Kimmeridge Clay (Redirected from Kimmeridge Clay Formation)

Kimmeridge Clay
Stratigraphic range: Kimmeridgian–Berriasian
Grey cliffs of Upper Kimmeridge Clay above the beach at Egmont Bight
TypeGeological formation
Unit ofAncholme Group (onshore), Humber Group (offshore)
Sub-unitsBirch Sandstone Member
Burns Sandstone Member
Claymore Sandstone Member
Dirk Sandstone Member
Magnus Sandstone Member
Ptarmigan Sandstone Member
Ribble Sandstone Member
UnderliesPortland Sand Formation, Speeton Clay Formation, Spilsby Sandstone
OverliesAmpthill Clay, Corallian Group
Lithology
PrimaryMudstone
OtherSiltstone, Sandstone, Conglomerate
Location
RegionEngland (surface)
North Sea (subsurface)
CountryUnited Kingdom
Type section
Named forKimmeridge Bay
LocationType area - coastal outcrops from Black Head, Weymouth to Chapman's Pool

The Kimmeridge Clay is a sedimentary deposit of fossiliferous marine clay which is of Late Jurassic to lowermost Cretaceous age and occurs in southern and eastern England and in the North Sea. This rock formation is the major source rock for North Sea oil. The fossil fauna of the Kimmeridge Clay includes turtles, crocodiles, sauropods, plesiosaurs, pliosaurs and ichthyosaurs, as well as a number of invertebrate species.

Description

Kimmeridge Clay is named after the village of Kimmeridge on the Dorset coast of England, where it is well exposed and forms part of the Jurassic Coast World Heritage Site. Onshore, it is of Late Jurassic (Kimmeridgian) age and outcrops across England, in a band stretching from Dorset in the south-west, north-east to North Yorkshire. Offshore, it extends into the Lower Cretaceous (Berriasian Stage) and it is found throughout the Southern, Central and Northern North Sea.

The foundations of the Humber Bridge on the southern (Barton) side of the bridge are on Kimmeridge Clay beneath superficial deposits, under the Humber estuary.

Economic importance

Kimmeridge Clay is of great economic importance, being the major source rock for oil fields in the North Sea hydrocarbon province. It has distinctive physical properties and log responses.

Vertebrate fauna

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

Fauna uncovered from the Kimmeridge Clay include:

Ray-finned fish

Ray-finned fishes of the Kimmeridge clay Formation
Genus Species Location Stratigraphic Position Abundance Notes Images

Thrissops

Indeterminate

Dorset

Most common Kimmeridge clay fish, known from several complete specimens

Housed at the etches collection, discovered by Steve Etches

Complete specimen

Pachythrissops

Indeterminate

Dorset

Housed at the etches collection, discovered by Steve Etches

Allothrissops

Indeterminate

Dorset

Housed at the etches collection, discovered by Steve Etches

Chondrostei

Indeterminate

Dorset

One specimen, a fin

Housed at the etches collection, discovered by Steve Etches

Lepidotes

Indeterminate

Dorset

Housed at the etches collection, discovered by Steve Etches

Gyrodus

Indeterminate

Dorset

Housed at the etches collection, discovered by Steve Etches

Caturus

Indeterminate

Dorset

Housed at the etches collection, discovered by Steve Etches

Caturus furcatus

Aspidorhynchus

Indeterminate

Dorset

Housed at the etches collection, discovered by Steve Etches

Hypsocormus

H.tenuirostris

Dorset

Rare

Housed at the etches collection, discovered by Steve Etches

Pachycormus

Indeterminate

Dorset

Rare

Housed at the etches collection, discovered by Steve Etches

Eurycormus

Indeterminate

Dorset

Rare, one complete specimen

Housed at the etches collection, discovered by Steve Etches

Leptolepidae

Indeterminate

Dorset

Fairly common, multiple near complete specimens.

