Neoproterozoic and Hercynian metamorphic events in the Central Mauritanides: Implications for the geodynamic evolution of West Africa

History of the West African Neoproterozoic Ocean: Key to the geotectonic history of circum-Atlantic Peri-Gondwana (Adrar Souttouf Massif, Moroccan Sahara)

“…Therefore, the 634 Ma age is interpreted to reflect the main peak of island arc formation due to oceanward subduction Murphy et al, 2013). This age is in accordance to other coeval subduction-related magmatic events along the western margin of the West African Craton Villeneuve and Dallmeyer, 1987;Dallmeyer and Lécorché, 1990;Hefferan et al, 2000;Doblas et al, 2002;Condie, 2003;Lahondère et al, 2005;Gasquet et al, 2008;Caby and Kienast, 2009;El Hadi et al, 2010;Fig. 8).…”

“…Although there is no simple connection between the northern and the central Mauritanides (Le Goff et al, 2001;Caby and Kienast, 2009), potentially equivalent and / or correlating Neoproterozoic units of oceanic origin occur at several localities along the western margin of the West African Craton Villeneuve et al, 2006;Villeneuve, 2008). One of them is represented by the amphibolites and eclogites of the Tarf Magneïna unit, Mauritania, which is located in the southern extension of the Adrar Souttouf Massif.…”

The relations between Gondwana and the adjacent peripheral Cadomian domain—constrains on the origin, history, and paleogeography of the peripheral domain

“…They related this event to a collision with a buried continental fragment farther west. However, Caby and Kienast (2009) did not recognize this event at lat. 17-18°N.…”

“…lat. 13°N it was reworked by the Variscan Mauritanide orogeny (Lécorché et al, 1989;Lytwyn et al, 2006;Villeneuve, 2008;Caby and Kienast, 2009;Villeneuve et al, 2010). The eastern units, thrust over the WAC, consist of low grade metasediments (with a Variscan overprint) that resemble the Neoproterozoic cover of the WAC, but with intercalated volcanics.…”

“…These record a suture formed by the closure of an oceanic basin at ca. 650-640 Ma that also produced high-P metamorphism (Caby and Kienast, 2009;Villeneuve et al, 2010). These rocks are overthrust from the west by a unit (M'Bout, Guidimakha, NiokoloKoba) dominated by calc-alkaline metavolcanics and granitoids that are interpreted as having formed in a ≥650 Ma magmatic arc that was deformed and metamorphosed at 640-620 Ma and cooled by ca.…”