Ediacaran Fluviolacustrine Depositional Systems of the Amane n’Tourhart and Tifernine Basins (Anti-Atlas, Morocco): Facies Analysis, Petrography, Paleoenvironments, and Climatic–Volcanic Controls

This study integrates sedimentological and stratigraphic insights into the Ediacaran fluviolacustrine successions of the Amane n’Tourhart and Tifernine basins. The Amane n’Tourhart Basin developed within a caldera volcanic context, whereas the Tifernine Basin formed in a pre-caldera setting. These successions provide valuable information about the sedimentary processes operating in late Ediacaran continental environments. Field observations, facies analysis, and petrography reveal a variety of siliciclastic, carbonate, mixed siliciclastic- carbonate, and volcaniclastic facies. These facies form associations indicative of alluvial fan, floodplain, and shallow-water lacustrine settings. Alluvial fan deposits are dominated by conglomerates and sandstones forming braided systems. Fluviolacustrine sequences show a transition from clayey siltstones with calcareous nodules to nodular and massive limestones, marking a gradual shift from fluvial to lacustrine conditions. Laminated limestones and stromatolites indicate intermittent microbial activity that contributed to carbonate precipitation. Sedimentation was strongly influenced by volcanic inputs and climatic fluctuations, alternating between humid and arid conditions. These factors drove cycles of channel incision, sediment infill, and lake expansion–contraction, illustrating the dynamic interplay of tectonics, volcanism, and climate that modulated deposition in these Ediacaran terrestrial basins.