Cambridge Greensand Explained

Cambridge Greensand
Type:Member
Age:Earliest Cenomanian ~
Period:Cenomanian
Prilithology:Glauconitic marl
Otherlithology:Phosphorite
Region:England
Coordinates:52.2°N 0.1°W
Paleocoordinates:41°N 1.8°W
Unitof:West Melbury Marly Chalk Formation
Underlies:Chalk Group
Overlies:Gault Formation
Thickness:0.1-
Extent:North Hertfordshire and Cambridgeshire
Namedfor:Cambridge
Location Ts:Arlesey Brickpit

The Cambridge Greensand is a geological unit in England whose strata are earliest Cenomanian in age.[1] It lies above the erosive contact between the Gault Formation and the Chalk Group in the vicinity of Cambridgeshire, and technically forms the lowest member bed of the West Melbury Marly Chalk Formation.[2] It is a remanié deposit, containing reworked fossils of late Albian age, including those of dinosaurs and pterosaurs.

Description

The lithology is made out of glauconitic marl, described as a "chalk mud", containing abundant ostracod, coccolith and foram remains, with a concentration of phosphatic nodules and bones at the base.

Vertebrate paleofauna

Birds

Birds
GenusSpeciesLocalityMaterialNotesImages
Enaliornis E. barrette Braincases, vertebrae, pelvis [and] limb elements[3] This genus is the oldest known hesperornithine
E sedgwicki Hindlimb elements
E. seeleyi Assorted cranial and postcranial elements

Dinosaurs

Ornithischians

Ornithischians
GenusSpeciesLocalityMaterialNotesImages
Anoplosaurus A. curtonotus "Partial postcranium"[4]
A. major "Cervical vertebrae." "Vertebrae."[5]
Acanthopholis A. eucercus"[Two] caudal centra."Nomen dubium
A. platypus"Phalanx, caudal centra."Nomen dubium
A. macrocercus"Osteoderms." "Vertebrae, fragmentary skeleton elements."Reassigned to Syngonosaurus
A. stereocercus"Osteoderms." "Vertebrae."Nomen dubium
Eucercosaurus E. tanyspondylus "Vertebrae."
TrachodonT. cantabrigiensis "Dentary tooth."[6] Nomen dubium

Saurischians

Pterosaurs

Pterosaurs
GenusSpeciesLocalityMaterialNotesImages
AmblydectesA. crassidensJaw fragments
A. eurygnathusJaw fragmentsPossibly a junior synonym of A. crassidens[8]
CamposipterusC. colorhinusAnterior rostra fragments
C. nasutusPartial rostrum
C. sedgwickiiAnterior rostrum
Draigwenia D. platystomusAnterior rostrum fragmentsFormerly Amblydectes platystomus
Lonchodraco L. machaerorhynchusReassigned to Ikrandraco machaerorhynchus
L. microdonJunior synonym of L. machaerorhynchus
Nicorhynchus N. capitoJaw fragmentsPossibly synonymous with Coloborhynchus[9]
OrnithocheirusO. simus[10] [11]
"Ornithocheirus" denticulatus
"Ornithocheirus" polyodon
Ornithostoma[12] [13] O. sedgwickiJaw fragmentsAzhdarchoid pterosaur

Ichthyosaurs

Ichthyosaurs
GenusSpeciesLocalityMaterialNotesImages
Cetarthrosaurus C. walkeri[14]
Maiaspondylus M. cantabrigiensis
Pervushovisaurus P. campylodon
Sisteronia S. seeleyi

Lepidosauria

Invertebrates

Ammonites

See also

Notes and References

  1. Hart. Malcolm B.. Fox. Lyndsey R.. 2020. Micropalaeontology and stratigraphical setting of the Cambridge Greensand. Geological Society, London, Special Publications. en. 498. 1. 147–163. 10.1144/SP498-2018-144. 2020GSLSP.498..147H. 210304478. 0305-8719.
  2. http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=CBG Cambridge Greensand
  3. "Table 11.1," in Weishampel, et al. (2004). Page 215.
  4. "Table 17.1," in Weishampel, et al. (2004). Page 367.
  5. "Table 19.1," in Weishampel, et al. (2004). Page 417.
  6. "Table 20.1," in Weishampel, et al. (2004). Page 443.
  7. "Table 13.1," in Weishampel, et al. (2004). Page 270.
  8. Holgado . Borja . 2021 . On the validity of the genus Amblydectes Hooley 1914 (Pterodactyloidea, Anhangueridae) and the presence of Tropeognathinae in the Cambridge Greensand . Anais da Academia Brasileira de Ciências . 93 . suppl 2 . 10.1590/0001-3765202120201658 . 1678-2690.
  9. Smith . Roy E. . Ibrahim . Nizar . Longrich . Nicholas . Unwin . David M. . Jacobs . Megan L. . Williams . Cariad J. . Zouhri . Samir . Martill . David M. . September 2023 . The pterosaurs of the Cretaceous Kem Kem Group of Morocco . PalZ . en . 97 . 3 . 519–568 . 10.1007/s12542-022-00642-6 . 0031-0220. free . 2023PalZ...97..519S .
  10. Taissa Rodrigues . Alexander Wilhelm Armin Kellner . amp . 2013 . Taxonomic review of the Ornithocheirus complex (Pterosauria) from the Cretaceous of England . ZooKeys . 308 . 1–112 . 10.3897/zookeys.308.5559 . 3689139 . 23794925 . free. 2013ZooK..308....1R .
  11. Unwin D.M., 2001, "An overview of the pterosaur assemblage from the Cambridge Greensand (Cretaceous) of Eastern England", Mitteilungen aus dem Museum für Naturkunde in Berlin, Geowissenschaftliche Reihe 4: 189–221
  12. Averianov A.O. . 2012 . Ornithostoma sedgwicki – valid taxon of azhdarchoid pterosaurs . Proceedings of the Zoological Institute RAS . 316 . 1 . 40–49. 10.31610/trudyzin/2012.316.1.40 .
  13. Smith . Roy E. . Martill . David M. . Unwin . David M. . Steel . Lorna . February 2021 . Edentulous pterosaurs from the Cambridge Greensand (Cretaceous) of eastern England with a review of Ornithostoma Seeley, 1871 . Proceedings of the Geologists' Association . en . 132 . 1 . 110–126 . 10.1016/j.pgeola.2020.10.004. 2021PrGA..132..110S .
  14. Valentin Fischer . Nathalie Bardet . Myette Guiomar . Pascal Godefroit . amp . 2014 . High Diversity in Cretaceous Ichthyosaurs from Europe Prior to Their Extinction . PLOS ONE . 9 . 1 . e84709 . 2014PLoSO...984709F . 10.1371/journal.pone.0084709 . 3897400 . 24465427 . free.
  15. P. M. Barrett and S. E. Evans. 2002. A reassessment of the Early Cretaceous reptile 'Patricosaurus merocratus' Seeley from the Cambridge Greensand, Cambridgeshire, UK. Cretaceous Research 23:231-240
  16. C. W. Wright and W. J. Kennedy. 1979. Origin and evolution of the Cretaceous micromorph ammonite family Flickiidae. Palaeontology 22:685-704

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