Earth:Eyam Limestone

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Short description: Geologic formation in England
Eyam Limestone
Stratigraphic range: Early Carboniferous (Uppermost Viséan), 336–326.4 Ma
[1]
Eyam Limestones - geograph.org.uk - 3178433.jpg
Eyam Limestone in Wirksworth
TypeGeological formation
Unit ofPeak Limestone Group
UnderliesLongstone Mudstone Formation
OverliesMonsal Dale Limestone Formation
AreaDerbyshire
Thickness9 to 54 m[2]
Lithology
PrimaryLimestone
Location
Region England
Country United Kingdom
ExtentPeak District
Type section
Named forEyam

The Eyam Limestone (formerly known as the Cawdor Group, Cawdor Limestone or Eyam Group) is a geologic formation in the Peak District, England . It preserves fossils dating back to the Viséan stage of the Carboniferous period, and represents a marine environment.[2]

Depositional environment

At the time of deposition, Britain was just south of the equator (<5° S) and part of the Euramerica continent. Study of the growth rings of fossil wood from other localities indicate that the British Isles had a monsoonal climate during the early Carboniferous, with tropical rainfall seasonality.[3] The Eyam Limestone was deposited on an extensive, thick carbonate ramp and platform on the northeast margin of the Widmerpool Gulf (an extensive basin which existed as an area of open water during the time of deposition). Reefs and their associated fore-reef and lagoonal environments are represented in the Eyam Limestone, with crinoids dominating the reef and providing habitats for other animals. The presence of photosymbiotic coral and micritic envelopes on some crinoid ossicles indicates the formation was deposited within the photic zone in a marine environment of normal salinity. The presence of the xenacanth Bransonella has been suggested to imply freshwater influence as xenacanths live mainly in freshwater habitats, however its presence in other marine formations suggests that Bransonella was a marine animal unlike its relatives.[1]

Apatite crystals formed by the recrystallization of phosphatic overgrowths are present on some conodont elements from the formation. As phosphatogenesis only occurs in the anoxic-oxic boundary while apatite precipitation occurs in the top few centimeters of the sediment column, this reveals that shallow sediment with low geothermal temperatures and dysoxic conditions were present in the Eyam Limestone.[1][4]

Fossil content

Cartilaginous fish

Cartilaginous fish reported from the Eyam Limestone
Genus Species Presence Material Notes Images
Acanthorhachis A. cf. spinatus Steeplehouse Quarry.[1] Basal body & spines.[1] A listracanthid.
Acanthorhachis spinatus.png
Anachronistes A. fordi Steeplehouse Quarry.[5] Teeth.[5] Junior synonym of Cooleyella.
Bransonella B. nebraskensis Steeplehouse Quarry & Cawdor Quarry.[1][6] Teeth.[1][6] A xenacanth.
Bransonelliformes.jpg
Carcharopsis C. prototypus Steeplehouse Quarry & Coleshill Quarry.[1][7] Teeth.[1][7] A squatinactiform.
Carcharopsis.jpg
Cladodus C. sp. Steeplehouse Quarry.[1] 4 teeth.[1] A cladoselachid.
Siksika and Cladodus.png
Cooleyella C. fordi Steeplehouse Quarry & Cawdor Quarry.[1][5][6] Teeth.[1][5][6] An anachronistid.
"Ctenacanthus" "C." costellatus Steeplehouse Quarry.[1] Partial tooth.[1] A ctenacanth.
Ctenoptychius C. lobatus Steeplehouse Quarry.[1] 3 teeth.[1] A petalodont.
Cypripediodens C. cristatus Once-a-week Quarry.[8] Teeth.[8] A petalodont.
Denaea D. cf. fournieri Steeplehouse Quarry & Cawdor Quarry.[1][6] Teeth.[1][6] A falcatid.
Denaea.jpg
Euchondrocephali gen. et. sp. indet. Indeterminate Cawdor Quarry.[6] Teeth.[6] Somewhat similar to orodontid teeth.
Euselachii gen. et. sp. indet. Indeterminate Cawdor Quarry.[6] Tooth.[6] An indeterminate euselachian.
Ginteria G. fungiforma Cawdor Quarry.[6] Teeth.[6] An anachronistid.
Lissodus L. wirksworthensis Teeth.[9] Reassigned to the genus Reesodus.
Petalorhynchus P. psittacinus Steeplehouse Quarry.[1] Crown & smaller tooth fragment.[1] A petalodont.
Petrodus P. patelliformis Steeplehouse Quarry.[1] Thousands of dermal denticles.[1] A symmoriid and the most abundant vertebrate in the formation.
Reesodus R. wirksworthensis Steeplehouse Quarry.[1] Tooth.[1] A hybodont.
Saivodus S. striatus Steeplehouse Quarry.[1] Tooth.[1] A ctenacanth.
Saivodus reconstruction.jpg
Squatinactis S. caudispinatus Cawdor Quarry.[6] 4 teeth.[6] A squatinactiform.
Squatinactis NT small.jpg
Thrinacodus T. dziki Steeplehouse Quarry & Cawdor Quarry.[1][6] Teeth.[1][6] A phoebodont.
Thrinacoselache gracia.jpg

