How are trace fossils formed?
Trace fossils may be impressions made on the substrate by an organism: for example, burrows, borings (bioerosion), footprints and feeding marks, and root cavities. The term in its broadest sense also includes the remains of other organic material produced by an organism – for example coprolites (fossilized droppings) or chemical markers – or sedimentological structures produced by biological means – for example, stromatolites. Trace fossils contrast with body fossils, which are the fossilised remains of parts of organisms’ bodies, usually altered by later chemical activity or mineralisation.
