Thorium-poor monazite and columbite-(Fe) mineralization in the Gleibat Lafhouda carbonatite and its associated iron-oxide-apatite deposit of the Ouled Dlim Massif,South Morocco |
| |
| Institution: | 1. Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany;2. Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) Hannover, Stilleweg 2, D-30655 Hannover, Germany;3. National Office of Hydrocarbons and Mines (ONHYM), 5 Avenue Moulay Hassan, Rabat, Morocco;1. Senckenberg Naturhistorische Sammlungen Dresden, Museum für Mineralogie und Geologie, Sektion Geochronologie, GeoPlasma Lab, Königsbrücker Landstraße 159, 01109 Dresden, Germany;2. CEREGE, Aix-Marseille Université, Centre Saint-Charles, case 67, 3 place Victor Hugo, 13331, Marseille, France;3. Institut für Geowissenschaften, Mineralogie, Goethe Universität Frankfurt, Altenhoeferallee 1, 60438 Frankfurt, Germany;4. Department of Earth Sciences, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa;5. Department of Geology, Faculty of Sciences-Semlalia, Cadi Ayyad University, Prince Moulay Abdellah Boulevard, P.O. Box 2390, Marrakech, Morocco;6. Centro de Geologia da Universidade de Lisboa (CeGUL), Faculdade de Ciências (FCUL), Departamento de Geologia (GeoFCUL), Campo Grande C6, 1749-016 Lisboa, Portugal;7. Directorate of Mining Development, Ministry of Energy, Mines, Water and Environment, Rabat, Morocco;1. Department of Applied Geology, Curtin University, Kent Street, Bentley, WA 6102, Australia;2. School of Earth Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia;1. Department of Mineralogy and Petrology, University of Granada, Campus Fuentenueva, 18002 Granada, Spain;2. Department of Geology, Laboratoire de Géologie Appliquée, Géomatique et Environnement, Faculté des Sciences Ben Msik, Université Hassan II Mohammedia-Casablanca, Morocco;3. Direction de Development Minier, Ministry of Energy, Water and Environment, Rabat, Morocco;1. Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China;2. Department of Geology and Pedology, Mendel University, Brno, Czech Republic;3. Department of Geological Sciences, University Of Manitoba, Manitoba, Canada;4. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China |
| |
| Abstract: | Recent exploration work in South Morocco revealed the occurrence of several carbonatite bodies, including the Paleoproterozoic Gleibat Lafhouda magnesiocarbonatite and its associated iron oxide mineralization, recognized here as iron-oxide-apatite (IOA) deposit type. The Gleibat Lafhouda intrusion is hosted by Archean gneiss and schist and not visibly associated with alkaline rocks. Metasomatized micaceous rocks occur locally at the margins of the carbonatite outcrop and were identified as glimmerite fenite type. Rare earth element (REE) and Nb mineralization is mainly linked to the associated IOA mineralization and is represented by monazite-(Ce) and columbite-(Fe) as major ore minerals. The IOA mineralization mainly consists of magnetite and hematite that usually contain large apatite crystals, quartz and some dolomite. Monazite-(Ce) is closely associated with fluorapatite and occurs as inclusions within the altered parts of apatite and along cracks or as separate phases near apatite. Monazite shows no zonation patterns and very low Th contents (<0.4 wt%), which would be beneficial for commercial extraction of the REE and which indicates monazite formation from apatite as a result of hydrothermal volatile-rich fluids. Similar monazite-apatite mineralization and chemistry also occurs at depth within the carbonatite, although the outcropping carbonatite is barren, suggesting an irregular REE ore distribution within the carbonatite body. The barren carbonatite contains some tiny unidentified secondary Nb-Ta-U phases, synchysite and monazite. Niobium mineralization is commonly represented by anhedral minerals of columbite-(Fe) which occur closely associated with magnetite-hematite and host up to 78 wt% Nb2O5, 7 wt% Ta2O5 and 1.6 wt% Sc2O3. This association may suggest that columbite-(Fe) precipitated by an interaction of Nb-rich fluids with pre-existing Fe-rich minerals or as pseudomorphs after pre-existing Nb minerals like pyrochlore. Our results most strongly suggest that the studied mineralization is economically important and warrants both, further research and exploration with the ultimate goal of mineral extraction. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
