Drone-borne mineral exploration in Central West Greenland; new insights from the Paleoproterozoic Karrat Group

During the last two field seasons, two different types of Unmanned Aerial Systems were tested and evaluated for mineral mapping in central West Greenland. A fixed-wing system turned out to be more suitable as large areas can be covered faster and more efficiently.

In 2017, a sensefly ebeePlus fixed-wing system with a 4 channel multispectral Sequoia camera (4 channels in VIS-NIR with 1.2 MP and an additional 16 MP RGB camera) was deployed. Flight altitude was set to achieve 11cm ground sampling distance (GSD). Processing followed in-house routines using Structure-from-Motion photogrammetry to get Digital Surface Models (DSM) and geometrically corrected orthomosaics. In total 6.4 km2 of the VMS showings in Kangiusap Kuua at Svartenhuk were covered. The VMS showings are hosted in the Nûkavsak Formation of the Paleoproterozoic Karrat Group. In certain stratigraphic horizons within the meta-turbidites, meta-basalt with associated sulfide-rich sea-floor alteration occurs. Flight plans were set to cover both alteration and host rock. A validation dataset includes sampling and spectral characterisation of selected hand specimens.

Gossan and associated alteration of host rock is easily mappable by integrated morphological and spectral analysis as they form ridges with a distinct iron feature. Moreover, traces of fractures and faults, their spatial distribution and relation to the altered horizon are retrieved.

This further highlights the capability of drone-borne application for high-resolution reconnaissance mapping within short turn-around times. Intermediate insights from the project Multi-sensor drones for geological mapping (MULSEDRO) will facilitate the application of drones under unfavourable conditions.