Geodynamic evolution of the 2.25-2.0 Ga Palaeoproterozoic magmatic rocks in the Man-Leo Shield of the West African Craton. A model of subsidence of an oceanic plateau

2009 ◽  
Vol 323 (1) ◽  
pp. 231-254 ◽  
Author(s):  
M. Lompo
Keyword(s):  
West African ◽  
Geodynamic Evolution ◽  
The West ◽  
West African Craton ◽  
Oceanic Plateau ◽  
Magmatic Rocks

Reply to discussion on “From Pan-African transpression to Cadomian transtension at the West African margin: New U-Pb zircon ages from the Eastern Saghro Inlier (Anti-Atlas, Morocco)” by Ikenne et al. 2020 (GSL-SP, 503, 209-233)

2021 ◽  
pp. jgs2021-034
Author(s):  
Ezzoura Errami ◽  
Ulf Linnemann ◽  
Jamal El Kabouri ◽  
Mandy Hofmann ◽  
Andreas Gärtner ◽  
...  
Keyword(s):  
West African ◽  
Ultramafic Rocks ◽  
Geodynamic Evolution ◽  
The West ◽  
West African Craton ◽  
Zircon Age ◽  
Pan African ◽  
Stratigraphic Position ◽  
Age Constraints ◽  
Early Neoproterozoic

The comment of Ikenne et al. concerns recently described U-Pb baddeleyite ages, around 1.71 and 1.65 Ga, obtained on intrusive sills and dykes in the Taghdout-Lkest Group in the SW domain of the Anti-Atlas (AA). These authors suggest an independent geodynamic evolution of the eastern and western domains of the Anti-Atlas prior to the Ediacaran period. Furthermore, they state that we do not take this magmatic event into account when interpreting our data. We like to emphasize that this is beyond the scope of our paper and does not affect our interpretation of the AA evolution during the deposition of the Ediacaran sedimentary successions (Saghro, Mgouna, and Ouarzazate goups). We agree with the comment that we did not distinguish the Taghdout-Lkest from the Bleida-Tachdamt groups and now we separate them in the revised figure 2. The different geodynamic evolution of the SW and NE Anti-Atlas domains in pre-Ediacaran times sensu Ikenne et al., is not consistent with abundant inherited Paleoproterozoic zircon detritus and Nd model ages (0.80-1.82 Ga) from the northeastern Anti-Atlas and the Meseta. There is no doubt about Late Paleoproterozoic baddeleyite ages, but they do not have an analogue in the zircon age record of the West African Craton, which is expected from ultramafic rocks with few zircon grains. However, they locally allow assuming a Late Paleoproterozoic deposition of the lower Taghdout-Lkest Group. Any age constraints for the upper parts of this group are lacking, thus allowing a hypothetic deposition between ca. 1.65 Ga and 0.83 Ga (the assumed age of initial Bleida-Tachdamt Group deposition). Therefore, it is very important to close the gap in detailed stratigraphic studies that would allow differentiating between the different Late Paleoproterozoic and Early Neoproterozoic events including the stratigraphic position of the upper Taghdout-Lkest Group and Bleida-Tachdamt group.

About this title - Mineralization and Sustainable Development in the West African Craton: From Field Observations to Modelling

10.1144/sp502 ◽  
2021 ◽  
Vol 502 (1) ◽  
pp. NP-NP
Author(s):  
T. Aïfa
Keyword(s):  
Sustainable Development ◽  
West African ◽  
Geodynamic Evolution ◽  
The West ◽  
Mineral Research ◽  
West African Craton ◽  
Origin And Evolution ◽  
Pan African ◽  
New Knowledge ◽  
Modelling Techniques

This Special Publication combines results obtained by interdisciplinary groups from numerous academic institutions working on Paleoproterozoic formations to decipher the origins of the main mineralization resources in the West African Craton (WAC) and their impacts on African economic development. Structural, geophysical, sedimentological, stratigraphical, geochemical, petrophysical and mineralogical analyses have been used to highlight the complexities involved in mineralization emplacement and its origin and evolution within the WAC. Fourteen articles contribute to new knowledge in mineral research. They show that the geodynamic evolution of the WAC is complex from one area to another: it involves subduction, collision and obduction during several deformation phases ranging from Birimian (2.3–2.0 Ga) to Pan-African (650–450 Ma) events. Various modelling techniques, when integrated, help in understanding the mechanisms of mineralization emplacement, some of which are still a matter of debate. The challenge for further studies is mitigation for sustainable development that can be appropriately used to minimize such damage.

