What do we call the structures that form when fine grained sediments at the bottom of a shallow body of water are exposed to the air and dry out?

The structures that form when fine-grained sediments at the bottom of a shallow body of water dry out and are exposed to the air are called desiccation cracks or mud cracks. These cracks occur as the sediment shrinks and fractures due to the loss of moisture. They are commonly found in environments such as lake beds or tidal flats where water levels fluctuate.