bioevent

{{Short description|Geological process}}

A bioevent or bio-event (a shortening of 'biotic event' or 'biological event') is an event recognised in a sequence of sedimentary rocks, where there is a significant change in the biota as recorded by assemblages of fossils over a relatively short period of time. It has been defined as "short-term (hours or days to kyrs) locally, regionally, or interregionally pervasive changes in the ecological, biogeographical, and/or evolutionary character of biotas that are isochronous or nearly so throughout their range".{{cite book |title=Paleontological Events - Stratigraphic, Ecological and Evolutionary Implications |last=Sageman |first=B.B. |author2=Kauffman E.G. |author3=Harries P.J. |author4=Elder W.P. |year= 1997|publisher= Columbia University Press|location= New York|editor=Brett C.E. & Baird G.C. |chapter= Cenomanian/Turonian bioevent and ecostratigraphy in the Western Interior Basin: contrasting scales of local, regional, and global events|pages= 520–570}} Bioevents either relate to diversification of a particular fossil group or a reduction, these may equate to speciation events or extinction events, or may only represent migration. Records of the appearance and disappearance of particular taxa at a single locality are insufficient to define a bioevent.{{cite book |title=The palynology and micropalaeontology of boundaries |last=Zhang |first= S.|author2=Barnes C.R. |year=2004 |editor=Beaudoin A.B. & Head M.J. |publisher=Geological Society |location= London|series=Special Publications|volume=230|chapter=Conodont bio-events, cladistics and response to glacio-eustasy, Ordovician-Silurian boundary through Llandovery, Anticosti Basin, Québec |pages= 76–78|isbn=9781862391604 |chapter-url=https://books.google.com/books?id=l_zOZZGM2hEC&dq=zhang+barnes+2004&pg=PA47 |access-date=15 March 2012}}