bioclast
Bioclast is a term used in geology and paleontology to refer to fragments of biological origin preserved in sedimentary rocks. A bioclast is any piece of formerly living material that survives weathering and burial, including calcareous shells and skeletons, tests of single-celled organisms, coral fragments, bryozoans, echinoderm spines, and other biogenic debris. Bioclasts can be macrofossils, such as large shell pieces, or microfossils, like foraminiferan tests or radiolarian siliceous remains.
Bioclasts are contrasted with lithoclasts, which are fragments of preexisting rocks derived from erosion of nonbiogenic
The presence and composition of bioclasts provide information on past ecosystems, depositional environments, and diagenetic history.