CHARACTERIZATION OF SUBSURFACE STRUCTURES USING GRAVITY DATA IN THE NE TAOUDENI BASIN (EL HANK SUB-BASIN, SW ALGERIA)

The Taoudeni Basin is recognized as largest sedimentary basin in Africa, covering a portion of the West African Craton and exhibiting episodic sedimentation since the Proterozoic era. Despite its economic enormous potential, the basin remains significantly underexplored. This paper focuses on the N-E Taoudeni Basin part (El-Hank sub-basin) in southwestern Algeria. In this study, gravity data were analyzed in conjunction with geological data to investigate the upper crustal structure of the study area. Various techniques were employed, including bandpass filter methods for constructing gravity anomaly maps, match filtering to create residual anomalies, and edge source detection methods such as Analytic Signal (AS), Theta Angle Map (TM), Normalized Horizontal Tilt (TDX), and Tilt Angle (TA). Additionally, the depths to major density contrasts were determined using 2D power spectrum analysis and 3D inversion of gravity data with Growth 3.0 code. Residual gravity anomalies and edge source detection maps reveal predominant lineaments in NNW-SSE and NNE-SSW directions, with secondary trends in NE-SW, NW-SE, and E-W directions. Furthermore, the 3D inversion results show variations in sedimentary sequence thickness, ranging from 3 km to 6 km in the central part of the basin, while basement outcrops are observed to the north. Horizontal sections depict dense geological structures extending up to 14000 meters in depth, indicating the presence of volcano-sedimentary formations, magmatic intrusions, and Chegga magnetics. Low-density anomalies imply the existence of sedimentary deposits and acidic volcanic materials. Research highlights basin's geological complexity and calls for thorough investigation to understand its history and characterize its structure for future exploration.