Two types of Remote Sensing technology have been applied in this work Landsat 8 OLI/TIRS and Airborne Magnetism.
Hence, Remote Sensing method appears to be an important tool in the regional exploration of significant mineralisations, especially those resulting from hydrothermal alteration processes. Indeed, Remote sensing allows the identification of hydrothermal alteration processes, as well as lineaments and other valuable geologic information (Sabins, 1999). Besides, Geological Remote Sensing is considered as an important approach to identify minerals through spectral anomalies enhanced by specific techniques (Sultan, 1987 Kaufmann, 1988). Therefore, surveys undertaken from Remote Sensing data are less-time/money consuming and they may provide better results than any ground investigation when properly utilized.
Indeed, remotely sensed data have the advantage of providing a synoptic overview of very large areas, regardless of fieldwork constraints (limited study area, inaccessibility, climate conditions, natural disasters, political and social instabilities). Introduction Since decades, the advent of accurate Remote Sensing technology has had a great impact on the development of many countries, by improving knowledge and insight on strategic economic domains such as mining and oil exploration, agriculture, water survey, environment, urbanization and risk management, etc. Keywords : Landsat 8 magnetic data digital image processing structural mapping hydrothermal alteration mapping Poli group. New regional maps, providing a useful insight for further mining exploration, were obtained.
The generation of a target exploration map, via ArcGIS 10.4.1, was performed by the overlay of hydrothermal alteration mapping and structural mapping. Other directions include NE-SW/ENE-WSW and N-S. The resulting lineaments showed a predominant E-W trending direction, which suggests a major tectonic event prevailing in the area.
#DIGITAL IMAGE PROCESSING IN MINERAL EXPLORATION SOFTWARE#
Besides, the CET grid analysis tool (horizontal gradient) from Geosoft software 8.4 and the line algorithm (pan band 8) from Geomatica 2013 allowed the extraction of subsurface and surface lineaments respectively. Thus, a classification map emphasizing on mineral targets was obtained from the PCA map. The PCA map was shown to better illustrate hydrothermally altered areas than Band ratio’s. Based on reference band ratio combinations (Sultan’s and Kaufmann’s) and Crosta Technique (PCA analysis), hydrothermally altered minerals such as hydroxyl-bearing minerals and iron oxides were identified. Hence, the enhancement of both Landsat 8 and magnetic data was achieved via digital image processing (DIP) techniques such as Band rationing (BR), Principal Component Analysis (PCA), Horizontal gradient (HG) and lineament extraction algorithms. In this study, Landsat 8 OLI/TIRS coupled with magnetic data were used in order to realize a regional litho-structural mapping of hydrothermal alteration targets, required for mineral exploration. A geological based remote sensing study was carried out over the Poli group in Garoua (northern Cameroon), renowned for its hydrothermally occurring mineralizations (Gold and Uranium).
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