Paleomagnetismo y magnetoestratigrafía de la Sierra de La Primavera, Jalisco
Main Article Content
Abstract
A preliminary 'report is made of a paleomagnetic study of several units belonging to the Sierra La Primavera, Jalisco State, Mexico. Most paleomagnetic directions presented normal polarities, which very likely correspond to the Brunhes normal polarity epoch (last 690 000 - 700 000 years). The only exception corresponds to the Tala Tuff, which presented intermediate polarities and a higher directional dispersion. These intermediate polarities could be related to a transitional event corresponding to the Blake excursion (110 000- 116 000 years). In this case, this relation would imply a slightly older age for this formation than that estirnated by the K-Ar method (i.e. about 96 000 years). This hypothesis can be sustained by the presence of secondary components in the normal remanent magnetism of the Tala Tuff, that could be related to hydrothermal alterations giving rise to a los of radiogenic argon. This also apparently solves the stratigraphic inconsistency posed by the K-Ar date for the Tala Tuff. The paleomagnetic results in general are compatible with the volcanic stratigraphy and K-Ar dating studies reported by Mahood and co-workers, which indicate that the Sierra La Primavera is a young volcanic feature developed mainly during the last 140 000 years.
Article Details
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
References
BOOTH, B., 1979. Assessing volcanic risk. J. Geol. Soc. London, 136, 331-340. DOI: https://doi.org/10.1144/gsjgs.136.3.0331
BREMER-BREMER, M. y J. URRUTIA-FUCUGAUCHI, 1985. Magnetoestratigrafía y variaciones del campo geomagnético en rocas volcánicas del centro de México. Rev. Ingeniería, 55, 41-45.
CAMPOS-ENRIQUEZ, J. O., 1986. Interpretación cuantitativa del vuelo aeromagnético-regional del área de La Primavera - Planillas, Jalisco. Informe inédito 25/86, CFE (México).
CLOUGH, B. J., J. V. WRIGHT and G. P. L. WALKER, 1982. Morphology and dimensions of the young comendite lavas of La Primavera volcano, Mexico. Geol. Mag. 111, 477-485. DOI: https://doi.org/10.1017/S0016756800026820
FERRIZ, H. y G. A. MAHOOD, 1986. Volcanismo riolítico en el Eje Neovolcánico Mexicano. Geofísica Internacional, 25, 1,117-156. DOI: https://doi.org/10.22201/igeof.00167169p.1986.25.1.803
FISHER, R. A., 1953. Dispersion on a sphere. Proc. Roy. Soc. London, 4217, 295-305. DOI: https://doi.org/10.1098/rspa.1953.0064
GILBERT, G. M., G. A. MAHOOD and I. S. E. CARMICHAEL, 1985. Volcanic stratigraphy of the Guadalajara area, Mexico. Geofísica Internacional, 24, 1, 169-191. DOI: https://doi.org/10.22201/igeof.00167169p.1985.24.1.1069
GUTIERREZ-NEGRIN, L., A. LOPEZ MARTINEZ and M. BALCAZAR GARCIA, 1984. Application of dating for searching geothermic sources. Nuclear Tracks Rad. Meas., 8, 385-389. DOI: https://doi.org/10.1016/0735-245X(84)90126-1
MAHANEY, W. C. (Ed.), 1984. Quaternary Dating Methods. Elsevier Sci. Publ., 428 pp.
MAHOOD, G. A., 1980. Geological evolution of a Pleistocene rhyolitic center Sierra La Primavera, Jalisco, Mexico. J. Volcanol. Geoth. Res., 8, 199-230. DOI: https://doi.org/10.1016/0377-0273(80)90105-5
MAHOOD, G. A., 1981a. Chemical evolution of a Pleistocene rhyolitic center, the Sierra La Primavera, Jalisco, Mexico. Contrib. Min. Petrol. 77, 127-140. DOI: https://doi.org/10.1007/BF00636517
MAHOOD, G. A., 1981b. A summary of the geology and petrology of the Sierra La Primavera, Jalisco, Mexico. J. Geophys. Res., 86, 10137-10152. DOI: https://doi.org/10.1029/JB086iB11p10137
MAHOOD, G. A. and R. E. DRAKE, 1982. K-Ar, dating of young rhyolitic rocks. A case study of the Sierra La Primavera, Jalisco, Mexico. Geol. Soc. Am. Bull. 93, 1232-1241. DOI: https://doi.org/10.1130/0016-7606(1982)93<1232:KDYRRA>2.0.CO;2
NIETO, O. J., A. L. DELGADO and P. E. DAMON, 1985. Geochronologic, petrologic and structural data related to large morphologic features between the Sierra Madre Occidental and the Mexican Volcanic Belt. Geofísica Internacional, 24, 4, 623-663. DOI: https://doi.org/10.22201/igeof.00167169p.1985.24.4.2181
ROMERO G., J. C. y V. P. REYES, 1979. Resultados preliminares de la exploración geoeléctrica en el área de Cerritos Colorados-La Azufrera de la zona geotérmica de La Primavera, Jal., Informe inédito 7-79, CFE (México).
RUTTER, N. W. (Ed.) 1984. Dating Methods of Pleistocene Deposits and Their Problems. Geoscience Canada Rep., Ser. 2.
URRUTIA-FUCUGAUCHI, J. y S. PAL, 1975. Procedimientos de campo en investigaciones paleomagnéticas. Anales de Instituto de Geofísica, UNAM, 21, 109-125.
URRUTIA-FUCUGAUCHI, J., 1977. Algunos métodos estadísticos usados en paleomagnetismo. Anales del Instituto de Geofísica, UNAM, 22-23, 87-98.
URRUTIA-FUCUGAUCHI, J., 1978. Análisis de estabilidad de la magnetización remanente natural. Anales del Instituto de Geofísica, UNAM, 24, 117-146.
URRUTIA-FUCUGAUCHI, J., 1979. Significado y utilización de magnetizaciones de múltiples fases. Anales del Instituto de Geofísica, UNAM, 25, 101-123.
URRUTIA-FUCUGAUCHI, J., D. J. MORAN ZENTENO y J. O. CAMPOS ENRIQUEZ, 1985. Paleomagnetismo, magnetoestratigrafía y magnetismo de rocas en el campo geotérmico de Los Azufres, Michoacán. Informe 05-85, CFE (México).
VENEGAS S., S., J. J. HERRERA F. y R. MACIEL F., 1985. Algunas características de la faja volcánica mexicana y de sus recursos geotérmicos. Geofísica Internacional, 24, 1, 47-81. DOI: https://doi.org/10.22201/igeof.00167169p.1985.24.1.1065
WALKER, G. P. L., J. V. WRIGHT, B. J. CLOUGH and B. BOOTH, 1981. Pyroclastic geology of the rhyolitic volcano of La Primavera, Mexico. Geol. Rundsch. 70, 1100-1118. DOI: https://doi.org/10.1007/BF01820184
WATKINS, N. D., B. M. GUNN, A. D. BAKSI, A. D., D. YORK and J. ADE-HALL, 1971. Paleomagnetism, geochemistry and potassium-argon ages of the Río Grande de Santiago volcanics, Central Mexico. Geol. Soc. Am. Bull., 82, 1955-1968. DOI: https://doi.org/10.1130/0016-7606(1971)82[1955:PGAPAO]2.0.CO;2