Latest Jurassic-Early Cretaceous synrift evolution of the Torrelapaja Subbasin (Cameros Basin): implications for Northeast Iberia palaeogeography

The reconstruction of the latest Jurassic-Early Cretaceous evolution of the Torrelapaja Subbasin (Cameros Basin, Spain) resulted in the characterization of three synrift sequences (SS-1, SS-2 and SS-3) bounded by major unconformities. Three major NW-SE normal faults combined with smaller scale faults of variable direction (around NE-SW) controlled the sedimentation. The complex geometry of the Torrelapaja Subbasin indicates a main extension direction of NE-SW, and a secondary NW-SE extension. Sedimentation of the Tithonian-middle Berriasian SS-1 occurred in alluvial fan systems, grading upwards to carbonate palustrine-lacustrine environments. A new vertebrate site with large size sauropod bones has been found in the middle part of SS-1. The lower boundary of the uppermost Hauterivian-lower Barremian SS-2 is locally a palaeokarst, with sedimentary infill including three new fossil sites with remains of ornithopod, sauropod and theropod dinosaurs. Sedimentation of SS-2 encompasses distal alluvial terrigenous facies with local palaeosoils and palustrine-lacustrine limestones grading upwards to middle-distal alluvial facies. After a late Barremian-early Albian stratigraphic gap, sedimentation resumed in coastal flat environments represented by the mudstones with intercalated skeletal (oyster-rich) sandy limestones with carbonaceous plant remains of the SS-3. A middle-late Albian age assignment of SS-3 based on regional correlation is supported by strontium isotopic data. This unit marks the first Early Cretaceous marine incursion in the area from the northern Atlantic realm. This is a notable change of the previous palaeogeographical reconstructions which established that the first marine encroachment occurred in the early Aptian and was sourced from Tethysian domains. 0 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study reconstructs the evolution of the Torrelapaja Subbasin in the Cameros Basin, Spain, during the Late Jurassic to Early Cretaceous, identifying three synrift sequences controlled by major and minor faults. Sedimentation occurred in alluvial fan systems, carbonate environments, and coastal flats. The first marine incursion in the Early Cretaceous is marked by the SS-3 unit.