Sables du Castrais Formation

The Sables du Castrais Formation, also known as the Molasses du Castrais, is a geologic formation of Eocene (Ypresian to Bartonian) age,[2][3] outcropping in the Montagne-Noire region of France.[3][4]

Sables du Castrais Formation
Stratigraphic range: Eocene, Ypresian–Bartonian
TypeGeological formation
Sub-units
  • Lophiodon lautricense and Paleotherium zone
  • Issel Member
  • Villeneuve-la-Comptal Member
  • Grès de Carcassonne Member
  • Argiles rutilants d'Issel et de Saint-Papoul
  • Grès d'Issel
  • Molasses de Castelnaudary
  • Issel Sandstones
UnderliesMolasses de Saix et de Lautrec Formation
OverliesDanian rocks
Thickness15–40 metres (49–131 ft) at the base and at Castelnaudary. 50–100 metres (160–330 ft) at Issel.
Lithology
PrimarySandstone, molasse and conglomerate
OtherGravel clays
Location
Coordinates43°22′05″N 1°59′26″E / 43.3681°N 1.9906°E / 43.3681; 1.9906
RegionMontagne-Noire
CountryFrance
ExtentCarcassonne, Castelnaudary, Issel, Réalmont and Saint-Papoul
Type section
Named byM. Richard (1946)[1]
Sables du Castrais Formation is located in France
Sables du Castrais Formation
Sables du Castrais Formation (France)

History edit

"Petrified fossil remains" were known from the Sables du Castrais Formation since at least the 18th century,[5] and several of these fossils were described by Cuvier (1804) and Cuvier (1822) as belonging to Palaeotherium and Lophiodon.[6][7]

In 1845, a jaw assigned to Lophiodon lautricensis was discovered in the formation and was described by Noulet (1851);[8] Noulet also mentioned that he had himself collected fossils from the formation alongside pharmacist J. Parayre as early as c. 1843.[9]

Léonce Roux du Carla discovered several more fossils from the Grès d'Issel Mermber of the Sables du Castrais formation from February 1855 until his death in 1859, and this helped Noulet (1858) to confirm the Eocene age of the deposit.[4] Despite this, all that remains today of du Carla's collection is a single jaw of Palaeotherium castrense from the Sables du Castrais Formation.[5]

Between 1850 and 1868, during the construction of the Castres - Albi railroad, several more fossils were recovered from the Sables du Castrais Formation,[5] including M. Zebrowsky's 1868 discovery of fossils within the area.[10]

The Grès d'Issel Member was identified by Henri de Sévérac in 1873,[11] and the Sables du Castrais Formation was first described by M. Richard in 1946.[1]

The Grès d'Issel Member is located in a quarry which closed around 1966 and is now inaccessible due to it currently being located underneath a private garden.[12]

Age of the formation edit

The age of the Sables du Castrais Formation was listed as Eocene by Noulet (1858)[4] and in 1867, Gervais noted that the Issel Member likely dated to the Early Eocene, while the Villeneuve-la-Comptal Member likely dated to the Middle Eocene.[13]

Caraven-Cachin (1898) was the first to assign the Sables du Castrais Formation to the Bartonian.[14] Stehlin (1910) and Escarguel (1999) dated the formation to the Lutetian-Bartonian and found it to overlie the Molasses de Saix et de Lautrec Formation.[15][16] Fauré (2011) agreed with the more recent dating of the formation to the Ypresian-Bartonian.[5]

Geology edit

The base of the Sables du Castrais Formation, which overlies Danian rocks,[12] is made up of Ypresian gravel clays and the Issel Sandstones, which range from 15–40 metres (49–131 ft), and the Argiles rutilants d'Issel et de Saint-Papoul Member is deposited within the gravel clays, and is between 20–30 metres (66–98 ft) thick.[12]

The Argiles rutilants d'Issel et de Saint-Papoul Member is overlain by the Lutetian Grès d'Issel Member, which is between 50–100 metres (160–330 ft) thick,[17] and is overlain by the Bartonian Molasses du Castelnaudary Member.[12][18][19] The whole formation underlies the Molasses de Saix et de Lautrec Formation.[5]

The Grès de Carcassonne Member also appears to be slightly younger than the Grès d'Issel Member, likely dating to the late Lutetian or early Bartonian.[20][17]

The Sables du Castrais Formation was described by Capera and Baillet (2014) as a typical fluviatile formation, with lenticular channels, formed by conglomerates and sandstones, with calcareous cement and large trough cross-strata.[21]

Paleofauna edit

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.

