;Wada et al 1994;Petrova et al 2002). In any case, detrital graphite may point to the presence of carbonaceous matter prior to the Precambrian times represented by the materials of the La Umbría series and a former (higher-grade) metamorphic event.…”

Section: A Syngenetic Graphitementioning

confidence: 99%

Significance of graphite occurrences in the Aracena Metamorphic Belt, Iberian Massif

et al. 2004

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-The significance of syngenetic and epigenetic graphite occurrences from the Variscan hightemperature/low-pressure Aracena Metamorphic Belt is discussed in the framework of the tectonothermal evolution of this southern zone of the Iberian Massif. Syngenetic graphite is associated with both low-to medium-grade metamorphic rocks (La Umbría series, Precambrian in age) and high-grade, granulite facies rocks (the Precambrian Fuente del Oro series and a Cambrian calc-silicate series). Epigenetic, fluid-deposited occurrences correspond to overgrowths on existing metamorphic graphite grains and vein-type mineralization. Two types of graphitized particles with remarkable differences in reflectance, anisotropy and size can be distinguished in the Precambrian metapelites of the La Umbría series. Large, >150 µm length, platy crystals with high reflectance and anisotropy are interpreted as detrital and are considered indirect evidence of an old orogenic cycle prior to the Cadomian Orogeny, during which metamorphism exceeded greenschist facies. The coexistence of two types of particles explains the scattering of values of the c parameter of graphite determined by XRD (c = 6.72-6.74 Å ), and the anomalously high temperatures of the DTA exothermic peak (close to 600• C) of graphite with respect to that inferred from mineral assemblages in these rocks. The presence of graphite-rich quartzites and gneisses within the Fuente del Oro series and the calc-silicate series is evidence of sedimentation under reducing conditions in a continental shelf. The characteristics of graphite reflect the high-grade metamorphic conditions attained in the southern area of the Aracena Metamorphic Belt. Pervasive flow of fluids related to a major Variscan extensional event resulted in overgrowths on the pre-existing graphite in the gneisses and quartzites of the calc-silicate series, as evidenced by the heterogeneous isotopic composition of graphite single crystals in these rocks. A later stage of graphite precipitation is represented by scarce vein-type occurrences in mafic granulites that document channelled flow of fluids.

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“…El aspecto físico del proceso de grafitización está caracterizado por el incremento de las dimensiones del plano interno (001), del diámetro (L a ) de los anillos, del espesor del empaquetamiento (cantidad de láminas o capas de grafeno) (L c ) y por la reducción de la distancia interplanar (d) de los cristales de grafito (Tagiri, 1981). Los valores de estos parámetros definen el grado de cristalinidad del material carbonoso, reflejando básicamente el ordenamiento de los átomos de carbono en la estructura cristalina, lo cual puede ser monitoreado por técnicas cristalográficas, tales como difracción de rayos X, espectroscopía Raman y microscopía electrónica; por otra parte, con estas técnicas se han generado ecuaciones que permiten estimar la máxima temperatura de metamorfismo (Tagiri, 1981;Tagiri & Oba, 1986;Wopenka & Pasteris, 1993;Wada et al, 1994).…”

Section: Introductionunclassified

“…El enlace 12 C -12 C es el primero en ser afectado por el esfuerzo termal (Hoefs & Frey, 1976). Los gases que emergen y contienen carbono, principalmente CH 4 , deben ser ricos en el isótopo ligero, derivando en un enriquecimiento del isótopo pesado en el residuo (Morikiyo, 1986;Wada et al, 1994). Después que el grafito de origen singenético se ha formado, la composición isotópica de éste puede variar bajo condiciones de equilibrio a través de reacciones de intercambio con compuestos de carbono (principalmente CH 4 y CO 2 ) en fase fluida, lo que implica la posible aparición de grafito epigenético (Hoefs & Frey, 1976;Crespo et al, 2005;Luque et al, 2012).…”

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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Graphitization of carbonaceous matter during metamorphism with references to carbonate and pelitic rocks of contact and regional metamorphisms, Japan

Cited by 113 publications

References 31 publications

Carbonaceous material in S-type Xihuashan granite.

Carbonaceous material in S-type Xihuashan granite.

Significance of graphite occurrences in the Aracena Metamorphic Belt, Iberian Massif

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)

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