The Taguelft syncline (Moroccan Central High Atlas) an example of extension-related mini-basin evidenced by paleomagnetic data

Abstract

The purpose of this work is to use paleomagnetic data to determine the tectonic evolution of the inverted High Atlas basin in the area of the Taguelft syncline. This syncline shows two well defined rock types of Jurassic age: marly limestones and red beds, and therefore provides the opportunity of comparing paleomagnetic results from rocks with different magnetic mineralogy. Forty-three sites, in an area of 250 km2 were the subject of a paleomagnetic and rock magnetic study. Both lithologies display a stable interfolding remagnetization, alternatively carried by magnetite in marly-limestones and hematite in red beds. The small circle intersections (SCI) method applied separately to the mean directions of the two rock types indicate a synchronous record of remagnetization, that can be dated as Mid-Cretaceous (100 Ma) by comparing the direction (SCI) with the expected directions obtained from the Global Apparent Wander Path in African coordinates. Small circle techniques were used to reconstruct the syncline geometry at the remagnetization time. Paleodips quantification reveals that this area behaved as an extension-related mini-basin, with strong control by salt migration, before and during the sedimentation of Bathonian red beds.