Paleomagnetism of the Central High Atlas.The Widespread Cretaceous Remagnetization and Structural Implications

  1. Juan J. Villalaín
  2. Pablo Calvín
  3. Irene Falcón
  4. Sara Torres-López
  5. María F. Bógalo
  6. Bennacer Moussaid
  7. Vicente C. Ruiz- Martínez
  8. Elisa M. Sánchez
Libro:
Tectonic evolution of the Moroccan High Atlas :: a paleomagnetic perspective : magnetic techniques (anisotropy of magnetic susceptibility and paleomagnetism) applied to the understanding of the evolution of an intra-plate mountain chain
  1. Casas Sainz, Antonio M. (coord.)
  2. Calvín Ballester, Pablo (coord.)
  3. Román Berdiel, María Teresa (coord.)
  4. Villalaín, J. J (coord.)

Editorial: Springer Nature Switzerland AG

ISBN: 9783031166921

Año de publicación: 2023

Páginas: 285-346

Tipo: Capítulo de Libro

DOI: 10.1007/978-3-031-16693-8_4 DIALNET GOOGLE SCHOLAR

Resumen

Previous works developed by our research group have shown that the Jurassic rocks of the Central high Atlas (CHA) have recorded a Cretaceous widespread remagnetization. In this chapter, a high resolution paleomagnetic study on 424 new paleomagnetic sites in Mesozoic units of CHA is presented. This work provides new information about the Cretaceous magnetic overprint of the CHA, as well as contributes to the knowledge of the geodynamic evolution of the Atlas. The new results confirm the extent of remagnetization throughout the study area (10,000 km2) in both carbonates (carried by magnetite) and red beds (carried by hematite) showing systematically normal polarity and an inter-folding acquisition. By using small circle techniques, the remagnetization direction (n = 531, Dec = 335.4°, Inc = 42.7° for carbonates and n = 62, Dec = 344.4°, Inc = 41.7° for red beds) and the age of acquisition (100 Ma ± 5 Ma for limestones) have been determined. The remagnetization properties in the carbonates and their paleomagnetic direction are maintained throughout the studied area and the different stratigraphic units. The small but statistically significant difference between the directions of remagnetization in carbonates and red beds suggests a delay in the acquisition in red beds. Remagnetization directions have been restored using small circle techniques, allowing to generate a set of 593 paleo-dips of the beds at 100 Ma. This valuable information has been used in Chap. “Kinematics of Structures and Basin Evolution in the Central High Atlas. Constraints from AMS and Paleomagnetic Data” to elaborate palinspastic reconstructions and to study the evolution of the different structures of the CHA. For this purpose, a new diagram (paleo-dip evolution diagram, PED) is here proposed.

Fuente de los datos: Dialnet