load cast

In geology, "load cast" refers to a sedimentary structure formed shortly after deposition. It occurs when denser material, like sandstone or limestone, sinks into softer, underlying mud. This process is a result of unequal loading on the sediment before it hardens into rock. Load casts are considered penecontemporaneous sedimentary structures, meaning they form around the same time as the sediment deposition. They are typically found on the base of a bed, often as casts filling depressions in the underlying mud surface. These structures are distinct from "bed load," which describes sediment transported along a stream bottom.123