Structural studies foresee a detailed three-dimensional model. In this work we present the results of constructing a virtual outcrop at the quarry base in the city of Turka. Such objects are especially valuable for structural geology, sedimentology, mining, etc.

From a geological point of view, it is located in the Outer Ukrainian Carpathians, tectonically it belongs to the Krosno nappe. Here, the rocks are mainly represented with sandstones, siltstones and argillites.

Workflow. The study predicted: 

- Reconnaissance of the object (detailed overview of the object of research, determination of future positions of control and reference points, and standing stations);

- Establishing and determining the coordinates of reference points (placement of six black and white marks);

- Determining the coordinates of control points (fixation on the outcrop body using the electronic total station Leica TCR 405);

- A terrestrial laser scanning process (3/4 scanning points are located approximately on the same line with a step of 25 and 15 meters, the fourth station is located at the top of the right slope of the quarry, the elevation is 29 m; scanning was performed with a Leica ScanStation C10 scanner);

- Photographing the object (in order to improve the quality of the future mesh model, some details and textures. 344 pictures were taken with a Canon Mark 3 5D digital camera);

- Creating a point cloud based on laser scanning data (Processing was performed in the Leica Cyclone Register 360 program. Five reference points were used to orient the cloud of points in the coordinate system);

- Creating a mash model based on point clouds and digital images (This step was done in the Reality Capture program. The accuracy of the mash model was assessed by comparing the coordinates of control points obtained from the mash model and surveying with TPS; the absolute spatial difference does not exceed five centimeters).

The geological field camp was financed by American Association of Petroleum Geologists (AAPG) for the first author.

How to cite: Oliinyk, M., Bubniak, I., Bubniak, A., Shylo, Y., Bihun, M., and Vikhot, Y.: Creation of 3D model of the Turkа quarry using terrestrial laser scanning, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-364, https://doi.org/10.5194/egusphere-egu23-364, 2023.

Outcrops are the focus of geological research. Oblique photogrammetric technology with the aid of unmanned aerial vehicles can build 3D digital outcrop models and further help to achieve visualization research of outcrops, which provides new ideas to solve the problems of low efficiency, high risk, and poor data reusability that exist in traditional geological research methods. This paper investigates the key technologies of 3D modeling of oblique images, 3D visualization of digital outcrops, and visualization of panoramic models, and design and implement a Web platform named DDE-Outcrop3D for real-scene 3D digital outcrops based on the Cesium open-source 3D earth engine. The platform achieves the visualization of high-precision 3D models of geological outcrops and combines the outcrop-related information such as text, pictures, videos, panoramas, documents, observation stops, and geological plotting with 3D outcrop models, realizing upload and panoramic roaming of 3D models of outcrops and self-supply, sharing, and visualization of outcrop-related information. As the first choice for the virtual field trips of the 21^st International Sedimentological Congress, the platform has been successfully applied to 12 of the 15 field routes. Compared with traditional geological research methods, the visualization of 3D outcrops can help geologists understand the spatial and temporal distribution of geological phenomena and features of outcrops more comprehensively and intuitively. This platform also achieves the co-construction and sharing of resources of outcrops under digital environment, saving the time and economic costs of geological expeditions.

Keywords: Oblique photogrammetry, Real-scene 3D outcrops, Cesium, Visualization platform

How to cite: Zhong, H., Chen, J., Lin, Z., Wang, S., Hou, M., Li, Y., and Wang, C.: Fieldwork anytime!——The functions and applications of DDE-Outcrop3D, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2729, https://doi.org/10.5194/egusphere-egu23-2729, 2023.

The large central well is primarily designed for easily installing, maintaining, and testing geophysical and hydrological sensors over the lifetime of the observatory, but it also provides a unique chance to observe the complex structuration of the vadose zone and its host. In particular, the scale and configurations of the site provide a unique view of these rocks. They are made accessible at a micro-to-decametric scale, which extends drill core observations, and provide a nearly 3D view. This is interesting by comparison with typical outcrops at that scale (e.g., quarries), which are mostly 2D. Preliminary observations, from surrounding drill cores, revealed a particularly complex limestone formation, which consists of a series of terrestrial limestones, with palustrine and lacustrine facies and breccias, affected by a long history of fractures and alterations, silicification, and karstification. A very detailed characterisation of these facies thus requires to provide a high-resolution context for the various measurements and simulations of the transfers in the vadose zone.

