Tagoudite Formation

The Tagoudite Formation (also known as the "Upper Tamadout Formation") is a geological formation of Toarcian (Lower Jurassic) age in the Béni-Mellal, Imilchil, Tinerhir, Tinejdad and Errachidia areas of the High Atlas (reaching areas near Rich in the Middle Atlas^[1]) of Morocco.^[2][3]

Tagoudite Formation
Stratigraphic range: Early-Middle Toarcian 184–180 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Profile at Jebel Akenzoud (Dadès Gorges) where the Tagoudite, Tafraout and Azilal Fms can be seen. (B) Close-up view of the left side ooidal shoal with lateral accretions (white arrows). (C) Stratigraphic correlation. (D) Close up of the right side shoulder. (E) Close up on the erosion surface.
Type	Geological Formation
Underlies	Aït Abdi Formation Aït Hani formation Agoudim 1 Formation Amellago Formation Bin el Ouidane Formation Tafraout Formation
Overlies	Aberdouz Formation Aganane Formation Choucht Formation Ouchbis Formation
Thickness	230 m (750 ft)
Lithology
Primary	Siliclastic Sandstone/Mudstone, Marlstone
Location
Location	Er-Rich
Coordinates	31.49°N 5.58°W / 31.49; -5.58
Approximate paleocoordinates	26.6°N 3.4°W / 26.6; -3.4
Region	High Atlas and Middle Atlas
Country	Morocco
Type section
Named for	Tagoudite Pass near Er-Rich
Named by	Riccardo Bernasconi
Year defined	1983
Region	Er-Rich, Midelt Province
Thickness at type section	~70 m (230 ft)
Tagoudite Formation (Morocco)

Description

Profile at Ouguerd Zegzaoune with the Tagoudite and Tafraout Fms

The Tagoudite Formation marks a major shift in Liassic sedimentation, replacing the carbonate turbidites of the Ouchbis Formation with mostly siliciclastic layers. These layers alternate between gray and green sandstone, sandy marls, and siltstones, forming sequences up to 20 meters thick.^[4] They show a decrease in grain size and an increase in marl content from bottom to top, with features like ripple marks and laminations. Microscopically, the turbidites are mainly fine silt, with varying amounts of quartz, feldspar, and carbonate detritus, and occasional pyrite. This formation suggests an open marine environment with sediment interruptions and materials coming from distant areas. It is widespread in the Central High Atlas, with thicknesses reaching up to 320 meters, and varies across different regions like Tounfite and Beni Mellal. In the Central Middle Atlas, sedimentation was interrupted by emersion before the formation's deposition.^[4] The deposits of the Tagoudite Formation are mostly restricted to the central High Atlas, with a thickness of approx. 200 m in the northwest vs at 30–70 m in the southeast, but retaining around 200 m at center areas like Foum Tillicht.^[5] More at the E it starts to disappear like at the Cirque de Jaafar, SW of Midelt or more at the E at Bou Redine Gorges, were the Agoudim 1 Formation directly overlies the Pliensbachian.^[6]

Biota

Phytoplankton marks oscillations of negative carbon isotope excursions at T-OAE and Pliensbachian-Toarcian (Pl-To) transition, dominated by open marine haptophytan or incertade sedis coccoliths like Biscutum, Carinolithus (including the index C. superbus, marker of the Polymorphum biozone), Calcivascularis, Calyculus, Lotharingius, Mitrolithus, Parhabdolithus or Schizosphaerella, measured in the Tagoudite Fm in areas like Amellago or Talghemt.^[7][8][9] Dinoflagellates are rare and limited to taxa such as Luehndea, Mancodinium and Mendicodinium.^[10]

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.

