Guettioua Formation

Guettioua Formation
Stratigraphic range: Bathonian-Callovian
~168–161 Ma
TypeGeological formation
UnderliesIouaridène Formation
OverliesTilougguit Formation / Tanant 3 limestones (variable)
ThicknessHighly variable: 80–600+ m (typically 150–600 m in type area)
Lithology
PrimarySandstone
OtherSiltstone, marl, conglomerate
Location
Coordinates32°30′N 5°48′W / 32.5°N 5.8°W / 32.5; -5.8
Approximate paleocoordinates27°54′N 1°24′W / 27.9°N 1.4°W / 27.9; -1.4
RegionAzilal Province, Béni Mellal Province, Ouarzazate Province
CountryMorocco
ExtentBéni Mellal-Khénifra, Central High Atlas (Guettioua, Aït-Attab, Aït-Toutline, Aït-Ourir, Toundoute nappe)
Type section
Named forGuettioua (cuvette des Guettioua)
Named byE. Roch
Guettioua Formation is located in Morocco
Guettioua Formation
Guettioua Formation (Morocco)

Location of the Guettioua Formation in Morocco

The Guettioua Formation or Formation des Grès des Guettioua is a geological formation in Morocco. It dates to the Bathonian stage of the Middle Jurassic. It largely consists of continental red sandstone and is the lateral equivalent of the marine El Mers Formation. It´s synonyms include Grès de Wansero, Grès des Guettioua or Infracénomanien/Jurassique continental.

History

The formation was introduced by E. Roch in 1933 for the red beds in the Guettioua basin overlying Bajocian limestones. Its age was long debated, initially considered "Dogger", later assigned to the Cretaceous by some authors due to apparent basal unconformities. Jenny, Le Marrec & Monbaron (1981) restricted the name to the red sandstones above Bajocian limestones and below the Iouaridène Formation, confirming a Bathonian age through dinosaur correlations, palynology of the overlying unit, revised radiometric dating of associated volcanics, and lateral facies comparisons with the El Mers and Anemzi formations.

Description

The Guettioua Formation is composed almost exclusively of reddish detrital sediments ranging from conglomerates to silts, varied quartz content, all brick-red, although gray-yellow conglomeratic channels occur, often containing plant debris, bone fragments, and occasionally azurite and malachite. The sandstones are feldspathic, with rounded quartz grains, feldspars (labradorite, bytownite), micas, volcanic rock fragments (rhyolites), and hematite. The formation records the Atlas first basaltic event (locally B1), formed by numerous lava flows that flowed towards the north and northwest of the basins. Due to the lenticular and channelized nature of the unit, no single type section is representative. The base may show a progressive transition with the underlying Tanant 3 Formation or a progressive syntectonic unconformity, resting on various older units down to the Imi-n-Ifri Formation in places. Upper boundary passes gradually upward into the red pelites of the Iouaridène Formation, known for abundant dinosaur trackways.

Sedimentology

The formation represents predominantly continental, deltaic to palustrine (marsh/lacustrine margin) environments. Diagnostic features include conglomeratic channels, raindrop impressions, ferric oxide staining, cross-stratification, lenticular bedding, abundant plant trunks, and terrestrial vertebrates. Synsedimentary tectonics caused significant thickness variations, basin tilting, and intraformational unconformities. Associated magmatic activity includes basaltic flows, dykes, and gabbroic intrusions in some areas (especially Aït-Attab and Aït-Toutline).

Thickness varies significantly (from 10–20 m in the Ait Ourir area to 500–600 m in the Msemrir syncline) due to syn-depositional tectonics and differential subsidence. The formation is widely exposed in the axial zone and northern front of the Central High Atlas, with occurrences also along the southern margin. Fluvial paleocurrent data indicate a dominant sediment transport toward the north-east and east. The western part of the Central High Atlas (Marrakesh High Atlas sector) acted as a topographic high supplying clastic material, while major depocenters and distributive fluvial fans developed eastward. This pattern reflects an early relief differentiation within the Atlas domain during the Bathonian.

