Early Neoproterozoic rift-related magmatism in the Anti-Atlas margin of the West African craton, Morocco

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.

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Structure, evolution and palaeogeography of the West African craton and bordering belts during the Neoproterozoic

Precambrian Research ◽

10.1016/0301-9268(94)90094-9 ◽

1994 ◽

Vol 69 (1-4) ◽

pp. 307-326 ◽

Cited By ~ 105

Author(s):

M. Villeneuve ◽

J.J. Cornée

Keyword(s):

West African ◽

Structure Evolution ◽

The West ◽

West African Craton

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

Geological Society London Special Publications ◽

10.1144/sp297.16 ◽

2008 ◽

Vol 297 (1) ◽

pp. 329-343 ◽

Cited By ~ 13

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

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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

Geological Society London Special Publications ◽

10.1144/sp323.11 ◽

2009 ◽

Vol 323 (1) ◽

pp. 231-254 ◽

Cited By ~ 29

Author(s):

M. Lompo

Keyword(s):

West African ◽

Geodynamic Evolution ◽

The West ◽

West African Craton ◽

Oceanic Plateau ◽

Magmatic Rocks

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

10.5194/egusphere-egu21-13336 ◽

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

The West African Craton (WAC) is one of the major cratons in the Rodinia jigsaw puzzle (~1000&#8211;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 &#177; 8.5 Ma and 855 &#177; 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-S&#227;o Francisco were associated in a long-lived WABAMGO juxtaposition (~1100&#8211;800 Ma).Keywords: West Africa, Neoproterozoic, Tonian, Rodinia, paleomagnetism.&#160;

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