Multisensor Satellite Data and Field Studies for Unravelling the Structural Evolution and Gold Metallogeny of the Gerf Ophiolitic Nappe, Eastern Desert, Egypt
The gold mineralization located in the southern Eastern Desert of Egypt mostly occurs in characteristic geologic and structural settings. The gold-bearing quartz veins and the alteration zones are confined to the ductile shear zones between the highly deformed ophiolitic blocks, sheared metavolcanic...
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MDPI AG
2023-04-01
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| Online Access: | https://www.mdpi.com/2072-4292/15/8/1974 |
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| author | Mohamed Abd El-Wahed Samir Kamh Mohamed Abu Anbar Basem Zoheir Mohamed Hamdy Abdelaziz Abdeldayem El Metwally Lebda Mohamed Attia |
| author_facet | Mohamed Abd El-Wahed Samir Kamh Mohamed Abu Anbar Basem Zoheir Mohamed Hamdy Abdelaziz Abdeldayem El Metwally Lebda Mohamed Attia |
| author_sort | Mohamed Abd El-Wahed |
| collection | DOAJ |
| description | The gold mineralization located in the southern Eastern Desert of Egypt mostly occurs in characteristic geologic and structural settings. The gold-bearing quartz veins and the alteration zones are confined to the ductile shear zones between the highly deformed ophiolitic blocks, sheared metavolcanics, and gabbro-diorite rocks. The present study attempts to integrate multisensor remotely sensed data, structural analysis, and field investigation in unraveling the geologic and structural controls of gold mineralization in the Gabal Gerf area. Multispectral optical sensors of Landsat-8 OLI/TIRS (L8) and Sentinel-2B (S2B) were processed to map the lithologic rock units in the study area. Image processing algorithms including false color composite (FCC), band ratio (BR), principal component analysis (PCA), minimum noise fraction (MNF), and Maximum Likelihood Classifier (MLC) were effective in producing a comprehensive geologic map of the area. The mafic index (MI) = (B13-0.9147) × (B10-1.4366) of ASTER (A) thermal bands and a combined band ratio of S2B and ASTER of (S2B3+A9)/(S2B12+A8) were dramatically successful in discriminating the ophiolitic assemblage, that are considered the favorable lithology for the gold mineralization. Three alteration zones of argillic, phyllic and propylitic were spatially recognized using the mineral indices and constrained energy minimization (CEM) approach to ASTER data. The datasets of ALSO PALSAR and Sentinel-1B were subjected to PCA and filtering to extract the lineaments and their spatial densities in the area. Furthermore, the structural analysis revealed that the area has been subjected to three main phases of deformation; (i) NE-SW convergence and sinistral transpression (D2); (ii) ~E-W far field compressional regime (D3), and (iii) extensional tectonics and terrane exhumation (D4). The gold-bearing quartz veins in several occurrences are controlled by D2 and D3 shear zones that cut heterogeneously deformed serpentinites, sheared metavolcanic rocks and gabbro-diorite intrusions. The information extracted from remotely sensed data, structural interpretation and fieldwork were used to produce a gold mineralization potential zones map which was verified by reference and field observations. The present study demonstrates the remote sensing capabilities for the identification of alteration zones and structural controls of the gold mineralization in highly deformed ophiolitic regions. |
| first_indexed | 2024-03-11T04:35:20Z |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-11T04:35:20Z |
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| spelling | doaj.art-d254aee502fc4861ab80bac1fd442d5f2023-11-17T21:10:15ZengMDPI AGRemote Sensing2072-42922023-04-01158197410.3390/rs15081974Multisensor Satellite Data and Field Studies for Unravelling the Structural Evolution and Gold Metallogeny of the Gerf Ophiolitic Nappe, Eastern Desert, EgyptMohamed Abd El-Wahed0Samir Kamh1Mohamed Abu Anbar2Basem Zoheir3Mohamed Hamdy4Abdelaziz Abdeldayem5El Metwally Lebda6Mohamed Attia7Geology Department, Faculty of Science, Tanta University, Tanta 31527, EgyptGeology Department, Faculty of Science, Tanta University, Tanta 31527, EgyptGeology Department, Faculty of Science, Tanta University, Tanta 31527, EgyptGeology Department, Faculty of Science, Benha University, Benha 13518, EgyptGeology Department, Faculty of Science, Tanta University, Tanta 31527, EgyptGeology Department, Faculty of Science, Tanta University, Tanta 31527, EgyptGeology