Camarillas Formation

The Camarillas Formation was first formally defined by Canérot et al. in 1982 and later redefined by Salas (1987).^[3]

Both Camarillas and Galve are in the Galve Sub-basin, a section of the Aliaga Basin, in the Iberian Range. All these basins were formed during the Permian–Triassic, when the main faults were active, and they are filled with Mesozoic–Quaternary sediments.

The Upper Permian to Upper Jurassic deposits at the site of the Camarillas Formation are all of continental origin. In a second extensional stage during the Late Jurassic to Early Cretaceous, the Atlantic and the Bay of Biscay opened, and the Iberian Peninsula rotated from left to right. At this time, the sediments were marine or showed the influence of the sea, as shown in the deposits of the Higuerueles and Villar del Arzobispo Formations in the Galve Sub-basin. Finally, during the Early Cretaceous and Oligocene–Miocene there were compressive phases with tectonic inversion and formation of continental basins.^[4]

Camarillas Formation, in beds of similar age to the La Maca outcrop in the Galve area where the remains of an iguanodontid dinosaur have been found. The Camarillas fossil site is in light brown clay and limestone rocks with fossil wood remains. The sedimentology is similar to that described in the Galve area, because the Camarillas Formation shows scarcely any lateral variations in facies within the Galve Sub-basin.

The Camarillas Formation sandstone is fluviatile, and four groups of paleochannels are distinguished, the first towards the bottom of the succession. These channels become thinner towards the top, and this was interpreted by Díaz and Yébenes (1987) as evidence that there was an alluvial fan with a multichannel system. The lithology of the deposits which fill these channels and their geometry are typical of low-sinuosity channels. Towards the top of the Camarillas Formation, there is a predominance of deltaic fan deposits with marked marine influence. Nevertheless, Soria (1997) mentioned that she found no facies association whose evolution and geometry suggested a well developed deltaic system.^[5]

The formation spreads across the Camarillas graben and the Remenderuelas half-graben.^[6]

The Camarillas Formation has provided a rich fossil assemblage comprising dinosaurs, crocodiles, snakes, turtles, fish and mammals. Several new species were described from the formation, among others the mammals Galveodon nannothus, Eobaatar hispanicus, Crusafontia cuencana, Lavocatia alfambrensis and Parendotherium herreroi, the turtle Galvechelone lopezmartinezae and the crocodyliform Bernissartia fagesii. Dinosaurs described include 'Iguanodon' galvensis, Gideonmantellia amosanjuanae and Camarillasaurus cirugedae.

The following fossils are reported from the formation:^[7]

• 
  Gideonmantellia
• 
  Camarillasaurus
• 
  Delapparentia

• List of dinosaur-bearing rock formations
• Tremp Formation
• Escucha Formation
• La Huérguina Formation
• Villar del Arzobispo Formation