{{Short description|Trace fossil}} thumb|''Psilonichnus'' An '''ichnofacies''' is an assemblage of trace fossils that provides an indication of the conditions that their formative organisms inhabited.
==Concept== Trace fossil assemblages are far from random; the range of fossils recorded in association is constrained by the environment in which the trace-making organisms dwelt.<ref name=Seilacher1967/> Palaeontologist Adolf Seilacher pioneered the concept of ichnofacies, whereby the state of a sedimentary system at its time of deposition could be deduced by noting the trace fossils in association with one another.<ref name=Seilacher1967>{{cite journal | author = Seilacher, A. | year = 1967 | title = Bathymetry of trace fossils | journal = Marine Geology | volume = 5 | issue = 5–6 | doi = 10.1016/0025-3227(67)90051-5 | pages = 413–428 }}</ref>
==Significance== Ichnofacies can provide information about water depth, salinity, turbidity and energy. In general, traces found in shallower water are vertical, those in deeper water are more horizontal and patterned.<ref name=Seilacher1967/> This is partly because of the relative abundance of suspended food particles, such as plankton, in the shallower waters of the photic zone, and partly because vertical burrows are more secure in the turbulent conditions of shallow water. In deeper waters, there is a necessary transition to sediment feeding (extracting nutrients from the mud).<ref name=Seilacher1967/> Food availability, hence trace type, is also controlled by energy: high energy environments keep food particles suspended, whereas in lower energy areas, food settles out evenly, and burrows will tend to spread out to cover as much area as economically as possible.<ref name=Seilacher1967/>
Ichnofacies have a major advantage over using body fossils to gauge the same factors: body fossils can be transported, but trace fossils are always ''in situ''.<ref name=Seilacher1967/>
==Recognized invertebrate ichnofacies==
{|align=center !colspan=4 align=center|Marine Invertebrate Ichnofacies<ref name="Seilacher1967" /><ref name=UCL>{{cite web|url=http://www.es.ucl.ac.uk/tf/ichno.htm|title=Ichnofacies|publisher=UCL|access-date=2013-10-27|archive-date=2013-10-29|archive-url=https://web.archive.org/web/20131029210738/http://www.es.ucl.ac.uk/tf/ichno.htm|url-status=dead}}</ref><ref name=Benton1997>{{cite book | last1=Benton | first1=M.J. |author-link = Michael Benton | last2=Harper | first2=D.A.T. | author-link2 = David Harper (palaeontologist) | year = 1997 | title = Basic Palaeontology | publisher = Longman Harlow, Essex, England | isbn = 9780582228573 }}</ref><ref name=":0" /> |- !Name !Common Ichnogenera !Substrate !Inferred Paleoenvironment |- |''Scoyenia''<ref name="Seilacher1967" /> |''Skolithos, Cruziana, Diplichnites, Rusophycus''<ref name="Woolfe1990">{{cite journal |author = Woolfe, K.J.|year = 1990|title = Trace fossils as paleoenvironmental indicators in the Taylor Group (Devonian) of Antarctica|journal = Palaeogeography, Palaeoclimatology, Palaeoecology|volume = 80|issue = 3–4|pages = 301–310|doi = 10.1016/0031-0182(90)90139-X}}</ref> |Variable - typically sandstones; red beds may be nearby |Diagnostic of terrestrial<ref name="Seilacher1967" />/freshwater<ref name="Woolfe1990" /> facies. |- |''Psilonichnus''<ref name=":1">{{Cite journal|title = The Psilonichnus ichnocoenose, and its relationship to adjacent marine and nonmarine ichnocoenoses along the Georgia coast|last1 = Frey|first1 = Robert W.