Estratigrafía de la "Cuenca de los Cameros" (Cordillera Ibérica Noroccidental, N de España) durante el tránsito Jurásico-Cretácico

Resum

This paper studies the 3800 m thick sequence of sedimentary rocks that comprises the Jurassic- Cretaceous boundary in the northeastern sector of the Iberian Ranges: Cameras continental Basin (North-Central Spain). The sedimentary sequence shows a complex organization marked by strong lateral facies changes, while these facies show a great vertical persistence. The Tera and Oncala allogroups, separated by an important unconformity, constitute the major sedimentary units in the area. In turn, each of this allograups can be subdivided into three and two alloformations, namely: 1. "Agreda Alloformation", formed by two independent lithosomes. The main one is up to 255 m thick. The age of this unit is Tithonian. 2. "Magana Alloformation", sedimentation extends to the whole Basin, which is clearly structured. The maximun thicknes of this unit is up to 695 m. 3. "Sierra Matute Alloformation", the Basin aparently is less structured, the thickness in excess of 640 m. 4. "Huerteles Alloformation", sedimentation is restricted to a marked through with deposits which may exceed 1000 m in thickness. 5. "Valdeprado Alloformation", sedimentation extends the whole Basin again, this unit can be thicker than 1160 m. These alloformations and allogroups can be correlated with other units proposed in other areas of the Iberian Basin, and a Tithonian and Berriasian age can be proposed for the "Tera Agr." and the "Oncala Agr.", respectivelly.