Datación paleomagnética de la parte sur del dique de Messejana- Plasencia
- A. Palencia 4
- M.L. Osete 4
- R. Vegas 3
- V. Villasante 4
- P. Silva 2
- P.E. Fonseca 1
- J.M. Miranda 2
- 1 GeoFCUL e LATTEX, Edif. C2 piso 5, Campo Grande, 1700 Lisboa. Portugal.
- 2 Centro de Geofísica da Universidade de Lisboa. Ruada Escola Politécnica, 58. 1269-102 Lisboa. Portugal.
- 3 Departamento Geodinámica, Facultad de C. Geológicas, Universidad Complutense, 28040 Madrid, España.
- 4 Departamento de Geofísica, Facultad de C. Físicas, Universidad Complutense, 28040 Madrid, España.
ISSN: 1576-5172
Año de publicación: 2000
Título del ejemplar: V Congreso Geológico de España (Alicante, 10-14 julio 2000)
Número: 1
Páginas: 121-123
Tipo: Artículo
Otras publicaciones en: Geotemas (Madrid)
Resumen
A Paleomagnetic investigation of 11 sites across the southern part of Messejana-Plasencia dike has been carried out. The magnetic behaviour o f pilot samples indicates that thermal demagnetisation is more effective than alternating field cleaning (AF) in isolating the Characteristic Remanent Magnetisation (ChRM). Therefore thermal demagnetisation was systematically used with the remaining samples. The ChRM is well grouped. Most sites exhibit normal polarities with the exception of two sites, where samples with reversed polarities have been observed. The paleomagnetic pole derived from the sites is well defined, with values of Plat=72.5, Plong=243.7 and Al)€;=6.0. This coincides with the pole calculated in a previous investigation (Schott et at. 1981) o f the dike. It is also in agreement with Toarcian poles from the Iberian Range (Osete et al. 2000) and statistically different from the Oxfordian Pole obtained in the same region. Previous radiometric studies suggested that the age o f dike intrusion is 160-200Ma. Paleomagnetic data indicates that the age o f intrusion can be constrained between 180-200Ma.