The Mesozoic-Cenozoic Atlas belt (North Africa): an overview

Piqué, Alain; Tricart, Pierre; Guiraud, René; Laville, Edgard; Bouaziz, Samir; Amrhar, Mostafa; Ouali, Rachid Aït

doi:10.1080/09853111.2002.10510752

Cited by 66 publications

(104 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, other authors confirmed that the Eocene shortening phase was not widespread throughout Tunisia as it was followed by periods of stress relaxation and extension. Therefore the main compressive phase rather corresponds to the Late Miocene Alpine phase with the NW-SE shortening axis followed later by post-Villafranchian phase with submeridional shortening axis (Boukadi et al 1998;Frizon De Lamonte et al 2000;Piqué et al 2002).…”

Section: Synthesis and Discussionmentioning

confidence: 99%

Kinematic evolution and quantification of deformation in external orogenic zones: a case study from the Tunisian Atlas

Bensalem¹,

Amamria²,

Ghanmi³

et al. 2016

Geologica Carpathica

View full text Add to dashboard Cite

Abstract:The quantification of deformation is one of the main objectives studied by geologists in order to control the evolution of tectonic structures and their kinematics during different tectonic phases. One of the most reliable methods of this theme is the direct calculation of quantity of deformation based on field data, while respecting several parameters such as the notion of tectonic inheritance and reactivation of pre-existing faults, or the relationship between the elongation and shortening axis with major faults. Thus, such a quantification of deformation in an area may explain the relations of thin-and thick-skinned tectonics during this deformation. The study of structural evolution of the Jebel Elkebar domain in the southern-central Tunisian Atlas permits us to quantify the deformation during the extensional phase by a direct calculation of the vertical throw along normal faults. This approach is verified by calculation of thickness of eroded strata in the uplifted compartment and of resedimented series, named the Kebar Formation, in the downthrown compartment. The obtained results confirm the importance of the Aptian-Albian extensional tectonic regime. The extent of deformation during the compressional phase, related to reactivation of pre-existing faults, is less than that of extensional phases; indeed the compressive reactivation did not compensate the vertical throw of normal faults. The geometry of the Elkebar fold is interpreted in terms of the "fault-related fold" model with a décollement level in the Triassic series. This permitted the partition of deformation between the basement and cover, so that the basement was allowed for a limited transport only, and the maximum of observed deformation was concentrated in the thin-skinned tectonics.

show abstract

Section: Synthesis and Discussionmentioning

confidence: 99%

Kinematic evolution and quantification of deformation in external orogenic zones: a case study from the Tunisian Atlas

Bensalem¹,

Amamria²,

Ghanmi³

et al. 2016

Geologica Carpathica

View full text Add to dashboard Cite

show abstract

“…Different areas of the Atlas are mainly controlled by the inherited flaws in the Variscan orogeny (Piqué et al, 2002). Three major phases can beings differentiated in the formations of the Atlas Mountains:…”

Section: Discussionmentioning

confidence: 99%

Geological Survey, Gitology, and Geophysical of Deposit Tighmart (High Atlas Demnat)

Wafik¹,

Najine²,

Zakaria³

et al. 2017

ESJ

View full text Add to dashboard Cite

The copper site Tighmart, study area is located about 27 km NNE of the city of Demnate in the Central High Atlas. On a stand dominated by Devonian shales and sandstones with limestone benches centimeter, rests a cover Triassic (sandstone, red clay with discontinuous basalt flows) and Jurassic (Lias carbonate bars, based on consistent training gypsiferous lower Lias). The set is structured faulted anticline and eroded. Electrical tomography has been used in order to characterize the structural elements that can promote the introduction of the copper, and the mineral density. This mineralization is concentrated locally in metric nodes, formed by the junction of the N70 ° faults and N40 °. This is very crushed zones decametric extension and where there is a large concentration of chalcocite associated with malachite and azurite rarely. In general, two areas have been identified on both sides of the old gallery: -The southern part crossed by the thalweg shows the dolerite attributed resistant levels through which the levels of oxides and hydroxides of iron and aluminum at depths of 8 to 13 m. This part of the sector does not really present significant reserves given that no continuity was confirmed. -The northern part of a very rugged topography presents no surface mineralization index. However, electrical tomography profiles in this sector show large anomalous beaches right pockets found in the gallery. The examination of the values of apparent resistivity advocates appearing mineralization from 23 m deep.

show abstract

“…The likely source of Th-derived Pb is the rocks in the Hercynian fold belt of North Africa, which include monazite-bearing Paleozoic metasediments and Hercynian granitoids [26]. These Paleozoic rocks are host to some of the world's economically significant base metal deposits [27], have been deformed and/or emplaced during the Hercynian orogeny, and form the basement exposed in scattered inliers of the Atlas systems in Morocco and Algeria [28,29]. Thus, it is plausible that basement rocks in Northern Tunisia are similar to those in Algeria and Morocco.…”

Section: Source(s) Of Metalsmentioning

confidence: 99%

Lead Isotopes as Tracers of Metal Sources and Timing of the Carbonate-Hosted Pb-Zn Deposits in the Nappes Zone, Northern Tunisia

Jemmali¹,

Souissi²

2018

Contributions to Mineralization

View full text Add to dashboard Cite

The polymetallic deposits in the Nappes zone, Northern Tunisia occur in the contact between Triassic-Miocene/Eocene carbonate rocks and in the Upper Cretaceous limestones. They can be divided into two groups: one is Pb-Zn mineralization with Hg and As in fractures with local intrusions of Neogene volcanics (e.g., Fej Hassene, Oued Maden), and the second is stratabound and karst Pb-Zn mineralization with arsenic and antimony hosted in the continental Neogene strata or situated immediately below them (Aïn Allega, Sidi Embarek, Jebel Hallouf-Sidi Bou Aouane, Bazina, Jalta and Jebel Ghozlane). Pb-isotopic compositions of galenas display a homogeneous Pb isotope signature. Generally, Pb isotope ratios on ores from the Jalta, Jebel Ghozlane, Jebel Hallouf, Oued Maden and Fedj Hassene plot between samples of the Late Miocene igneous rocks and the sedimentary country rocks of the Nefza area and between the upper crust and orogen curves. This intermediate position may imply potential mixing between end-member sources. Because the Pb-Zn mineralization is fault-controlled and spatially associated with the post-nappe Miocene series and the calculated model age is about 10.86 Ma, one is led to argue that the mineralization in the Nappes zone deposits occurred during the last paroxysmal phase of the Alpine folding (i.e., Miocene age).

show abstract

The Mesozoic-Cenozoic Atlas belt (North Africa): an overview

Cited by 66 publications

References 50 publications

Kinematic evolution and quantification of deformation in external orogenic zones: a case study from the Tunisian Atlas

Kinematic evolution and quantification of deformation in external orogenic zones: a case study from the Tunisian Atlas

Geological Survey, Gitology, and Geophysical of Deposit Tighmart (High Atlas Demnat)

Lead Isotopes as Tracers of Metal Sources and Timing of the Carbonate-Hosted Pb-Zn Deposits in the Nappes Zone, Northern Tunisia

Contact Info

Product

Resources

About