Kimmeridge Clay | |
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Stratigraphic range: | |
![]() Grey cliffs of Upper Kimmeridge Clay above the beach at Egmont Bight | |
Type | Geological formation |
Unit of | Ancholme Group (onshore), Humber Group (offshore) |
Sub-units | Birch Sandstone Member Burns Sandstone Member Claymore Sandstone Member Dirk Sandstone Member Magnus Sandstone Member Ptarmigan Sandstone Member Ribble Sandstone Member |
Underlies | Portland Sand Formation, Speeton Clay Formation, Spilsby Sandstone |
Overlies | Ampthill Clay, Corallian Group |
Lithology | |
Primary | Mudstone |
Other | Siltstone, Sandstone, Conglomerate |
Location | |
Region | England (surface) North Sea (subsurface) |
Country | United Kingdom |
Type section | |
Named for | Kimmeridge Bay |
Location | Type section - North Sea well 47/15- 1 at 885-919 m depth Type 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. [1] 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.
![]() | This section needs expansion. You can help by adding to it. (May 2016) |
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. [2] 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. [1]
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. [3]
Kimmeridge Clay is of great economic importance, [2] being the major source rock for oil fields in the North Sea hydrocarbon province. [4] It has distinctive physical properties and log responses. [5]
Color key
| Notes Uncertain or tentative taxa are in small text; |
Fauna uncovered from the Kimmeridge Clay include: [6]
Ray-finned fishes of the Kimmeridge clay Formation | ||||||
---|---|---|---|---|---|---|
Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images |
Indeterminate | Dorset | Most common Kimmeridge clay fish, known from several complete specimens | Housed at the Etches Collection, discovered by Steve Etches | ![]() | ||
Indeterminate | Dorset | Housed at the Etches Collection, discovered by Steve Etches | ||||
Indeterminate | Dorset | Housed at the Etches Collection, discovered by Steve Etches | ||||
Indeterminate | Dorset | One specimen, a fin | Housed at the Etches Collection, discovered by Steve Etches | |||
Indeterminate | Dorset | Housed at the Etches Collection, discovered by Steve Etches | ||||
Indeterminate | Dorset | Housed at the Etches Collection, discovered by Steve Etches | ||||
Indeterminate | Dorset | Housed at the Etches Collection, discovered by Steve Etches | ![]() | |||
Indeterminate | Dorset | Housed at the Etches Collection, discovered by Steve Etches | ||||
H.tenuirostris | Dorset | Rare | Housed at the Etches Collection, discovered by Steve Etches | |||
Indeterminate | Dorset | Rare | Housed at the Etches Collection, discovered by Steve Etches | |||
Indeterminate | Dorset | Rare, one complete specimen | Housed at the Etches Collection, discovered by Steve Etches | |||
Indeterminate | Dorset | Fairly common, multiple near complete specimens. | Housed at the Etches Collection, discovered by Steve Etches | |||
Lobe-finned fishes of the Kimmeridge clay Formation | ||||||
---|---|---|---|---|---|---|
Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images |
Indeterminate | Dorset | One specimen, cranial material | Coelacanth. Housed at the Etches Collection, discovered by Steve Etches. More than 2 metres long | |||
Cartilaginous fishes of the Kimmeridge clay Formation | ||||||
---|---|---|---|---|---|---|
Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images |
Indeterminate | Dorset | Known from many dorsal spines | Housed at the Etches Collection, discovered by Steve Etches | |||
Indeterminate | Known from many dorsal spines | Housed at the Etches Collection, discovered by Steve Etches | ||||
Indeterminate | Known from many dorsal spines, perhaps a complete head | Housed at the Etches Collection, discovered by Steve Etches | ||||
Indeterminate | One specimen | Housed at the Etches Collection, discovered by Steve Etches | ||||
Indeterminate | Known from a complete specimen, and other isolated remains | Housed at the Etches Collection, discovered by Steve Etches | ||||
K. etchesi | Encombe (holotype) and Rope Lake Head (paratype) | Known from two partial skeletons | A spathobatid ray; housed at the Etches Collection, discovered by Steve Etches | |||
Durnonovariaodus [10] | D. maiseyi | Pectinatites pectinatus ammonite zone | One partial skeleton | A hybodontid |
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" [11] | Thalassochelydian sea turtle | ||
Achelonia | A. formosa | Ely, Cambridgeshire | "CAMSM J29898 to CAMSM J29955 (holotype), a partial, disarticulated skeleton" [11] | Thalassochelydian sea turtle, formerly considered the distinct species "Enaliochelyschelonia" [12] | ||
Pelobatochelys | P. blakii | Weymouth | Carapace fragments | Thalassochelydian sea turtle | ||
Plesiochelys [13] | 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) [13] | Thalassochelydian sea turtle | ||
Tropidemys [13] | 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 |
