Provenance and Tectonic Evolution of Lower Ediacaran Siliciclastics along the Northern Gondwana Margin: Geochemical and Isotopic Evidence from the Saghro Group (Anti-Atlas, Morocco)

This study investigates the provenance, weathering history, and tectono-sedimentary evolution of Lower Ediacaran siliciclastic rocks of the Imiter Formation (Saghro Group, Imiter Sub-inlier, Anti-Atlas, Morocco) deposited along the northern margin of Gondwana. An integrated approach combining petrography, whole-rock major and trace element geochemistry, rare earth elements (REE), Sm–Nd isotopes, and organic geochemistry (TOC and δ¹³Cₒᵣg) was used to constrain sediment sources and deposi-tional conditions. Geochemical proxies, including Th/Sc, La/Sc, and Zr/Sc ratios, to-gether with REE distribution patterns, indicate that the sediments were mainly derived from felsic to intermediate rocks of the upper continental crust, with only minor sedi-ment recycling. The negative εNd(t) values (−8.5 to −6.2) and Paleoproterozoic Nd model ages (1.6–2.1 Ga) further suggest erosion of evolved crustal sources related to the West African Craton. Weathering indices (CIA, CIW, PIA) suggest weak to moder-ate chemical weathering under predominantly arid conditions. Redox-sensitive proxies (V–Ni, V/Cr, V/(V+Ni)) and low TOC contents (0.1–0.3 wt.%) indicate deposition under mainly oxic to dysoxic conditions with only transient reducing episodes. Tectonic dis-crimination diagrams, supported by regional magmatism, point to sedimentation within an extensional basin evolving from active margin to continental rift conditions during the late Pan-African orogeny. The Imiter Formation records a system dominat-ed by crustal recycling, syn-rift tectonics, and dynamic redox conditions in a shallow marine environment.