Ichnofacies

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.¹ 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.¹

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.¹ 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).¹ 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.¹

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.¹

Recognized invertebrate ichnofacies

Marine Invertebrate Ichnofacies¹²³⁴
Name	Common Ichnogenera	Substrate	Inferred Paleoenvironment
Scoyenia¹	Skolithos, Cruziana, Diplichnites, Rusophycus⁵	Variable - typically sandstones; red beds may be nearby	Diagnostic of terrestrial¹/freshwater⁵ facies.
Psilonichnus⁶	Psilonichnus, Coenobichnus, Cellicalichnus, Macanopsis⁴	Highly variable grain size, sand, soft substrate⁶	Coastal barrier islands, strand plains, delta plains, estuaries, lagoons, and bays.⁴⁶
Trypanites⁷	Entobia, Trypanites, Gastrochaenolites, Caulostrepsis, Maeandropolydora, Conchotrema⁴	Hardground, endurated substrates⁷	Coastal cliffs, reefs, beachrock⁸
Teredolites⁹¹⁰	Teredolites, Thalassinoides⁴	Resistant woody and coaly substrates¹¹	Driftwood, peat¹¹
Glossifungites¹	Diplocraterion, Skolithos, Spongeliomorpha, Rhizocorallium, Arenicolites, Thalassinoides, Fuersichnus¹⁴	Firmground, dewatered muds¹	Shallow, marginal marine, deltaic or estuarine erosion surfaces.¹
Skolithos¹	Skolithos, Ophiomorpha, Arenicolites, Diplocraterion¹⁴	Unconsolidated littoral sands¹	Beaches and sandy tidal flats, shallow water, foreshore to upper-shoreface, above wavebase¹⁴
Cruziana¹	Arthrophycus, Phycodes, Rhizocorallium, Teichichnus, Arenicolites, Rosselia, Bergaueria, Thalassinoides, Lockeia, Protovirgularia, Curvolithus, Dimorphichnus, Cruziana, Rusophycus¹⁴	Sand and silt heterolithic successions and organic detritus⁴	Mid to distal continental shelves. Below normal wave base, but not necessarily below storm wave base¹⁴
Zoophycos¹	Zoophycos, Phycosiphon, Chondrites¹⁴	Marine softground, impure sands and silts¹	Deeper water, bottom of shelf; turbidite facies¹
Nereites¹	Nereites, Megagrapton, Protopaleodictyon, Spirophycus, Helminthoraphe, Glockerichnus, Spiroraphe, Cosmoraphe, Urohelminthoida, Desmograpton, Paleodictyon, Scolicia¹⁴	Fine-grained muds and clays interbedded with turbidite silts¹⁴	Deep water, pelagic, base-of-slope turbidity systems¹⁴

Recognized vertebrate ichnofacies

Vertebrate Ichnofacies¹²¹³
Name	Common Ichnogenera	Substrate	Inferred Paleoenvironment
Chelichnus¹³ (Laoporus)¹²	Chelichnus, Brasilichnium¹²¹³	Unconsolidated, larger-grained sands	Aeolian sand dunes¹³
Grallator¹²	Grallator, Jindongornipes, Koreanoformis, Avipeda, Brachychirotherium, Rhynchosauroides, Eubrontes¹²¹³		Lacustrine shorelines¹³
Brontopodus¹³	Charirichnium, Ceratopsipes, Amblydactylus, Brontopodus¹³	Clastic or carbonate¹³	Coastal plain, marine shoreline¹³
Batrachichnus¹³	Batrachichnus, Limnopus, Amphisauropus, Dromopus, Dimetropus, Gilmoreichnus, Chirotherium		Tidal flat-fluvial plain¹³
Characichnos¹³	Characichnos, Undichna, Lunichnium, Puertollanopus, Serpentichnus, Batrachichnus, Hatcherichnus¹³	Semi-consolidated firmgrounds	Subaqueous lacustrine, estuarine, and deltaic environments¹³