This contribution presents the construction of the numerical architecture and the acquisition process implemented for accommodating the very restricted access to direct observations during the construction of the well, which encompasses laser scanning (lidar) and high-resolution photogrammetry. The implications of the different acquisition protocols implemented during the process are discussed in terms of impacts on resolution, coverage, and spatial accuracy. The scanning was performed through 14 distinct stages, where only around 1.5 m height was accessible each time. One of the challenges was thus to stitch the different model rings into a common model. In the end, a complete model of the well surface was recorded with an average resolution of 3 pixels per millimetre.

How to cite: Laurent, G., Mallet, C., Dewez, T., Lefrançois, L., Abbar, B., Abbas, M., and Azaroual, M.: Digital Outcrop Acquisition for the Observatory of the Vadose Zone (OZNS), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15336, https://doi.org/10.5194/egusphere-egu23-15336, 2023.

The construction and interpretation of digital outcrop models (DOM) from outcropping reservoir analogues enable to capture and characterize reservoir heterogeneities (in terms of facies, diagenesis, and petrophysical properties) from centimeter to kilometer scales, thus allowing to improve upscaling approaches in 3D reservoir modeling. Digital outcrop models offer a reliable tridimensional representation of sedimentary heterogeneities, which can strongly impact fluid flow and therefore geothermal reservoir exploitation.

The Roda Sandstones (Lower Eocene) are considered as a world-class outcropping example for deltaic sedimentary systems outcropping in the Graus-Tremp Basin (South Pyrenean Basin). Thanks to the quality of its outcrops and to the drilling of 50 to 80-meter-long cores in their vicinity, the Roda Sandstones are commonly used for educational and research purposes (Crumeyrolle et al., 1992; Martinius, 2012).

Over the past 15 years, a few digital outcrop models have been published from the Roda Sandstones (Enge et al., 2007; Leren et al., 2010). These models were only constructed at a small scale (decimeter to hectometer) and did not allow to capture the large-scale architecture of the Roda fluvio-deltaic system. In this study, we built a complete photogrammetric model of one of the prograding sand wedges of the Roda Sandstones (also called Y body) from more than 11000 photos acquired by drone. The model is accurately georeferenced thanks to a dGPS campaign carried out simultaneously with the drone acquisitions. This outcrop model covers a total area of about 4km², and the pixel resolution ranges between 3 mm and 3 cm.

A significant amount of quantitative and qualitative information could be extracted from this digital outcrop model, that helps at constraining the reservoir model. Its interpretation in a software dedicated to the geological interpretation of DOMs enabled to take measurements (e.g., dips, distances, etc.), to identify and to trace the main stratigraphic surfaces, locate the field observations and samples, allowing to precisely assess the architecture and the facies distribution of the Y sandbody.

The results show a multiphase sandbody, made up of different prograding lobes, with variable progradation directions and a diversity of sedimentary structures formed by the competition between fluvial and tidal currents, contributing to the complexity of the sedimentary system. Paleocurrent directions, sediment thicknesses, numerical outcrops painted in facies, digitized sedimentological sections, and boreholes interpreted in facies were used as input data to build a static facies model. The geological static model was then filled with porosity and permeability properties and used as a base for fluid flow simulations in order to assess the impact of sedimentary heterogeneities in deltaic reservoirs for geothermal exploitation purposes.

How to cite: Mas, P., Bourillot, R., Brigaud, B., Deschamps, R., and Saint-Bezar, B.: From 3D digital outcrops to fluid flow reservoir simulations in a deltaic system: An integrated approach, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-565, https://doi.org/10.5194/egusphere-egu23-565, 2023.

