Blesa Formation
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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.
- Upper Blesa Sequence - Valdejunco Member
- Middle Blesa Sequence - Josa Member
- Lower Blesa Sequence - Cabezo Gordo Member, Morenillo member
| Blesa Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Geological formation |
| Unit of | Maestrazgo Basin |
| Sub-units |
|
| Underlies | Alacón Formation |
| Overlies | Unconformity with Jurassic strata |
| Thickness | Up to 150 m |
| Lithology | |
| Primary | Clay, Marl, Limestone |
| Other | Conglomerate |
| Location | |
| Region | Europe |
Distribution of the Belsa Formation within the Oliete Sub-Basin (in olive) | |
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
| Ma | Age | Paleomap \ Basins | Cantabrian | Olanyà | Cameros | Maestrazgo | Oliete | Galve | Morella | South Iberian | Pre-betic | Lusitanian | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 100 | Cenomanian |  | La Cabana | Sopeira | Utrillas | Mosquerela | Caranguejeira | |||||||
| Altamira | Utrillas | |||||||||||||
| Eguino | ||||||||||||||
| 125 | Albian | Ullaga - Balmaseda | Lluçà | Traiguera | ||||||||||
| Monte Grande | Escucha | Escucha | Jijona | |||||||||||
| Itxina - Miono | ||||||||||||||
| Aptian | Valmaseda - Tellamendi | Ol Gp. - Castrillo | Benassal | Benassal | Olhos | |||||||||
| Font | En Gp. - Leza | Morella/Oliete | Oliete | Villaroya | Morella | Capas Rojas | Almargem | |||||||
| Patrocinio - Ernaga | Senyús | En Gp. - Jubela | Forcall | Villaroya | Upper Bedoulian | Figueira | ||||||||
| Barremian | Vega de Pas | Cabó | Abejar | Xert | Alacón | Xert | Huérguina | Assises | ||||||
| Prada | Artoles | Collado | Moutonianum | Papo Seco | ||||||||||
| Rúbies | Tera Gp. - Golmayo | Alacón/Blesa | Blesa | Camarillas | Mirambel | |||||||||
| 150 | Hauterivian |  | Ur Gp. - Pinilla | Llacova | Castellar | Tera Gp. - Pinilla | Villares | Porto da Calada | ||||||
| hiatus | ||||||||||||||
| Huerva | Gaita | |||||||||||||
| Valanginian | Villaro | Ur Gp. - Larriba | Ped Gp. - Hortigüela | |||||||||||
| Ped Gp. - Hortigüela | Ped Gp. - Piedrahita | |||||||||||||
| Peñacoba | Galve | Miravetes | ||||||||||||
| Berriasian |  | Cab Gp. - Arcera | Valdeprado | hiatus | Alfambra | |||||||||
| TdL Gp. - Rupelo | Arzobispo | hiatus | Tollo | |||||||||||
| On Gp. - Huérteles Sierra Matute | ||||||||||||||
| Tithonian | Lastres | Tera Gp. - Magaña | Higuereles | Tera Gp. - Magaña | Lourinhã | |||||||||
| Arzobispo | ||||||||||||||
| Ágreda | ||||||||||||||
| Legend | Major fossiliferous, oofossiliferous, ichnofossiliferous, coproliferous, minor formation | |||||||||||||
| Sources | ||||||||||||||