Conodonts

Conodonts reported from the Eyam Limestone
Genus Species Presence Material Notes Images
Gnathodus G. girtyi Steeplehouse Quarry.[1] Partial S element.[1] An idiognathodontid.
Gnathodus elements.png
?Hindeodus ?H. sp. Steeplehouse Quarry.[1] P1 element fragment.[1] An anchignathodontid.
Hindeodus elements.jpg
?Idioprioniodus ?I. sp. Steeplehouse Quarry.[1] Two P1 element fragments.[1] A prioniodinid.
Kladognathus K. sp. Steeplehouse Quarry.[1] M element.[1] A coelodontid.
Kladognathus elements.png
Lochriea L. commutata Steeplehouse Quarry.[1] Two P1 elements.[1] A spathognathodontid.
L. mononodosa Steeplehouse Quarry.[1] P1 element.[1] A spathognathodontid.
L. sp. Steeplehouse Quarry.[1] Two P2 elements.[1] A spathognathodontid.

Invertebrates

Arthropods

Arthropods reported from the Eyam Limestone
Genus Species Presence Material Notes Images
Cummingella C. cf. carringtonensis Monyash.[10] A phillipsiid trilobite.
C. sampsoni Stoney Middleton & near Hassop.[11] Multiple specimens.[11] A phillipsiid trilobite.
Cummingella belisama dorsal light2 CRF.jpg
C. cf. tuberculingenata Monyash.[10] A phillipsiid trilobite.
Griffithides G. whitewatsoni Stoney Middleton.[11] Multiple specimens.[11] A proetid trilobite.
Griffithides globiceps 432.JPG