The formation extends with relatively consistent facies to the Ait Ourir region. West of Demnate, distinction from underlying red units is difficult. Thickness varies strongly due to tectonic activity. Eastward, marls and pelites intercalate, producing variegated ("Neapolitan slice") facies. It is also recognised on the southern flank of the High Atlas.

Biota

Invertebrates

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.

Genus/Family Species Location Material Notes Images
Conichnus C. isp. Tizi N'Talghemt Plug-shaped vertical burrows Made by clams or snails
Rhizocorallium R. commune Tizi N'Talghemt Spreite burrows Polychaetes?
Thalassinoides T. suevicus Tizi N'Talghemt Three-dimensional large burrow system Decapod crustacean?
Unionida indet. Indeterminate Wawmda Shells Freshwater Bivalve

Amniotes

Genus/Family Species Location Material Notes Images
Anchisauripus? A. isp. Msemrir Footprints Neotheropod tracks
Atlasaurus A. imelakei Wawmda "Numerous fragments from several individuals" Either Brachiosaur or Eusauropod
Atlasaurus
Carmelopodus cf.C. untermannorum Msemrir Footprints Ceratosauria tracks
Carnosauria indet. Indeterminate Msemrir Footprints Incertade Sedis
Changpeipus C. carbonicus Msemrir Footprints Neotheropod tracks
Crocodylopodus C. isp. Msemrir Footprints Crocodylomorpha tracks
Eubrontes E. isp. Tizi N'Talghemt Footprints Neotheropod tracks
Grallator cf. G. isp. Msemrir Footprints Neotheropod tracks
Iguanodontipus I. burreyi; I. isp. Tizi N'Talghemt Footprints Iguanodont tracks
Kayentapus cf.K. isp. Msemrir Footprints Neotheropod tracks
Lacertipus? L.? isp. Msemrir Footprints Lacertiform (Squamata? or Rhynchocephalia?)
Sauropoda indet. Indeterminate Aît Issa Indeterminate bones Incertade Sedis
Indeterminate Tizi-n-Isly Footprints Incertade Sedis
Theropoda indet. Indeterminate Wawmda Teeth Incertade Sedis
Indeterminate Aît Issa; Msemrir Footprints Incertade Sedis
Toyamasauripus T. isp. Tizi N'Talghemt Footprints Ornithopod? tracks
Trisauropodiscus T. isp. Msemrir Footprints "Avian-like" theropod or ornithopod trackmakers

Plants

Genus/Family Species Location/Level Material Notes Images
Baculatiporites B. piloleus LM494, Demnate Spores Ferns spores of the family Osmundaceae
Classopollis C. senegalensis LM494, Demnate Pollen Conifer pollen of the family Hirmeriellaceae
Concavissimisporites C. verrucosus LM494, Demnate Pollen Ferns spores of the family Lygodiaceae
Modern Lygodiaceae
Corollina C. bussonii LM494, Demnate Pollen Conifer pollen of the family Hirmeriellaceae
C. caratinii LM494, Demnate Pollen Conifer pollen of the family Hirmeriellaceae
C. quezelii LM494, Demnate Pollen Conifer pollen of the family Hirmeriellaceae
C. yvesi LM494, Demnate Pollen Conifer pollen of the family Hirmeriellaceae
Cupressacites C. oxycedroides LM494, Demnate Pollen Conifer pollen, family Cupressaceae
Modern Cupressaceae
Deltoidospora D. minor LM494, Demnate Spores Ferns spores Incertade Sedis
Diadocupressacites D. moghrebiensis LM494, Demnate Pollen Conifer pollen, family Cupressaceae(?)
Ephedripites E. sp. 1 LM494, Demnate Pollen Gnetalean pollen of the family Ephedraceae
Modern Ephedraceae
E. sp. 2 LM494, Demnate Pollen Gnetalean pollen of the family Ephedraceae
E. sp. 3 LM494, Demnate Pollen Gnetalean pollen of the family Ephedraceae
Exesipollenites E. sp. LM494, Demnate Pollen Conifer pollen, family Cupressaceae
Ginkgocycadophytus G. nitidus LM494, Demnate Pollen Ginkgoales or Cycad pollen
Ichyosporites I. sp. LM494, Demnate Spores Lycopodiaceae or Anemiaceae
Leptolepidites L. verrucatus LM494, Demnate Spores Ferns spores of the family Dennstaedtiaceae
Modern Dennstaedtiaceae
Matonisporites M. sp. LM494, Demnate Spores Ferns spores of the family Matoniaceae
Modern Matoniaceae
Perinopollenites P. sp. LM494, Demnate Pollen Conifer pollen, family Cupressaceae
Perotrilites P. granulatus LM494, Demnate Spores Ferns spores of the family Marsileaceae
Modern Marsileaceae
Rotverrusporites R. tenuis LM494, Demnate Pollen Ferns spores of the family Ophioglossaceae
Modern Ophioglossaceae
Spheripollenites S. psilatus LM494, Demnate Pollen Conifer pollen of the family Hirmeriellaceae
S. cf. subgranulatus LM494, Demnate Pollen Conifer pollen of the family Hirmeriellaceae
Todisporites T. major LM494, Demnate Spores Ferns spores of the family Osmundaceae
Modern Osmundaceae
Tuberositriletes T. sp. LM494, Demnate Spores Ferns spores of the family Lygodiaceae