|date = 1987|journal = Bulletin of Canadian Petroleum Geology|last2 = Pemberton|first2 = S. George|issue = 35}}</ref> |''Psilonichnus, Coenobichnus, Cellicalichnus, Macanopsis''<ref name=":0" /> |Highly variable grain size, sand, soft substrate<ref name=":1" /> |Coastal barrier islands, strand plains, delta plains, estuaries, lagoons, and bays.<ref name=":0" /><ref name=":1" /> |- |''Trypanites''<ref name=":2">{{Cite journal|title = Uniformity in marine invertebrate ichnology|last1 = Frey|first1 = R. W.|date = 1980|journal = Lethaia|doi =10.1111/j.1502-3931.1980.tb00632.x|last2 = Seilacher|first2 = Adolf|volume = 13| issue=3 |pages = 183–207}}</ref> |''Entobia, Trypanites, Gastrochaenolites, Caulostrepsis, Maeandropolydora, Conchotrema''<ref name=":0" /> |Hardground, endurated substrates<ref name=":2" /> |Coastal cliffs, reefs, beachrock<ref>{{Cite book|title = Facies Models|last1 = Frey|first1 = Robert W.|pages = 189–207|last2 = Pemberton|first2 = S. George}}</ref> |- |''Teredolites''<ref>{{Cite journal|title = A Cretaceous woodground: the Teredolites ichnofacies|last1 = Bromely|first1 = Richard G.|date = 1984|journal = Journal of Paleontology|volume = 58|pages = 488–498|last2 = Pemberton|first2 = S. George|others = R.A. Rahmani}}</ref><ref>{{Cite journal|title = Modern perspectives on the Teredolites ichnofacies: observations from Willapa Bay, Washington|last1 = Gingras|first1 = M.K.|date = 2004|journal = PALAIOS|doi = 10.1669/0883-1351(2004)019<0079:mpotti>2.0.co;2|last2 = MacEachern|first2 = J.A.|volume = 19|pages = 79–88|others = Pickerill, R.K.| s2cid=96426958 | url=http://doc.rero.ch/record/13979/files/PAL_E990.pdf }}</ref> |''Teredolites, Thalassinoides''<ref name=":0" /> |Resistant woody and coaly substrates<ref name=":3">{{Cite journal|title = Ichnology and sedimentology of shallow to marginal marine systems|last1 = Pemberton|first1 = S. George|date = 2001|journal = Geological Association of Canada Short Course Notes|issue = 228|pages = 29–62|last2 = Spila|first2 = M.|others = Pulham, A.J., Saunders, T., MacEachern, J.A., Robbins, D., and Sinclair, I.K.}}</ref> |Driftwood, peat<ref name=":3" /> |- |''Glossifungites''<ref name="Seilacher1967" /> |''Diplocraterion, Skolithos, Spongeliomorpha, Rhizocorallium, Arenicolites, Thalassinoides, Fuersichnus''<ref name="Seilacher1967" /><ref name=":0">{{Cite book|title = Ichnology: Organism-Substrate Interactions in Space and Time|last1 = Buatois|first1 = Luis|publisher = Cambridge University Press|year = 2011|isbn = 978-0-521-85555-6|location = New York|pages = 67–69|last2 = Mangano|first2 = M. Gabriela}}</ref> |Firmground, dewatered muds<ref name="Seilacher1967" /> |Shallow, marginal marine, deltaic or estuarine erosion surfaces.