Brachiopods

Brachiopods reported from the Eyam Limestone
Genus Species Presence Material Notes Images
Acanthoplecta A. mesoloba Monyash.[10] A productid.
Alitaria A.? panderi Monyash.[10] A productid.
A. sp. Monyash.[10] A productid.
Antiquatonia A. hindi Monyash.[10] A productid.
A. cf. hindi Monyash.[10] A productid.
A. cf. insculpta Monyash.[10] A productid.
A. sulcata Monyash.[10] A productid.
A. sp. Monyash.[10] A productid.
Antiquatonia coloradoensis fossil brachiopod (Boggs Shale, Pottsville Group, Pennsylvanian; Blunt Run, Muskingum County, Ohio, USA) 3.jpg
Avonia A. aculeata Monyash.[10] A productid.
A. davidsoni Monyash.[10] A productid.
A. youngiana Monyash.[10] A productid.
A. cf. youngiana Monyash.[10] A productid.
A. sp. Monyash.[10] A productid.
Brachythyris B. ovalis Monyash.[10] A spiriferid.
B. cf. ovalis Monyash.[10] A spiriferid.
Buxtonia B. sp. Monyash.[10] A productid.
Coledium C. sp. Monyash.[10] A rhynchonellid.
Dictyoclostus D. sp. Monyash.[10] A productid.
Dictyoclostus sp. (fossil brachiopod) (Byer Sandstone, Lower Mississippian; Chatham, Ohio, USA) 4.jpg
Echinoconchus E. punctatus Monyash.[10] A productid.
E. subelegans Monyash.[10] A productid.
Eomarginifera E. cf. lobata Monyash.[10] A productid.
E. longispinus Monyash.[10] A productid.
Fluctuaria F. undata Monyash.[10] A productid.
Fusella F. sp. Monyash.[10] A spiriferid.
Girtyella G. sacculus Monyash.[10] A terebratulid.
Hustedia H. ulothrix Monyash.[10] An athyridid.
Hustedia brentwoodensis opening.jpg
Kochiproductus K. sp. Monyash.[10] A productid.
Krotovia K. spinulosa Monyash.[10] A productid.
Linoproductoidea indet. Indeterminate Monyash.[10] A productid.
Linoprotonia L. sp. Monyash.[10] A productid.
Marginicinctus M. sp. Monyash.[10] A productid.
Marginiferoidea indet. Indeterminate Monyash.[10] A productid.
Martinia M. sp. Monyash.[10] A spiriferid.
Orthoidea indet. Indeterminate Monyash.[10] An orthid.
Overtonia O. fimbriata Monyash.[10] A productid.
Pleuropugnoides P. pleurodon Monyash.[10] A rhynchonellid.
P. sp. Monyash.[10] A rhynchonellid.
Productina P. margaritacaea Monyash.[10] A productid.
P. sp. Monyash.[10] A productid.
Productus P. productus Monyash.[10] A productid.
P. sp. Monyash.[10] A productid.
Productus Fossil - geograph.org.uk - 3670308.jpg
Pugilis P. cf. pugilis Monyash.[10] A productid.
P. sp. Monyash.[10] A productid.
Pugnax P. acuminatus Monyash.[10] A rhynchonellid.
P. codiformis Monyash.[10] A rhynchonellid.
P. pseudopugnus Monyash.[10] A rhynchonellid.
P. cf. pugnoides Monyash.[10] A rhynchonellid.
P. sp. Monyash.[10] A rhynchonellid.
Pustula P. sp. Monyash.[10] A productid.
Rugosochonetes R. sp. Monyash.[10] A productid.
Schizophoria S. resupinata Monyash.[10] An orthid.
S. sp. Monyash.[10] An orthid.
Schizophoria.jpg
Sinuatella S. cf. sinuata Monyash.[10] A productid.
S. sp. Monyash.[10] A productid.
Spirifer S. bisulcatus Monyash.[10] A spiriferid.
S. cf. bisulcatus Monyash.[10] A spiriferid.
S. planicostus Monyash.[10] A spiriferid.
S. triangularis Monyash.[10] A spiriferid.
Spiriferoidea indet. Indeterminate Monyash.[10] A spiriferid.

Bryozoans

Bryozoans reported from the Eyam Limestone
Genus Species Presence Material Notes Images
Fenestelloidea Indeterminate Monyash.[10]

Cnidarians

Cnidarians reported from the Eyam Limestone
Genus Species Presence Material Notes Images
Diphyphyllum D. sp. Monyash.[10] A horn coral.

Echinoderms

Echinoderms reported from the Eyam Limestone
Genus Species Presence Material Notes Images
Crinoidea indet. Indeterminate Monyash.[10]

Molluscs

Molluscs reported from the Eyam Limestone
Genus Species Presence Material Notes Images
Aviculopecten A. interstitialis Monyash.[10] A bivalve.
Aviculopecten subcardiformis01.JPG
Aviculopinna A. mutica Monyash.[10] A pinnid bivalve.
Bivalvia indet. Indeterminate Monyash.[10] A bivalve.
Conocardium C. sp. Monyash.[10] A rostroconch.
Conocardiumkonincki.jpg
Girtypecten G. stellaris Monyash.[10] A bivalve.
Leiopteria L. sp. Monyash.[10] A bivalve.
Parallelodon P. sp. Monyash.[10] A parallelodontid bivalve.
Museo delle Grigne - EL70 - Parallelodon (Beushausenia) esinensis.jpg
Pinna P. flabelliformis Monyash.[10] A pinnid bivalve.

