Le Sénonien du Haut Atlas occidental, Maroc: sédimentologie, analyse séquentielle et paléogéographie

Algouti, Ah.; Algouti, Abdellah; Taj-Eddine, Kamal

doi:10.1016/s0899-5362(99)00121-9

Cited by 15 publications

(17 citation statements)

References 5 publications

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“…In summary, the Tasdremt sector was above sea level during at least two periods: (i) Coniacian (or possibly Late Turonian) to Early Santonian, and (ii) Campanian to the earliest Maastrichtian. Other periods might however have allowed exposure during the main sedimentary pulses (Algouti et al 1999). It is worth mentioning that the landscape was significantly different from the current relief, and was most probably at a low elevation, i.e., a few meters above sea level (Algouti et al 1999).…”

Section: Timing Of Sedimentation Weathering Karstification and Minmentioning

confidence: 99%

“…6 a and c). No specific features characterize the dolomitic sandstone and conglomerate of the upper detritic sequence (Late Santonian and Maastrichtian according to Algouti et al (1999)). They are composed of various fragments originating from the lower CT dolostones or the bedrock, showing variable detrital minerals.…”

Section: Mineralogy and Petrography Of The Host Rocksmentioning

confidence: 99%

“…10 Chronology of Tasdremt manganese ores illustrating that Mn oxides precipitated in three phases at~91.5 Ma (phase 1),~77.5-82 Ma (phase 2), and likely at~65-67 Ma (phase 3). Sedimentation periods in the Tasdremt area are based on Ambroggi (1963) and Algouti et al (1999) intermediate to high temperature domains are consideredleaving out the apparent high ages of the low temperature domain -, sample 16TIG29 yields the oldest apparent ages (c. 91.5 Ma), which is concomitant with the highest 37 Ar Ca / 39 Ar K ratios (1.4-1.7; Fig. 9a).…”

Section: Timing Of the Tasdremt Mn Oresmentioning

confidence: 99%

“…The CT dolostones were exposed to weathering agents after withdrawal of the CT sea (Froitzheim 1984;Froitzheim et al 1988;Thein 1990;Rhalmi et al 1997Rhalmi et al , 2000Frizon de Lamotte et al 2009), most probably due to a pre-Senonian incipient tectonic phase that caused the emersion of North Africa (Algouti et al 1999;Frizon de Lamotte et al 2009;Leprêtre et al 2018). Algouti et al (1999) detailed the sedimentary evolution of the Senonian series in an area spreading over the western High Atlas, from Agadir (west) to Imini (east). The sector from Tasdremt to Imini was an emerged land until the late Santonian ( Fig.…”

Section: Timing Of Sedimentation Weathering Karstification and Minmentioning

confidence: 99%

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

et al. 2020

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The eastern part of the Souss Basin (Morocco) contains several Mn deposits in the Tasdremt district. Three Mn 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 km to 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. 40 Ar/ 39 Ar 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 O 2-free groundwater that mixed with O 2-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 Paleoproterozoic Mn 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.

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Section: Timing Of Sedimentation Weathering Karstification and Minmentioning

confidence: 99%

Section: Mineralogy and Petrography Of The Host Rocksmentioning

confidence: 99%

Section: Timing Of the Tasdremt Mn Oresmentioning

confidence: 99%

Section: Timing Of Sedimentation Weathering Karstification and Minmentioning

confidence: 99%

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

et al. 2020

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“…Aptian to Turonian times are represented by marine, marly and calcareous strata (Ambroggi, 1963;Bourgeoini et al, 2002;Ettachfini et al, 2005;Jati et al, 2010;Peybernès et al, 2013). The Upper Cretaceous mainly calcareous sedimentation (Andreu, 1989) was then disturbed by a first Santonian-Campanian compressional deformation (Guiraud and Bosworth, 1997) and became mostly clastic (Algouti et al, 1999). The Tertiary Alpine compression (mainly middle-late Eocene to Pleistocene) then inverted the Lower Jurassic normal and transcurrent faults, and folded the EAB Frizon de Lamotte et al, 2000, 2011.…”

Section: Geological Backgroundmentioning

confidence: 99%

Aptian–early Albian sedimentation in the Essaouira-Agadir basin, Western Morocco

Jaillard

Kassab

Giraud

et al. 2019

Cretaceous Research

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Aptian to early Albian times are marked by various geodynamic and paleoenvironmental events such as large igneous province volcanism , perturbations of climate and the carbon cycle, and sea-level changes. The Essaouira-Agadir basin (EAB), located on the Atlantic passive margin of Morocco, offers good and fossiliferous exposures of the Aptian-Albian sedimentary series. A detailed analysis of this succession made it possible to establish a biostratigraphic framework. The identification of discontinuities allowed to define eight depositional sequences. As most of them are correlatable with depositional sequences of other Tethyan areas, they suggest that eustacy was the main parameter controlling sedimentation. The analysis of sedimentary facies and nannofossil assemblages provides information on paleoenvironmental changes. Sedimentation in the EAB evolved from a very low energy, carbonate ramp in the early Aptian to a low energy, slightly deeper, mixed carbonate-clastic ramp in the early Albian. This change occurred along with an increase of clastic input, a change from oligotrophic to mesotrophic faunal assemblages, and a decrease of sea-surface temperatures. The occurrence of current sedimentary features, sporadic dysaerobic deposits and local phosphatic and glauconitic crusts suggests that upwelling currents were significant during this period. Paleogeographic and isopach maps support a transgressive trend in the late Aptian and early Albian, and unravel subsidence anomalies suggesting mild halokinetic movements during Aptian-early Albian times.

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The Atlas System

Lamotte

Zizi

Missenard

et al.

Lecture Notes in Earth Sciences

119

118

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Le Sénonien du Haut Atlas occidental, Maroc: sédimentologie, analyse séquentielle et paléogéographie

Cited by 15 publications

References 5 publications

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

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

Aptian–early Albian sedimentation in the Essaouira-Agadir basin, Western Morocco

The Atlas System

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