Saint-Chinian Formation
Stratigraphic range:
TypeGeologic formation
UnderliesLa Maurerie Formation
OverliesLa Dentelle Formation
Thicknessaround 500 m
Lithology
PrimaryShale
OtherSandstone
Location
Coordinates43°25′07″N 2°56′43″E / 43.418624°N 2.945366°E / 43.418624; 2.945366
Region Occitanie
Country France
Type section
Named forSaint-Chinian
Saint-Chinian Formation is located in France
Saint-Chinian Formation
Saint-Chinian Formation (France)

The Saint-Chinian Formation is a geological formation composed of shales with limestone inclusions, dating from the Lower Ordovician (Tremadocian).

It is one of the six geological formations from the Saint-Chinian Cambro-Ordovician basin, comprising, from the most ancient to the most recent : La Dentelle Formation, Saint-Chinian Formation, La Maurerie Formation, Cluse de l'Orb Formation and Setso member, Foulon Formation and Landeyran Formation. This formation outcrops on the southern flanks of the Montagne Noire in Southern France.[1]

The formation received its name from the small city of Saint-Chinian, a commune located in the Hérault department in Occitania.

It is dated from the biostratigraphic sub-zone characterized by Taihungshania miqueli and Asaphelina barroisi berardi.[1]

Paleoenvironment

The thin nature of the silico-clastics deposits, the presence of slump, combined with a trilobite fauna dominated by members of the Asaphidae family indicates a marine environment of external distal platform.[2]

Paleofauna

Shales of the Saint-Chinian Formation bears in certain areas accumulations of phosphated nodules, each potentially bearing a trilobite. Those are the so-called "schistes à gateaux"[3]..

Nautiloids

GenusSpeciesLocalityAgeNotesImages
CyclostomicerasC. thoraliEuloma filacovi ZoneLate TremadocianA cyclostomiceratid ellesmerocerid[4]
SalocerasS. chinianenseEuloma filacovi ZoneLate TremadocianAn eothinoceratid ellesmerocerid[4]
S. murvielenseEuloma filacovi ZoneLate TremadocianAn eothinoceratid ellesmerocerid[4]
S. pradenseTaihungshania miqueli acme SubzoneLate TremadocianAn eothinoceratid ellesmerocerid[4]
RiocerasR. escandeiEuloma filacovi Zone ; Asaphelina barroisi berardi and Taihungshania miqueli SubzoneLate TremadocianA rioceratid ellesmerocerid[4]
FelinocerasF. constrictumEuloma filacovi ZoneLate TremadocianA rioceratid ellesmerocerid[4]
AnnbactrocerasA. martyiEuloma filacovi ZoneLate TremadocianA baltoceratid orthocerid[4]
A. felinenseEuloma filacovi ZoneLate TremadocianA baltoceratid orthocerid[4]
BactrocerasB. mourguesiEuloma filacovi ZoneLate TremadocianA baltoceratid orthocerid[4]
CochliocerasC.? aff. roemeriEuloma filacovi Zone ; Asaphelina barroisi berardi and Taihungshania miqueli SubzoneLate TremadocianA baltoceratid orthocerid[4]
ThoralocerasT. bactroceroidesEuloma filacovi Zone ; Asaphelina barroisi berardi and Taihungshania miqueli SubzoneLate TremadocianA troedsonellid dissidocerid[4]
LobendocerasL. undulatumEuloma filacovi Zone ; Asaphelina barroisi berardi and Taihungshania miqueli SubzoneLate TremadocianA protocameroceratid endocerid[4]

Trilobites

GenusSpeciesLocalityAgeNotesImages
ParamegalaspisP. immarginataPrades-sur-VernazobreLate Tremadocian-Early ArenigAn asaphid[5]
AsaphellusA. frequensPrades-sur-VernazobreLate Tremadocian-Early ArenigAn asaphid[5]
A.? sp.Félines-MinervoisLate Tremadocian-Early ArenigAn asaphid[5]
AocaspisA. macrophtalmaLa Rouvelane, près de Prades-sur-VernazobreLate Tremadocian-Early ArenigAn nileid[6]
GeragnostusG. occitanusSaint-ChinianEarly ArenigA geragnostid[7]
G. callaveiSaint-ChinianEarly ArenigA geragnostid[7]
G. pusioSaint-ChinianEarly ArenigA geragnostid[7]
MicragnostusM. languedocensisSaint-ChinianEarly ArenigA micragnostid[7]
TrinodusT. chinianensisSaint-ChinianEarly ArenigA trinodid[7]
T. corpulentusSaint-ChinianEarly ArenigA trinodid[7]
T. abruptusSaint-ChinianEarly ArenigA trinodid[7]
T. oviformisSaint-ChinianEarly ArenigA trinodid[7]

