Multistage genesis of the late Cretaceous manganese karst-hosted Tasdremt deposit (High Atlas, Morocco)

Augustin Dekoninck; Gilles Ruffet; Yves Missenard; Oriane Parizot; Mohamed Magoua; Abdellah Mouttaqi; Gaetan Rochez; Johan Yans

doi:10.1007/s00126-020-01017-0

Multistage genesis of the late Cretaceous manganese karst-hosted Tasdremt deposit (High Atlas, Morocco)

Augustin Dekoninck, Gilles Ruffet, Yves Missenard, Oriane Parizot, Mohamed Magoua, Abdellah Mouttaqi, Gaetan Rochez, Johan Yans

Research output: Contribution to journal › Article › peer-review

Abstract

The eastern part of the Souss Basin (Morocco) contains several Mn deposits in the Tasdremt district. ThreeMn orebodies occur within
the Cenomanian-Turonian dolostones and the Senonian (Coniacian to Maastrichtian) detrital series, the main orebody being located at
the boundary between them. The Mn ores consist of coronadite group minerals, mostly coronadite and hollandite, in a karstified
dolostone. New field observations, petrographic analyses, and geochemical data define the Tasdremt deposits as a karst-hosted
accumulation (11–60 wt.% Mn), particularly enriched in Ba (1.5–8.2 wt.%) and Pb (1.0–5.0 wt.%) with poor contaminations in Al,
Fe, and P. This study shows that the ore-forming process is similar to that occurring in the Imini C3 level, located ~ 100 kmto the northeast.
Such similarities with the high-grade pyrolusite-bearing ore suggest that the Tasdremt deposit is a lateral equivalent of the Imini
deposits. However, the scarcity of pyrolusite in Tasdremt results in lower Mn grades, the Tasdremt ores being considered an aborted/
incomplete system in comparison with the Imini deposits. 40Ar/39Ar geochronology of K-bearing Mn oxides yields late Cretaceous
ages, defining three phases at ~ 91.5 Ma, ~ 77.5–82 Ma, and ~ 65–67 Ma. Although the source of metals remains hypothetical,
mineralizing fluids were carried by O2-free groundwater that mixed with O2-rich shallow meteoric waters at the Tasdremt depositional
site. The dissolution of the host dolostones and the karst environment have provided suitable conditions for the precipitation of Mn
oxides, causing the coeval increase of pH and Eh, respectively. The Early Atlasic deformation during the Late Cretaceous is associated
with mineralization events and was responsible for creation of low stand reliefs from Tasdremt to Imini. This period enabled
karstification and mineralization. Connecting the Tasdremt deposits to other African Mn deposits is difficult since the latter consist
of laterite resting above PaleoproterozoicMn protores, and consequently formed under different conditions from karst-hosted deposits.
It is likely that other Mn occurrences formed along the Atlas belt in similar settings.

Original language	English
Pages (from-to)	935-956
Number of pages	22
Journal	Mineralium Deposita
Volume	56
Issue number	5
DOIs	https://doi.org/10.1007/s00126-020-01017-0
Publication status	Published - 18 Sept 2020

Keywords

Ar/ Ar
Imini
K-Mn oxides
Karst
Manganese deposit
Morocco
Tasdremt

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10.1007/s00126-020-01017-0

Cite this

@article{c92af50c66b2465f87b8e250941937cc,

title = "Multistage genesis of the late Cretaceous manganese karst-hosted Tasdremt deposit (High Atlas, Morocco)",

abstract = "The eastern part of the Souss Basin (Morocco) contains several Mn deposits in the Tasdremt district. ThreeMn orebodies occur withinthe Cenomanian-Turonian dolostones and the Senonian (Coniacian to Maastrichtian) detrital series, the main orebody being located atthe boundary between them. The Mn ores consist of coronadite group minerals, mostly coronadite and hollandite, in a karstifieddolostone. New field observations, petrographic analyses, and geochemical data define the Tasdremt deposits as a karst-hostedaccumulation (11–60 wt.% Mn), particularly enriched in Ba (1.5–8.2 wt.%) and Pb (1.0–5.0 wt.%) with poor contaminations in Al,Fe, and P. This study shows that the ore-forming process is similar to that occurring in the Imini C3 level, located ~ 100 kmto the northeast.Such similarities with the high-grade pyrolusite-bearing ore suggest that the Tasdremt deposit is a lateral equivalent of the Iminideposits. However, the scarcity of pyrolusite in Tasdremt results in lower Mn grades, the Tasdremt ores being considered an aborted/incomplete system in comparison with the Imini deposits. 40Ar/39Ar geochronology of K-bearing Mn oxides yields late Cretaceousages, defining three phases at ~ 91.5 Ma, ~ 77.5–82 Ma, and ~ 65–67 Ma. Although the source of metals remains hypothetical,mineralizing fluids were carried by O2-free groundwater that mixed with O2-rich shallow meteoric waters at the Tasdremt depositionalsite. The dissolution of the host dolostones and the karst environment have provided suitable conditions for the precipitation of Mnoxides, causing the coeval increase of pH and Eh, respectively. The Early Atlasic deformation during the Late Cretaceous is associatedwith mineralization events and was responsible for creation of low stand reliefs from Tasdremt to Imini. This period enabledkarstification and mineralization. Connecting the Tasdremt deposits to other African Mn deposits is difficult since the latter consistof laterite resting above PaleoproterozoicMn protores, and consequently formed under different conditions from karst-hosted deposits.It is likely that other Mn occurrences formed along the Atlas belt in similar settings.",

