Introduction of 3D digital outcrops in the teaching of Earth Science studies at the University of Barcelona: The Sallent case study (Ebro Basin)

One of the elements that have traditionally been used in Earth Sciences and in the social dissemination of geological knowledge is the visit to outcrops. During COVID pandemic, however, the educational community was forced to consider alternatives to field-based learning through the application of outcrop digitization technology and the development of virtual field trips to make them accessible from home. These digital teaching and learning methodologies, instead of disappearing after the removal of mobility restrictions by COVID, have spread and are already considered a complement to field-based learning in Earth Sciences and in other disciplines. In this sense, digital content specifically adapted to educational curricula through information and communication technologies (ICT) has proliferated.

 

Virtual outcrops, created using drone-based photogrammetry or LiDAR, optimize fieldwork with an educational or informative nature by complementing the “in situ” visits. Also, they allow blended learning of areas that cannot be visited due to lack of time, distance, or accessibility. In any case, the virtual outcrops are a powerful teaching tool since: a) provide points of view that cannot be observed in the field; and b) allow a quick extraction and analysis of geological information (i.e. attitude of bedding, joints and fault planes, geometry of rock bodies, distribution of facies or lithologies, etc.) in the 3D space that can be used to complement or, in some cases, to substitute the collected ones in the field. For these reasons, we consider indispensable to expand and improve the creation of this type of digital content, not only to be able to complement (not replace) fieldwork and increase the training capacity of the students, but also to increase the digital database and cope with possible future situations with mobility restrictions. In this scenario, the number of virtual outcroppings available or ready for teaching are still small and most of them do not include teaching tools.

 

The objective of this work is to generate educational content by means of disruptive digital technologies applied to geological outcrops in the Sallent area to expand and facilitate the dissemination capabilities, use, and teaching possibilities of these digital contents at BSc. and MSc. studies of Earth Sciences. The target area corresponds to the Southern deformation Front of the Pyrenees within the Ebro foreland basin. At surface, outcrops are made of upper Eocene fluvial-lacustrine fine-grained terrigenous, limestone, and gypsum strata. Deformation is characterized by decametric to hectometric scale thrusts, backthrusts, and folds detached on the Cardona Salt Fm. These structures are clearly visible on the field due to the frequent colour changes in the sedimentary succession. The developed digital teaching tool includes several natural isolated outcrops and a continuous well-exposed railway trench section of hundreds of meters digitized combining drone-based photogrammetry and LiDAR.