Alpine remagnetization and tectonic rotations in the French Pyrenees

K. M. Storetvedt, E. Márton, M. C. Abranches, K. Rother

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

A palaeomagnetic study of the 100 to 90 m.y. old alkaline igneous rocks of the French Pyrenees has in part revealed large between-site scatter caused by highly variable declination. Magnetomineralogical evidence suggests that the original titano-magnetite has undergone variable low-temperature oxidation through martitization and maghemitization processes, suggesting that the rocks have been remagnetized. When viewed in the context of the Upper Cretaceous-Lower Tertiary inclination pattern based on Portuguese palaeomagnetic data, it is concluded that the rocks most likely acquired their present magnetization during early Campanian-Maastrichtian time, i.e. 20-30 m.y. after their original cooling. On the other hand, this magnetization postdates a major phase of late Cretaceous compressive deformation. Subsequent strike-slip movement along the Pyrenean zone in the Lower Tertiary led to variable rotation of cover units along the orogenic belt, producing the inconsistent palaeomagnetic declination picture presently observed. It is concluded that the geological history of the alkaline rocks of the French Pyrenees, from the magmatic stage to the subsequent events of remagnetization and tectonic deformation, is strongly associated with the Alpine-age rotational instability of Iberia. The principal kinematic history of the Peninsula comprised ca. 40°counterclockwise rotation (relative to Europe) during Cenomanian-Turonian time (100-90 m.y. ago) followed by ca. 70°clockwise rotation in the early Campanian (ca. 75 m.y. ago).

Original languageEnglish
Pages (from-to)658-674
Number of pages17
JournalGeologische Rundschau
Volume87
Issue number4
DOIs
Publication statusPublished - Mar 1 1999

Keywords

  • French Pyrenees
  • Remagnetization
  • Rotations of Iberia
  • Tectonomagnetic events
  • Upper Cretaceous rocks

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

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