Oxford Clay

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Oxford Clay
Stratigraphic range: Middle to Late Jurassic (Callovian-Oxfordian), 166–160  Ma
OxfordClay Weymouth.JPG
Coastal exposure of the Oxford Clay Formation near Weymouth
Type Geological formation
Unit of Ancholme Group
Sub-unitsPeterborough Member, Stewartby Member, Weymouth Member
Underlies West Walton Formation, Corallian Group
Overlies Kellaways Formation, Osgodby Formation
ThicknessUp to 185 metres, typically 50 to 70 m on East Midlands Shelf
Lithology
Primary Claystone
Other Mudstone
Location
Region Oxford, Peterborough, Dorset, Yorkshire
Country England
Type section
Named for Oxford

The Oxford Clay (or Oxford Clay Formation) is a Jurassic marine sedimentary rock formation underlying much of southeast England, from as far west as Dorset and as far north as Yorkshire. The Oxford Clay Formation dates to the Jurassic, specifically, the Callovian and Oxfordian ages, [1] and comprises two main facies. The lower facies comprises the Peterborough Member, a fossiliferous organic-rich mudstone. This facies and its rocks are commonly known as lower Oxford Clay. The upper facies comprises the middle Oxford Clay, the Stewartby Member, and the upper Oxford Clay, the Weymouth Member. The upper facies is a fossil poor assemblage of calcareous mudstones.

Contents

Oxford Clay appears at the surface around Oxford, Peterborough and Weymouth and is exposed in many quarries around these areas. The top of the Lower Oxford Clay shows a lithological change, where fissile shale changes to grey mudstone. The Middle and Upper Oxford Clays differ slightly, as they are separated by an argillaceous limestone in the South Midlands.

Palaeontology

The Oxford Clay is well known for its rich fossil record of fish and invertebrates. [2] Many of the fossils are well preserved, occasionally some are found exceptionally well preserved. Animals which lived in the Oxford Clay Sea include plesiosaurs, marine crocodiles, ichthyosaurs, cephalopods (such as belemnites), bivalves (such as Gryphaea ), and a variety of gastropods. Dinosaur eggs are stratigraphically present in the Lower Oxford Clay. Geographically, they are located in Cambridgeshire, England. [3]

Life restoration of Eustreptospondylus and Lexovisaurus in the Oxford Clay environment Eustreptospondylus attacking Lexovisaurus.jpg
Life restoration of Eustreptospondylus and Lexovisaurus in the Oxford Clay environment

Ornithischians

Indeterminate euronithopod remains stratigraphically present in the Lower Oxford Clay and geographically located in Cambridgeshire, England. [3]

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Ornithischians of the Oxford Clay
GenusSpeciesLocationStratigraphic positionMaterialNotesImages

Callovosaurus

C. leedsi [3]

  • Cambridgeshire [3]

Lower [3]

"Femur." [4]

An iguanodontian dryosaur.
Callovosaurus Callovosaurus.jpg
Callovosaurus
Lexovisaurus Lexovisaurus3.png
Lexovisaurus

Lexovisaurus [5]

L. durobivensis [6]

  • Cambridgeshire [3]
  • Dorset [7]

Lower [6]

A holotype pelvis.A stegosaur

Indeterminate [8]

  • Bedfordshire [9]

Loricatosaurus [3]

L. priscus [3]

  • Cambridgeshire [3]

Lower [3]

A stegosaur.

Sarcolestes [3]

S. leedsi [3]

  • Cambridgeshire [3]

Lower [3]

"Partial mandible." [10]

An ankylosaur.

Saurischians

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Saurischians of the Oxford Clay
GenusSpeciesLocationStratigraphic positionMaterialNotesImages

Cetiosauriscus [3]

C. stewarti [3]

  • Cambridgeshire [3]

Lower [3]

"Rear half of a skeleton." [11]

Cetiosauriscus Cetiosauriscus restoration.jpg
Cetiosauriscus
Eustreptospondylus Eustrept1DB1.jpg
Eustreptospondylus
Metriacanthosaurus Metriacanthosaurus.jpg
Metriacanthosaurus

Eustreptospondylus [12]

E. oxoniensis [12]

Upper [12]

Disarticulated skull and skeleton, with some referred limb elements. [13]

Sauropoda

Indeterminate [14]

The caudal vertebrae from Cambridgeshire were mistakenly considered part of the syntypic series of "Ornithopsis" leedsi by Upchurch and Martin (2003). [15]

Theropoda

Indeterminate [12]

Middle [12]

Metriacanthosaurus

M. parkeri
  • Weymouth
Upper

Plesiosaurs

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
GenusSpeciesLocationMemberAbundanceNotesImages

Cryptoclidus

C. eurymerus

A cryptoclidid

Cryptoclidus Cryptoclidus NT small.jpg
Cryptoclidus
Eardasaurus Eardasaurus full skeleton.jpg
Eardasaurus
Liopleurodon Liopleurodon after Tarlo.jpg
Liopleurodon
Muraenosaurus Muraenosaurus l2.jpg
Muraenosaurus
Pachycostasaurus Pachycostasaurus recon.png
Pachycostasaurus
Peloneustes Peloneustes SW.png
Peloneustes
Simolestes Simolestes1DB.jpg
Simolestes