Foraminifera

Genus	Species	Location	Material	Notes	Images
Dentalina[11]	D. terquemi D. sp.	Bou-Oumardoul	Tests/shells	A foraminifer of the family Nodosariinae.
Citharina[12]	C. sp.	Taquat N'Agrd	Tests/shells	A foraminifer of the family Vaginulininae.
Everticyclammina[11][13]	E. sp.	Aguerd N´Igli Aguerd N´Wahmane Col de Ghnim Ouguerd Zegzaoune Tizi n-M´Barek	Tests/shells	A foraminifer of the Everticyclamminidae family.
Ichtyolaria[11][14]	I. carinata I. gr.major	Bou-Oumardoul Talghemt	Tests/shells	A foraminifer of the family Ichthyolariinae.
Lenticulina[15][14][16]	L. matutina L. gottingensis L. acutiangulata L. münsteri L. toarcense L. chichery L. sp.	Anergui Bou-Oumardoul Taquat N'Agrd Talghemt	Tests/shells	A foraminifer of the family Lenticulininae.
Lingulina[15]	L. brizaeformis L. pupa L. dentaliformis L. tenera	Bou-Oumardoul Taquat N'Agrd	Tests/shells	A foraminifer of the family Lenticulininae.
Marginulina[15]	M. prima M. spinata	Taquat N'Agrd	Tests/shells	A foraminifer of the family Marginulininae.
Ophtalmidium[13][15][17][16]	O. concentricum O. sp.	Aguerd N´Igli Anergui Bou-Oumardoul Ilourhmane Jebel Toksine Ouguerd Zegzaoune Taquat N'Agrd Timghissine	Tests/shells	A foraminifer of the family Ophthalmidiidae.
Orbitopsella[18]	O. praecursor	Col de Ghnim	Tests/shells	A foraminifer of the family Orbitopsellinae.
Pseudocyclammina[11][13]	P. sp.	Aguerd N´Igli Bou-Oumardoul	Tests/shells	A foraminifer of the family Hauraniidae.
Pseudonodosaria[15][14]	P. tennis P. multicostata P. gr.pygmea P. sp.	Bou-Oumardoul Ilourhmane Ouguerd Zegzaoune Talghemt Taquat N'Agrd	Tests/shells	A foraminifer of the family Nodosariinae.
Reinholdella[11][13][16]	R. sp.	Anergui Bou-Oumardoul	Tests/shells	A foraminifer of the family Ceratobuliminidae.
Verneuilinoides[14]	V. cf.subvitreus	Talghemt	Tests/shells	A foraminifer of the family Verneuilinoidinae

Ichnofossils

Ichnogenus	Ichnospecies	Location	Made by	Images
Arenicolites[19][20]	A. ispp.	Bou-Oumardoul Ilourhmane Jbel Taguendouft Jebel Toksine Ouguerd Zegzaoune Tamadoute Taquat N'Agrd Tougza	Amphipoda Arenicolidae Capitellidae Sipuncula Spionida	Arenicolites specimens from Mongolia
Chondrites[20]	C. ispp.	Agrd N´Igli Bou-Oumardoul Ilourhmane Jebel Toksine Ouguerd Zegzaoune	Polychaeta Sipuncula	Chondrites trace fossil from Scotland
Rhizocorallium[21][20]	R. parallelum R. ispp.	Agrd N´Igli Aït Allal Jbel Akenzoud Jbel Taguendouft Jebel Toksine NW Dades Valley Todrha-Dades Wahmane	Actinopterygii Decapoda Polychaeta	Rhizocorallium from Australia
Scolicia[19]	S. ispp.	Bou-Oumardoul Ilourhmane Ouguerd Zegzaoune	echinoids Gastropoda
Skolithos[20]	S. ispp.	Jbel Taguendouft Jebel Toksine	Decapoda Phoronidans Polychaeta	Representation of Skolithos along the possible makers
Thalassinoides[19][20]	T. ispp.	Bou-Oumardoul Ilourhmane Jebel Toksine Ouguerd Zegzaoune	Actinopteri Anomura Decapoda Dipnoi Polychaeta Sipuncula	Thalassinoides from France
Zoophycos[19][20]	Z. ispp.	Agrd N´Igli Aït Allal Bou-Oumardoul Ilourhmane Jebel Toksine Ouguerd Zegzaoune Wahmane	Arenicolidae Capitellidae Sipuncula Spionida	Zoophycos fossil from Kentucky

Brachiopoda

Genus	Species	Location	Material	Notes	Images
Quadratirhynchia[22]	Q. vasconcellosi	Akka n’Igoulzane Jebel Bou Ifliyou Jebel Ich Taskouine	Shells	A brachiopod of the family Tetrarhynchiidae
Homoeorhynchia[23][22]	H. meridionalis H. batalleri	Akka n’Igoulzane Jebel Bou Ifliyou Jebel Ich Taskouine Oued Mijdider	Shells	A brachiopod of the family Rhynchonellinae.
Pseudogibbirhynchia[22]	P. jurensis	Jebel Ich Taskouine	Shells	A brachiopod of the family Pamirorhynchiinae
Soaresirhynchia[22]	S. tamazirta S. bouchardi	Jebel Ich Taskouine	Shells	A brachiopod of the family Basiliolinae
Telothyris[23][22]	T. jauberti T. arnaudi	Akka n’Igoulzane Jebel Bou Ifliyou Jebel Ich Taskouine	Shells	A brachiopod of the family Lobothyrididae.

