INTEGRATION OF GRAVIMETRIC AND FIELD GEOLOGICAL INVESTIGATIONS FOR STUDYING TECTONICS AND GEODYNAMICS IN THE CENTRAL PART OF THE ATLAS INTRACONTINENTAL FOLD SYSTEM (AZILAL PROVINCE, MOROCCO)

Abstract

The Azilal Province in the Central High Atlas (Morocco) provides an excellent natural laboratory to investigate how inherited basement structures and Triassic evaporitic décollements interact to control tectonic architecture during intraplate mountain building. Here we integrate gravity-based structural mapping with field structural observations to characterize the dominant structural trends and their crustal significance. We analyze the Bouguer anomaly data from the WGM2012 global gravity model and apply the horizontal gradient magnitude filtration and automatic lineament extraction using the CET grid analysis. The resulting lineament network highlights two principal fault systems trending NE-SW and NW-SE, with subordinate E-W to ENE-WSW lineaments. Euler deconvolution solutions cluster along these trends and indicate source depths of several kilometers, supporting the interpretation of a crustal-scale structural grain. Field observations (fold geometries, fault orientations, and kinematic indicators) corroborate the gravity-derived framework and show that both NE-SW and NW-SE structural families are expressed at the surface. In particular, a major NE-striking normal fault affecting the Toarcian-Bajocian succession records the persistence of inherited extensional discontinuities that influenced basin configuration and subsequent deformation. The spatial association between mapped diapiric belts and gravity-derived structural trends further suggests that salt mobilization was guided by pre-existing fault corridors and facilitated by evaporitic detachments. Overall, the combined geophysical and geological datasets indicate that basement inheritance and evaporite-controlled decoupling exert a first-order control on deformation style, basin segmentation and diapir localization in the Azilal segment, refining regional models for the evolution of the Central High Atlas.