Detrital zircon U-Pb ages in the Rif Belt (northern Morocco): Paleogeographic implications

Detrital zircon U-Pb age distributions in Mesozoic and Cenozoic rocks from the External Rif and Maghrebian Flysch Complex (including the so-called Mauretanian internal flysch units) are very similar, strongly suggesting that the External Rif and the entire Maghrebian Flysch Complex were part of the same NW African paleomargin. These patterns include scarce Paleozoic zircon grains that show influence from the Sehoul Block. Neoproterozoic and Paleoproterozoic grains are abundant with a dominant Ediacaran zircon population at ca. 590 Ma, which could have been sourced from the Variscan Moroccan Mesetas, the northern components of the West African Craton, or from Triassic sediments from the Central High Atlas and Argana basins. Mesoproterozoic zircon ages between 1.1 and 1.6 Ga were also observed (15% in the combined age spectra), the nearest sources for these being in the central part of the West African Craton. Transport of the Mesoproterozoic grains to the NW African paleomargin requires northward-directed fluvial systems parallel to the Central Atlantic continental margin of Africa. In contrast, samples from the Internal Rif or Alborán Domain are different to those from the External Rif and Maghrebian Flysch Complex, especially in the scarcity of Mesoproterozoic zircons, suggesting that the Alborán Domain was not a source area for zircons found in the NW African paleomargin.