See also

  • List of fossiliferous stratigraphic units in England

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.30 1.31 1.32 1.33 1.34 1.35 1.36 1.37 1.38 1.39 1.40 1.41 1.42 Smith, Roy; Martill, David M.; Duffin, Christopher (2017-06-01). "The shark-beds of the Eyam Limestone Formation (Lower Carboniferous, Viséan) of Steeplehouse Quarry, Wirksworth, Derbyshire, UK". Proceedings of the Geologists' Association 128 (3): 374–400. doi:10.1016/j.pgeola.2017.04.004. ISSN 0016-7878. https://www.academia.edu/33671880. 
  2. 2.0 2.1 "BGS Lexicon of Named Rock Units - Result Details". https://webapps.bgs.ac.uk/lexicon/lexicon.cfm?pub=EYL. 
  3. Falcon-Lang, H. J. (March 1999). "The Early Carboniferous (Courceyan–Arundian) monsoonal climate of the British Isles: evidence from growth rings in fossil woods" (in en). Geological Magazine 136 (2): 177–187. doi:10.1017/S0016756899002307. ISSN 0016-7568. https://www.researchgate.net/publication/41816712. 
  4. Sanz-López, Javier; Blanco-Ferrera, Silvia (2012-10-01). "Overgrowths of large authigenic apatite crystals on the surface of conodonts from Cantabrian limestones (Spain)" (in en). Facies 58 (4): 707–726. doi:10.1007/s10347-012-0295-3. ISSN 1612-4820. https://doi.org/10.1007/s10347-012-0295-3. 
  5. 5.0 5.1 5.2 5.3 Duffin, Christopher; Ward, David (1983-01-01). "Neoselachian sharks' teeth from the Lower Carboniferous of Britain and the Lower Permian of the USA". Palaeontology. https://www.academia.edu/2891464. 
  6. 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 6.11 6.12 6.13 6.14 6.15 Ginter, Michał; Duffin, Christopher; Dean, Mark; Korn, Dieter (2014). "Late Viséan pelagic chondrichthyans from northern Europe". Acta Palaeontologica Polonica. doi:10.4202/app.00084.2014. https://www.researchgate.net/publication/274774718. 
  7. 7.0 7.1 Cuny, Gilles (2008-01-01). "Carcharopsis prototypus and the adaptations of single crystallite enameloid in cutting dentitions". Acta Geologica Polonica. https://www.academia.edu/1391669. 
  8. 8.0 8.1 Duffin, Christopher J.; Ward, David J. (2017-07-19). "A new janassid petalodont chondrichthyan from the Early Carboniferous of Derbyshire, UK" (in en). Proceedings of the Geologists' Association 128 (5–6): 809–814. doi:10.1016/j.pgeola.2017.06.008. https://www.researchgate.net/publication/318544690. 
  9. Duffin, C. (1985). "Revision of the hybodont selachian genus Lissodus BROUGH (1935)". Palaeontographica Abteilung A-palaozoologie-stratigraphie. 
  10. 10.00 10.01 10.02 10.03 10.04 10.05 10.06 10.07 10.08 10.09 10.10 10.11 10.12 10.13 10.14 10.15 10.16 10.17 10.18 10.19 10.20 10.21 10.22 10.23 10.24 10.25 10.26 10.27 10.28 10.29 10.30 10.31 10.32 10.33 10.34 10.35 10.36 10.37 10.38 10.39 10.40 10.41 10.42 10.43 10.44 10.45 10.46 10.47 10.48 10.49 10.50 10.51 10.52 10.53 10.54 10.55 10.56 10.57 10.58 10.59 10.60 10.61 10.62 10.63 10.64 10.65 10.66 10.67 10.68 10.69 10.70 10.71 Gutteridge, P. (May 1990). "The origin and significance of the distribution of shelly macrofauna in late Dinantian carbonate mud mounds of Derbyshire" (in en). Proceedings of the Yorkshire Geological Society 48 (1): 23–32. doi:10.1144/pygs.48.1.23. ISSN 0044-0604. https://www.lyellcollection.org/doi/10.1144/pygs.48.1.23. 
  11. 11.0 11.1 11.2 11.3 Tilsley, J. W. (December 1988). "New data on Carboniferous (Dinantian) trilobites from the Peak District, Derbyshire, England" (in en). Proceedings of the Yorkshire Geological Society 47 (2): 163–176. doi:10.1144/pygs.47.2.163. ISSN 0044-0604. https://www.researchgate.net/publication/249557212.