Notes on the petrology of the Oaxacan complex
Keywords:
lithological, petrography, chloritic, polymetamorphism, metaphoric episodeAbstract
The results of a geological reconnaissance of Precambrian gneisses near the city of Oaxaca are presented. Six main lithological varieties of paragneisses were recognized, their petrography described, followed by discussions about their genesis and the conditions under which they were metamorphosed. It is concluded that this part of the Oaxacan Complex, in the southernmost extension of the Grenville Structural Belt, was derived from a sedimentary sequence of clays, primarily calcareous and dolomitic, with some layers of dolomite and locally chloritic. These rocks were metamorphosed under the characteristic high-pressure and temperature conditions of the granulite facies, but a partial decrease in lithostatic pressure produced rocks of slightly lower grade with cordierite. Rocks transitional to the amphibolite facies, at a lower temperature, may have formed either through polymetamorphism or by local gradients of pressure and temperature during a single metamorphic episode.
References
Aguilera, G. y Ordóñez, E. (1893). Datos para la geología de México. Imprenta y Fotocolografía del Cosmos, 87 p.
Anderson, T . H. y Silver, L. T . (1971) Age of granulite metamorphism during the Oaxacan orogeny. Geol. Soc. Amer. Abstr. with Progy., Boulder Colo. Mtg., 3(7), 492.
Barrera, T . (1946). Guía geológica de Oaxaca. Inst. Geol. México, Mem. Buelna, R. R.
Cannon, R. T. (1966) Plagioclase zoning and twinning in relation to the metamorphic history of some amphibolites and granulites. Am. Jour. Sci., (264), 526-542.
De Cserna, Z. (1971) Precambrian Sedimentation, tectonics and magmatism in Mexico. Geol. Rundschau, (60), 1488-1513.
Eade, K. E., Fahrig, W. F. y Maxwell, J. A. (1966) Composition of crystalline shield rocks and fractionating effects of regional metamorphism. Nature, (211), 1245-1249.
Faust, G. T. (1949) Dedolomitization and its relation to a possible derivation of a magnesium-rich hydrothermal solution. Am. Mineral., (34), 789-823.
Félix, J. (1899) Übersicht über die Entwicklung der geologischen Formationen in Mexico, nebst einem Anhang iiber die Hohlenbildungen dieses Landes en Beitrage zur. Geotogie und Palaontologie der Republik Mexico, (2), 155-186.
Fries, C., Schmitter, E. Damon, P. E. y Livingston, D. E. (1962) Rocas precámbricas de edad grenvilliana de la parte central de Oaxaca en el sur de México. Inst. Geol. Bol., 64(3) 45-53.
Fries, C. y R incón-Orta, C. (1965) Nuevas aportaciones geocronológicas y técnicas empleadas en el laboratorio de geocronometría. Inst. Geol. Bol., 73(2), 57-133.
Fries, C., Schlaepfer, C. y Rincón Orta, C. (1966) Nuevos datos geocronológicos del Complejo Oaxaqueño. Soc. Geol. Mex., (29), 59-66.
Fries, C., Rincón Orta, C., Silver, L. T., et. al.(1973) Nuevas aportaciones a la geocrono-
petrología del complejo oaxaqueño de la Faja Tectónica Oaxaqueña. Inst. Geol., (100), 11-26.
Fyfe, W. S. y Turner, F. J. (1966) Reappraisal of the metamorphic facies concept. Contr. Mineral and Petrol., 12, 354-364.
Fyfe, W . S., T urner, F. J. y V erhoogen, J. (1958) Metamorphic reactions and metamorphic facies. Geol. Soc. Amer. Mem., 73.
Garson, M. S. (1955) Flow phenomena in a limestone on Changalumi Hill, southern Nyasaland. Geol. Mag., (92), 155-161.
Gevers, T . W . y Dunne, J. C. (1942) Charnockitic rocks near Port Edward, Alfred County, Natal. Geol. Soc. S. Africa, Trans., 45, pp. 183-214.
Holland, T . H. (1893) The petrology of Job Charnock’s tombstone. Asiatic Soc. Bengal Journ., (62).
Geol. Survey. (1900). The charnockite series, a group of Archaen hypersthenic rocks
in Peninsular India. 28.
Howie, R. A. (1955). The geochemistry of the charnockite series of Madras, India. Royal Soc. Edinburgh Trans., (62), 725-768.
Hsu, K. J. (1955) Granulites and mylonites of the region about Cucamonga and San Antonio canyons, San Gabriel Mountains, California. Univ. California. Geol. Sci., (30), 223-352.
Kesler, S. E. (1973) Basement rock structural trends in southern Mexico. Geol. Soc. America. Bull, Kesler, S. E. y Heath, S. A. (1970) Structural trends in the southernmost North American Precambrian. Geol. Soc. America„ Bull., (81), 2471-2476.
Kullerud, G. y Yoder, H. S. (1959) Pyrite stability relations in the Fe-S system. Econ. Geol, (54), 533-572.
Lambert, R. St . J. (1965) The metamorphic facies concept. Mineral Mag., (34), 283-291
Ordóñez, E. y Aguilera, G. (1896). Itinerarios Geológicos. Inst. Geol. México, (4-6) 19-29.
Ordóñez, E . (1904) Las rocas arcaicas de México. Soc. Cient. Antonio Alzate, Mem., (22), 315-331.
Parras, K. (1958) On the charnockites in the light of a highly metamorphicrock complex in southwestern Finland. Comm. Géol. Finlande Bull., 181.
Rast, N., R uiz-Castellanos, M., R othemberg L. y Ortega-Gutiérrez, F. (1970). Resultados geológicos, estratigráficos y estructurales de un recorrido a lo largo de la Carretera Federal 190. Izúcar de Matamoros, Pue., y algunas localidades adyacentes. Inst. Geol.
Rodríguez-Torres, R. (1970). Geología metamórfica del área de Acatlán, Estado de Puebla. Soc. Geol. Mex. Libro-Guía de la excursión, México-Oaxaca, 51-54.
Schmitter-Villada, E. (1970). Nelsonita de ilmenita y magnetita de la región de Huitzo, Estado de Oaxaca. Soc. Geol. Mex. Libro-Guía de la excursión, México-Oaxaca, 167-173.
Vail, R. (1965). An outline of the geochronology of the late-Precambrian formations of eastern central Africa. Royal Soc. London Proc. Ser. A, (284), 354-369.
Winkler , H. G. F. (1965) Petrogenesis of the metamorphic rocks. Springer Verlag.
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