The Blesa Formation is a geological

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

in Teruel and La Rioja, Spain whose strata date back to the

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded ...

of the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

. Dinosaur remains as well as eggs are among the fossils that have been recovered from the formation.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. . Along with the fragmentary

anhanguerian Ornithocheiromorpha (from Ancient Greek, meaning "bird hand form") is a group of pterosaurs within the suborder Pterodactyloidea. Fossil remains of this group date back from the Early to Late Cretaceous periods (Valanginian to Turonian stages) ...

pterosaur ''

Iberodactylus ''Iberodactylus'' is a genus of pterodactyloid pterosaurs belonging to the clade Anhangueria, that during the Early Cretaceous lived in the area of present Spain. The type species is ''Iberodactylus andreui''. History of discovery and naming I ...

''. 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.

Vertebrate paleofauna

Reptiles

Pterosaurs

Mammals

Correlation

References

{{coord missing, Spain Geologic formations of Spain Lower Cretaceous Series of Europe Cretaceous Spain Barremian Stage Ichnofossiliferous formations Ooliferous formations Paleontology in Spain Formations Formations