Mixed and recycled detrital zircons in the Paleozoic rocks of the Eastern Moroccan Meseta: paleogeographic inferences
Metadatos
Afficher la notice complèteAuteur
Accotto, Cristina; Martínez Poyatos, David Jesús; Azor, Antonio; Talavera, Cristina; Evans, Noreen; Jabaloy Sánchez, Antonio; Azdimousa, Ali; Tahiri, Abdelfatah; El Hadi, HassanEditorial
Elsevier
Materia
Eastern Moroccan Meseta Paleozoic paleogeography West African Craton U-Pb geochronology Zircon provenance
Date
2019Referencia bibliográfica
Accotto et al. (2019) Mixed and recycled detrital zircons in the Paleozoic rocks of the Eastern Moroccan Meseta: paleogeographic inferences. Lithos. DOI: 10.1016/j.lithos.2019.04.011
Patrocinador
Ministerio de Economía y Competividad (MINECO) of Spain CGL2015-71692-P, BES-2016-078168; Australian Research Council (LE150100013); Auscope NCRIS (AQ44 Australian Education Investment Fund program)Résumé
The paleogeographic evolution of the Moroccan Variscides has been a matter of discussion for several decades,
with current theoriesmostly based on classical geological correlations. In this regard, the scarce number of studies
devoted to U-Pb geochronological analyses of detrital zircon populations is particularly limiting when trying
to ascribe the different domains to a single continental piece either derived from the West African Craton or to
different sources, with some located in the Nubian Shield or the SaharanMetacraton. In thiswork, detrital zircon
grains from 10 samples of sandstones from the Paleozoic (Ordovician to Devonian) sequence of the Eastern
Meseta andMiddle Atlaswere dated in order to identify possible sediment sources and elucidate the paleogeography
of this easternmost portion of the Moroccan Variscides. The main detrital zircon populations have
Ediacaran-Cryogenian ages (610–670 Ma, related to the Cadomian and/or Pan-African orogeny) and middle
Paleoproterozoic ages (1980–2080 Ma, related to the Eburnean orogeny), which are in agreement with previous
data from the Western Meseta, suggesting similarity between both Mesetas, and strong West African Craton
affinity. Such an affinity verifies themost accepted paleogeographic interpretation considering that theMoroccan
Mesetas remained attached to northern Gondwana during the entire Paleozoic period. The main differences
between our samples and those from the Western Meseta concern the minor detrital zircon populations, such
as the Cambro-Ordovician and the Tonian-Stenian ones. In particular, Eastern Meseta and Middle Atlas samples
lack a Cambro-Ordovician detrital zircon population, usually interpreted as related to the rifting that opened the
Rheic Ocean. This population is locally reported in the Western Meseta and widely described in southwestern
Europe, where magmatism of this age is well known. Furthermore, the most northeastern samples are also
characterized by a Tonian-Stenian detrital zircon population (up to 30% of the data), which might imply northeastern
African sources (Saharan Metacraton and/or Arabian-Nubian Shield)