keywords = "manganese deposit, tasdremt, imini, 40Ar/39Ar, K-Mn oxides, karst, Morocco, Ar/ Ar, Imini, K-Mn oxides, Karst, Manganese deposit, Morocco, Tasdremt",

author = "Augustin Dekoninck and Gilles Ruffet and Yves Missenard and Oriane Parizot and Mohamed Magoua and Abdellah Mouttaqi and Gaetan Rochez and Johan Yans",

note = "Funding Information: We are grateful to the “Office National des Mines et des Hydrocarbures” (ONHYM) for having shared documents, brought logistical and scientific support, and facilitated access to outcrops in the Tiranimine, Tasdremt and Aoufour deposits. We thank Dr. L. Dewaide for her help and advice to collect samples on the field. We appreciate the help of Prof. J. Wouters and Dr. N. Tumanov of the PC2 platform (UNamur) for collecting XRD patterns. We also thank J.-P. Cullus and Prof. F. Boulvain for preparing thin sections, as well as P. Kubben and Prof. A. Bernard for making polished sections. This research also used the resources of the Electron Microscopy Service located at the University of Namur (“Plateforme Technologique Morphologie — Imagerie”). Y. Missenard and O. Parizot benefited from the French “Institut des Sciences de l{\textquoteright}Univers” (INSU) funding – Tellus-Syster program. We warmly thank P. Vasconcelos and T. De Putter for their careful and constructive review of this paper. Finally, we express gratitude to A. Gilg (editor) for handling this manuscript to its final version, as well as G. Beaudoin (editor-in-chief). Publisher Copyright: {\textcopyright} 2020, Springer-Verlag GmbH Germany, part of Springer Nature.",

year = "2020",

month = sep,

day = "18",

doi = "10.1007/s00126-020-01017-0",

language = "English",

volume = "56",

pages = "935--956",

journal = "Mineralium Deposita",

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publisher = "Springer Verlag",

number = "5",

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TY - JOUR

T1 - Multistage genesis of the late Cretaceous manganese karst-hosted Tasdremt deposit (High Atlas, Morocco)

AU - Dekoninck, Augustin

AU - Ruffet, Gilles

AU - Missenard, Yves

AU - Parizot, Oriane

AU - Magoua, Mohamed

AU - Mouttaqi, Abdellah

AU - Rochez, Gaetan

AU - Yans, Johan

N1 - Funding Information: We are grateful to the “Office National des Mines et des Hydrocarbures” (ONHYM) for having shared documents, brought logistical and scientific support, and facilitated access to outcrops in the Tiranimine, Tasdremt and Aoufour deposits. We thank Dr. L. Dewaide for her help and advice to collect samples on the field. We appreciate the help of Prof. J. Wouters and Dr. N. Tumanov of the PC2 platform (UNamur) for collecting XRD patterns. We also thank J.-P. Cullus and Prof. F. Boulvain for preparing thin sections, as well as P. Kubben and Prof. A. Bernard for making polished sections. This research also used the resources of the Electron Microscopy Service located at the University of Namur (“Plateforme Technologique Morphologie — Imagerie”). Y. Missenard and O. Parizot benefited from the French “Institut des Sciences de l’Univers” (INSU) funding – Tellus-Syster program. We warmly thank P. Vasconcelos and T. De Putter for their careful and constructive review of this paper. Finally, we express gratitude to A. Gilg (editor) for handling this manuscript to its final version, as well as G. Beaudoin (editor-in-chief). Publisher Copyright: © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.

PY - 2020/9/18

Y1 - 2020/9/18

N2 - The eastern part of the Souss Basin (Morocco) contains several Mn deposits in the Tasdremt district. ThreeMn orebodies occur withinthe Cenomanian-Turonian dolostones and the Senonian (Coniacian to Maastrichtian) detrital series, the main orebody being located atthe boundary between them. The Mn ores consist of coronadite group minerals, mostly coronadite and hollandite, in a karstifieddolostone. New field observations, petrographic analyses, and geochemical data define the Tasdremt deposits as a karst-hostedaccumulation (11–60 wt.% Mn), particularly enriched in Ba (1.5–8.2 wt.%) and Pb (1.0–5.0 wt.%) with poor contaminations in Al,Fe, and P. This study shows that the ore-forming process is similar to that occurring in the Imini C3 level, located ~ 100 kmto the northeast.Such similarities with the high-grade pyrolusite-bearing ore suggest that the Tasdremt deposit is a lateral equivalent of the Iminideposits. However, the scarcity of pyrolusite in Tasdremt results in lower Mn grades, the Tasdremt ores being considered an aborted/incomplete system in comparison with the Imini deposits. 40Ar/39Ar geochronology of K-bearing Mn oxides yields late Cretaceousages, defining three phases at ~ 91.5 Ma, ~ 77.5–82 Ma, and ~ 65–67 Ma. Although the source of metals remains hypothetical,mineralizing fluids were carried by O2-free groundwater that mixed with O2-rich shallow meteoric waters at the Tasdremt depositionalsite. The dissolution of the host dolostones and the karst environment have provided suitable conditions for the precipitation of Mnoxides, causing the coeval increase of pH and Eh, respectively. The Early Atlasic deformation during the Late Cretaceous is associatedwith mineralization events and was responsible for creation of low stand reliefs from Tasdremt to Imini. This period enabledkarstification and mineralization. Connecting the Tasdremt deposits to other African Mn deposits is difficult since the latter consistof laterite resting above PaleoproterozoicMn protores, and consequently formed under different conditions from karst-hosted deposits.It is likely that other Mn occurrences formed along the Atlas belt in similar settings.