Department, Faculty of Science, Kafr El Sheikh University, Kafr El Sheikh 33511, EgyptGeology Department, Faculty of Science, Kafr El Sheikh University, Kafr El Sheikh 33511, EgyptThe gold mineralization located in the southern Eastern Desert of Egypt mostly occurs in characteristic geologic and structural settings. The gold-bearing quartz veins and the alteration zones are confined to the ductile shear zones between the highly deformed ophiolitic blocks, sheared metavolcanics, and gabbro-diorite rocks. The present study attempts to integrate multisensor remotely sensed data, structural analysis, and field investigation in unraveling the geologic and structural controls of gold mineralization in the Gabal Gerf area. Multispectral optical sensors of Landsat-8 OLI/TIRS (L8) and Sentinel-2B (S2B) were processed to map the lithologic rock units in the study area. Image processing algorithms including false color composite (FCC), band ratio (BR), principal component analysis (PCA), minimum noise fraction (MNF), and Maximum Likelihood Classifier (MLC) were effective in producing a comprehensive geologic map of the area. The mafic index (MI) = (B13-0.9147) × (B10-1.4366) of ASTER (A) thermal bands and a combined band ratio of S2B and ASTER of (S2B3+A9)/(S2B12+A8) were dramatically successful in discriminating the ophiolitic assemblage, that are considered the favorable lithology for the gold mineralization. Three alteration zones of argillic, phyllic and propylitic were spatially recognized using the mineral indices and constrained energy minimization (CEM) approach to ASTER data. The datasets of ALSO PALSAR and Sentinel-1B were subjected to PCA and filtering to extract the lineaments and their spatial densities in the area. Furthermore, the structural analysis revealed that the area has been subjected to three main phases of deformation; (i) NE-SW convergence and sinistral transpression (D2); (ii) ~E-W far field compressional regime (D3), and (iii) extensional tectonics and terrane exhumation (D4). The gold-bearing quartz veins in several occurrences are controlled by D2 and D3 shear zones that cut heterogeneously deformed serpentinites, sheared metavolcanic rocks and gabbro-diorite intrusions. The information extracted from remotely sensed data, structural interpretation and fieldwork were used to produce a gold mineralization potential zones map which was verified by reference and field observations. The present study demonstrates the remote sensing capabilities for the identification of alteration zones and structural controls of the gold mineralization in highly deformed ophiolitic regions.https://www.mdpi.com/2072-4292/15/8/1974multispectral satellite dataPALSARgold explorationGabal Gerf ophiolite nappethrust-dominated transpressionalgold-bearing quartz veins |
| spellingShingle | Mohamed Abd El-Wahed Samir Kamh Mohamed Abu Anbar Basem Zoheir Mohamed Hamdy Abdelaziz Abdeldayem El Metwally Lebda Mohamed Attia Multisensor Satellite Data and Field Studies for Unravelling the Structural Evolution and Gold Metallogeny of the Gerf Ophiolitic Nappe, Eastern Desert, Egypt Remote Sensing multispectral satellite data PALSAR gold exploration Gabal Gerf ophiolite nappe thrust-dominated transpressional gold-bearing quartz veins |
| title | Multisensor Satellite Data and Field Studies for Unravelling the Structural Evolution and Gold Metallogeny of the Gerf Ophiolitic Nappe, Eastern Desert, Egypt |
| title_full | Multisensor Satellite Data and Field Studies for Unravelling the Structural Evolution and Gold Metallogeny of the Gerf Ophiolitic Nappe, Eastern Desert, Egypt |
| title_fullStr | Multisensor Satellite Data and Field Studies for Unravelling the Structural Evolution and Gold Metallogeny of the Gerf Ophiolitic Nappe, Eastern Desert, Egypt |
| title_full_unstemmed | Multisensor Satellite Data and Field Studies for Unravelling the Structural Evolution and Gold Metallogeny of the Gerf Ophiolitic Nappe, Eastern Desert, Egypt |
| title_short | Multisensor Satellite Data and Field Studies for Unravelling the Structural Evolution and Gold Metallogeny of the Gerf Ophiolitic Nappe, Eastern Desert, Egypt |
| title_sort | multisensor satellite data and field studies for unravelling the structural evolution and gold metallogeny of the gerf ophiolitic nappe eastern desert egypt |
| topic | multispectral satellite data PALSAR gold exploration Gabal Gerf ophiolite nappe thrust-dominated transpressional gold-bearing quartz veins |
| url | https://www.mdpi.com/2072-4292/15/8/1974 |
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