Geochemistry and petrogenesis of early Ediacaran volcanic rocks from taourirte district (Western High Atlas, Morocco): Origin and geodynamic implications

In the Taourirte area (Western High Atlas-Morocco), early Ediacaran volcanic activity is recorded. Volcanic rocks are mainly basalts, basaltic andesites and andesites. Petrological and geochemical studies are performed on the volcanic rocks in order to constrain their magmatic fingerprints and their geodynamic setting. Whole-rock geochemical characteristics, high TiO2 contents ranging from 1.2 to 2.81 wt%, high Zr/Y (5.43-12.08), Zr/Nb (23.81-10.50) and Zr/P2O5 (0.03-0.2) ratios, suggest an intracontinental tholeiitic affinity for these meta-volcanites. They have Ti/Y ratio varying from 240 to 1200 and Th/Ta ranging from 0.68 to 5.2 supporting their derivation from an enriched mantle source, akin to that of E-MORB, during an extensional regime. They were deposited in pull-apart basin evolved during a post-collisional regime. Their geochemical signature is a result of complex interaction processes between parental asthenospheric mantle melt and the surrounding crust.