Canjuers Lagerstätte

Canjuers Lagerstätte
Stratigraphic range: Tithonian
Canjuers military camp: Bessons quarry, where the Compsognathus fossil was found
TypeKonservat-Lagerstätte
Unit ofCalcaires blancs de Provence
UnderliesBiomicrites de Sainte-Croix
Thickness12 m
Lithology
PrimaryLithographic limestone
OtherChert
Location
Coordinates43°42′31″N 6°22′27″E / 43.708695°N 6.374173°E / 43.708695; 6.374173
Region Provence-Alpes-Côte d'Azur
Country France
Type section
Named forCanjuers plateau
Canjuers Lagerstätte is located in France
Canjuers Lagerstätte
Canjuers Lagerstätte (France)

The Canjuers Lagerstätte is a Konservat-Lagerstätte located inside the military camp of Canjuers, in Haute Provence, in the Var department in South-East France.[1]

Geology and stratigraphy

From a stratigraphic point of view, this fossil deposit is located inside the Calcaires blancs de Provence geological formation, a 200-meter-thick limestone assemblage. The lithographic limestone of Canjuers, which bears almost all significant fossils from the Lagerstätte, is a thin layer (around 6 meters) at the basis of the Biomicrites de Sainte-Croix member, the later member of the Calcaires blancs de Provence.[2] This layer has been dated by ammonite analysis to the Lower Tithonian (Neochetoceras mucronatum biozone[3]), around 150 Mya.

The Canjuers site facies outcrop in the Petit Plan de Canjuers plateau, and a quarry was exploited in the locality "Les Bessons". They correspond to deposits inside a sub-circular depression whose area is estimated to be only 1 km2.[1] Their total thickness is around 12 m. They are divided in three lithologic units, from bottom to top :

  • The lithographic limestone per se, made of thin limestone, finely laminated, around 6 m thick. Those bears almost every remarkable fossils from the site (Lagerstätte).
  • Bioclastic limestone 4.5 m thick. Those are packstone or grainstone limestone, with chert nodule levels. Their bioclasts are made of corals, sea urchins, bivalves, brachiopods and sponges fragments, with burrows and some plant remains. The banks show quasi-planar oblique surface.
  • The sub-lithographic limestone with chert nodule levels, 1.5 m wide, in thick banks perforated by burrows attributed to the ichnotaxon Tubularina lithographica.[4]

Paleoenvironment

The lithographic limestone deposit environment was protected from the Tethys Ocean open sea by a continuous reef barrier. The lithographic limestone was deposited in a large lagoon whose various parts were successively above and below water, and where several small coral islands emerged. Meteoric water supplies are likely.[3]

