Dr. Rowan Martindale, a paleoecologist and geobiologist at the University of Texas at Austin, was hiking through Morocco’s Dadès Valley in the Central High Atlas Mountains when an unusual detail in the rocks made her stop.
She and her team, including Stéphane Bodin of Aarhus University, were moving through the rugged landscape to investigate the ecology of ancient reef systems that once lay beneath the sea.
Reaching those reefs meant crossing repeated stacks of turbidites, sediments left behind by powerful underwater debris flows. Turbidites often preserve ripple marks, but Martindale noticed something else layered on top of the ripples. The surface showed small, irregular corrugations that did not fit what she expected to see.









