Editing Trace fossil (section)

== Ichnofacies ==
{{main|Ichnofacies}}
[[Ichnofacies]] are assemblages of individual trace fossils that occur repeatedly in time and space.<ref name=":0">{{Cite book|url=https://raregeologybooks.files.wordpress.com/2015/03/principles-of-sedimentology-and-stratigraphy-by-sam-jr-boggs.pdf|title=Principles of Sedimentology and Stratigraphy|last=Boggs, Jr.|first=Sam|publisher=Pearson Education, Inc.|year=2006|isbn=978-0-13-154728-5|edition=4th|location=Upper Saddle River, NJ|pages=102–110|access-date=2017-02-01|archive-url=https://web.archive.org/web/20160331122234/https://raregeologybooks.files.wordpress.com/2015/03/principles-of-sedimentology-and-stratigraphy-by-sam-jr-boggs.pdf|archive-date=2016-03-31}}</ref> Palaeontologist [[Adolf Seilacher]] pioneered the concept of ichnofacies, whereby geologists infer the state of a sedimentary system at its time of deposition by noting the fossils in association with one another.<ref name="Seilacher1967" /> The principal ichnofacies recognized in the literature are ''[[Skolithos]]'', ''[[Cruziana]]'', ''[[Zoophycos]]'', ''[[Nereites]], Glossifungites, [[Scoyenia]], [[Trypanites]], [[Teredolites]],'' and ''[[Psilonichnus|Psilonichus]]''.<ref name=":0" /><ref name=":1">{{Cite book|title=Facies Models 4|last1=MacEachern|first1=James|last2=Pemberon|first2=S. George|last3=Gingras|first3=Murray K.|last4=Bann|first4=Kerrie L.|year=2010|isbn=978-1-897095-50-8|editor-last=James|editor-first=Noel|pages=19–58|chapter=Ichnology and Facies Models|publisher=Geological Association of Canada |editor-last2=Dalrymple|editor-first2=Robert W.}}</ref> These assemblages are not random. In fact, the assortment of fossils preserved are primarily constrained by the environmental conditions in which the trace-making organisms dwelt.<ref name=":1" /> Water depth, [[salinity]], hardness of the substrate, dissolved oxygen, and many other environmental conditions control which organisms can inhabit particular areas.<ref name=":0" /> Therefore, by documenting and researching changes in ichnofacies, scientists can interpret changes in environment.<ref name=":1" /> For example, ichnological studies have been utilized across mass extinction boundaries, such as the [[Cretaceous–Paleogene extinction event|Cretaceous–Paleogene mass extinction]], to aid in understanding environmental factors involved in mass extinction events.<ref>{{Cite journal|last1=Buatois|first1=Luis A.|last2=Angulo|first2=Solange|last3=Mangano|first3=María G.|date=2013-04-01|title=Onshore expansion of benthic communities after the Late Devonian mass extinction|journal=Lethaia|language=en|volume=46|issue=2|pages=251–261|doi=10.1111/let.12001|issn=1502-3931}}</ref><ref>{{Cite book|title=Trace Fossils: Concepts, Problems, Prospects|last1=Marrow|first1=Jared R.|last2=Hasiotis|first2=Stephen T.|publisher=Elsevier Science|year=2007|isbn=978-0-444-52949-7|editor-last=Miller III|editor-first=William|pages=575–598|chapter=Endobenthic Response through Mass-Extinction Episodes: Predictive Models and Observed Patterns}}</ref>