C. richardsoni

A cryptoclidid

Eardasaurus

E. powelli

A thalassophonean pliosaurid

Liopleurodon

L. ferox

A thalassophonean pliosaurid

L. pachydeirus

A thalassophonean pliosaurid

Marmornectes

M. candrewi

A pliosaurid

Muraenosaurus

M. leedsi

A cryptoclidid

Pachycostasaurus

P. dawnii

A pliosaurid

Peloneustes

P. philarchus

A thalassophonean pliosaurid

Picrocleidus

P. beloclis

A cryptoclidid

Pliosaurus

P. andrewsi

A thalassophonean pliosaurid; represents a new genus distinct from Pliosaurus

Simolestes

S. vorax

A thalassophonean pliosaurid

Tricleidus

T. seeleyi

A cryptoclidid

Pachycormiformes

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
GenusSpeciesLocationMemberAbundanceNotesImages
Leedsichthys L. problematicusGiant filter feeding pachycormiform
Martillichthys M. renwickaeFilter feeding pachyocormiform
" Hypsocormus""H." tenuirostrisCarnivorous pachycormiform, not closely related to Hypsocormus, and more closely related to Orthocormus

Thalattosuchians

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
GenusSpeciesLocationMemberAbundanceNotesImages

Lemmysuchus

L. obtusidens

A teleosauroid belonging to the Machimosauridae

Neosteneosaurus Steneosaurus durobrivensis.jpg
Neosteneosaurus
Thalattosuchus Metriorhynchus superciliosum.jpg
Thalattosuchus
Suchodus Suchodus durobrivense.jpg
Suchodus
Tyrannoneustes Tyrannoneustes.png
Tyrannoneustes

Charitomenosuchus

C. leedsi

A machimosaurid teleosauroid

Steneosaurus

S. edwardsi

Now referred to Neosteneosaurus.

S. durobrivensis

Junior synonym of N. edwardsi.

Neosteneosaurus

N. edwardsi

A machimosaurid teleosauroid

Mycterosuchus

M. leedsi

A teleosaurid teleosauroid

Metriorhynchus

M. superciliosus

This species was referred to a new genus, Thalattosuchus. [16]

Thalattosuchus

T. superciliosus

A metriorhynchine metriorhynchid

Gracilineustes

G. leedsi

A metriorhynchine metriorhynchid

Suchodus

S. brachyrhynchus

A geosaurine metriorhynchid

S. durobrivensis

A geosaurine metriorhynchid

Tyrannoneustes [17]

T. lythrodectikos

A geosaurine metriorhynchid

Economic use

Oxford Clay has a porous consistency and is soft and is often used in the making of roads. It is also the source of the Fletton stock brick of which much of London is built. For brick making, the Oxford Clay has the advantage of containing carbon which provides part of the fuel required in firing it so reducing the requirement for an external fuel source.

See also

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References

  1. "Oxford Clay Formation". The BGS Lexicon of Named Rock Units. British Geological Survey . Retrieved 21 August 2017.
  2. Martill, D.M.; Hudson J.D. (1991). Fossils of the Oxford Clay. Palaeontological Association.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 "10.9 Cambridgeshire, England; 1. Lower Oxford Clay," in Weishampel, et al. (2004). Page 540.
  4. "Table 18.1," in Weishampel, et al. (2004). Page 396.
  5. Weishampel, et al. (2004). Pages 539-540.
  6. 1 2 "10.7 Dorset, England; 3. Lower Oxford Clay" and "cambridgeshire">"10.9 Cambridgeshire, England; 1. Lower Oxford Clay," in Weishampel, et al. (2004). Pages 539-540.
  7. "10.7 Dorset, England; 3. Lower Oxford Clay," in Weishampel, et al. (2004). Page 539.
  8. Listed as "?Lexovisaurus sp." in "10.10 Bedfordshire, England; 1. Oxford Clay," in Weishampel, et al. (2004). Page 540.
  9. "10.10 Bedfordshire, England; 1. Oxford Clay," in Weishampel, et al. (2004). Page 540.
  10. "Table 17.1," in Weishampel, et al. (2004). Page 367.
  11. "Table 13.1," in Weishampel, et al. (2004). Page 265.
  12. 1 2 3 4 5 6 7 "10.14 Oxfordshire, England; 8. Middle Oxford Clay," in Weishampel, et al. (2004). Page 540.
  13. "Table 4.1," in Weishampel, et al. (2004). Page 72.
  14. 1 2 "10.14 Wiltshire, England; 4. Oxford Clay," in Weishampel, et al. (2004). Page 540.
  15. Noé LF, Liston JJ, Chapman SD. 2010. ‘Old bones, dry subject’: the dinosaurs and pterosaur collected by Alfred Nicholson Leeds of Peterborough, England. Geological Society, London, Special Publications 343: 49–77.
  16. Young, M.T.; Brignon, A.; Sachs, S.; Hornung, J.; Foffa, D.; Kitson, J.J.N.; Johnson, M.M.; Steel, L. (2021). "Cutting the Gordian knot: a historical and taxonomic revision of the Jurassic crocodylomorph Metriorhynchus". Zoological Journal of the Linnean Society. 192 (2): 510–553. doi:10.1093/zoolinnean/zlaa092.
  17. Mark T. Young; Marco Brandalise de Andrade; Stephen L. Brusatte; Manabu Sakamoto; Jeff Liston (2013). "The oldest known metriorhynchid super-predator: a new genus and species from the Middle Jurassic of England, with implications for serration and mandibular evolution in predacious clades". Journal of Systematic Palaeontology. 11 (4): 475–513. doi:10.1080/14772019.2012.704948. S2CID   85276836.

Bibliography

Further reading