Canjuers Lagerstätte Explained

Canjuers Lagerstätte
Type:	Konservat-Lagerstätte
Period:	Tithonian
Prilithology:	Lithographic limestone
Otherlithology:	Chert
Namedfor:	Canjuers plateau
Country:	France
Coordinates:	43.7087°N 6.3742°W
Unitof:	Calcaires blancs de Provence
Underlies:	Biomicrites de Sainte-Croix
Thickness:	12 m

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. 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.

Paleontology

Actinopterygians

Genus	Species	Order	Family	Images
Caturus	C. sp.		Caturidae
Eugnathus	E. sp.		Caturidae
Gyrodus	G. sp.		Gyrodontidae
Proscinetes	P. sp.		Pycnodontidae
			Pachycormidae
Pholidophorus	P. sp.		Pholidophoridae
Leptolepis	L. sp.		Leptolepidae
Tharsis	T. sp.		Leptolepidae
Ophiopsis	O. sp.		Ophiopsidae
			Elopidae
Lepidotes	L. sp.		Lepidotidae
Belonostomus	B. sp.		Aspidorhynchidae
Naiathelon	N. okkidion

Sarcopterygians

Genus	Species	Order	Family	Images
Undina	U. sp.
Coccoderma	C. sp.

Reptiles

Genus	Species	Order	Family	Images
Solnhofia	S. sp.		Plesiochelydae
Eurysternum	E. sp.		Eurysternidae
Pleurosaurus	P. ginsburgi		Pleurosauridae
	P. goldfussi		Pleurosauridae
Homoeosaurus	H. maximiliani		Sphenodontidae
Leptosaurus	L. pulchellus		Sphenodontidae
Piocormus	P. laticeps		Sphenodontidae
Aeolodon	A. priscus		Teleosauridae
Cycnorhamphus	C. suevicus		Gallodactylidae
Compsognathus	C. longipes		Compsognathidae

Echinoderms

Genus	Species	Order	Family	Images
Plegiocidaris	P. marginata		Cidaroida
Rhabdocidaris	R. nobilis		Cidaroida
Diplocidaris	D. gigantea		Cidaroida
Hemicidaris	H. crenularis		Hemicidaroida
Acrocidaris	A. nobilis		Hemicidaroida
Hessotiara	H. florescens		Hemicidaroida
Pseudosalenia	P. aspera		Salenioida
Pleurodiadema	P. stutzi		Phymosomatoida
Acropeltis	A. aequituberculata		Arbacioida
Magnosia	M. nodulosa		Arbacioida
Pentasteria	P. sp.		Paxillosida
Geocoma	G. canjuersensis		Ophiuridae
	G. aff. carinata		Ophiuridae
			Amphiuridae
Ophiurella	O. aff. speciosa		incertae sedis
Comaturella	C. pinnata		Comatulida
Saccocoma	S. tenella		Roveacrinida

Brachiopods

Genus	Species	Order	Family	Images
Torquirhynchia	T. guebhardi
Septaliphoria	S. obtusa
Somalirhynchia ?	S. sp.
Juralina	J. insignis'
Moeschia	M. aff. foraminata
Ismenia	I. pectunculoides
"Zeilleria"	Z. aff. pentagonalis

Molluscs

Genus	Species	Order	Family	Images
Modiolus	M. imbricatus
Entolium	E. corneolum
Chlamys	C. textoria
Spondylopecten	S. subpunctatus
Nanogyra	N. striata
Actinostreon	A. gregareum
Dorsoplanitoides	D. triplicatus
Usseliceras	U. (Subplanitoides) altegyratum
	U. (Subplanitoides) aff. spindelense
	U. (Subplanitoides) cf. schwertschlageri
	U. (Usseliceras) cf. franconicum
Hibolites	H. sp.

Crustaceans

Genus	Species	Order	Family	Images
Cycleryon	C. bourseaui^[5]
Kouphichnium	K. lithographicum		Xiphosura

Notes and References

1. Karin. Peyer. Sylvain. Charbonnie. Ronan. Allain. Emilie. Läng. Renaud. Vacant. 2014. A new look at the Late Jurassic Canjuers conservation Lagerstätte (Tithonian, Var, France).. Comptes Rendus Palevol . 13. 5. 403–420. 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. 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. 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. 10.1080/14772019.2013.777809. 128805162.