Rip-up clasts (also known as mud chips) are clasts of muddy sediment of variable size that are found within sandstone or conglomerate. As the name suggests, they form when high-energy currents erode pre-existing mud from the bottom of the basin, transporting it as clasts that are later re-deposited. Rip-up clasts form in muddy sediments because mud is impermeable and cohesive, allowing it to remain as compact clasts when it is torn away from the substratum by a current. This sedimentary structure is common in many marine and continental environments where erosion alternates with deposition, for example alluvial plains, deltas, and underwater fans.
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