Structural analysis, tectonic fracturing modeling, and kinematic evolution along the South Atlas Fault at the northern border of the Tinghir-Errachidia-Boudenib basin (Pre-African Trough, Morocco)

Abstract

The structural evolution of the High Atlas orogenic belt is characterized by the formation of the thrust propagation folds. The exploration and understanding of the southern central-eastern High Atlas orogenic wedge system are still in their infancy. The significance of the growth of the Tinghir-Errachidia-Boudenib foreland basin (TEB) is underestimated due to limited constraints on surface structural styles and kinematics analysis, as well as insufficient surface data. This question is addressed by using several multi-sources and multi-scale data including a geological map constrained from fieldwork and kinematic analysis, combined with subsurface magnetic data. The integration and analysis of these data provided a comprehensive understanding tectonic fracturing model and reconstruct the kinematic evolution of the northern border of the TEB basin. Analysis of surface and subsurface data identify E−, ENE-to WNW- trending Jbel Tisdar and Jbel Rhouir anticlines interpreted as a fault-propagation fold. Magnetic investigations show a positive anomaly superposed on the hinge of the Jbel Tisdar and the Jbel Rhouir anticlines indicating a Triassic and/or Paleozoic uplifted magnetic materials. Along the southern Atlas margin, brittle tectonic is represented by E−to ENE-reverse faults with a small dextral strike-slip component and NNE-to NE-trending strike-slip faults with a reverse component and associated with NW- trending ones. Fracturing mechanism fault-propagation fold highlights three fracture sets: (i) syn-folding E−trending axial fractures; (ii) syn-folding NW- trending transverse fractures and (iii) late-folding NE-trending fractures. Fault kinematics analyses provide a transpressional tectonic regime, responsible for the structuring (folding, faulting, fracturing) of the Jbel Tisdar and the Jbel Rhouir fault-propagation fold, developed in response to Alpine compressional inversion of the central-eastern High Atlas belt.