Relationship between structure, morphology, and carbon isotopic composition of graphite in marbles: Implications for calcite-graphite carbon isotope thermometry
-
M. Satish-Kumar
,
John A. Jaszczak
Abstract
Carbon isotope exchange between calcite and graphite is a useful and reliable geothermometer for medium- to high-grade marbles. However, in rare instances, such as at Naxos, Greece, apparent disequilibrium carbon isotope fractionation between calcite and graphite has been previously reported. In this study, new results are presented on the morphological features, X-ray diffraction studies, Raman spectroscopic studies, and carbon isotope studies of graphite. Three morphologically distinct graphite types are identified. The first type is fine grained with distinct polygonal crystal aggregates having smooth pinacoid faces. The second type consists of large botryoidal aggregates with typical crystal overgrowth features, and the third type is “normal” large platy crystals associated with phlogopite. Graphite morphological features using an FE-SEM suggests that the botryoidal aggregates are composed of complexly intergrown and stacked graphite layers, comprised of cone-helix structures. Different types of graphite display distinct Lc(002) and DG values as well as a sharp first-order Raman peak at -1580 cm-1 with disordered bands. The presence of Raman disordered bands in fine-grained well-crystallized graphite is attributed to edge effects. Carbon isotope analysis of graphite reveals that marble with fine-grained well-crystallized graphite show a consistent isotope fractionation with the calcite, which perfectly match temperature estimates based on the mineral isograds. In contrast, coarse botryoidal graphite gives heterogeneous carbon isotope values (about a few per mill) and show anomalous carbon isotope fractionation between the calcite and graphite. The graphite associated with phlogopite also shows variations in the carbon isotope values. Combining morphologic, crystallographic, and carbon isotopic data we conclude that the variations in carbon isotopic composition were caused by the overgrowth of graphite on the preexisting grain and that morphological observations and structural characterizations of graphite crystals is a key for predicting isotopic equilibration during metamorphism.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Roebling Medal Lecture. The three partners of metamorphic petrology
- Relationship between structure, morphology, and carbon isotopic composition of graphite in marbles: Implications for calcite-graphite carbon isotope thermometry
- Crystal structure, mosaicity, and strain analysis of Hawaiian olivines using in situ X-ray diffraction
- Characterization of deep weathering and nanoporosity development in shale—A neutron study
- Structural water in ferrihydrite and constraints this provides on possible structure models
- Critical evaluation of the revised akdalaite model for ferrihydrite
- Neutron diffraction study of hydrogen in birnessite structures
- Pressless split-sphere apparatus equipped with scaled-up Kawai-cell for mineralogical studies at 10–20 GPa
- Dislocation microstructures in majorite garnet experimentally deformed in the multi-anvil apparatus
- Density of carbonated peridotite magma at high pressure using an X-ray absorption method
- Stability and bulk modulus of Ni3S, a new nickel sulfur compound, and the melting relations of the system Ni-NiS up to 10 GPa
- Far-infrared spectra of synthetic [4][(Al2-xGax)(Si2–yGey)](OH,OD,F)2-kinoshitalite: Characterization and assignment of interlayer Ba-Oinner and Ba-Oouter stretching bands
- High-temperature elasticity of polycrystalline orthoenstatite (MgSiO3)
- Anatomy of a metabentonite: Nucleation and growth of illite crystals and their coalescence into mixed-layer illite/smectite
- Zn-O tetrahedral bond length variations in normal spinel oxides
- A new thermodynamic analysis of the intergrowth of hedenbergite and magnetite with Ca-Fe-rich olivine
- Raman spectroscopic investigations of some Tl-sulfosalt minerals containing pyramidal (As,Sb)S3 groups
- A first record of strong structural relaxation of TO4 tetrahedra in a spinel solid solution
- The high-pressure behavior of orthorhombic amphiboles
- XAS determination of the Fe local environment and oxidation state in phonolite glasses
- Chemical variation and significance of micas from the Fregeneda-Almendra pegmatitic field (Central-Iberian Zone, Spain and Portugal)
- Light-induced molecular change in HgI2·As4S4: Evidence by single-crystal X-ray diffraction and Raman spectroscopy
- Low-temperature electron paramagnetic resonance studies on natural calumetite from Khetri copper mine, Rajasthan, India
- Chromatite and its Cr3+- and Cr6+-bearing precursor minerals from the Nabi Musa Mottled Zone complex, Judean Desert
- Hazenite, KNaMg2(PO4)2⋅14H2O, a new biologically related phosphate mineral, from Mono Lake, California, U.S.A.
- The fractional latent heat of crystallizing magmas
Articles in the same Issue
- Roebling Medal Lecture. The three partners of metamorphic petrology
- Relationship between structure, morphology, and carbon isotopic composition of graphite in marbles: Implications for calcite-graphite carbon isotope thermometry
- Crystal structure, mosaicity, and strain analysis of Hawaiian olivines using in situ X-ray diffraction
- Characterization of deep weathering and nanoporosity development in shale—A neutron study
- Structural water in ferrihydrite and constraints this provides on possible structure models
- Critical evaluation of the revised akdalaite model for ferrihydrite
- Neutron diffraction study of hydrogen in birnessite structures
- Pressless split-sphere apparatus equipped with scaled-up Kawai-cell for mineralogical studies at 10–20 GPa
- Dislocation microstructures in majorite garnet experimentally deformed in the multi-anvil apparatus
- Density of carbonated peridotite magma at high pressure using an X-ray absorption method
- Stability and bulk modulus of Ni3S, a new nickel sulfur compound, and the melting relations of the system Ni-NiS up to 10 GPa
- Far-infrared spectra of synthetic [4][(Al2-xGax)(Si2–yGey)](OH,OD,F)2-kinoshitalite: Characterization and assignment of interlayer Ba-Oinner and Ba-Oouter stretching bands
- High-temperature elasticity of polycrystalline orthoenstatite (MgSiO3)
- Anatomy of a metabentonite: Nucleation and growth of illite crystals and their coalescence into mixed-layer illite/smectite
- Zn-O tetrahedral bond length variations in normal spinel oxides
- A new thermodynamic analysis of the intergrowth of hedenbergite and magnetite with Ca-Fe-rich olivine
- Raman spectroscopic investigations of some Tl-sulfosalt minerals containing pyramidal (As,Sb)S3 groups
- A first record of strong structural relaxation of TO4 tetrahedra in a spinel solid solution
- The high-pressure behavior of orthorhombic amphiboles
- XAS determination of the Fe local environment and oxidation state in phonolite glasses
- Chemical variation and significance of micas from the Fregeneda-Almendra pegmatitic field (Central-Iberian Zone, Spain and Portugal)
- Light-induced molecular change in HgI2·As4S4: Evidence by single-crystal X-ray diffraction and Raman spectroscopy
- Low-temperature electron paramagnetic resonance studies on natural calumetite from Khetri copper mine, Rajasthan, India
- Chromatite and its Cr3+- and Cr6+-bearing precursor minerals from the Nabi Musa Mottled Zone complex, Judean Desert
- Hazenite, KNaMg2(PO4)2⋅14H2O, a new biologically related phosphate mineral, from Mono Lake, California, U.S.A.
- The fractional latent heat of crystallizing magmas