A major part of Northern Bavaria in Southeast Germany is covered by sedimentary rocks of the Franconian Platform (mainly sandstones, mudstones and limestones). These Permo-Mesozoic continental to shallow marine sediments overlay the Variscan basement and are partially affected by Syn-Variscan structures (Freudenberger and Schwerd, 1996). Further tectonic overprint including Permo-Mesozoic basin extension, Cretaceous inversion and Cenozoic intraplate deformation (e.g., Wiest et al. unpublished) developed a complex fault system. Regionally sparse drill core data as well as large forestry and agricultural cultivation complicate the structural interpretation of the entire area. Drone photogrammetry 3D models from locally selected limestone quarries provide a perfect insight into the structural evolution of Northern Bavaria. Centimetre to several hundreds of metres scale faults, joints and folds are clearly visible and measurable within the models. These local photogrammetry models are implemented into a large scale (Franconian Platform) interpreted 3D model which helps to understand and visualize the major structural features. The photogrammetry models can be used for regional and structural geology teaching purposes. A finished large scale 3D model will be made publicly available through the Bavarian State Office for the Environment LfU (www.lfu.bayern.de).

References:

Freudenberger, W., and Schwerd, K., 1996, Erläuterungen zur Geologischen Karte von Bayern 1:500 000, München, Bayerisches Geologisches Landesamt, 329 p.

Wiest, J.D., Köhn, D., Stollhofen, H., and Dengler, K., The fault network of the Franconian Platform (SE Germany) – workflow, uncertainty, scaling, implications, unpublished.

How to cite: Lang, J. and Koehn, D.: Structural Visualization of Permo-Mesozoic Sediments in Northern Bavaria, Germany – Drone Photogrammetry as a practical Tool for large Areas, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7755, https://doi.org/10.5194/egusphere-egu23-7755, 2023.

The study and characterization of fracture network find applications in a wide range of fields, from the analysis and modelling of mechanical and hydraulic properties of rock masses, to petroleum reservoirs, waste repositories, aquifers and Carbon Capture and Sequestration (CCS). In this context, the use of Digital Outcrop Models (DOMs), overcame the limitations of the classic field survey, such as limited access and logistics, providing a solid framework for the collection of large and quantitative datasets. Here we present a semi-automatic workflow for DOMs structural interpretation, carried out on outcrops of fractured gneiss, prasinites and calcschist of the Dent-Blanche Nappe and Combin Zone, exposed on the Italian side of the Cervino/Matterhorn in Valtournenche. Our methodology is based on a combination of traditional field survey and remote sensing techniques (photogrammetry or laser scanning). The preliminary step is the selection of representative outcrops in terms of structural and lithological properties of a larger rock volume, based on a thorough knowledge of regional structural geology and tectonics; moreover, the outcrop must be representative in terms of morphology and orientation. At this stage it is important to select outcrops that have several faces (e.g. vertical face and a horizontal pavement), so it will be possible to evaluate both the orientation and height distribution on the vertical face and the length distribution on the horizontal “pavement”. The main purpose of the traditional field survey is the analysis of kinematics, relative chronology and mineralization - all parameters needed to characterize fracture sets in terms of their genesis and deformative evolution. At the same time, remote sensing dataset are collected and the output is a point cloud DOM (PC-DOM) colorized with RGB values. After a pre-processing phase where the PC-DOM is cleaned from edge noise (resulting from the photogrammetric processing), vegetation and debris (naturally present in most outcrops), orientation data are collected manually, using suitable software tools (e.g. Compass plugin in CloudCompare or PZero). This step allows, together with the results of the field survey, selecting different fracture sets and characterizing their orientation statistics. The second step consist in a manual segmentation of the PC-DOM based on the previous characterization of fracture sets. In the final step, data are automatically extracted using specific algorithm calibrated based on previous steps (e.g. FACETS plugin in CloudCompare). In the end, this workflow aims at maximizing data collection from DOMs to be used as a basis for the subsequent extraction of statistical parameters such as length and height distribution, orientation statistics, abutting and crosscutting relationship between different sets, connectivity, etc.

How to cite: Casiraghi, S., Bistacchi, A., Agliardi, F., Arienti, G., Monopoli, B., Dal Piaz, G., and Bertolo, D.: Structural interpretation of Digital Outcrop Models on point clouds using a semi-automatic workflow: case studies on fractured metamorphic rocks (Aosta Valley, Italy), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9632, https://doi.org/10.5194/egusphere-egu23-9632, 2023.

