Application of Remote Sensing and GIS in Mineral Alteration Mapping and Lineament Extraction Case of Oudiane Elkharoub (Requibat Shield, Northern of Mauritania)

The integration of remotely sensed data allowed the successful characterization of the mineral alteration zones of the Oudiane Elkharoub area in the Northeastern part of Reguibat Shield using image transformation techniques. As both chemical and geochemical analyses showed significant Au, Ag, Cu, Pb, Mn, Cr, Ni, Th and Y anomalies, it’s very interesting to apply the remote sensing and GIS in mineral resources mapping. The remote sensing is a direct adjunct to the field, lithologic and structural mapping, and more recently, GIS has played an important role in the study of mineralization areas. The integration of several evidential maps highlighted the plausible areas with high concentrations of chlorite, epidote, kaolinite, calcite, alunite, hematite, illite and sulfur among other key mineral alterations that reflect the intensity of hydrothermal effects and the probable sites of ore bodies. The methodological approach integrates geological information acquired from Aster and Landsat 8 OLI/TIRS (Operational Land Imager/Thermal InfraRed Sensor) images and a multi-criteria GIS analysis. The superimposition of various lineament and hydrothermal alteration maps and the consideration of precious and base metal indicators allowed the zoning of sites likely to contain mineral concentrations. Remote sensing becomes an important tool for locating mineral deposits in its own right, when the primary and secondary processes of mineralization result in the formation of spectral anomalies. Reconnaissance lithological mapping is usually the first step of mineral resource mapping. This is complimented with structural mapping, as mineral deposits usually occur along or adjacent to geologic structures, and alteration mapping, as mineral deposits are commonly associated with hydrothermal alteration of the surrounding rocks. Ground truthing and laboratory studies including XRD analysis were utilized to verify the results.

Mineralization and Exploration Perspectives in the Oudiane Elkharoub Zone, Birimian Domain, Reguibat Shield, Mauritania

The Oudiane Elkharoub Zone is one of the major areas of the Reguibat Shield due to its position in the extreme northeast of the Birimian formation (dated between 1.6 and 2.7 Ga) within the Reguibat Shield, coupled with its closeness to with the Archean Domain in the Shield’s southern portion and with the Taoudeni Basin to the east. The results of field mapping, together with chemical (Fire Assay) and XRF (fluorescence spectrometer X-ray) analyses, shows significant Au, Ag, Cu, Pb, Mn, Cr, Ni, Th and Y anomalies in samples taken from the Oudiane Elkharoub Zone. The results of those analyses will allow us to build a geochemistry maps for the anomalous metal for the study area, understand the relationships between different rock units and the mineralization and the mineralization control and their style, such as structural or lithological control. This context reflects a structural control of the Mineralization according to the conducted analyses and the observation on the field. The mineralization auriferous mainly hosted in quartz vein or quartz-carbonate vein with sulfide (pyrrhotite and pyrite) alteration.