Modernizing Geologic Mapping In Yellowstone: The Role Of Geodatabases In The Field

Editor's note:Yellowstone Caldera Chronicles is a weekly column written by scientists and collaborators of the Yellowstone Volcano Observatory. This week's contribution is from Montana State University undergraduate student Liam Arnold, completing a summer research experience with M.S. student Liv Wheeler and Associate Professor Dr. Madison Myers at Montana State University.

Geologic mapping has come a long way—from paper maps to powerful digital databases. But how do researchers store and organize all this data? Join us as we explore the role of geodatabases.

Geologic mapping has evolved over the years, from relying solely on paper, pencil, and field observations, to incorporating modern digital tools and technologies. While geologists continue to rely on fundamental tools such as a rock hammer and hand lens, we also incorporate GPS to locate our exact position and link spatial data with field observations. But what path does the data take between the field and the final geologic map you might see online or in a bookstore? That’s where the geodatabase comes in—an online system used to store and manage geographic data.

When geologists are working on a mapping project, the data they collect are useless unless they are organized in a way that ensures easy access, long-term usability, and consistency. That’s the role of the geodatabase—to store and visualize field data. The geodatabase is a centralized storage format that can manage both spatial and non-spatial data. Over the past five years, students and researchers associated with Montana State University (MSU) have been translating their field data into online databases, with some of the data being incorporated into the final geologic map.

There are many ways to create and manage geodatabases, but the most commonly used is ArcGIS Pro’s file geodatabase. Field data (outcrop and rock descriptions, mineral and textural information, etc.) are entered and stored into a file structure. Although similar to a standard folder stored on your computer, file geodatabases have enhanced functions, like the ability to visually relate data from one location to another based on the GPS coordinates recorded in the field. This allows researchers, both at MSU and other institutions, to see how their data are related spatially. For example, in geological mapping this means we can visualize how samples are related across a mapping area.

So, how has Montana State University been using geodatabases to help with the remapping of Yellowstone National Park? When in the field, notes vary depending on the quality of the outcrop and what we observe within the rock, but a few things remain consistent. Accurate location coordinates, elevation, and a timestamp are recorded at each stop. These attributes are the foundation which allows our data to be visualized. When finished in the field, the data is organized by locality and then added into ArcGIS Pro and formatted into the geodatabase. The data are converted into individual points with associated tables that contain all the attribute data, photos and sample identification. In this way, all of the details of a specific outcrop—from photos to location—can be associated with a specific place on a geologic map.

Once the data are finalized in the geodatabase, they will act as the foundation to produce a final geologic map. We can use the spatial relations shown in the geodatabase to form interpretations and delineate boundaries between different geologic units. These points can be overlain with topography or DEMs (Digital Elevation Models) to assist in determining more accurate contacts, especially in areas with complex terrain or limited exposure. This integrated approach ensures that the final map is accurate and backed up with real world observations and data, and that these maps and observations can easily be accessed by other scientists.

This enhanced workflow of geologic mapping not only benefits the current mapping projects and Montana State University but also future work related to Yellowstone’s geology. Stay tuned—MSU is currently updating maps in the Sour Creek Dome and Madison Junction areas of Yellowstone National Park to incorporate newly understood geologic histories of those regions!