USING REMOTE SENSING AND GIS TECHNIQUES IN DETECTING THE ORIGIN OF UMM CHAIMIN DEPRESSION, WEST IRAQ

Abstract

The Umm Chaimin Depression is the most outstanding and conspicuous geomorphic feature in the southwestern part of the Iraqi Western Desert. It is an almost circular depression with 2.9 Km diameter and 28 m depth. The exposed carbonate rocks on the surface and in depth belong to Ratga Formation (Eocene) that forms flat area and the beds dip off the depression. Therefore, the depression is invisible unless from a distance of few tens of meters, although a lot of rock fragments of different sizes occur near the rims.Previously, different concepts are recorded about the origin of the depression. These are meteoritic impact, volcanic origin, gas explosion and karst origin. In this study, different geological, geophysical and remote sensing data with GIS techniques are used to indicate the origin of the depression. Eighteen different parameters are studied and used for comparing the present characteristics of the Umm Chaimin Depression with those of aforementioned four different origins. Majority of the parameters fit with those of karst origin.