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Crustal-Derived LCT Pegmatites as Potential Critical Metal Sources in the Bas Draa Inlier, Western Anti-Atlas, Morocco

Fatiha Askkour a, Moha Ikenne a, Brian L Cousens b, Mehdi Ousbih a, Mustapha Souhassouc, Mohamed Mahmoud Sebbab d, Mohamed Ez-Zghoudy a, Abdessamad El Atillah e, Moulay Ahmed Boumehdi f

  • Affiliations:  a LAGAGE, Department of Geology, Faculty of Sciences, Ibn Zohr University, B.P. 8016, Cité Dakhla, Agadir, Morocco b Isotope Geochemistry and Geochronology Research Centre, Department of Earth Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada c Polydisciplinary Faculty of Taroudant, Ibn Zohr University, Taroudant, Morocco d Spaces, Societies, Environment, Planning and Development Laboratory, Department of Geography and Planning, Faculty of Languages, Arts and Human Sciences- Ait Melloul, Ibnou Zohr University, Ait Melloul, Morocco e Regional Directorate of Energy and Mines of Agadir, Ministry of Energy Transition and Sustainable, Morocco. f 3GEOLAB, Department of Geology, Faculty of Sciences Semlalia, Cadi Ayyad University, 40000 Marrakech, Morocco 

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 17

  • Programme No: 4.1.8

  • Theme 4 > Session 1

Abstract

Pegmatites are increasingly recognized as essential sources of critical metals required for the energy transition, fueling advances in battery technology, renewable energy infrastructure, and various high-tech applications. Given their strategic importance, pegmatite studies have become a focal point of research, though many questions remain about their formation and evolution. In the Bas Draa Inlier of Morocco's western Anti-Atlas, a prominent swarm of aplitic and pegmatitic dykes traverses Precambrian intrusions and metasedimentary rocks. These dykes, varying from a few centimeters to several kilometers in length, are composed of quartz, muscovite, feldspar, tourmaline, petalite, apatite, zircon, garnet, and gahnite. They exhibit strongly peraluminous characteristics, with mineralogical and geochemical features indicating their classification within the LCT (Li-Cs-Ta) pegmatite family. Specifically, the Bas Draa pegmatites show a low total rare earth element (REE) content (<500 ppm), and their mineral assemblage---including petalite, tourmaline, garnet, and gahnite---reflects enrichment in Pb, Rb, and Cs, alongside depletion in Ba and Nb on a primitive mantle-normalized multi-element plot. The petrogenesis of these pegmatites appears to be crustal anatexic, likely originating from the surrounding metasedimentary host rocks rather than nearby granites. This is further supported by their highly mafic tourmaline compositions (Schorl-Foitite), the presence of epidote, and distinct field relationships. The Bas Draa pegmatites thus represent a unique case of crustal-derived LCT pegmatites in the region, with promising implications for future sourcing of critical elements needed to sustain the global shift towards renewable energy.