Housed at the etches collection, discovered by Steve Etches

Lobe-finned fish

Lobe-finned fishes of the Kimmeridge clay Formation
Genus Species Location Stratigraphic Position Abundance Notes Images

Holophagus

Indeterminate

Dorset

One specimen, cranial material

Coelacanth. Housed at the etches collection, discovered by Steve Etches. More than 2 metres long

Cartilaginous fish

Cartilaginous fishes of the Kimmeridge clay Formation
Genus Species Location Stratigraphic Position Abundance Notes Images

Asteracanthus

Indeterminate

Dorset

Known from many dorsal spines

Housed at the etches collection, discovered by Steve Etches

Chimaera

Indeterminate

Known from many dorsal spines

Housed at the etches collection, discovered by Steve Etches

Hybodus

Indeterminate

Known from many dorsal spines, perhaps a complete head

Housed at the etches collection, discovered by Steve Etches

Ischyodus

Indeterminate

One specimen

Housed at the etches collection, discovered by Steve Etches

Rhinobatidae

Indeterminate

Known from a complete specimen, and other isolated remains

Housed at the etches collection, discovered by Steve Etches

Kimmerobatis

K. etchesi

Known from multiple partial skeletons

A spathobatid ray
Durnonovariaodus D. maiseyi Pectinatites pectinatus ammonite zone One partial skeleton A hybodontid

Turtles

Turtles of the Kimmeridge clay Formation
Genus Species Location Stratigraphic Position Abundance Notes Images
Craspedochelys C. passmorei Swindon "NHMUK R5871 (holotype), subcomplete shell with associated postcranial remains, including parts of the girdles, the left humerus, and partial cervical vertebrae" Thalassochelydian sea turtle
Achelonia A. formosa Ely, Cambridgeshire "CAMSM J29898 to CAMSM J29955 (holotype), a partial, disarticulated skeleton" Thalassochelydian sea turtle, formerly considered the distinct species "Enaliochelys chelonia"
Pelobatochelys P. blakii Weymouth Carapace fragments Thalassochelydian sea turtle
Plesiochelys P. etalloni "basicranium with partial otic chambers and fragment of the right maxilla" Thalassochelydian sea turtle
Thalassemys T. bruntrutana, T. hugii Isle of Purbeck (bruntrutana), Abingdon, Oxfordshire (hugii) "A partial carapace and associated limb and girdle elements (NHMUK R8699)" (Purbeck) "A large shell (OUMNH J.66966)" (Oxfordshire) Thalassochelydian sea turtle
Tropidemys P. langii Weymouth "NHMUK OR44178b, an isolated neural; NHMUK OR45920, right costals 1–3; NHMUK OR45921, a left first costal; NHMUK R2733, a left fourth costal" Thalassochelydian sea turtle

Archosaurs

Thalattosuchians

Genus Species Location Member Abundance Notes Images

Bathysuchus

B. megarhinus

A pelagic teleosaurid.

Cricosaurus
Dakosaurus
Plesiosuchus
Torvoneustes

Cricosaurus

C. gracilis

A metriorhynchine metriorhynchid

Dakosaurus

D. maximus

A geosaurine metriorhynchid

Metriorhynchus

M. brevirostris

A metriorhynchine metriorhynchid

Plesiosuchus

P. manseli

A geosaurine metriorhynchid

Torvoneustes

T. carpenteri

A geosaurine metriorhynchid

T. coryphaeus

A geosaurine metriorhynchid

Ornithischians

Indeterminate ankylosaur osteoderms have been found in Wiltshire, England. Indeterminate stegosaurid remains have been found in Dorset and Wiltshire, England.

Genus Species Location Member Abundance Notes Images

Cumnoria

C. prestwichii

  • Oxfordshire

"Fragmentary skull and skeleton."

Iguanodontian
Cumnoria
Dacentrurus

Dacentrurus

D. armatus

  • Cambridgeshire
  • Dorset
  • Wiltshire
vertebrae, a massive right femur (thigh bone), ribs and a near complete pelvis.

Stegosaur. Wiltshire remains include specimens previously referred to Omosaurus armatus and O. hastiger.

Ornithopoda

Indeterminate

  • Dorset?

Kimmeridge clay remains considered to represent a possible close relative of Bugenasaura are now regarded as the remains of an indeterminate euornithopod.(The specimen may have had its locality and horizon mislabelled.)

Omosaurus

O.armatus

  • Wiltshire
Reclassified as Dacentrurus armatus because the generic name Omosaurus was preoccupied.

O. hastiger

  • Wiltshire

Saurischians

Indeterminate ornithomimmid remains have been found in Dorset, England. An undescribed theropod genus was found in Dorset.