Mollusks

Genus	Species	Location	Material	Notes	Images
Alectryonia[24]	A. (Lopha) amellagensis	Agoudim Amellago	Shells	A marine member of the family Ostreidae.	Modern Lopha specimen
Calliphylloceras[25]	C. nilssoni	Amellago	Shells	An ammonite of the family Calliphylloceratinae
Canavaria[25]	C. aff. zancleana C. cf. rosenbergi	Amellago	Shells	An ammonite of the family Hildoceratidae.
Chlamys[24][26]	C. semiarticulatus C. aff.uhligi	Agoudim Amellago Bou Dahar	Shells	A marine member of the family Pectinidae.	Modern Chlamys specimens
Dactylioceras[27][28][25]	D. (Orthodactylites) aff. crosbeyi D. cf.helianihoides D. (Eodactylites) mirabile D. (Eodactylites) simplex D. (Eodactylites) cf.polymorphum D. (Eodactylites) pseudocommune D. pseudocrassulosum[24] D. cf. tauromenense	Agoudim Almou-n' Tarzekt Amellago Jbel Aouloum Jbel Bou Hamid Jbel Taguendouft SE Cherket Tagounit Talghemt Tamadoute Taquat N'Agrd Tougza	Shells	An ammonite of the family Dactylioceratidae.	Dactylioceras reconstruction
Eleganticeras[29][25]	E. exaratum E. sp.	Amellago Foum Tillicht	Shells	An ammonite of the family Hildoceratidae.
Gryphaea[24][30]	G. sportella G. cristata G. (Bilobissa) sp.	Agoudim Ait Athmane Amellago	Shells	A saltwater/brackish bivalve of the family Gryphaeidae.	Specimen of the genus
Harpax[24]	H. spp.	Agoudim Aït-Haceïne Amellago	Shells	A marine member of the family Plicatulidae.
Harpoceras[29][25]	H. serpentinum H. pseudoserpentinum H. falciferum H. subplanatum	Amellago	Shells	An ammonite of the family Hildoceratidae.	Harpoceras reconstruction
Hildaites[25]	H. striatus H. wrighti	Amellago	Shells	An ammonite of the family Hildoceratidae.
Hildoceras[27][28][31]	H. sublevisoni H. lusitanicum H. bifrons H. spp.	Agrd N´Igli Aït Allal Akka n’Igoulzane Foum Tillicht Ouguerd Zegzaoune Taquat N'Agrd Wahmane	Shells	An ammonite of the family Hildoceratidae.	H. sublevisoni
Juraphyllites[32][25]	J. libertus	Talghemt	Shells	An ammonite of the family Hildoceratidae.
Lytoceras[25]	L. monpianense L. paulosiomaiicum L. ex gr. villae	Agoudim Amellago	Shells	An ammonite of the family Lytoceratidae.
Murleyiceras[24]	M. sp.	Almou-n' Tarzekt	Shells	An ammonite of the family Hildoceratidae.
Neithea[24]	N. ayarii	Agoudim Amellago	Shells	A marine member of Neitheidae.
Nerinea[33]	N. spp.	Jebel Toksine	Shells	A nerineoidean, member of the family Nerineidae	Specimen of the genus
Neolioceratoides[32][25]	N. hoffmanni	Amellago Talghemt	Shells	An ammonite of the family Hildoceratidae.
Paltarpites[32][24]	P. paltum P. cf.palius P. sp.	Jbel Aouloum Talghemt	Shells	An ammonite of the family Hildoceratidae.
Platyacra[34]	P. (Asperilla) russoi	Amellago	Shells	A trochoidean, member of the family Angariidae
Praepolyplectus[25]	P. sp.	Amellago	Shells	An ammonite of the family Hildoceratidae.
Purpurina[34]	P. rudis	Amellago	Shells	A caenogastropodan, member of the family Purpurinidae	Modern Purpurina specimen
Pholadomya[35]	P. bucardium P. fidicula P. spp.	Agrd N´Igli Amellago	Shells	A marine member of the family Pholadomyidae.
Spondylus[26]	S. numidus	Aghbalou N'Kerdous	Shells	A marine member of the family Spondylidae.	Modern Spondylus specimens
Trichites[35]	T. spp.	Agrd N´Igli Amellago	Shells	A marine member of the family Pinnidae.

Arthropoda

Genus	Species	Location	Material	Notes	Images
Bairdia[36]	B. aff.carinata B. spp.	Talghemt	Shells	A marine ostracod of the family Bairdiinae.
Bairdiacypris[36]	B. spp.	Talghemt	Shells	A marine ostracod of the family Bairdiinae.
Kinkelinella[36]	K. sermoisensis K. sp.	Talghemt	Shells	A marine ostracod of the family Protocytheridae. Local dominant Lower Toarcian taxon
Ogmoconcha[36]	O. sp.	Talghemt	Shells	A marine ostracod of the family Healdiidae.
Polycope[37]	P. spp.	Bou-Oumardoul	Shells	A marine ostracod of the family Polycopidae.

