Characteristics of Heterogeneous Shimbar Karstic Systems in Southwest Iran

Abstract

The study area of intensely tectonised rocks consists mainly of Asmari limestone formation (lower Miocene) and the impermeable Pabdeh-Gurpi formation (Oligocene) which lies beneath the karstic rocks and acts as a hydraulic barrier. The bare sedimentary formations generally crop out and in situ soil and regolith cover the limestone rock. The main structural features are anticlines, faults and fractures. The structural (fault) and geomorphological (polje) features have dissected the study area into three distinct karstic systems. Understanding a karstic horizon requires understanding many aspects of the system. This includes structural analysis, geomorphologic, hydrodynamic and geochemical approaches. Therefore, to achieve the goal a comprehensive investigation including structural geology, geomorphology, hydrogeology and hydrochemistrywere carried out in the Shimbar karstic area. Hydrodynamic characteristics perceived at the outlet of major springs consisting of Dareh-e-Anari (DA), Abshekalo (AS) and Sarhoni (SH) revealed poorly and well developed karstified systems. The collected data indicated that ponor and polje are operating as underground transporting systems and convey drained water from two smaller reservoirs (AS and SH) into the main reservoir (DA). The principal aim of this research was to determine: 1) flow nature to make out prevail aquifer condition, 2) reservoirs dynamic potential and 3) chemical characteristics of the discontinuous aquifers.