Postulated Precambrian Basement of the Iraq Southern Desert: A New Look Utilizing Magnetic Data

The Iraq Southern Desert (S.D.) forms part of the stable shelf of the Arabian Platform, characterized by a thick and generally non-magnetic sedimentary cover that overlies the Precambrian and reworked Proterozoic basement. Airborne magnetic survey data are utilized to study the magnetic intra-basement and potentially more profound crustal variations in S.D. A third-order polynomial trend is removed that represents the regional field. The calculated residual field map shows high amplitude negative anomalies in some isolated locations. These anomalies lie on the northeast and north–south pervasive magnetic lineaments that favorably correlate to postulated tectonic extension. The lineament structure may reveal extensional tectonics that caused latterly differential subsidence within the shallow crust in a similar form to the well-known N–S trending Al-Ma'aniyah Depression in the extreme northwest of S.D. suggesting the occurrence of structural lows or proximal sub-basin systems. The residual magnetic anomalies are inseparably correlative to the structural lows. The reliable Euler deconvolution approach, which was recently proposed by Melo and Barbosa (2020), is applied to the total, regional, and residual magnetic products for depth estimation. The estimated depth, based on 38 selected anomalous areas on the residual map and assuming contact and dyke source geometries, is between 4 and 9 km.