Pilgrim Hot Springs Electromagnetics Geophysical Survey

Pilgrim Hot Springs airborne electromagnetic survey, Seward Peninsula, Alaska, covers a portion of the Southwest corner of the Bendeleben quadrangle, north-northeast of Nome, Alaska. The survey was conducted to characterize subsurface electrical resistivity variations, supporting interpretations of hydrothermal circulation, fluid pathways, and near-surface thaw zones. The resulting dataset provides insights into the geologic framework and supports geothermal exploration by enabling evaluation of subsurface conditions, identification of energy prospects, and guidance for future drilling. Time-domain electromagnetic data were acquired using the helicopter-mounted SkyTEM 306HP system on September 8-9, 2023, by SkyTEM Canada Incorporated. A total of 73.2 line-kilometers were flown over a single survey block measuring 10.7 square kilometers. The block was flown with north-south line orientation and a nominal spacing of 100 meters, reduced to 50 meters near the center. Mean ground clearance was 35.8 +/- 15.7 meters, with a nominal survey speed of 101.4 +/- 7.8 km/hr. Data were inverted using Aarhus Workbench EM software to produce two subsurface resistivity models. SkyTEM Canada Incorporated generated a preliminary model from a laterally constrained inversion (referred to in the data files as skytem_lci), which applies only along-track constraints. Aqua Geo Frameworks produced a spatially constrained inversion model (referred to in the data files as agf_sci), which incorporates both along-track and cross-track constraints. The Aqua Geo Frameworks model is recommended for end-users, as it resolves finer-scale structures, including layering in the near-surface thaw zone. We also provide a 3D voxel dataset registered to elevation rather than raw depth for the model.

Publications

• GPR 2025-1. Pilgrim Hot Springs airborne electromagnetic survey, Seward Peninsula, Alaska.