Second Round of USGS Studies Begin to Define What Minerals Lie Beneath Portions of the Upper Midwest

U.S. Geological Survey scientists will conduct a high-resolution airborne survey to study the rock layers under a region of the south-central Upper Peninsula, Michigan, and parts of northeastern Wisconsin, starting in early April and lasting until as late as August. When the data analysis is complete, resulting geologic maps will help USGS researchers improve an assessment of mineral resources in the region.

As part of this research, a low-flying airplane will be used. Residents and visitors should not be alarmed to witness this airplane flying low to the ground near the broader Iron Mountain-Ralph-Escanaba-Menominee region. A similar USGS study will occur around the same time, but will produce a map at a different scale and spatial area.

The airplane is under contract to the USGS through EON Geosciences. The aircraft will be operated by experienced pilots who are specially trained and approved for low-level flying. All flights are coordinated with the Federal Aviation Administration to ensure accordance with U.S. law.

The survey area is known to contain historically significant iron deposits, as well as several other types of mineral deposits either known or suspected to be present.

“This study will help USGS and partnered scientists understand the region’s fundamental geology and mineral potential in much greater detail than is currently known,” said USGS scientist Benjamin Drenth, a Denver-based researcher leading the survey.

The airplane will carry instruments to measure variations in the Earth’s magnetic field. Because different rock types vary in content of magnetic minerals, the resulting maps allow visualization of the geologic structure below the surface. The instruments carried on the aircraft only make passive measurements, and thus pose no health risk to humans or animals.

This survey will be flown in a grid pattern. North-south lines will be flown approximately 500-700 feet apart at elevations from 250-1000 feet above the ground, and 1 mile apart in an east-west direction. All survey flights will occur during daylight hours.

The Michigan Geological Survey is a technical partner with the USGS on the project, assisting with coordination with the Michigan geologic and elected community.