Application Of Remote Sensing Technique To The Gold Exploration In Wadi Halfa District, Nubia Shied Of North Africa

The Nubia shield, located in the northern Africa, is a very promising but poorly-understood gold district. The Wadi Haifa district, located in the nothern Sudan, is the west part of Nubia shied. Remote sensing technique can be used to guide exploration in this area because of its arid condition and well-outcropped basement rocks.This study utilized multispectral remote sensing data, ETM+and ASTER, to extract lithologic structure and gold-related alteration information, then took the field check, and made comprehensive analysis of multi-source geo-information, finally made the exploration prediction.The study achieved the following knowledge and results:1.Through correction and mosaic work of remote sensing image, it could get the basic data. After relevant analysis of band, ETM+7,4,1was choosed to do the RGB combination of synthetic image which is the base map for visual interpretation. The methods of mask and high-end cutting are used to eliminate the interference factors which influence alteration information extraction.2.Through remote sensing interpretation, the paper divided lithology distribution and extracted main linear-annular structure information. Based on statisticaly analyzing the linear structures on the remote image, the NE linear structure was defined as the main tectonic framework.3. The method of principal component analysis was used to extract the iron altered information and hydroxyl mineralized alterd information. The results show that the distribution of alteration anomalies mainly controlling by the NE linear structures and circular rock.4. Based on the regional geological setting and ore-controlling factors,the paper integrated RS information, geological information and geochemical information, and created A, B and C three remote sensing promising areas.