Mammals edit

Artiodactyl
Taxa Species Locality Stratigraphic position Material Notes Images
Catadontherium C ? paquieri
Cebochoerus C.(Gervachoerus) campichii
C.(Cebochoerus) helveticus
Choeropotamus C. lautricensis
Dacrytherium D. elegans
Pseudoamphimeryx P. sp.
Robiacina R. minuta
Tapirulus Tapirulus cf. schlosseri
Xiphodon X. castrense
Lipotyphia
Taxa Species Locality Stratigraphic position Material Notes Images
Saturninia S. sp.
Marsupial
Taxa Species Locality Stratigraphic position Material Notes Images
Paratherium P. sp.
Pan-Carnivora
Taxa Species Locality Stratigraphic position Material Notes Images
Hyaenodon H. nouleti
H. sp
Quercygale Q. angustidens
Perissodactyl
Taxa Species Locality Stratigraphic position Material Notes Images
Anchylophus A. cf. desmaresti
A. cf. gaudini
Eurohippus E. parvulus
 
Lophiodon L. isselense.
 
L. lautricense.
L. sp.
Plagiolophus P. cartailhaci
P. cf. minor
Leptolophus L. nouleti
Lophiaspis L. occitanicus
Paralophiodon[12] P. isselense[12]
Palaeotherium P. castrense
 
P. (Frantzenitherium) lautricense
P. isselanum[7]
P. rhinocerodes
P. siderolithicum
P. pomeli
Propalaeotherium P. sp.
Primates
Taxa Species Locality Stratigraphic position Material Notes Images
Adapis A. aff. parisiensis
A. rouxii
Necrolemur N. sp.
Rodent
Taxa Species Locality Stratigraphic position Material Notes Images
Gliravus G. sp.
Suevoscurius S. sp.
Pseudoltinomys P. sp.

Reptiles edit

Crocodilians
Taxa Species Locality Stratigraphic position Material Notes Images
Asiatosuchus A. depressifrons[12]  
Atacisaurus A. glareae[17]
A. cf. sp.[17]
Crocodylus C. rouxii
Dentaneosuchus D. crassiproratus[17][3] A mandibular symphysis. A giant sebecid crocodile.
 
Iberosuchus I. cf. macrodon
Kentisuchus[12] K. astrei[12]
Pristichampsus P. rollinati
 
Turtles
Taxa Species Locality Stratigraphic position Material Notes Images
Allaeochelys A. pareyrei
A. nouleti
A. castrensis
Hadrianus H. castrensis
Neochelys N. mengauti
N. sp.[22]
Trionyx T. filholi
T. sp.[23]

