Magnetostratigraphy and palæontology of the continental Middle Miocene of the Aït Kandoula Basin, Morocco

Abstract

The Aït Kandoula Basin is one of richest known Miocene mammal localities in the south of the High-Atlas. Research of the fossiliferous levels undertaken in the past several years in this basin has yielded some micromammal associations and a limited quantity of large mammals. A magnetostratigraphic study has been carried out on a Middle Miocene fluviatile/lacustrine deposit of the Aït Kandoula Basin. Fifty-five samples in 48 different stratigraphic levels were collected from a thickness of 206 m of the section. These palæomagnetic samples were analysed, and rock magnetic experiments show that the natural remanence magnetisation generally results from the presence of magnetite or hematite. The Azdal section that has been sampled displays three reversed and four normal polarities. The correlation to the geomagnetic polarity time scale relies on the biostratigraphical data previously proposed for the fauna found in the levels of the same section. The proposed correlation puts the Azdal section in the Chron C5An.2n and in the upper part of C5AAn. This suggests sedimentation rates of 25.6 cm ka −1. The Beni-Mellal fossiliferous layer is the first one known in the Middle Miocene of North Africa. This correlation makes it possible to allow an age of 13 My for the Beni-Mellal layer whose fauna is identical to level 1 of the Azdal section.