Northeastern Morocco is made up of several units belonging to the Alpine belt and its foreland. Miocene to plio-quaternary volcanic rocks with variable mineralogy and geochemistry dominate the geology of this region. ...Northeastern Morocco is made up of several units belonging to the Alpine belt and its foreland. Miocene to plio-quaternary volcanic rocks with variable mineralogy and geochemistry dominate the geology of this region. The presence of active faults in different directions explains the high tectonic instability and the high frequency of earthquakes. This study contributes to the effort of understanding the geothermal potential of the Northeast of Morocco. Heat source and permeability are both key factors in the geothermal process. Indeed, lineaments analysis constrains the structures and their directions and indicates severely faulted zones, which are the most promising areas for geothermal exploration. For this purpose, we used Landsat data combined with geological and structural maps available in this region. Different image processing techniques were applied including band ratio (6/2) and directional filters. To validate the results, we conducted a comparative study between linear structures, available geological data, and previous studies. Results of the automatic extraction method of lineaments from Landsat 8 OLI/TIRS indicate three main lineament systems: 1) a NE-SW system ranging from N40 to N70;2) an N-S system ranging from N10 to N45;3) an EW to WNW-ESE systems ranging from N80 to N120. Most of lineaments extracted are localized in Kebdana, Amejjaou, Nador and Melilla regions. Compared to previous studies, the NE-SW system is consistent with an extensive period (Tortonian to Pliocene);the NW-SE system is consistent with the last compressive episode (Pliocene);the N-S system is consistent with the first compressive period (Late/End Tortonian).展开更多
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 tech...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.展开更多
文摘Northeastern Morocco is made up of several units belonging to the Alpine belt and its foreland. Miocene to plio-quaternary volcanic rocks with variable mineralogy and geochemistry dominate the geology of this region. The presence of active faults in different directions explains the high tectonic instability and the high frequency of earthquakes. This study contributes to the effort of understanding the geothermal potential of the Northeast of Morocco. Heat source and permeability are both key factors in the geothermal process. Indeed, lineaments analysis constrains the structures and their directions and indicates severely faulted zones, which are the most promising areas for geothermal exploration. For this purpose, we used Landsat data combined with geological and structural maps available in this region. Different image processing techniques were applied including band ratio (6/2) and directional filters. To validate the results, we conducted a comparative study between linear structures, available geological data, and previous studies. Results of the automatic extraction method of lineaments from Landsat 8 OLI/TIRS indicate three main lineament systems: 1) a NE-SW system ranging from N40 to N70;2) an N-S system ranging from N10 to N45;3) an EW to WNW-ESE systems ranging from N80 to N120. Most of lineaments extracted are localized in Kebdana, Amejjaou, Nador and Melilla regions. Compared to previous studies, the NE-SW system is consistent with an extensive period (Tortonian to Pliocene);the NW-SE system is consistent with the last compressive episode (Pliocene);the N-S system is consistent with the first compressive period (Late/End Tortonian).
文摘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.
