Kinematic Evolution Model of Fault-Related Anticline based on the Study of the Striated Pebbles of the Related Growth-Strata: A Case Study of the Es Satah Anticline in Southern Tunisian Atlas, Tunisia

摘要

Through several stations on the forelimb of the Es Satah anticline belonging to Gafsa basin part of the southern Tunisian Atlas, an analysis of the striations encountered on the pebbles surfaces in the conglomerates of the growth-strata shows a remarkable variation; vertically and laterally from one station to another. Taking into account of the simple shear deformation, field observations have revealed several indexes of the flexural flow. Both of the tectonic and micro-tectonic studies in the Gafsa basin have shown the trending shortening (sigma 1) ranging from 150 degrees to 180 degrees N. Therefore, the striation azimuths were determined according to three profiles, I, II and III. These profile stretch from the NE to the SW on the forelimb of Es Satah anticline which displays a variation ranging from 167 degrees to 138 degrees N, from 165 degrees to 147 degrees N and from 154 degrees to 138 degrees N, respectively. Since these variations are incoherent with the regional shortening (sigma 1) direction, it allows us to discard any evidence of a direct relationship between the regional trending shortening (sigma 1) and the striation azimuths of the pebbles surfaces of growth-strata and to speculate a possible direct correlation between those variations and the kinematic evolution of the Es Satah anticline. Accordingly, we have suggested a conceptual model which paved the way to follow step by step the anterior stages of the deformation and identify the different palaeo-periclinal limits of the Es Satah anticline.