Microbial modulation of sedimentary processes and bed-surface preservation: insights from modern and Ediacaran coastal-flat deposits

Abstract

Microbially Induced Sedimentary Structures (MISS) record the feedback between microbial mats and physical sedimentary processes, yet their palaeoenvironmental interpretation requires process-based constraints. In this study, we compare MISS preserved in late Ediacaran heterolithic deposits of the Cerro Negro Formation (Tandilia System, Argentina) with mat influenced surfaces from a modern coastal flat at Paso Seco (northern Patagonia) to link recurring structures to depositional and early preservation pathways. At Paso Seco, ripples and sand sheets form during storm flooding. During subsequent quiescence and exposure, cohesive microbial mats develop rapidly, trapping and binding fine-grained sediments, draping ripple troughs, and generating wrinkle textures, low-relief domes and bulges, and mat-controlled modification of desiccation cracks.