Eyam Limestone
Eyam Limestone | |
---|---|
Stratigraphic range: Early Carboniferous (Uppermost Viséan), [1] | |
![]() Eyam Limestone in Wirksworth | |
Type | Geological formation |
Unit of | Peak Limestone Group |
Underlies | Longstone Mudstone Formation |
Overlies | Monsal Dale Limestone Formation |
Area | Derbyshire |
Thickness | 9 to 54 m[2] |
Lithology | |
Primary | Limestone |
Location | |
Region | ![]() |
Country | ![]() |
Extent | Peak District |
Type section | |
Named for | Eyam |
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
[edit]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
[edit]Color key
| Notes Uncertain or tentative taxa are in small text; |
Cartilaginous fish
[edit]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. | ![]() |
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. | ![]() |
Carcharopsis | C. prototypus | Steeplehouse Quarry & Coleshill Quarry.[1][7] | Teeth.[1][7] | A squatinactiform. | ![]() |
Cladodus | C. sp. | Steeplehouse Quarry.[1] | 4 teeth.[1] | A cladoselachid. | ![]() |
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. | ![]() |
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. | ![]() |
Squatinactis | S. caudispinatus | Cawdor Quarry.[6] | 4 teeth.[6] | A squatinactiform. | ![]() |
Thrinacodus | T. dziki | Steeplehouse Quarry & Cawdor Quarry.[1][6] | Teeth.[1][6] | A phoebodont. | ![]() |
Conodonts
[edit]Conodonts reported from the Eyam Limestone | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Gnathodus | G. girtyi | Steeplehouse Quarry.[1] | Partial S element.[1] | An idiognathodontid. | ![]() |
?Hindeodus | ?H. sp. | Steeplehouse Quarry.[1] | P1 element fragment.[1] | An anchignathodontid. | ![]() |
?Idioprioniodus | ?I. sp. | Steeplehouse Quarry.[1] | Two P1 element fragments.[1] | A prioniodinid. | |
Kladognathus | K. sp. | Steeplehouse Quarry.[1] | M element.[1] | A coelodontid. | ![]() |
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
[edit]Arthropods
[edit]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. | ![]() | |
C. cf. tuberculingenata | Monyash.[10] | A phillipsiid trilobite. | |||
Griffithides | G. whitewatsoni | Stoney Middleton.[11] | Multiple specimens.[11] | A proetid trilobite. |
Brachiopods
[edit]Bryozoans
[edit]Bryozoans reported from the Eyam Limestone | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Fenestelloidea | Indeterminate | Monyash.[10] |
Cnidarians
[edit]Cnidarians reported from the Eyam Limestone | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Diphyphyllum | D. sp. | Monyash.[10] | A horn coral. |
Echinoderms
[edit]Echinoderms reported from the Eyam Limestone | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Crinoidea indet. | Indeterminate | Monyash.[10] |
Molluscs
[edit]Molluscs reported from the Eyam Limestone | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Aviculopecten | A. interstitialis | Monyash.[10] | A bivalve. | ||
Aviculopinna | A. mutica | Monyash.[10] | A pinnid bivalve. | ||
Bivalvia indet. | Indeterminate | Monyash.[10] | A bivalve. | ||
Conocardium | C. sp. | Monyash.[10] | A rostroconch. | ![]() | |
Girtypecten | G. stellaris | Monyash.[10] | A bivalve. | ||
Leiopteria | L. sp. | Monyash.[10] | A bivalve. | ||
Parallelodon | P. sp. | Monyash.[10] | A parallelodontid bivalve. | ![]() | |
Pinna | P. flabelliformis | Monyash.[10] | A pinnid bivalve. |
See also
[edit]References
[edit]- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq Smith, Roy; Martill, David M.; Duffin, Christopher (1 June 2017). "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. Bibcode:2017PrGA..128..374S. doi:10.1016/j.pgeola.2017.04.004. ISSN 0016-7878.
- ^ a b "BGS Lexicon of Named Rock Units - Result Details". webapps.bgs.ac.uk. Retrieved 1 September 2023.
- ^ Falcon-Lang, H. J. (March 1999). "The Early Carboniferous (Courceyan–Arundian) monsoonal climate of the British Isles: evidence from growth rings in fossil woods". Geological Magazine. 136 (2): 177–187. Bibcode:1999GeoM..136..177F. doi:10.1017/S0016756899002307. ISSN 0016-7568. S2CID 130499005.
- ^ Sanz-López, Javier; Blanco-Ferrera, Silvia (1 October 2012). "Overgrowths of large authigenic apatite crystals on the surface of conodonts from Cantabrian limestones (Spain)". Facies. 58 (4): 707–726. Bibcode:2012Faci...58..707S. doi:10.1007/s10347-012-0295-3. ISSN 1612-4820. S2CID 140725466.
- ^ a b c d Duffin, Christopher; Ward, David (1 January 1983). "Neoselachian sharks' teeth from the Lower Carboniferous of Britain and the Lower Permian of the USA". Palaeontology.
- ^ a b c d e f g h i j k l m n o p 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.
- ^ a b Cuny, Gilles (1 January 2008). "Carcharopsis prototypus and the adaptations of single crystallite enameloid in cutting dentitions". Acta Geologica Polonica.
- ^ a b Duffin, Christopher J.; Ward, David J. (19 July 2017). "A new janassid petalodont chondrichthyan from the Early Carboniferous of Derbyshire, UK". Proceedings of the Geologists' Association. 128 (5–6): 809–814. Bibcode:2017PrGA..128..809D. doi:10.1016/j.pgeola.2017.06.008.
- ^ Duffin, C. (1985). "Revision of the hybodont selachian genus Lissodus BROUGH (1935)". Palaeontographica Abteilung A. S2CID 233061921.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi bj bk bl bm bn bo bp bq br bs bt Gutteridge, P. (May 1990). "The origin and significance of the distribution of shelly macrofauna in late Dinantian carbonate mud mounds of Derbyshire". Proceedings of the Yorkshire Geological Society. 48 (1): 23–32. Bibcode:1990PYGS...48...23G. doi:10.1144/pygs.48.1.23. ISSN 0044-0604.
- ^ a b c d Tilsley, J. W. (December 1988). "New data on Carboniferous (Dinantian) trilobites from the Peak District, Derbyshire, England". Proceedings of the Yorkshire Geological Society. 47 (2): 163–176. Bibcode:1988PYGS...47..163T. doi:10.1144/pygs.47.2.163. ISSN 0044-0604.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 25 March 2022. Retrieved 17 December 2021.