Interprétation géodynamique du domaine pan-africain (Précambrien terminal) de l'Anti-Atlas (Maroc) à partir de données géologiques et géochronologiques

1980 ◽  
Vol 17 (1) ◽  
pp. 142-155 ◽  
Author(s):  
M. Leblanc ◽  
J. R. Lancelot
Keyword(s):  
Continental Margin ◽  
Active Continental Margin ◽  
West African ◽  
The Other ◽  
Geochronological Data ◽  
Geodynamic Evolution ◽  
The West ◽  
West African Craton ◽  
Northern Margin ◽  
Pan African

U–Pb and Rb–Sr ages performed in the Anti-Atlas (Morocco), especially in Bou Azzer area, demonstrate a Pan-African orogeny (680–570 Ma), along the northern margin of the West African craton (2000 Ma). Geological and geochronological data allow the reconstitution of a coherent succession of events of Pan-African ages. The geodynamic evolution of this domain comprises a stage of oceanic opening (ophiolites) followed with a stage of closure: obduction of the ophiolites on the craton, then subduction under an active continental margin. This segment of the Pan-African belt can be correlated with the other parts of the belt, located on the eastern margin of the West African craton.

The magmatic evolution at the Moroccan outboard of the West African craton between the Late Neoproterozoic and the Early Palaeozoic

2008 ◽  
Vol 297 (1) ◽  
pp. 329-343 ◽  
Author(s):  
H. Ezzouhairi ◽  
M. L. Ribeiro ◽  
N. Ait Ayad ◽  
M. E. Moreira ◽  
A. Charif ◽  
...  
Keyword(s):  
West African ◽  
Magmatic Evolution ◽  
The West ◽  
West African Craton ◽  
Late Neoproterozoic ◽  
Early Palaeozoic

Paleomagnetism of the ~860 Ma Manso dyke swarm, West Africa: implications for the assembly of Rodinia

2021 ◽  
Author(s):  
Paul Yves Jean Antonio ◽  
Lenka Baratoux ◽  
Ricardo Ivan Ferreira Trindade ◽  
Sonia Rousse ◽  
Anani Ayite ◽  
...  
Keyword(s):  
West Africa ◽  
West African ◽  
Dyke Swarm ◽  
Jigsaw Puzzle ◽  
The West ◽  
West African Craton ◽  
Contact Test ◽  
Fine Grained ◽  
Paleomagnetic Pole ◽  
Coarse To Fine

<p>The West African Craton (WAC) is one of the major cratons in the Rodinia jigsaw puzzle (~1000–750 Ma). In the Rodinian models, the position of West Africa is mainly constrained by the assumption that it had been a partner of Amazonia since the Paleoproterozoic. Unfortunately, no paleomagnetic data are available for these cratons when the Rodina supercontinent is considered tectonically stable (~1000-750 Ma). Thus, every new reliable paleomagnetic pole for the West African Craton during the Neoproterozoic times is of paramount importance to constrain its position and testing the Rodinia models. In this study we present a combined paleomagnetic and geochronological investigation for the Manso dyke swarm in the Leo-Man Shield, southern West Africa (Ghana). The ~860 Ma emplacement age for the NNW-trending Manso dykes is thus well-constrained by two new U-Pb apatite ages of 857.2 ± 8.5 Ma and 855 ± 16 Ma, in agreement with baddeleyite data. Remanence of these coarse-to-fine grained dolerite dykes is carried by stable single to pseudo-single domain (SD-PSD) magnetite. A positive baked-contact test, associated to a positive reversal test (Class-C), support the primary remanence obtained for these dykes (13 sites). Moreover, our new paleomagnetic dataset satisfy all the seven R-criteria (R=7). The ~860 Ma Manso pole can thus be considered as the first key Tonian paleomagnetic pole for West Africa. We propose that the West Africa-Baltica-Amazonia-Congo-São Francisco were associated in a long-lived WABAMGO juxtaposition (~1100–800 Ma).</p><p><strong>Keywords:</strong> West Africa, Neoproterozoic, Tonian, Rodinia, paleomagnetism.</p><p> </p>

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