New U–Pb zircon ages from the Eastern Saghro massif in the Anti-Atlas of Morocco demonstrate a link between Pan-African transpressive collision at c. 600 Ma and transtension caused by the onset of Cadomian subduction and arc development from c. 570 Ma onwards. We present new U–Pb laser ablation inductively coupled plasma mass spectrometry ages of detrital and magmatic zircon from the Saghro, M'Gouna, and Ouarzazate Groups. The siliciclastic deposits of the Saghro Group were deposited in a back-arc setting developed on stretched continental crust of the West African margin. Collision with the Atlas–Meseta domain led to the closure of the back-arc basin before 600 Ma. Time of exhumation and surface exposure of the newly formed Pan-African basement is bracketed to c. 30 Ma owing to the maximum depositional age of 571 ± 4 Ma of the overlying M'Gouna Group. The U–Pb age of 567 ± 4 Ma for the lowermost ignimbrite of the Ouarzazate Group limits the time for the deposition of the M'Gouna Group to less than 4 Ma. The Pan-African orogeny was finished at c. 600 Ma whereas the onset of transtension related to Cadomian back-arc formation was very much younger from c. 570 Ma onwards.

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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<p align="JUSTIFY">Convergence zones are marked by a variety of settings that may follow each other in modern-day tectonics, including compressive phases such as subduction, obduction, collision but also extensive ones such as back-arc opening or stress-relaxation during orogenesis. Hence, the protracted evolution leading to a super-continent block amalgamation may be difficult to decipher and so may be the forcings on external enveloppes such as volcanism or erosion caused by the different phases.</p> <p align="JUSTIFY">This question arises critically at the time of the Pan-African Orogenesis (1-0.5 Ga) assembling Gondwana, a time of supposedly dramatic and diachronical changes for external envelopes: glaciations of debated scales, deposition of various Banded Iron Formations, first (Ediacarian) fauna, replacement by Cambrian faunas. Our goal is to explore in detail the geodynamical succession leading to the amalgamation of blocks along the northern margin of the West African Craton (WAC), outcropping in the Central Anti-Atlas region, Morocco. This region is characterized by the occurrence of extended convergence-related magmatism, ophiolite emplacement and basins fillings (including BIF) during Cryogenian and Ediacaran periods.</p> <p align="JUSTIFY">Data obtained from compilation of cartographic work, whole-rock geochemistry and datation reveals a polyphased but still poorly constrained evolution through proxies of continentality (<span lang="en-US">ε</span>Nd) and of crustal thickness (Sr/Y ratio). We present new data spanning metamorphic petrology, basin stratigraphy, coupled datation and trace element analysis in detrital zircons in order to better understand the evolution of the geodynamic, magmatic and drainage systems. <span lang="en-US">We propose a geodynamic scenario based on these data:</span></p> <ul> <li> <p align="JUSTIFY"><span lang="en-US">Development of an early oceanic arc (760-720 Ma) with juvenile magmatic signature (3<</span><span lang="en-US">ε</span><span lang="en-US">Nd(t)<7), its accretion on the WAC is followed by an episode of calc-alkaline magmatism (710-700 Ma).</span></p> </li> <li> <p lang="en-US" align="JUSTIFY">Second arc development (700-670 Ma) only seen in detrital and inherited zircons, its accretion at 670 Ma is followed by late-orogenic magmatism (660-650 Ma) associated with decreasing crustal thickness (from 70 to 25 km).</p> </li> <li> <p lang="en-US" align="JUSTIFY">Third arc development on the newly formed continent margin (640-600 Ma) until oceanic closure and collision. Intense late orogenic magmatism occurs (590-570 Ma), coeval with the decreasing crustal thickness (from 100 to 30 km).</p> </li> <li> <p lang="en-US" align="JUSTIFY">A late phase of calc-alkaline is recorded (570-550 Ma) at constant and regular crustal thickness (25 km). A 550 Ma compressive event is recorded, very few calc-alkaline follows.</p> </li> <li> <p lang="en-US" align="JUSTIFY">The onset of Cambrian with the development of a large passive margin capping the whole region. This change coincides with disappearance of ice-house climate evidence from the global sedimentological record.</p> </li> </ul>