Physical volcanology, geochemistry and basin evolution of the Ediacaran volcano-sedimentary succession in the Bas Draâ inlier (Ouarzazate Supergroup, Western Anti-Atlas, Morocco)

Chemical analysis of BDS volcanic and subvolcanic rocks belongs to high-k calc-alkaline and alkali-calcic to alkaline magmatic trend typical for a post-collision setting. Trace elements spidergrams show a pattern typical for subduction-related suites of orogenic belts. REE patterns show moderate enrichment in LREE relative to flat HREE, with strong negative Eu anomaly in rhyolitic rocks. Geotectonic diagrams suggest an affinity transitional between subduction- and within-plate settings. BDS magmatism can be explained by a magma source enriched in inherited components from Pan-African subduction. Volcanosedimentary facies, structural features, geochemical composition and radiometric data of BDS suggests correlation with the upper Ouarzazate Supergroup of the Anti-Atlas. Geodynamic evolution of the BDS was an expression of an extensional setting that operated in northern Gondwana margin precursory to the Cambrian anorogenic volcanic activity.