References edit

  1. ^ a b M. Richard. (1946). Contribution a l'étude du basin d'Aquitaine, Les Gisements de Mammiferes Tertiares. Memoires de la Societe Geologique de France, Nouvelle Serie 24(52):1-380
  2. ^ Marandat, B. (1987) La biostratigraphie mammalienne de l'Éocène continental du versant sud de la Montagne noire. Reconsidération d'après les nouvelles données. Muench. Geowiss. Abh. (A), 10 (1987), pp. 149-158
  3. ^ a b c Martin, J. E.; Pochat-Cottilloux, Y.; Laurent, Y.; Perrier, V.; Robert, E.; Antoine, P.-O. (2023). "Anatomy and phylogeny of an exceptionally large sebecid (Crocodylomorpha) from the middle Eocene of southern France". Journal of Vertebrate Paleontology. e2193828. doi:10.1080/02724634.2023.2193828. S2CID 258361595.
  4. ^ a b c Noulet, J.-B. (1858) – Du terrain éocène supérieur considéré comme l’un des étages constitutifs des Pyrénées. Bulletin de la Société géologique de France, 1858, p. 277-284
  5. ^ a b c d e Fauré, Philippe. (2011). UN PATRIMOINE GEOLOGIQUE PEU CONNU : LES GISEMENTS DE VERTEBRES FOSSILES DE L’EOCENE MOYEN DU CASTRAIS (TARN, LUTETIEN SUPERIEUR A BARTONIEN SUPERIEUR).
  6. ^ Cuvier, G. (1804). Sur les espèces d’animaux dont proviennent les os fossiles répandus dans la pierre à plâtre des environs de Paris. Ann. Mus. Nat. Hist. Nat. (1804), pp. 275-303 (Pl. 23-29)
  7. ^ a b Cuvier, G. (1822) – Recherche sur les ossements fossiles où l’on rétablit les caractères de plusieurs animaux dont les révolutions du globe ont détruit les espèces. Nouvelle édition.. Tome second, 1er partie.
  8. ^ Noulet, J.B. (1851) – Sur une nouvelle espèce de Pachyderme fossile du genre Lophiodon (Lophiodon lautricensis). Mémoires de l’Académie des Sciences Inscription et Belles Lettre de Toulouse, 4 ser., t. I, p. 245-250.
  9. ^ Noulet, J.-B. (1863) – Etude sur les fossiles du terrain éocène supérieur de l’Agout (Tarn). Mémoires de l’Académie des Sciences Inscription et Belles Lettre de Toulouse, 6e sér., t. I, p. 181-206.
  10. ^ Noulet, J.B. (1870) – Du Chéropotame de Lautrec, espèce nouvelle des grès à Palaeotherium du bassin de l’Agout (Tarn). Mémoires de l’Académie des Sciences Inscription et Belles Lettre de Toulouse, 7e sér., t.. II, p. 331-335.
  11. ^ Ortega, F.; Buscaloni, A.D; Gasaparini, Z. (1996). "Reinterpretation and new denomination of Atacisaurus crassiproratus (Middle Eocene; Issel, France) as cf. Iberosuchus (Crocodylomorpha, Metasuchia)". Geobios. 29 (3): 353–364. doi:10.1016/S0016-6995(96)80037-4.
  12. ^ a b c d e f g h i Jouve, Stéphane (2016-04-17). "A new basal tomistomine (Crocodylia, Crocodyloidea) from Issel (Middle Eocene; France): palaeobiogeography of basal tomistomines and palaeogeographic consequences". Zoological Journal of the Linnean Society. 177 (1): 165–182. doi:10.1111/zoj.12357. ISSN 0024-4082.
  13. ^ Gervais P. (1867-69) – Zoologie et Paléontologie générales. Nouvelles recherches sur les Vertébrés vivants et fossiles. Paris, Arthus Bertrand, Editeur. 50 pl.
  14. ^ Caraven-Cascin, A., (1898) – Description géographique, géologique, minéralogique, paléontologique, paléthnologique et agronomique des départements du Tarn et Tarn et Garonne. Privat, Toulouse & Masson, Paris, 1898, 684 p.
  15. ^ Stehlin, H.G. (1910) – Die Säugetiere des schweitzerischen Eocaens. 6ème part. Mémoire de la Société Paléontologique suisse, t. XXXVI, p. 838-1164-258
  16. ^ ESCARGUEL G. (1999) – Les rongeurs de l’Eocène inférieur et moyen d’Europe occidentale. Systématique, Phylogénie, biochronologie et paléobiogéographie des niveaux repères MP 7 à MP 14. Paleovertebrata, 28, n° 2-4, p. 89-351.
  17. ^ a b c d e Astre, G. (1931). "Les crocodiliens fossiles des terrains tertiaires sous pyrénéens". Bulletin de la Société d'Histoire naturelle de Toulouse. 61: 25–71.
  18. ^ Cavaillé, A., Debat, P., Calas, G. (1975). Castelnaudary, notice explicative. Carte géologique de la France à 1/50 000. 1036, Orléans: BRGM, 17 pp.
  19. ^ Adnet, S., Crochet, J-Y., Baillet, L. (2014). Gisement à vertébrés lutétiens d'Issel. Inventaire du patrimoine géologique du Languedoc-Roussilon, LRO-1104, DREAL Languedoc-Roussillon, 4 pp.
  20. ^ Depéret, C. (1921). Sur Un Petit Lophiodontidae (Lophiaspis Occitanicus Mutation Cesserasicus) Des Grès éocènes de Laure (Aude). Bulletin de La Société d'Etudes Scientifiques de l'Aude 27: 44–54.
  21. ^ Capera, J-C., Baillet, L. (2014). Carrière de grès éocènes de Carcassonne. Inventaire du patrimoine géologique du Languedoc-Roussilon, LRO-1052, DREAL Languedoc-Roussillon, 4 pp.
  22. ^ F. Lapparent de Broin. (2003). Neochelys sp. (Chelonii, Erymnochelyinae), from Silveirinha, early Eocene, Portugal. Ciencias da Terra (UNL) 15:117-132
  23. ^ F. Broin. (1977). Contribution a l'etude des Cheloniens. Cheloniens continentaux due Cretace et du Tertiare de France. Memoires du Museum National d'Histoire Naturelle, Nouvelle Serie, Serie C, Sciences de la terre 38:1-366.