Dr. Badreldin A.H. Hassan
Remote Sensing and Seismological Sciences, Authority, National Center for Research, Khartoum, Sudan
Prof. Khalid A. Elsayed Zeinelabdein
Department of Geology, Faculty of Petroleum and Minerals, Al Neelain University, Khartoum, Sudan
Purpose: This research is focused on the structural controls on gold mineralisation in the central North Darfur State, west Sudan. The region is rich in its mineral resources; nevertheless, it lacks detailed geological studies for better understanding its potentiality. In addition to some security problems, its accessibility difficulties make traditional field-based geological studies impossible. Accordingly, the main objectives of the present work are to utilise the means of remote sensing and GIS techniques, in addition to limited fieldwork, to determine structural controls on gold mineralisation through individual and integrated interpretations of multispectral data, and to develop a regional model of the structural geology and gold occurrences in the study area.
Methodology: The study area comprises various geological units ranging from a Precambrian metamorphic complex (which has been extensively
weathered and eroded), to Pleistocene rift filling unconsolidated sediments, volcanics, and several base metal occurrences. Landsat 7 ETM+ images were used, digitally processed and enhanced to recognise the hydrothermal alteration zoning that constitutes a significant remote sensing guide to gold mineralisation.
Findings: Band ratio images disclosed the presence of several prospects that are now major gold deposits at Kassab, Umm Gussa, Hashaba, Alagab, Gabr Elghnam, Kulkul, Dabatuga and Ortow areas. The geophysical data have also proved to be a valuable tool to understand the surface and subsurface structures. The structural orientation analysis has revealed four dominant lineament orientations in the area: N-S, E-W, NW-SE and NE-SW, which are consistent with the regional tectonics. The control on gold was assessed in terms of lithological as well as in terms of structural elements. Most of the gold occurrences were found variably in shear zones and sutures. The prominent NE trending fault, identified from the satellite gravity data, has apparently controlled the distribution of gold occurrence of the study area. Furthermore, most of the gold occurrences of the study area have shown an intimate association with interpreted high gravity zones and quartz veins.
Practical implications: The results of the present work will have important implications for future gold exploration.
Keywords: remote sensing, mineral exploration, gold mineralisation; North Darfur State.