Genus Species Location Stratigraphic position Material Notes Images

Bothriospondylus

B. suffosus

  • Wiltshire

"[Seven] dorsal and sacral centra."

Considered a nomen dubium.
Juratyrant

Cetiosaurus

C. humerocristatus

  • Dorset

Now Duriatitan.

Indeterminate

  • Oxfordshire

Remains previously referred to an indeterminate species of Cetiosaurus are now regarded as indeterminate sauropod material.

Duriatitan

D. humerocristatus

  • Dorset

Humerus

A titanosauriform

Gigantosaurus

G. megalonyx

  • Cambridgeshire

Remains previously referred to Gigantosaurus megalonyx are now regarded as indeterminate sauropod material.

"Ischyrosaurus"

I. manseli

  • Oxfordshire

"Humerus."

Remains previously referred to Ischyrosaurus manseli are now regarded as indeterminate sauropod material.

Juratyrant

J. langhami

  • Dorset

Partial skeleton

A primitive tyrannosaur

Torvosaurus Indeterminate Swindon, Dorset Tibia (OUMNH J.29886) and maxilla fragment, collected separately A megalosaurid

Theropoda

Indeterminate

  • Wiltshire
  • Dorset
A tooth from Foxhangers, Wiltshire (NHMUK 46388), phalanges from an unspecified locality in Wiltshire (DZSWS 3009), and a proximal caudal verte-

bra from Shotover, Oxfordshire (OUMNH J.47134).

Remains previously referred to Megalosaurus are now regarded as indeterminate theropod material.

Sauropoda

Indeterminate

  • Oxfordshire
  • Cambridgeshire
  • Norfolk

Remains previously attributed to one or more indeterminate species of Ornithopsis (incl. O. leedsii) are now regarded as possible indeterminate sauropod material.

Pterosaurs

Genus Species location Material Notes Images
Cuspicephalus C. scarfi

Dorset

Partial Skull Missing Crest, lower jaw and dentition
Cuspicephalus
Rhamphorhynchus

Rhamphorhynchus

R.etchesi

Dorset

Germanodactylus

indeterminate

Dorset

Plesiosaurs

Genus Species Location Member Abundance Notes Images

Bathyspondylus

B. swindoniensis

Plesiosaur of unknown affinities

Kimmerosaurus
Pliosaurus brachydeirus

Colymbosaurus

C. megadeirus

A cryptoclidid

C. trochantericus

Nomen dubium

Kimmerosaurus

K. langhami

A cryptoclidid

Plesiosaurus

"P." manseli

Distinct from Colymbosaurus.

Pliosaurus

P. brachydeirus

A thalassophonean pliosaurid

P. brachyspondylus

Nomen dubium

P. carpenteri

A thalassophonean pliosaurid

P. kevani

A thalassophonean pliosaurid

P. portentificus

A nomen dubium

P. ?rossicus

A thalassophonean pliosaurid; taxonomic identification of specimens tentative

P. westburyensis

A thalassophonean pliosaurid

P. sp. 1

Partial skeleton, CAMSM J.35991

A thalassophonean pliosaurid; previously assigned to the nomen dubium P. brachyspondylus

P. sp. 2

Mandible, NHMUK PV OR 39362

A thalassophonean pliosaurid; previously assigned to the nomen dubium P. macromerus

Spitrasaurus

Indeterminate

Ichthyosaurs

Genus Species Location Stratigraphic Position Abundance Notes Images

Brachypterygius

B.extremus

Dorset

Brachypterygius
Grendelius
Nannopterygius
Thalassodraco
Ophthalmosaurus

Grendelius

G.mordax

Dorset

Ichthyosauridae

Indeterminate

Dorset

Giant, near complete specimen. Proposed to have been 6 metres long when complete. Housed at the Etches collection in dorset.

Macropterygius

M.trigonus

Dorset

Nomen dubium - classified by a single vertebra

Nannopterygius

N.enthekiodon

Dorset

Thalassodraco

T. etchesi

Dorset

The Pectinatites pectinatus ammonite zone

Ophthalmosaurus

Indeterminate

Dorset

Invertebrates

An aptychus with the name Trigonellites latus, from the Kimmeridge Clay Formation

The invertebrate fauna of the Kimmeridge Clay includes:

See also


This page was last updated at 2023-10-30 20:44 UTC. Update now. View original page.

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