(U-Th)/He dating of supergene iron (oxyhydr-)oxides of the Nefza-Sejnane district (Tunisia): new insights into mineralization and mammalian biostratigraphy

Johan YANS, Michele Verhaert, Cécile Gautheron, Pierre-Olivier Antoine, Béchir Moussi, Augustin Dekoninck, Sophie Decrée, R. Chaftar, N. HATIRA, Christian Dupuis, Rosella Pinna-Jamme, Fakher Jamoussi

Research output: Contribution to journalArticlepeer-review

110 Downloads (Pure)

Abstract

The mining district of Nefza-Sejnane (Tunisia) encloses numerous ores and raw material deposits, all formed in relation with successive Fe-rich fluids of meteoric and/or hydrothermal origins. Here, for the first time in Tunisia, (U-Th)/He ages were obtained on supergene goethite from various localities/deposits of the district highlight direct dating of significant weathering episodes during late Tortonian and late Pleistocene. These weathering events are most likely associated with favorable conditions that combine (i) wet climate displaying sufficient meteoric water/fluid; and (ii) regional exhumation, due to large-scale vertical lithospheric movements enhancing the percolation of fluids. Matched with previous works, these results refine the stratigraphic frame for the polymetallic mineralization and clay deposits in the district, confirming the influence of meteoric fluids circulation during the late Cenozoic. As a consequence of the new (U-Th)/He data, we moreover propose a taxonomic and stratigraphic revision of the well-known mammalian fauna from the Fe-rich Douahria locality, suggesting an early Tortonian age for the fossils, i.e., prior to the first episode of meteoric event in the area.

Original languageEnglish
Article number260
Pages (from-to)1-19
Number of pages19
JournalMinerals
Volume11
Issue number3
DOIs
Publication statusPublished - 1 Mar 2021

Funding

Acknowledgments: P.-O.A. is particularly grateful to Emmanuel Robert (Universit\u00E9 de Lyon; Douahria specimens) and to Christine Argot (Mus\u00E9um National d\u2019Histoire Naturelle, Paris; comparison material) for having granted access to the collections they are in charge of, and to Fabrice Lihoreau and Denis Geraads for sharing their expertise. This work was partly funded by the Belgian Science Policy Office, project BR/121/A3/PALEURAFRICA, and by the project entitled \u201CValorisation des argiles tunisiennes\u201D of WBI (Wallonie-Bruxelles International). This research used resources of the Electron Microscopy Service, which is a member of the \u201CPlateforme Technologique Morphologie\u2013Imagerie\u201D of the University of Namur (UNamur). Mich\u00E8le Verhaert thanks the Belgian National Fund for Scientific Research (FNRS), for providing a FRIA PhD grant. C.G. thanks the RECA ANR-17-CE01-0012-01 project for funded (U-Th)/He analysis. Wallonie-Bruxelles International: Projet 8-axe 2 Agence Nationale de la Recherche: RECA ANR-17-CE01-0012-01.

FundersFunder number
Fonds De La Recherche Scientifique - FNRS
Wallonie-Bruxelles International
Agence Nationale de la RechercheRECA ANR-17-CE01-0012-01, ANR-17-CE01-0012
UK Research and Innovation103674
Belgian Federal Science Policy OfficeBR/121/A3/PALEURAFRICA
RECAANR-17-CE01-0012-01

    Keywords

    • (U-Th)/He
    • Douahria mammalian fauna
    • Goethite
    • Supergene
    • Tunisia

    Fingerprint

    Dive into the research topics of '(U-Th)/He dating of supergene iron (oxyhydr-)oxides of the Nefza-Sejnane district (Tunisia): new insights into mineralization and mammalian biostratigraphy'. Together they form a unique fingerprint.

    Cite this