MagArrowTM Drone Enabled Aeromagnetic Surveys in the Great Sand Dunes National Park - San Luis Valley, CO

Abstract:

The MagArrowTM is a drone enabled Cesium vapor optically pumped magnetometer designed and engineered by Geometrics, Inc. for use with small unmanned aircraft systems (UAS). IGS conducted low altitude aeromagnetic surveys in 2017 and 2018 within the Great Sand Dunes National Park in southern Colorado. The first survey was executed to obtain the magnetic signature of a unique crater-like topographic feature as well as to evaluate the efficacy of drone enabled magnetometry with respect to a terrestrial magnetic survey. A second survey was executed in 2018 survey over a much larger to better define the near surface basement geology underlying and encompassing the topographic feature.

The MagArrowTM data compare closely to the ground magnetic data and, in fact, are in many ways preferable to the data acquired on the ground using a Geometrics G859 cesium vapor optically magnetometer. The speed of acquistion and relative ease of deployment are obvious advantages favoring drone enabled magnetometry. However, the short flight time of the hexacopter used for each survey could the limit the viability of the methodology. Fortunately, several drone manufacturers are developing small UAS capable of two (2) or more hours of continuous flight.

The drone enabled detailed magnetic map of the one (1) square mile survey block suggests a complex basement geology consisting of a localized horst and graben feature offset by cross faulting along the mountain range front.