Fossils explained 40/The Lady Burn Starfish Beds

摘要

Exceptional preservation in the fossil record can take various forms. It can include the articulated skeleton of a large vertebrate, such as an ichthyosaur or a mammoth, in which the bones still maintain the same relative positions as they did in life. Exceptional preservation can also include fossils from time intervals that are considered essentially unfossiliferous, such as the late Precambrian Ediacara biota (see Geology Today, v.17 pp. 115-120, 2001), representing a phase of metazoan life dominated by unmineralized organisms. Such 'soft-bodied' fossils are perhaps best known from the slightly younger (Middle Cambrian) Burgess Shale fauna of British Columbia (see Geology Today, v.17, pp. 231-235, 2001), which includes a truly diverse biota of both skeletonized and unskeletonized animals. All of these examples of preservation of an unusually high quality can be considered Konservat-Lagerstatten, or fossil conservation deposits, although the term is most commonly applied to those deposits that preserve unmineralized organisms and soft tissues.