A rounded or irregular grain of fine-grained calcium carbonate, typically measuring less than a millimeter in diameter, found in limestone. Unlike ooids, peloids lack concentric internal structure and are often formed from the fecal pellets of marine organisms or the breakdown of larger calcareous fragments. Geologists use their presence and sorting to interpret the energy levels of ancient marine depositional environments.
Heard on the job
The thin section shows a high concentration of peloids mixed with skeletal fragments in a micrite matrix.