Paleontology

Genus[1] Species Order Family Images
Caturus C. sp. Amiiformes Caturidae
Eugnathus E. sp. Amiiformes Caturidae
Gyrodus G. sp. Pycnodontiformes Gyrodontidae
Proscinetes P. sp. Pycnodontiformes Pycnodontidae
Pachycormidae Pachycormiformes Pachycormidae
Pholidophorus P. sp. Pholidophoriformes Pholidophoridae
Leptolepis L. sp. Leptolepiformes Leptolepidae
Tharsis T. sp. Leptolepiformes Leptolepidae
Ophiopsis O. sp. Ionoscopiformes Ophiopsidae
Elopidae Elopiformes Elopidae
Lepidotes L. sp. Lepisosteiformes Lepidotidae
Belonostomus B. sp. Aspidorhynchiformes Aspidorhynchidae
Naiathelon N. okkidion Elopomorpha
Genus[1] Species Order Family Images
Undina U. sp. Actinistia
Coccoderma C. sp. Actinistia
Genus[1] Species Order Family Images
Palaeocarcharias P. sp. Lamniformes
Genus[1] Species Order Family Images
Solnhofia S. sp. Chelonia Plesiochelydae
Eurysternum E. sp. Chelonia Eurysternidae
Pleurosaurus P. ginsburgi Rhynchocephalia Pleurosauridae
P. goldfussi Rhynchocephalia Pleurosauridae
Homoeosaurus H. maximiliani Rhynchocephalia Sphenodontidae
Leptosaurus L. pulchellus Rhynchocephalia Sphenodontidae
Piocormus P. laticeps Rhynchocephalia Sphenodontidae
Aeolodon A. priscus Mesoeucrocodylia Teleosauridae
Cycnorhamphus C. suevicus Pterosauria Gallodactylidae
Compsognathus C. longipes Dinosauria Compsognathidae
Genus[1] Species Order Family Images
Plegiocidaris P. marginata Echinoidea Cidaroida
Rhabdocidaris R. nobilis Echinoidea Cidaroida
Diplocidaris D. gigantea Echinoidea Cidaroida
Hemicidaris H. crenularis Echinoidea Hemicidaroida
Acrocidaris A. nobilis Echinoidea Hemicidaroida
Hessotiara H. florescens Echinoidea Hemicidaroida
Pseudosalenia P. aspera Echinoidea Salenioida
Pleurodiadema P. stutzi Echinoidea Phymosomatoida
Acropeltis A. aequituberculata Echinoidea Arbacioida
Magnosia M. nodulosa Echinoidea Arbacioida
Pentasteria P. sp. Asteroidea Paxillosida
Geocoma G. canjuersensis Ophiuroidea Ophiuridae
G. aff. carinata Ophiuroidea Ophiuridae
Amphiuridae Ophiuroidea Amphiuridae
Ophiurella O. aff. speciosa Ophiuroidea incertae sedis
Comaturella C. pinnata Crinoidea Comatulida
Saccocoma S. tenella Crinoidea Roveacrinida
Genus[1] Species Order Family Images
Torquirhynchia T. guebhardi Rhynchonellida
Septaliphoria S. obtusa Rhynchonellida
Somalirhynchia ? S. sp. Rhynchonellida
Juralina J. insignis' Terebratulida
Moeschia M. aff. foraminata Terebratulida
Ismenia I. pectunculoides Terebratulida
"Zeilleria" Z. aff. pentagonalis Terebratulida
Genus[1] Species Order Family Images
Modiolus M. imbricatus Bivalvia
Entolium E. corneolum Bivalvia
Chlamys C. textoria Bivalvia
Spondylopecten S. subpunctatus Bivalvia
Nanogyra N. striata Bivalvia
Actinostreon A. gregareum Bivalvia
Dorsoplanitoides D. triplicatus Cephalopoda
Usseliceras U. (Subplanitoides) altegyratum Cephalopoda
U. (Subplanitoides) aff. spindelense Cephalopoda
U. (Subplanitoides) cf. schwertschlageri Cephalopoda
U. (Usseliceras) cf. franconicum Cephalopoda
Hibolites H. sp. Cephalopoda
Genus Species Order Family Images
Cycleryon C. bourseaui[5] Decapoda
Kouphichnium[1] K. lithographicum Chelicerata Xiphosura

References

  1. ^ a b c d e f g h i j Peyer, Karin; Charbonnie, Sylvain; Allain, Ronan; Läng, Emilie; Vacant, Renaud (2014). "A new look at the Late Jurassic Canjuers conservation Lagerstätte (Tithonian, Var, France)". Comptes Rendus Palevol. 13 (5): 403–420. doi:10.1016/j.crpv.2014.01.007.
  2. ^ Atrops, F. (1991). "Le Tithonique en Provence à la lumière de la datation par ammonites du gisement de Canjuers (Var, France)". Comptes Rendus de l'Académie des Sciences, Série II. 313 (8): 909–915.
  3. ^ a b Atrops, F. (1994). "Présence d'ammonites du Tithonien inférieur dans les Calcaires lithographiques de Canjuers (Var, France) ; conséquences stratigraphiques et paléogéographiques". Geobios Mem. Spec. 16: 137–146. doi:10.1016/S0016-6995(94)80028-6.
  4. ^ Gaillard, C.; Bernier, P.; Gall, J.C.; Gruet, Y.; Barale, G.; Bourseau, J.P.; Buffetaut, E.; Wenz, S. (1994). "Ichnofabric from the Upper Jurassic lithographic limestone of Cerin, Southeast France". Palaeontology. 37 (2): 285–304.
  5. ^ Audo, D.; Charbonnier, S.; Schweigert, G.; Saint Martin, J.-P. (2014). "New eryonid crustaceans from the Late Jurassic Lagerstätten of Cerin (France), Canjuers (France), Wattendorf (Germany) and Zandt (Germany)". Journal of Systematic Palaeontology. 12 (4): 459–479. doi:10.1080/14772019.2013.777809. S2CID 128805162.