Fieldwork is a pedagogical cornerstone of many geoscience degrees. During the academic year 2020-21, the worldwide COVID-19 pandemic made outdoors fieldwork difficult, resulting in an urgent need to develop virtual alternatives. However, there is still more to learn about the impact of teaching fieldwork virtually on the student learning experience. This study aims to compare the student learning experience during virtual and outdoor fieldwork and establish the value of digital techniques to improve the inclusivity of geosciences degrees. Quantitative and qualitative data were collected to assess students’ attitudes to both outdoor and virtual fieldwork in terms of accessibility, inclusivity and their learning experience. Our results show overall positive student responses to virtual fieldwork, with over half stating it adequately replicated the learning experience of outdoor fieldwork. Students also value outdoor fieldwork for the degree of autonomy it provides, and idea-sharing with peers; yet simultaneously the majority believed outdoor fieldwork is inherently exclusionary. This study concludes that virtual fieldwork, taught using interactive three-dimensional virtual outcrops set within virtual worlds, replicates the outdoor fieldwork learning experience as closely as possible. However, students missed some fundamental and important aspects of outdoor fieldwork, such as being outside in an immersive environment, or the social interactions with peers and staff that are specific to on-location fieldwork. This study recommends the use of virtual fieldtrips in addition to residential on-location fieldwork, as for a significant number of students virtual fieldwork may be a better way of accessing this valued pedagogy of the geosciences. Furthermore, virtual fieldwork has the potential to make geosciences more inclusive and attractive to a wider range of students.

How to cite: Laurent, V., Guillaume, L., and Genge, M.: Geological fieldwork in the time of COVID-19: Comparing the student learning experience during virtual and outdoor fieldwork, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5926, https://doi.org/10.5194/egusphere-egu23-5926, 2023.

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.

How to cite: De Matteis, M., Gratacós, O., Ferrer, O., Roca, E., Garcia-Sellés, D., López-Blanco, M., Cabello, P., and Borràs, F.: Introduction of 3D digital outcrops in the teaching of Earth Science studies at the University of Barcelona: The Sallent case study (Ebro Basin), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12159, https://doi.org/10.5194/egusphere-egu23-12159, 2023.

Background

During the recent worldwide lockdowns due to the COVID-19 pandemic, several institutions around the world, out of necessity replaced their customary field work with virtual field trips, using existing photographic materials gathered over many years conducting the same fieldtrip, causing the lecturers to conclude that this was a reasonable alternative as the marks scored were similar. 

Several years before the pandemic hit, UWC’s Applied Geology section had already embarked on the development of high-resolution virtual field tours (VFTs)to use as supplementary material in the provision of field education to our geology students, based on the geocognition concept.  This was done as rising costs and increasing health and safety rules effectively forced us to keep fieldwork for students to an absolute minimum, which is unacceptable in geology education. Additionally, in this manner, students could be exposed to classical geology sites from anywhere in the world without having to travel there, as an archive of prime teaching outcrops could be built like this.

Methodology

We created the Virtual Field Tours using High Resolution Photography and constructed the tours using Pano2VR enhanced with videos and drone images. In three different projects we tested for learning gain after exposure to our VFTs by using identical pre and post VFT questionnaires. Pandemic restrictions forced us to replace our first-year introductory field trips by VFTs.

Key Results

In a final assessment testing for understanding of geological principles based on their usage of these VFTs, the assessment results for first year students showed encouraging signs of learning gains. In the second project we exposed second year students, third year students and Honours students as well as graduate geologists to the basic principles of slope stability in engineering geology. In this case we presented a lecture, followed by a questionnaire on the concepts mentioned, followed by the VFT and again the same questionnaire where we demonstrated a distinct learning gain. Finally, we used a lecture on basic characteristics of sedimentary features in turbidite deposits, enhanced by a comprehensive VFT to prepare Honours level students for a weeklong field trip. Comparing their final report with the final report of the previous year’s group of students also demonstrated learning gain.

Conclusion

While we acknowledge that real-life field work can never be replaced, we have demonstrated that properly designed VFTs can be successfully used to enhance learning at real-life field work.

How to cite: van Bever Donker, J., Marshal, D., Huber, M., Maart, R., Mayekiso, L., Solomon, H., and Mgabisa, N.: The effectiveness of using virtual reality materials in preparing students for geological fieldwork, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13788, https://doi.org/10.5194/egusphere-egu23-13788, 2023.