Microdrones in field-based structural geology: a photogrammetry and fracture quantification case study from the North Mountain Basalt, Nova Scotia, Canada

Drone use in geoscience research and teaching is becoming widespread, with diverse applications documented. Many studies favour consumer-level drones, however, recent developments in so-called ‘microdrones’ (takeoff weight <250 g) necessitates further investigation to determine possible benefits, limitations, and future developments. Microdrone deployment is often advantageous in numerous jurisdictions due to fewer regulations, lower cost, and simple transportation. In this study, we deployed a DJI Mini 2 microdrone to study the ca. 201 Ma North Mountain Basalt (NMB) exposed in coastal outcrops along the Bay of Fundy, Nova Scotia, Canada. We report benefits of the microdrone as a field aid with three related approaches: 1) general site location and characterisation, 2) drone-based photogrammetry using ArcGIS Drone2Map, and 3) quantitative fracture mapping using FracPaQ. Application of these methods, showed that microdrone-acquired imagery from the NMB exposures provides a valuable resource for interpretation post-fieldwork. The microdrone-derived data shows, two near-perpendicular fracture sets in the NMB: ~NNE-SSW and ~ESE-WNW, with some variation along the coastline. Overall, we determined that microdrones offer field-based geoscientists a valuable tool due to quick deployment, a simple image capture process and relatively straight forward data processing, and thus predict that this approach to enhancing fieldwork will continue to advance.