Eigen-6c4 Gravity and Alos Palsar Radar Data Integration for Delineating Geological Lineaments in North Ghadames Basin, NW Libya

IntroductionThe ambiguity regarding the geological interpretation has the potential to be significantly decreased with the use of remote sensing, geophysical data, and the history of geology.

Aims

The objective of this work is to delineate geological lineaments and faults using EIGEN-6C4 satellite gravity and ALOS PALSAR radar data in the north Ghadames basin, of northwest Libya.

Methods

The satellite gravity dataset of the study region was used to perform a complete Bouguer anomaly map of the study area to start the gravity interpretation. Then different filters were performed on the gravity dataset, such as the total horizontal gradient (THG), CET grid analysis, 3-dimensional Euler solution (ED), and a tilt derivative (TDR) using the commercial Oasis Montaj programme. The techniques of edge identification (THG, TDR, and also CET grid analysis) are utilised for locating and identifying the boundaries or edges of geological structures that contribute to gravity anomalies. The 3-dimensional Euler solution, in conjunction with the TDR method, is employed to precisely figure out the positions and estimated depths associated with subsurface sources. Radiometric calibration, speckle filtering, and geometric correction were applied to preprocess the ALOS PALSAR L 1.1 image via the Sentinel Application Platform (SNAP) software. For automatic extraction, the PCI Geomatica software's LINE module was applied.

Results

The gravity data results indicate that the main trends of the identified geological lineaments are oriented in the North-South, East-West, Northwest-Southeast, and North-Northwest to South-Southeast directions. Furthermore, the depths of the sources observed underneath the study region differ from 250 m to 2750 m. The orientation of extracted lineaments from the ALOS PALSAR L1.1 images, specifically the horizontal-horizontal as well as horizontal-vertical polarisation images, predominantly have orientations in the north-south, north-northeast to south-southwest, east-west, north-northwest to south-southeast, and northeast-southwest directions within the study area.

Conclusion

All these findings of lineaments are associated with the tectonic features of the area. Consequently, identifying these lineaments/faults is important to reduce the ambiguity of geological interpretation and provide more information on the dominant trends for future exploration activities in the study region.