Earth:Blesa Formation

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Blesa Formation
Stratigraphic range: Barremian
TypeGeological formation
Unit ofMaestrazgo Basin
Sub-units
  • Upper Blesa Sequence - Valdejunco Member
  • Middle Blesa Sequence - Josa Member
  • Lower Blesa Sequence - Cabezo Gordo Member, Morenillo member
UnderliesAlacón Formation
OverliesUnconformity with Jurassic strata
ThicknessUp to 150 m
Lithology
PrimaryClay, Marl, Limestone
OtherConglomerate
Location
RegionEurope
Los Quiñones site.jpg
Distribution of the Belsa Formation within the Oliete Sub-Basin (in olive)

The Blesa Formation is a geological formation in Teruel and La Rioja, Spain whose strata date back to the Barremian of the Early Cretaceous.[1] Dinosaur remains as well as eggs[2] are among the fossils that have been recovered from the formation.[3] Along with the fragmentary anhanguerian pterosaur Iberodactylus.[4] While the lower and upper parts of the formation were deposited in a continental setting, the middle portion of the formation is largely nearshore marine, with remains of plesiosaurs.

Stratigraphy and Lithology

The Belsa Formation is found within the Maestrazgo Basin. Within the stratigraphic sequence it overlies Jurassic rocks in a syn-rift unconformity, and underlies the Alacón Formation.

The formation is up to 150 metres thick and is divided into three distinct unconformity bounded units, which are called the Lower, Middle and Upper Blesa Sequences. The Lower Blesa sequence varies greatly in thickness from less than 10 m up to 100 m is divided up into two members, the lower Cabezo Gordo Member, which consists of red clays and the upper Morenillo Member, which consists of limestones and marls, both of these sequences were deposited in a continental setting. The Middle Blesa Sequence is of a fairly uniform 25-50 metre thickness. Most of the sequence consists of the Josa Member, which consists of oyster rich marls and limestones deposited in a coastal or shallow restricted bay environment. The Upper Blesa Sequence is of variable thickness from 15–70 m. The lower 1–10 m consists of continentally derived clays and marls with sandstone and conglomerate intercalations while the upper 10–60 m are dominated by carbonates.[1]

Vertebrate paleofauna

Reptiles

Reptiles of the Blesa Formation
Taxa Species Presence Material Notes Images
Iguanodontia Indeterminate Lower Blesa Sequence 3 distinct taxa, one of which has affinities with Delapparentia[1]
Iguanodontia Unnamed Upper Blesa Sequence "Vertebrae, ribs, left illium, partial sacrum, and partial left tibia."[5]
Ankylosauria Indeterminate Lower Blesa Sequence "Isolated teeth, dermal plates and vertebra"
Spinosauridae Indeterminate Lower, Upper Blesa Sequence Isolated Teeth
Dromaeosauridae Indeterminate Lower Blesa Sequence Isolated Teeth
?Carcharodontosauridae Indeterminate Lower, Upper Blesa Sequence Isolated Teeth
Euhelopidae Indeterminate Lower Blesa Sequence Isolated Teeth
Sauropoda Indeterminate Lower Blesa Sequence, La Cantalera-1 Post-cranial material
Crocodylomorpha Indeterminate Lower Blesa Sequence Possibly four distinct taxa
Plesiosauria Indeterminate Middle Blesa Sequence

Pterosaurs

Pterosaurs of the Blesa Formation
Taxa Species Presence Material Notes Images
Istiodactylidae Indeterminate Lower Blesa Sequence Isolated Teeth
Ornithocheiridae Indeterminate Lower Blesa Sequence Isolated Teeth
Iberodactylus I. andreui Middle Blesa Sequence Partial skull

Mammals

Mammals of the Blesa Formation
Taxa Species Presence Material Notes Images
Cantalera C. abadi Lower Blesa Sequence Teeth Pinheirodontid
Eobataar Indeterminate Lower Blesa Sequence Teeth

Correlation

See also

  • List of dinosaur-bearing rock formations

References

  1. 1.0 1.1 1.2 Aurell, M.; Soria, A. R.; Bádenas, B.; Liesa, C. L.; Canudo, J. I.; Gasca, J. M.; Moreno-Azanza, M.; Medrano-Aguado, E. et al. (June 2018). "Barremian synrift sedimentation in the Oliete sub-basin (Iberian Basin, Spain): palaeogeographical evolution and distribution of vertebrate remains". Journal of Iberian Geology 44 (2): 285–308. doi:10.1007/s41513-018-0057-3. ISSN 1698-6180. 
  2. Moreno-Azanza, Miguel; Canudo, José Ignacio; Gasca, José Manuel (September 2014). "Spheroolithid eggshells in the Lower Cretaceous of Europe. Implications for eggshell evolution in ornithischian dinosaurs". Cretaceous Research 51: 75–87. doi:10.1016/j.cretres.2014.05.017. ISSN 0195-6671. 
  3. Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Europe)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. p. 561. ISBN:0-520-24209-2.
  4. Holgado, Borja; Pêgas, Rodrigo V.; Canudo, José Ignacio; Fortuny, Josep; Rodrigues, Taissa; Company, Julio; Kellner, Alexander W. A. (December 2019). "On a new crested pterodactyloid from the Early Cretaceous of the Iberian Peninsula and the radiation of the clade Anhangueria". Scientific Reports 9 (1): 4940. doi:10.1038/s41598-019-41280-4. ISSN 2045-2322. PMID 30894614. 
  5. E. Medrano-Aguado, J. Parrilla-Bel, J.M. Gasca, A. Alonso, J.I. Canudo, Ornithopod diversity in the Lower Cretaceous of Spain: new styracosternan remains from the Barremian of the Maestrazgo Basin (Teruel province, Spain), Cretaceous Research, 2022, 105458, ISSN 0195-6671, https://doi.org/10.1016/j.cretres.2022.105458. (https://www.sciencedirect.com/science/article/pii/S0195667122003226)