See also

References

  1. ↑ Weishampel, David B; et al. (2004). "Dinosaur distribution (Middle Jurassic, Africa)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 542-543. ISBN 0-520-24209-2.
  2. ↑ Jenny, J. (1985). "Carte Géologique du Maroc au 1: 100.000, feuille Azilal". Notes et Mémoires du Service Géologique du Maroc. 339 (2): 1–104. Retrieved 25 January 2022.
  3. 1 2 3 4 5 6 7 Jenny, J. (1988). "Carte géologique du Maroc au 1/100 000: feuille Azilal (Haut Atlas central). Mémoire explicatif". Notes et Mémoires du Service géologique. 378 (1): 1–122. Retrieved 25 January 2022.
  4. 1 2 3 4 El Ouali, Mohamed; Kabiri, Lahcen; Essafraoui, Badre; Charroud, Ali; Krencker, François-Nicolas; Bodin, Stéphane (2021-11-01). "Stratigraphic and geodynamic characterization of Jurassic–Cretaceous "red beds" on the Msemrir–Errachidia E–W transect (central High Atlas, Morocco)". Journal of African Earth Sciences. 183 104330. doi:10.1016/j.jafrearsci.2021.104330. ISSN 1464-343X.
  5. ↑ Kohring, Rolf (1992-02-01). "Biological metal accumulation in the red beds (Guettioua Member) of the Bathonian (Dogger) of Msemrir, Central High Atlas, Morocco". Geologische Rundschau. 81 (1): 85–90. doi:10.1007/BF01764541. ISSN 1432-1149.
  6. 1 2 Adardor, Said; Haddoumi, Hamid; Rachdi, Abdelmalek; Ettachfini, El Mostafa; Baidder, Lahssen; Chennouf, Rachid; Charrière, André (2021-06-01). "Jurassic-Cretaceous Red beds of the southern Front of Moroccan Central High Atlas (Aghbalou N'Kerdouss-Tadighoust region): Sedimentological, lithostratigraphical and paleogeographical studies". Journal of African Earth Sciences. 178 104185. doi:10.1016/j.jafrearsci.2021.104185. ISSN 1464-343X.
  7. 1 2 Guezal, Jaouad; El Baghdadi, Mohamed; Barakat, Ahmed (2015-02-01). "The Jurassic–Cretaceous volcanism of the Atlas of Beni-Mellal (Central High Atlas, Morocco): evidence from clinopyroxene composition". Arabian Journal of Geosciences. 8 (2): 977–986. doi:10.1007/s12517-013-1256-z. ISSN 1866-7538.
  8. 1 2 3 Cavallina, Chiara; Benvenuti, Marco; Papini, Mauro (2025-10-01). "The Middle Jurassic fluvial record of the Central High Atlas (Guettioua Formation, Morocco): seasonal rivers in a dynamic palaeogeography". Journal of Palaeogeography. 14 (4) 100272. doi:10.1016/j.jop.2025.100272. ISSN 2095-3836.
  9. 1 2 3 4 5 6 El Ouali, Mohamed; Essafraoui, Badre; Kabiri, Lahcen; El-Ouali, Laila; Abioui, Mohamed; Vinn, Olev (2026-06-04). "Invertebrate ichnofossils and dinosaur undertracks from the Middle Jurassic of Tizi N'Talghemt area, Central High Atlas, Morocco". Palaeoworld 201139. doi:10.1016/j.palwor.2026.201139. ISSN 1871-174X.
