Affiliation:
1. Iraq Geological Survey (GEOSURV), Department of Geology, Geophysics Division, Baghdad, Iraq. (corresponding author)
2. University of Leeds, School of Earth and Environment, Leeds, UK.
3. University of Baghdad, College of Science, Department of Geology, Baghdad, Iraq.
Abstract
The Southern Desert (SD) of Iraq is located in the southernmost region of Iraq and is tectonically located on the stable part (proximal domain) of the Arabian Platform. The area is characterized by a considerable thickness of nonmagnetic Phanerozoic sediments overlying a reworked Proterozoic basement. Due to the intense nature of the karst near-surface geology, the basement has neither been seismically imaged nor drilled. In such situations, potential field (gravity and magnetic) exploration methods can often help to identify and map the deep structure of the basement. Here, the aeromagnetic field data, which cover all of the SD, are used to determine the structure and approximate depth of the basement. We use the combined results of the tilt derivative and phase preserving dynamic range compression (PPDRC) methods to qualitatively delineate the main basement structures and then use the source parameter imaging (SPI), tilt-depth (TD), and finite SPI (FSPI) methods to determine the basement depths. The qualitative interpretation of the tilt derivative and PPDRC methods identifies three north–south to northeast–southwest-trending linear negative anomalies that could represent extensional grabens in the basement surface. These grabens divide the basement into three blocks: the northwest block, the central block, and the southeast block. The magnetic anomalies over the basement blocks suggest that the northwest and central blocks are cut by a set of north–south to north-northwest–south-southeast and northeast–southwest faults. Depth estimation methods over the uplifted blocks have minimum depths between 4 and 5 km, whereas, over the graben, the depths range from 7 km to in excess of 12 km. The FSPI method, unlike the SPI and TD methods that use an infinite depth source body, gives depths generally deeper by up to 1.1 km if the assumed Curie-point depth is 21 km. A more realistic Curie-point depth of 32 km is used in the final interpretation model. These inferred basement blocks, grabens, and subbasin structures agree in general with the regional structures associated with the Arabian Peninsula and could provide an important framework for developing future hydrocarbon exploration strategies of the SD.
Publisher
Society of Exploration Geophysicists
Reference48 articles.
1. Magnetometric Identification of Sub-basins for Hydrocarbon Potentialities in Qattara Ridge, North Western Desert, Egypt
2. Structural mapping of the west central Arabian Shield (Saudi Arabia) using downward continued magnetic data
3. Abnormality of geothermal gradients in Iraqi western desert inferred from borehole temperatures
4. Al-Bahadily, H., 2022, Evolution the geological view of the Southern Desert of Iraq using gravity and magnetic data: Ph.D. dissertation, University of Baghdad.
5. Al-Bahadily, H., A. Al-Rahim, and A. Long, 2024, Postulated Precambrian basement of the Iraq Southern Desert: A new look utilizing magnetic data, in A. Çiner, ed. Recent Research on Geotechnical Engineering, Remote Sensing, Geophysics and Earthquake Seismology: Springer.