Vein-type graphite in Jurassic volcanic rocks of the external zone of the Betic Cordillera, Southern Spain.

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Barrenechea, José F. and Luque del Villar, Francisco Javier and Rodas, Magdalena and Pasteris, Jill D. (1997) Vein-type graphite in Jurassic volcanic rocks of the external zone of the Betic Cordillera, Southern Spain. The Canadian mineralogist, 35 . pp. 1379-1390. ISSN 0008-4476

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Abstract

We have investigated volcanic-rock-hosted graphitem in eralization in the Huelma area of the Betic Cordillera, in southern Spain, in order to establish the mineralogical characteristics of the graphite andthe mechanism of its formation. The graphite is highlycrystalline, asrevealed by XRDandRaman spectroscopic data, andrelatively pure chemically (C content >90wt.%). XRD data demonstrate that some of themineralized bodies contain both hexagonal and rhombohedral graphite. Carbon isotopic compositions (-23.0< δ13 C <-20.7 ‰ ) and other geological observations indicate that thecarbon in the graphite was derived from organic matter included in the metamorphic basement. Cooling of a C-O-H fluid appears to be the most likely mechanism for precipitation of the graphite, although hydration reactions also may have played a role. The presence of rhombohedral
graphiteis discussed with reference to the kinetics of graphite formation.


Item Type:Article
Uncontrolled Keywords:Graphite, Fluid deposition, Volcanic rocks, X-ray diffraction, Raman spectroscopy, Betic Cordillera, Spain
Subjects:Sciences > Geology > Mineralogy
ID Code:70700
Deposited On:23 Feb 2022 12:50
Last Modified:23 Feb 2022 12:50

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