Abstract:
Carbonate karstic formations outcrop in about 23% of the Zagros Region. Seventy-two karstic anticlines were selected to study regional flow. Based on geometry of the anticline and outflow position, a conceptual model is presented for delineation of flow direction, at least within Zagros. The anticlines were divided into two main groups based on presence or absence of hydraulic connectivity between the limbs. The geological and tectonic settings are the main controlling factors within these two groups. Sixty-four out of the seventy-two anticlines showed no hydraulic connectivity between their limbs. Each group was further classified into four subgroups based on the location of the discharge zones, namely one or both plunge apex noses, limb, traversing river, or a combination of plunge apexes, limbs and river. The discharge zones may be located in the adjacent or in the successive anticlines. The discharge zones are mainly controlled by local base level. In most of the cases having no hydraulic connection between the limbs, the direction of flow is initially along the bedding plane dip and finally parallel to the strike at the foot of the anticline. In most of the cases having connections between two limbs, the regional directions of flow, in the connected part, are opposite from the direction of bedding plane dip and eventually parallel to strike. The results show that the primary controlling factors of regional flow are the anticlinal structure of aquifers and geometry of the bedrock.