Artículo
Abstract:
Measurements are described of the directions of magnetization of 101 samples from six lava flows, one dyke and redbeds from the Lower Cretaceous Sierra de los Cóndores Group, Argentina. The magnetic remanence of the lowest basaltic flow (Embalse Río Tercero Formation) was unstable. Primary remanent magnetizations of the other five lava flows, the dyke and redbeds (Vulcanitas Cerro Colorado Formation) were isolated after detailed A.C. and thermal cleaning; all these units have reversed magnetization. On the basis of the mean direction, referred to the bedding, of cleaned remanent magnetization of each unit a virtual geomagnetic pole is computed; the mean of these virtual geomagnetic poles, SAK2, is: 14°E 81°S, α95 = 13°; we think that SAK2 is a geomagnetic pole. The position of the pole for the Vulcanitas Cerro Colorado Formation (118.5 ± 6 my) is reasonably close to the Serra Geral Formation pole (115-125 my); this supports the interpretation that South America and Africa were separated in Lower Cretaceous time and suggests that the earth magnetic field was, on average, similar to that of a geocentric dipole in the Lower Cretaceous. The reversed remanent magnetization and the K-Ar age (118.5 ± 6 my) of the Vulcanitas Cerro Colorado Formation define the existence of a previously unrecognized period of reversed polarity at the Lower Cretaceous. © 1972.
Registro:
| Documento: | Artículo |
| Título: | Palaeomagnetism of the Lower Cretaceous Vulcanitas Cerro Colorado Formation of the Sierra de los Cóndores Group province of Córdoba, Argentina |
| Autor: | Valencio, D.A. |
| Filiación: | Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Nuñez, Buenos Aires, Argentina |
| Año: | 1972 |
| Volumen: | 16 |
| Número: | 3 |
| Página de inicio: | 370 |
| Página de fin: | 378 |
| DOI: | http://dx.doi.org/10.1016/0012-821X(72)90154-9 |
| Título revista: | Earth and Planetary Science Letters |
| Título revista abreviado: | Earth Plan. Sci. Lett. |
| ISSN: | 0012821X |
| Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0012821X_v16_n3_p370_Valencio |
Referencias:
- Valencio, Vilas, Palaeomagnetism of Late Palaeozoic and Early Mesozoic rocks of South America (1972) Earth Planet. Sci. Letters, 15, p. 75
- Valencio, Vilas, Palaeomagnetism of some Middle Jurassic lavas from South-east Argentina (1970) Nature, 225, p. 262
- Creer, Palaeomagnetism of the Serra Geral Formation (1962) Geophysical Journal, 7, p. 1. , Royal Astronomical Society
- Creer, A palaeomagnetic survey of South American rocks formations. Philosophical Transaction (1970) Royal Soc., 167, p. 457. , London
- W.D. MacDonald and N.D. Opdyke, Tectonic rotations suggested by palaeomagnetic results from Northern Colombia, South America, to be published in J. Geophys. Res; Gordillo, Lencinas, Geología y petrología del extremo norte de la Sierra de los Cóndores, Córdoba (1967) Boletín de la Academia Nacional de Ciencias, 46, p. 73
- R.R. Gonzalez and A. Toselli, La efusividad del Mesozoico Argentino y su relacíon conáreas sudamericanas, to be published in Anales Sociedad Brasileira de Geologia; Fisher, Dispersion on a sphere (1953) Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 217, p. 295. , Sect. A
- Briden, A new palaeomagnetic result from the Lower Cretaceous of East-Central Africa (1967) Geophysical Journal of the Royal Astronomical Society, 12, p. 375
- McElhinny, Burek, Palaeomagnetic Stratigraphy (1971) Nature, 232, p. 98
- K.M. Creer, Mesozoic Palaeomagnetic Reversal Column, to be published in Nature
Citas:
---------- APA ----------
(1972) . Palaeomagnetism of the Lower Cretaceous Vulcanitas Cerro Colorado Formation of the Sierra de los Cóndores Group province of Córdoba, Argentina. Earth and Planetary Science Letters, 16(3), 370-378.http://dx.doi.org/10.1016/0012-821X(72)90154-9
---------- CHICAGO ----------
Valencio, D.A. "Palaeomagnetism of the Lower Cretaceous Vulcanitas Cerro Colorado Formation of the Sierra de los Cóndores Group province of Córdoba, Argentina" . Earth and Planetary Science Letters 16, no. 3 (1972) : 370-378.http://dx.doi.org/10.1016/0012-821X(72)90154-9
---------- MLA ----------
Valencio, D.A. "Palaeomagnetism of the Lower Cretaceous Vulcanitas Cerro Colorado Formation of the Sierra de los Cóndores Group province of Córdoba, Argentina" . Earth and Planetary Science Letters, vol. 16, no. 3, 1972, pp. 370-378.http://dx.doi.org/10.1016/0012-821X(72)90154-9
---------- VANCOUVER ----------
Valencio, D.A. Palaeomagnetism of the Lower Cretaceous Vulcanitas Cerro Colorado Formation of the Sierra de los Cóndores Group province of Córdoba, Argentina. Earth Plan. Sci. Lett. 1972;16(3):370-378.http://dx.doi.org/10.1016/0012-821X(72)90154-9
