Virtual outcrop models: Digital techniques and an inventory of structural models from North-Northwest Iberia (Cantabrian Zone and Asturian Basin)

The first steps to study natural structures are data collection, their representation and their geological inter-pretation. There is no doubt that the development of digital techniques in recent times has facilitated these tasks. Here we present an inventory of virtual outcrop models from the Cantabrian Zone and Asturian Basin, North-Northwest Iberian Peninsula, and the procedure employed to obtain the data, construct the models and inter-pret them geologically. These models correspond to contractional folds and faults of Palaeozoic age, and to Mesozoic extensional structures affected by Cenozoic tectonic inversion in the form of folds and thrusts. The digital techniques and data employed are fieldwork, as well as Google Earth images, orthophotographs, ster-eoscopical pairs of photographs and virtual outcrop models, constructed using Structure from Motion photo-grammetry based on images extracted from Google Earth or from photographs taken in the field using a tripod or unmanned aerial vehicles. The analysis of these models has provided us with geological information that would have been difficult to obtain using traditional techniques. Apart from their scientific interest, the examples shown may be helpful for structural geologists who wish to obtain 3D geological models, maps and sections, and additional structural information from field examples, as well as elements to prepare a virtual fieldtrip and/or for educational purposes.

Automated summary

This study presents the procedure employed to obtain data, construct models and interpret them geologically for virtual outcrop models from the Cantabrian Zone and Asturian Basin in the Iberian Peninsula. The digital techniques and data used include fieldwork, Google Earth images, orthophotographs, stereoscopical pairs of photographs, and virtual outcrop models constructed using Structure from Motion photogrammetry. The analysis of these models has provided valuable geological information that would have been difficult to obtain using traditional techniques.