Mapping Beneath the Surface: Sanborn Geophysics and USGS Survey the SD-MN-IA Border Region

The USGS partnered with Sanborn Geophysics to conduct a high-resolution airborne geophysical survey over southeastern South Dakota, southwestern Minnesota, and northwestern Iowa

U.S. Geological Survey (USGS)

The Challenge

This project aimed to expand fundamental geological knowledge, assess critical mineral potential, and support national resource management and infrastructure planning.

The Outcome

Sanborn Geophysics provided essential geophysical data to enhance geological understanding and resource management.

The Details

Project Scope

Sanborn Geophysics designed and executed the survey with state-of-the-art equipment and methodologies.

Conducted low-level airplane flights at altitudes of approximately 330 feet, increasing to 1,000 feet over population-dense areas, in compliance with FAA regulations.
Collected magnetic field variations and low-level gamma energy data using high-precision passive instrumentation installed on aircraft equipped with elongated “stinger” sensors.
Survey lines were spaced at 650 feet apart to ensure high-resolution coverage across the region.

Key Features of the Survey

The project incorporated innovative technology and collaboration to meet USGS goals.

Discreet Data Collection: Passive instruments captured detailed geophysical data without emissions, ensuring safety for humans, animals, and the environment.
Collaborative Design: Developed in coordination with state geological surveys in South Dakota, Minnesota, and Iowa to address regional mapping gaps.
High-Resolution Models: Processed data will create 3D representations of subsurface geology to depths exceeding 3,280 feet (1 kilometer).

Key Results

Sanborn Geophysics provided essential geophysical data to enhance geological understanding and resource management.

Quantitative Results: Surveyed over 7,950 square miles across three states, supporting critical mineral exploration and land-use planning.
Improved insights into subsurface composition and structure, including water resource pathways and radon risks.
Supported the USGS Earth Mapping Resources Initiative to modernize the nation’s geologic framework.