Echinoderms

GenusSpeciesLocalityAgeNotesImages
ArauricystisA. primaevaA cornute stylophoran[12]
A. occitanaA cornute stylophoran[12]
CothurnocystisC. fellinensisA cornute stylophoran[12]
C. courtessoleiA cornute stylophoran[12]
PhyllocystisP. blayaciA cornute stylophoran[12]
P. crassimarginataA cornute stylophoran[12]
ThoralicystisT. griffeiA cornute stylophoran[12]
TrigonocarpusT. singularisA cornute stylophoran[12]
ChauvelicystisC. spinosaA cornute stylophoran[12]
C. vizcainoiA cornute stylophoran[12]
GalliaecystisG. lignieresiA cornute stylophoran[12]
G. ubaghsiA cornute stylophoran[12]
AmygdalothecaA. griffeiA cornute stylophoran[12]
AnatifopsisA. trapeziiformisA mitrate stylophoran[12]
BalanocystitesB. escandeiA mitrate stylophoran[12]
PeltocystisP. cornutaA mitrate stylophoran[12]
VizcainocarpusV. dentigerA mitrate stylophoran[12]
ChinianocarposC. thoraliA mitrate stylophoran[12]
MinervaecystisM. vidaliA solute homoistelean[12]
BalantiocystisB. thoraliAn eocrinoïd[12]
AethocrinusA. mooreiA cladide crinoïd[12]
MacrocystellaM. azaiziA dichoporite rhombifere. Two subspecies are present : M. a. paucicristatus and M. a. multicristata [12]
HemicystitesH. boehmiA edrioasteroïd[12]
 ?Pyrgocystis ?P. sp.A edrioasteroïd[12]
ChinianasterC. levyiA goniactinid stelleroïd[12]
VillebrunasterV. thoraliA goniactinid stelleroïd[12]
AmpullasterA. ubaghsiA goniactinid stelleroïd[12]
PradesuraP. jacobiA stenurid stelleroïd[12]

Other fossil remains of marine animals are known from the formation:[13]

References

  1. 1 2 "L'Ordovicien du bassin de Saint-Chinian" (PDF). Excursion ASNAT. 21 September 2019.
  2. Vidal, Muriel (1996). "Some Asaphidae from the Saint-Chinian Formation, Lower Ordovician, Montagne Noire (France): Systematics and palaeoenvironments". Geobios. 29 (6): 725–744. doi:10.1016/S0016-6995(96)80018-0.
  3. Thoral, Marcel (1946). "Cycles géologiques et formations nodulifères de la Montagne Noire". Publications du musée des Confluences, Année 1946. 1: 1–63.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 Kröger, B.; Evans, D. H. (2011). "Review and palaeoecological analysis of the late Tremadocian – early Floian (Early Ordovician) cephalopod fauna of the Montagne Noire, France". Museum für Naturkunde. 14(1): 5–34. doi:10.1002/mmng.201000013.
  5. 1 2 3 Vidal, M. (1996). "Quelques Asaphidae (Trilobita) de la Formation de Saint-Chinian, Ordovicien inférieur, Montagne Noire (France): Systématique et paléoenvironnements". Geobios. 29(6): 725–744. doi:10.1016/S0016-6995(96)80018-0.
  6. Dolambi, T.; Gond, P. (1992). "Aocaspis nov. gen., nouveau Trilobite Nileidae de l'Ordovicien inférieur de Montagne Noire (France)". Geobios. 25(2): 213–224. doi:10.1016/S0016-6995(06)80400-6.
  7. 1 2 3 4 5 6 7 8 Howell, B. F. (1935). "Cambrian and Ordovician trilobites from Herault, southern France". Journal of Paleontology. 9 (3): 222–238.
  8. Capera, J. C.; Courtessole, R.; Pillet, J. (1978). "Contribution à l'étude de l'Ordovicien inférieur de la Montagne Noire : biostratigraphie et révision des Agnostida". Annales de la Société Géologique du Nord. 98 (1): 67–87.
  9. Thoral, M. (1935). Imprimerie de la Charité (ed.). Contribution à l'étude paléontologique de l'Ordovicien inférieur de la Montagne Noire et révision sommaire de la faune cambrienne de la Montagne Noire. Montpellier. pp. 362 pp.{{cite book}}: CS1 maint: location missing publisher (link)
  10. 1 2 Vizcaino, D.; Alvaro, J.; Lefebvre, B. (2001). "The lower Ordovician of the southern Montagne Noire". Annales de la Société Géologique du Nord. 8 (2): 213–220.
  11. Alvaro, J.; Lefebvre, B.; Vizcaino, D. (2001). "Catalogue of the fossil species defined in the Lower Paleozoic of the southern Montagne Noire". Annales de la Société Géologique du Nord. 8 (2): 227–232.
  12. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Vizcaïno, D.; Lefebvre, B. (1999). "Les échinodermes du Paléozoïqueinférieur de Montagne Noire: Biostratigraphie et paléodiversité". Geobios. 32(2): 353–356. doi:10.1016/S0016-6995(99)80049-7.
  13. Babin, C.; Courtessole, R.; Melou, M.; Pillet, J.; Vizcaino, D.; Yochelson, E. L. (1982). Brachiopodes (Articulés) et mollusques (bivalves, rostroconches, monoplacophores, gastéropodes) de l'Ordovicien inférieur (Trémadocien-Arenigien) de la Montagne Noire (France méridionale). pp. 1–63.
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