Abstract:

This contribution presents the educational application of virtual outcrops generated through photogrammetric techniques, within the framework of the GEODIGIT project (Digital Transition in Geology: New Challenges from Field and Laboratory Data), funded by the Next Generation EU program. The project focuses on the digitization and dissemination of geological hand specimens and outcrops included in the Inventory of Geological Sites of Interest of Catalonia, as well as selected locations within the Catalunya Central, Orígens and Geoparkea UNESCO Global Geoparks. It is an initiative aimed to promote the conservation, accessibility, and pedagogical use of geological heritage through digital technologies.

Here, we present a first virtual outcrop located at the Illa Roja beach in the municipality of Begur (Girona, NE Spain). This site (GT352, in the official Catalonia Geosites Inventory) has been selected due to its exceptional geological diversity, its didactic potential for both secondary and higher education, and the temporal restrictions to on‑site ground access due to rockfall hazards.

The virtual outcrop was constructed using a multi-scale photogrammetric workflow:
(1) drone-based image acquisition to generate a high-resolution 3D model of the outcrop at landscape scale, and
(2) close-range photogrammetry of hand samples using a turntable system to obtain detailed digital models of representative lithologies.

In addition, thin sections were prepared from selected samples and analyzed under transmitted light microscopy to identify mineral assemblages and textures, enabling a comprehensive petrographic characterization.

The generated data including 3D models, petrographic descriptions as well as geological maps and cross-sections from existing literature, were compiled into standardized summary sheets and assembled within an open-access web platform. This digital resource has been designed to be adaptable to different educational levels, facilitating inquiry-based learning and the development of spatial reasoning skills in Earth Sciences.

In particular, the Illa Roja virtual outcrop provides a unique opportunity to characterize an unconformity, illustrating the relationship between the Paleozoic basement and the overlying Paleogene sedimentary cover of the Ebro Basin. Additionally, it also enables to illustrate the site’s rich geological record, including metamorphic, igneous, and sedimentary rocks as well as their relationships and the deformation structures such as faults, folds, foliations and joints. The whole dataset also facilitates students to reconstruct the relative chronology of geological events.

This example highlights the potential of photogrammetry-based virtual outcrops as scalable educational tools. These resources can be further enhanced through integration into virtual and augmented reality environments, fostering immersive and interactive learning experiences. Such approaches are particularly valuable in overcoming logistical, accessibility, and safety constraints associated with traditional fieldwork, while complementing rather than replacing in situ geological training. Ongoing work is focused on expanding this catalogue of virtual geosites, with new sites currently under development, reinforcing the scalability and long-term educational potential of this initiative.

Keywords:

Virtual outcrops, Earth Science teaching, inquiry-based learning, Geological heritage.