(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

doi:10.3390/min11030260

(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

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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 language	English
Article number	260
Pages (from-to)	1-19
Number of pages	19
Journal	Minerals
Volume	11
Issue number	3
DOIs	https://doi.org/10.3390/min11030260
Publication status	Published - 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.

Funders	Funder number
Fonds De La Recherche Scientifique - FNRS
Wallonie-Bruxelles International
Agence Nationale de la Recherche	RECA ANR-17-CE01-0012-01, ANR-17-CE01-0012
UK Research and Innovation	103674
Belgian Federal Science Policy Office	BR/121/A3/PALEURAFRICA
RECA	ANR-17-CE01-0012-01

Keywords

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

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YANS, J., Verhaert, M., Gautheron, C., Antoine, P.-O., Moussi, B., Dekoninck, A., Decrée, S., Chaftar, R., HATIRA, N., Dupuis, C., Pinna-Jamme, R., & Jamoussi, F. (2021). (U-Th)/He dating of supergene iron (oxyhydr-)oxides of the Nefza-Sejnane district (Tunisia): new insights into mineralization and mammalian biostratigraphy. Minerals, 11(3), 1-19. Article 260. https://doi.org/10.3390/min11030260

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

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.",

keywords = "(U-Th)/He, Douahria mammalian fauna, Goethite, Supergene, Tunisia",

author = "Johan YANS and Michele Verhaert and C{\'e}cile Gautheron and Pierre-Olivier Antoine and B{\'e}chir Moussi and Augustin Dekoninck and Sophie Decr{\'e}e and R. Chaftar and N. HATIRA and Christian Dupuis and Rosella Pinna-Jamme and Fakher Jamoussi",

note = "Funding Information: Wallonie-Bruxelles International: Projet 8-axe 2 Agence Nationale de la Recherche: RECA ANR-17-CE01-0012-01. Publisher Copyright: {\textcopyright} 2021 by the authors. Licensee MDPI, Basel, Switzerland.",

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YANS, J , Verhaert, M, Gautheron, C, Antoine, P-O, Moussi, B, Dekoninck, A, Decrée, S, Chaftar, R, HATIRA, N, Dupuis, C, Pinna-Jamme, R & Jamoussi, F 2021, '(U-Th)/He dating of supergene iron (oxyhydr-)oxides of the Nefza-Sejnane district (Tunisia): new insights into mineralization and mammalian biostratigraphy', Minerals, vol. 11, no. 3, 260, pp. 1-19. https://doi.org/10.3390/min11030260

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T1 - (U-Th)/He dating of supergene iron (oxyhydr-)oxides of the Nefza-Sejnane district (Tunisia)

T2 - new insights into mineralization and mammalian biostratigraphy

AU - YANS, Johan

AU - Verhaert, Michele

AU - Gautheron, Cécile

AU - Antoine, Pierre-Olivier

AU - Moussi, Béchir

AU - Dekoninck, Augustin

AU - Decrée, Sophie

AU - Chaftar, R.

AU - HATIRA, N.

AU - Dupuis, Christian

AU - Pinna-Jamme, Rosella

AU - Jamoussi, Fakher

N1 - Funding Information: Wallonie-Bruxelles International: Projet 8-axe 2 Agence Nationale de la Recherche: RECA ANR-17-CE01-0012-01. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/3/1

Y1 - 2021/3/1

N2 - 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.

AB - 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.

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KW - Goethite

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ER -

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

Abstract

Funding

Keywords

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