Geochronology and isotopic geochemistry of Ediacaran high-K calc-alkaline felsic volcanism: An example of a Moroccan perigondwanan (Avalonian?) remnant in the El Jadida horst (Mazagonia)

Abstract Reliable new U/Pb zircon data from volcanic felsic rocks outcropping in the El Jadida region (Moroccan Coastal block) were carried out on five samples. Concordant U/Pb zircon data yielded two main crystallization ages at about 605 Ma (described for the first time in this area) and 580 Ma. These Neoproterozoic ages correspond to the Cadomian and/or to the end of the Pan-African orogenic cycle. The presence of inherited Mesoproterozoic zircons in the felsic magmatic rocks suggests that this older continental crust belonged to the Eastern Avalonia terrane, where sources of the same age are already known. Furthermore, isotopic Sm/Nd analyses were carried out on the same rocks and the results suggested that the source of the studied volcanic rocks has a TDM model age between 1.59 and 1.86 Ga, which may correspond to Paleo-Mesoproterozoic crustal components. The low values of ɛNd, together with the absence of magmatic mafic microgranular enclaves in the studied rocks, preclude any involvement of the mantle in the genesis of the El Jadida felsic rocks. Finally, combining our new data with other data previously published (e.g. El Houicha et al., 2018), we interpret the El Jadida Ediacaran high-K calc-alkaline magmatism horst (Mazagonia) as an example of a Moroccan perigondwanan (Avalonian?) remnant.