<ref name="Seilacher1967" /> |- |''Skolithos''<ref name="Seilacher1967" /> |''Skolithos, Ophiomorpha, Arenicolites, Diplocraterion''<ref name="Seilacher1967" /><ref name=":0" /> |Unconsolidated littoral sands<ref name="Seilacher1967" /> |Beaches and sandy tidal flats, shallow water, foreshore to upper-shoreface, above wavebase<ref name="Seilacher1967" /><ref name=":0" /> |- |''Cruziana''<ref name="Seilacher1967" /> |''Arthrophycus, Phycodes, Rhizocorallium, Teichichnus, Arenicolites, Rosselia, Bergaueria, Thalassinoides, Lockeia, Protovirgularia, Curvolithus, Dimorphichnus, Cruziana, Rusophycus''<ref name="Seilacher1967" /><ref name=":0" /> |Sand and silt heterolithic successions and organic detritus<ref name=":0" /> |Mid to distal continental shelves. Below normal wave base, but not necessarily below storm wave base<ref name="Seilacher1967" /><ref name=":0" /> |- |''Zoophycos''<ref name="Seilacher1967" /> |''Zoophycos, Phycosiphon, Chondrites''<ref name="Seilacher1967" /><ref name=":0" /> |Marine softground, impure sands and silts<ref name="Seilacher1967" /> |Deeper water, bottom of shelf; turbidite facies<ref name="Seilacher1967" /> |- |''Nereites''<ref name="Seilacher1967" /> |''Nereites, Megagrapton, Protopaleodictyon, Spirophycus, Helminthoraphe, Glockerichnus, Spiroraphe, Cosmoraphe, Urohelminthoida, Desmograpton, Paleodictyon, Scolicia''<ref name="Seilacher1967" /><ref name=":0" /> |Fine-grained muds and clays interbedded with turbidite silts<ref name="Seilacher1967" /><ref name=":0" /> |Deep water, pelagic, base-of-slope turbidity systems<ref name="Seilacher1967" /><ref name=":0" /> |}
== Recognized vertebrate ichnofacies == {{anchor|Charirichnium}} {| class="wikitable" ! colspan="4" |Vertebrate Ichnofacies<ref name=":4">Lockley, M.G., Hunt, A.P., and Meyer, C.A., 1994. Vertebrate tracks and the ichnofacies concept: Implications for palaeoecology and palichnostratigraphy. In ''The Palaeobiology of Trace Fossils'', ed. S.K. Donovan, Chichester, UK: John Wiley & Sons, p. 241-268.</ref><ref name=":5">{{Cite journal|title = Tetrapod ichnofacies: a new paradigm|last1 = Hunt|first1 = Adrian P.|date = 2007|journal = Ichnos|doi = 10.1080/10420940601006826 |last2 = Lucas|first2 = Spencer G.| volume=14 |issue = 1–2|pages = 59–68| s2cid=129687395 }}</ref> |- |'''Name''' |'''Common Ichnogenera''' |'''Substrate''' |'''Inferred Paleoenvironment''' |- |''Chelichnus''<ref name=":5" /> ''(Laoporus)''<ref name=":4" /> |''Chelichnus, Brasilichnium''<ref name=":4" /><ref name=":5" /> |Unconsolidated, larger-grained sands |Aeolian sand dunes<ref name=":5" /> |- |''Grallator''<ref name=":4" /> |''Grallator, Jindongornipes, Koreanoformis, Avipeda, Brachychirotherium, Rhynchosauroides, Eubrontes''<ref name=":4" /><ref name=":5" /> | |Lacustrine shorelines<ref name=":5" /> |- |''Brontopodus''<ref name=":5" /> |'''''Charirichnium''', Ceratopsipes, Amblydactylus, Brontopodus''<ref name=":5" /> |Clastic or carbonate<ref name=":5" /> |Coastal plain, marine shoreline<ref name=":5" /> |- |''Batrachichnus''<ref name=":5" /> |''Batrachichnus, Limnopus, Amphisauropus, Dromopus, Dimetropus, Gilmoreichnus, Chirotherium'' | |Tidal flat-fluvial plain<ref name=":5" /> |- |''Characichnos''<ref name=":5" /> |''Characichnos, Undichna, Lunichnium, Puertollanopus, Serpentichnus, Batrachichnus, Hatcherichnus''<ref name=":5" /> |Semi-consolidated firmgrounds |Subaqueous lacustrine, estuarine, and deltaic environments<ref name=":5" /> |}
==See also== * Trace fossil classification * Bioturbation
==References==
{{reflist}}
==External links== * [http://www.es.ucl.ac.uk/tf/ichno.htm Types of Ichnofacies- University College London] {{Webarchive|url=https://web.archive.org/web/20131029210738/http://www.es.ucl.ac.uk/tf/ichno.htm |date=2013-10-29 }}
Category:Trace fossils