Echinodermata

Rare Ophiuroid impressions can be observed.^[38]

Genus	Species	Location	Material	Notes	Images
Apiocrinites[39]	A. amalthei	Agoudim Amellago	Columnar ossicles	A crinoid of the family Apiocrinitidae
Cotylederma[39]	C. spp.	Agoudim Amellago	Columnar ossicles	A crinoid of the family Cotyledermatidae
Diplechinus[39]	D. despujolsi D. spp.	Agoudim Amellago	Ambulacrum, spines	An echinoid of the family Stomechinidae
Diplocidaris[39]	D. menchikofli	Agoudim Amellago	Ambulacrum, spines	An echinoid of the family Diplocidaridae
Dubarechinus[39]	D. despujolsi	Agoudim Amellago	Ambulacrum, spines	An echinoid of the family Orthopsidae
Firmacidaris[39]	F. precincta	Agoudim Amellago	Ambulacrum, spines	An echinoid of the family Cidaridae
Hemicidaris[39]	H. (Dorycidaris) termieri	Agoudim Amellago	Ambulacrum, spines	An echinoid of the family Hemicidaridae
Pentacrinites[39]	P. spp.	Agoudim Amellago	Columnar ossicles	A crinoid of the family Pentacrinitidae	Reconstruction of a few specimens
Polypedina[39]	P. tounatensis	Agoudim Amellago	Ambulacrum, spines	An echinoid of the family Pedinidae

Actinopteri

Several scales and teeth of fishes are know from several locations, coming from freshwater/lagoonal layers.^[40]

Genus	Species	Location	Material	Notes	Images
Leptolepis[41][42]	L. spp.	Jbel Bou Hamid	Semiarticulated specimens	Marine bony fish of the family Leptolepidae.	L. coryphaenoides specime

Viridiplantae

Phytoclasts, spores, pollen and Tasmanites & Botryococcus algae indicate that the palaeoenvironment of the lower Toarcian Amellago area was likely proximal continental shelf with a high terrestrial input, and notorious influence of brackish water in the depositional environment.^[43] This interval is numerically dominated by Classopollis, which usually accounts for more than 60.95% of the palynomorphs present.^[43]

Genus	Species	Location	Material	Notes	Images
Alisporites[44]	A. spp.	Amellago	Pollen	Affinities with Peltaspermaceae or Corystospermaceae
Callialasporites[44]	C. trilobatus C. spp.	Amellago	Pollen	Affinities with Araucariaceae.	Callialasporites was probably related to modern plants such as Araucaria.
Classopollis[44]	C. spp.	Amellago	Pollen	Affinities with Cheirolepidiaceae.
Cyathidites[44]	C. minor	Amellago	Spores	Affinities with Cyatheaceae.	Cyathidites was probably related to modern plants such as Cyathea.
Kraeuselisporites[44]	K. reissingeri	Amellago	Spores	Affinities with Selaginellaceae.	Kraeuselisporites was probably related to modern plants such as Selaginella.
Ischyosporites[44]	I. variegatus	Amellago	Spores	Affinities with Schizaeaceae/Anemiaceae.	Ischyosporites was probably related to modern plants such as Anemia.
Quadraeculina[44]	Q. anaellaeformis	Amellago	Pollen	Affinities with Podocarpaceae or Pinaceae.	Quadraeculina was probably related to modern plants such as Dacrycarpus.

See also

• Toarcian turnover
• Toarcian formations
  • Tafraout Formation, SISTER UNIT, Morocco
  • Azilal Formation, SISTER UNIT, Morocco
  • Aganane Formation, Morocco
  • Calcaires du Bou Dahar, Morocco
  • Marne di Monte Serrone, Italy
  • Podpeč Limestone, Slovenia
  • El Pedregal Formation, Spain
  • Mizur Formation, North Caucasus
  • Sachrang Formation, Austria
  • Posidonia Shale, Lagerstätte in Germany
  • Irlbach Sandstone, Germany
  • Ciechocinek Formation, Germany and Poland
  • Krempachy Marl Formation, Poland and Slovakia
  • Djupadal Formation, Central Skane
  • Lava Formation, Lithuania
  • Whitby Mudstone, England
  • Fernie Formation, Alberta and British Columbia
    • Poker Chip Shale
  • Whiteaves Formation, British Columbia
  • Navajo Sandstone, Utah
  • Los Molles Formation, Argentina
  • Mawson Formation, Antarctica
  • Kandreho Formation, Madagascar
  • Kota Formation, India
  • Cattamarra Coal Measures, Australia