  10. ↑ Monbaron, M. (1983). "Dinosauriens du Haut-Atlas Central (Maroc): état des recherches et précisions sur la découverte d'un squelette complet de grand Cériosaure = Dinosaurs of the Central High Atlas (Marocco) : state of research and details of discovery of complete skeleton of large Ceriosaur". Actes de la Société jurassienne d'émulation. 86.
  11. 1 2 3 4 Ait Haddou, O.; Hminna, A.; Lagnaoui, A.; Klein, H.; Arouch, M.; Fergougui, M.; Bel Haouz, W. (2026). "New dinosaur tracksites from the Middle-?Late Jurassic of Msemrir (Central High Atlas, Morocco)". Historical Biology: 1–18.
  12. 1 2 Monbaron, Michel; Russell, Dale A.; Taquet, Philippe (1999). "Atlasaurus imelakei n.g., n.sp., a brachiosaurid-like sauropod from the Middle Jurassic of Morocco alen". Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science. 329 (7): 519–526. doi:10.1016/S1251-8050(00)80026-9. ISSN 1251-8050. Archived from the original on 2024-04-14.
  13. ↑ "Table 13.1," in Weishampel, et al. (2004). Page 271.
  14. ↑ "Table 13.1," in Weishampel, et al. (2004). Page 265.
  15. 1 2 3 Jenny, Jacques; Le Marrec, Alain; Monbaron, Michel (1981-06-01). "Les empreintes de pas de Dinosauriens dans le Jurassique moyen du Haut Atlas central (Maroc): Nouveaux gisements et precisions stratigraphiques". Geobios. 14 (3): 427–431. doi:10.1016/S0016-6995(81)80186-6. ISSN 0016-6995.
  16. ↑ Hadri, M.; Boutakiout, M.; Gómez, F.; Pérez-Lorente, F. (2015). "Crocodyliform footprints from "les couches rouges" of the Middle Jurassic of Msemrir, High Atlas, Morocco" (PDF). Geogaceta. 58: 39–42.
  17. 1 2 Lkebir, Noura; He, Yao-Yan; Zeng, Xiong-Wei; Wang, Cheng-Gang; Wu, Fa-Fu; Zhao, Lai-Shi; Niu, Zhi-Jun (2026-06-22). "Middle Jurassic isolated dinosaur tracks from Msemrir (Central High Atlas, Morocco): Evidence for theropod occurrence and paleogeographic distribution". Palaeoworld 201147. doi:10.1016/j.palwor.2026.201147. ISSN 1871-174X.
  18. ↑ Ait Haddou, Omar; Lagnaoui, Abdelouahed; Hminna, Abdelkbir; Arouch, Mohamed; Bel Haouz, Wahiba; Fergougui, Mohamed; Assafar, Hicham; Rmich, Aziz; El Kamali, Nezha (2026-04-20). "New evidence of lacertiform tracks from the Middle-? Late Jurassic of Msemrir (Central High Atlas, Morocco): Palaeobiogeographical and palaeocoecological implications". Historical Biology: 1–13. doi:10.1080/08912963.2026.2646997. ISSN 0891-2963.
  19. ↑ Belvedere, Matteo; Dyke, Gareth; Hadri, Majid; Ishigaki, Shinobu (2011-03-01). "The oldest evidence for birds in Northern Gondwana? Small tridactyl footprints from the Middle Jurassic of Msemrir (Morocco)". Gondwana Research. 19 (2): 542–549. doi:10.1016/j.gr.2010.08.004. ISSN 1342-937X.
  20. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Courtinat, B.; Le Marrec, A. (1986). "Nouvelles donnees palynologiques sur les "Coaches Rouges" (Jurassique Moyen) de la Region de Demnat (Haut-Atlas,Moroc)" (PDF). Bulletin de l'Institut Scientifique. 10 (2): 15–20.