Systematics of detrital zircon U–Pb ages from Cambrian–Lower Devonian rocks of northern Morocco with implications for the northern Gondwanan passive margin
Metadatos
Afficher la notice complèteAuteur
Accotto, Cristina; Martínez Poyatos, David Jesús; Azor Pérez, Antonio; Jabaloy Sánchez, AntonioEditorial
Elsevier
Materia
NW African Variscides Moroccan mesetas West African craton Northern Gondwanan margin Provenance study Cambrian rifting
Date
2021-09-09Referencia bibliográfica
Cristina Accotto... [et al.]. Systematics of detrital zircon U–Pb ages from Cambrian–Lower Devonian rocks of northern Morocco with implications for the northern Gondwanan passive margin, Precambrian Research, Volume 365, 2021, 106366, ISSN 0301-9268, [https://doi.org/10.1016/j.precamres.2021.106366]
Patrocinador
Ministerio de Economia y Competitividad (MINECO) of Spain through the project PANGEATOR CGL2015-71692; Scanning Electron Microscope (SEM) Facility at the University of Edinburgh; Australian Geophysical Observing System grant by AQ44 Australian Education Investment Fund program; Australian Research Council LE150100013; Universidad de Granada / CBUA BES-2016-078168Résumé
The systematic acquisition of U–Pb geochronological data from detrital zircon grains has become an essential
tool in tectonic studies focused on reconstructing the pre–Variscan geography of the northern Gondwanan
passive margin. New detrital zircon ages for 16 samples from the Cambrian–Lower Devonian succession of the
Moroccan Mesetas (northern Morocco) are reported here. The results, combined with previously published data,
reassert the strong West African Craton affinity of the Paleozoic sedimentary rocks, characterized by dominant
Cadomian/Pan–African (c. 850–540 Ma) and Eburnean (c. 2.2–1.9 Ga) detrital zircon populations and a minor
Leonian/Liberian (c. 2.5 Ga) population. Primary sources of these zircon grains are well established as the West
African Craton located just to the south, but also in the Precambrian basement that locally crops out in the
Moroccan Mesetas themselves. During the Cambrian–Early Ordovician, erosion preferentially dismantled
Cadomian (c. 590–540 Ma) arc–derived rocks of the Gondwanan continental margin, while later, the slightly
older Pan–African (c. 650–600 Ma) basement became the main sediment source. In the studied samples, irregularly
present minor detrital zircon populations suggest additional sediment provenance from secondary sources
such as: (i) remote northeastern African cratons (e.g., Saharan Metacraton and/or Arabian–Nubian Shield) that
likely could have provided the c. 1.1–0.9 Ga and, possibly, the c. 1.9–1.7 Ga zircon grains, and (ii) rift–related
Cambrian–Early Ordovician volcanic centers in the Moroccan Mesetas that supplied heterogeneously distributed
– although locally dominant in small areas – sedimentary detritus before rift abortion and burial underneath the
overlying passive margin sedimentary succession.