AB - The eastern part of the Souss Basin (Morocco) contains several Mn deposits in the Tasdremt district. ThreeMn orebodies occur withinthe Cenomanian-Turonian dolostones and the Senonian (Coniacian to Maastrichtian) detrital series, the main orebody being located atthe boundary between them. The Mn ores consist of coronadite group minerals, mostly coronadite and hollandite, in a karstifieddolostone. New field observations, petrographic analyses, and geochemical data define the Tasdremt deposits as a karst-hostedaccumulation (11–60 wt.% Mn), particularly enriched in Ba (1.5–8.2 wt.%) and Pb (1.0–5.0 wt.%) with poor contaminations in Al,Fe, and P. This study shows that the ore-forming process is similar to that occurring in the Imini C3 level, located ~ 100 kmto the northeast.Such similarities with the high-grade pyrolusite-bearing ore suggest that the Tasdremt deposit is a lateral equivalent of the Iminideposits. However, the scarcity of pyrolusite in Tasdremt results in lower Mn grades, the Tasdremt ores being considered an aborted/incomplete system in comparison with the Imini deposits. 40Ar/39Ar geochronology of K-bearing Mn oxides yields late Cretaceousages, defining three phases at ~ 91.5 Ma, ~ 77.5–82 Ma, and ~ 65–67 Ma. Although the source of metals remains hypothetical,mineralizing fluids were carried by O2-free groundwater that mixed with O2-rich shallow meteoric waters at the Tasdremt depositionalsite. The dissolution of the host dolostones and the karst environment have provided suitable conditions for the precipitation of Mnoxides, causing the coeval increase of pH and Eh, respectively. The Early Atlasic deformation during the Late Cretaceous is associatedwith mineralization events and was responsible for creation of low stand reliefs from Tasdremt to Imini. This period enabledkarstification and mineralization. Connecting the Tasdremt deposits to other African Mn deposits is difficult since the latter consistof laterite resting above PaleoproterozoicMn protores, and consequently formed under different conditions from karst-hosted deposits.It is likely that other Mn occurrences formed along the Atlas belt in similar settings.

KW - manganese deposit

KW - tasdremt

KW - imini

KW - 40Ar/39Ar

KW - K-Mn oxides

KW - karst

KW - Morocco

KW - Ar/ Ar

KW - Imini

KW - K-Mn oxides

KW - Karst

KW - Manganese deposit

KW - Morocco

KW - Tasdremt

UR - http://www.scopus.com/inward/record.url?scp=85092573315&partnerID=8YFLogxK

U2 - 10.1007/s00126-020-01017-0

DO - 10.1007/s00126-020-01017-0

M3 - Article

SN - 0026-4598

VL - 56

SP - 935

EP - 956

JO - Mineralium Deposita

JF - Mineralium Deposita

IS - 5

ER -

Multistage genesis of the late Cretaceous manganese karst-hosted Tasdremt deposit (High Atlas, Morocco)

Abstract

Keywords

Access to Document

Other files and links

Geological and geochemical constrains on the genesis of the sedimentary-hosted Bou Arfa Mn(-Fe) deposit (Eastern High Atlas, Morocco)

Origin of the Moroccan Touissit-Bou Beker and Jbel Bou Dahar supergene non-sulfide biomineralization and its relevance to microbiological activity, late Miocene uplift and climate changes

Detailed mineralogy and petrology of manganese oxyhydroxide deposits of the Imini district (Morocco)

Morphology - Imaging

Physical Chemistry and characterization(PC2)

Cite this

Multistage genesis of the late Cretaceous manganese karst-hosted Tasdremt deposit (High Atlas, Morocco)

Abstract

Keywords

Access to Document

Other files and links

Research output

Geological and geochemical constrains on the genesis of the sedimentary-hosted Bou Arfa Mn(-Fe) deposit (Eastern High Atlas, Morocco)

Origin of the Moroccan Touissit-Bou Beker and Jbel Bou Dahar supergene non-sulfide biomineralization and its relevance to microbiological activity, late Miocene uplift and climate changes

Detailed mineralogy and petrology of manganese oxyhydroxide deposits of the Imini district (Morocco)

Equipment

Morphology - Imaging

Physical Chemistry and characterization(PC2)

Cite this