Genus | Species | Location | Member | Abundance | Notes | Images |
---|---|---|---|---|---|---|
B. megarhinus | A pelagic teleosaurid. [14] | ![]() ![]() ![]() ![]() | ||||
C. gracilis | ||||||
D. maximus | A geosaurine metriorhynchid | |||||
M. brevirostris | A metriorhynchine metriorhynchid | |||||
P. manseli | A geosaurine metriorhynchid | |||||
T. carpenteri [15] | A geosaurine metriorhynchid | |||||
T. coryphaeus [17] | A geosaurine metriorhynchid | |||||
Indeterminate ankylosaur osteoderms have been found in Wiltshire, England. [18] Indeterminate stegosaurid remains have been found in Dorset and Wiltshire, England. [6]
Genus | Species | Location | Member | Abundance | Notes | Images |
---|---|---|---|---|---|---|
C. prestwichii [6] |
| "Fragmentary skull and skeleton." [19] | Iguanodontian | ![]() ![]() | ||
D. armatus [6] | 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. [6] | ||||
Indeterminate [6] |
| Kimmeridge clay remains considered to represent a possible close relative of Bugenasaura [20] are now regarded as the remains of an indeterminate euornithopod. [6] (The specimen may have had its locality and horizon mislabelled.) | ||||
O.armatus [6] |
| Reclassified as Dacentrurus armatus because the generic name Omosaurus was preoccupied. [6] | ||||
O. hastiger [6] |
| |||||
Indeterminate ornithomimmid remains have been found in Dorset, England. [6] An undescribed theropod genus was found in Dorset. [6]
Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
---|---|---|---|---|---|---|
B. suffosus [6] |
| "[Seven] dorsal and sacral centra." [21] | Considered a nomen dubium. | ![]() | ||
C. humerocristatus [6] |
| Now Duriatitan . [22] | ||||
Indeterminate [6] |
| Remains previously referred to an indeterminate species of Cetiosaurus are now regarded as indeterminate sauropod material. [6] | ||||
D. humerocristatus |
| |||||
G. megalonyx [6] |
| Remains previously referred to Gigantosaurus megalonyx are now regarded as indeterminate sauropod material. [6] | ||||
" Ischyrosaurus " [6] |
| "Humerus." [24] | Remains previously referred to Ischyrosaurus manseli are now regarded as indeterminate sauropod material. [6] | |||
J. langhami |
| Partial skeleton | A primitive tyrannosaur | |||
Torvosaurus [27] | Indeterminate |
| Tibia (OUMNH J.29886) and maxilla fragment, collected separately | A megalosaurid | ||
Indeterminate | A tooth from Foxhangers, Wiltshire (NHMUK 46388), phalanges from an unspecified locality in Wiltshire (DZSWS 3009), and a proximal caudal vertebra from Shotover, Oxfordshire (OUMNH J.47134). [27] | Remains previously referred to Megalosaurus are now regarded as indeterminate theropod material. [6] | ||||
Indeterminate [6] | Remains previously attributed to one or more indeterminate species of Ornithopsis (incl. O. leedsii) are now regarded as possible indeterminate sauropod material. [6] | |||||
Genus | Species | Location | Material | Notes | Images |
---|---|---|---|---|---|
Cuspicephalus | C. scarfi [28] | Dorset | Partial Skull | Missing Crest, lower jaw and dentition | ![]() ![]() |
Germanodactylus | indeterminate [29] | Charnel, Dorset | May be a non-pterodactyloid monofenestratan instead [28] | ||
Rhamphorhynchus | R. etchesi [30] | Encombe, Dorset [30] | |||
Ctenochasmatoidea | indeterminate [31] | Abingdon, Oxfordshire | Left first wing finger phalanx |
Genus | Species | Location | Member | Abundance | Notes | Images |
---|---|---|---|---|---|---|
B. swindoniensis | Plesiosaur of unknown affinities | ![]() ![]() | ||||
C. megadeirus | ||||||
C. trochantericus | Nomen dubium | |||||
K. langhami | A cryptoclidid | |||||
"P." manseli | Distinct from Colymbosaurus. [32] | |||||
P. brachydeirus | ||||||
P. brachyspondylus [33] | Nomen dubium | |||||
P. carpenteri | A thalassophonean pliosaurid | |||||
P. kevani | A thalassophonean pliosaurid | |||||
P. portentificus [35] | A nomen dubium | |||||
P. ?rossicus | A thalassophonean pliosaurid; taxonomic identification of specimens tentative [33] | |||||
P. westburyensis | A thalassophonean pliosaurid | |||||
P. sp. 1 | Partial skeleton, CAMSM J.35991 | A thalassophonean pliosaurid; previously assigned to the nomen dubiumP. brachyspondylus [33] [34] | ||||
P. sp. 2 | Mandible, NHMUK PV OR 39362 | A thalassophonean pliosaurid; previously assigned to the nomen dubiumP. macromerus [33] [34] | ||||
Indeterminate | ||||||
Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images |
---|---|---|---|---|---|---|
B.extremus | Dorset | ![]() ![]() ![]() ![]() ![]() | ||||
G.mordax | Dorset | |||||
Indeterminate | Dorset | Giant, near complete specimen. Proposed to have been 6 metres long when complete. Housed at the Etches Collection in Dorset. | ||||
M.trigonus | Dorset | Nomen dubium - classified by a single vertebra | ||||
N.enthekiodon | Dorset | |||||
T. etchesi | Dorset | The Pectinatites pectinatus ammonite zone | ||||
Indeterminate | Dorset | |||||
The invertebrate fauna of the Kimmeridge Clay includes: [36] [37]