References

Seilacher, A. (1967). "Bathymetry of trace fossils". Marine Geology. 5 (5–6): 413–428. doi:10.1016/0025-3227(67)90051-5.
"Ichnofacies". UCL. Archived from the original on 2013-10-29. Retrieved 2013-10-27.
Benton, M.J.; Harper, D.A.T. (1997). Basic Palaeontology. Longman Harlow, Essex, England. ISBN 9780582228573.
Buatois, Luis; Mangano, M. Gabriela (2011). Ichnology: Organism-Substrate Interactions in Space and Time. New York: Cambridge University Press. pp. 67–69. ISBN 978-0-521-85555-6.
Woolfe, K.J. (1990). "Trace fossils as paleoenvironmental indicators in the Taylor Group (Devonian) of Antarctica". Palaeogeography, Palaeoclimatology, Palaeoecology. 80 (3–4): 301–310. doi:10.1016/0031-0182(90)90139-X.
Frey, Robert W.; Pemberton, S. George (1987). "The Psilonichnus ichnocoenose, and its relationship to adjacent marine and nonmarine ichnocoenoses along the Georgia coast". Bulletin of Canadian Petroleum Geology (35).
Frey, R. W.; Seilacher, Adolf (1980). "Uniformity in marine invertebrate ichnology". Lethaia. 13 (3): 183–207. doi:10.1111/j.1502-3931.1980.tb00632.x.
Frey, Robert W.; Pemberton, S. George. Facies Models. pp. 189–207.
Bromely, Richard G.; Pemberton, S. George (1984). "A Cretaceous woodground: the Teredolites ichnofacies". Journal of Paleontology. 58. R.A. Rahmani: 488–498.
Gingras, M.K.; MacEachern, J.A. (2004). "Modern perspectives on the Teredolites ichnofacies: observations from Willapa Bay, Washington" (PDF). PALAIOS. 19. Pickerill, R.K.: 79–88. doi:10.1669/0883-1351(2004)019<0079:mpotti>2.0.co;2. S2CID 96426958.
Pemberton, S. George; Spila, M. (2001). "Ichnology and sedimentology of shallow to marginal marine systems". Geological Association of Canada Short Course Notes (228). Pulham, A.J., Saunders, T., MacEachern, J.A., Robbins, D., and Sinclair, I.K.: 29–62.
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.
Hunt, Adrian P.; Lucas, Spencer G. (2007). "Tetrapod ichnofacies: a new paradigm". Ichnos. 14 (1–2): 59–68. doi:10.1080/10420940601006826. S2CID 129687395.

External links

Types of Ichnofacies- University College London Archived 2013-10-29 at the Wayback Machine

[Seilacher1967-1] Seilacher, A. (1967). "Bathymetry of trace fossils". Marine Geology. 5 (5–6): 413–428. doi:10.1016/0025-3227(67)90051-5.

[UCL-2] "Ichnofacies". UCL. Archived from the original on 2013-10-29. Retrieved 2013-10-27.

[Benton1997-3] Benton, M.J.; Harper, D.A.T. (1997). Basic Palaeontology. Longman Harlow, Essex, England. ISBN 9780582228573.

[:0-4] Buatois, Luis; Mangano, M. Gabriela (2011). Ichnology: Organism-Substrate Interactions in Space and Time. New York: Cambridge University Press. pp. 67–69. ISBN 978-0-521-85555-6.

[Woolfe1990-5] Woolfe, K.J. (1990). "Trace fossils as paleoenvironmental indicators in the Taylor Group (Devonian) of Antarctica". Palaeogeography, Palaeoclimatology, Palaeoecology. 80 (3–4): 301–310. doi:10.1016/0031-0182(90)90139-X.

[:1-6] Frey, Robert W.; Pemberton, S. George (1987). "The Psilonichnus ichnocoenose, and its relationship to adjacent marine and nonmarine ichnocoenoses along the Georgia coast". Bulletin of Canadian Petroleum Geology (35).

[:2-7] Frey, R. W.; Seilacher, Adolf (1980). "Uniformity in marine invertebrate ichnology". Lethaia. 13 (3): 183–207. doi:10.1111/j.1502-3931.1980.tb00632.x.

[8] Frey, Robert W.; Pemberton, S. George. Facies Models. pp. 189–207.

[9] Bromely, Richard G.; Pemberton, S. George (1984). "A Cretaceous woodground: the Teredolites ichnofacies". Journal of Paleontology. 58. R.A. Rahmani: 488–498.

[10] Gingras, M.K.; MacEachern, J.A. (2004). "Modern perspectives on the Teredolites ichnofacies: observations from Willapa Bay, Washington" (PDF). PALAIOS. 19. Pickerill, R.K.: 79–88. doi:10.1669/0883-1351(2004)019<0079:mpotti>2.0.co;2. S2CID 96426958.

[:3-11] Pemberton, S. George; Spila, M. (2001). "Ichnology and sedimentology of shallow to marginal marine systems". Geological Association of Canada Short Course Notes (228). Pulham, A.J., Saunders, T., MacEachern, J.A., Robbins, D., and Sinclair, I.K.: 29–62.

[:4-12] 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.

[:5-13] Hunt, Adrian P.; Lucas, Spencer G. (2007). "Tetrapod ichnofacies: a new paradigm". Ichnos. 14 (1–2): 59–68. doi:10.1080/10420940601006826. S2CID 129687395.

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