Survey planes recording area data

The United States Geological Survey and agencies from four states recently announced low-level airplane flights in the Central Great Plains. Scientists from Iowa, Minnesota, South Dakota and Nebraska are partnering to image geology using airborne geophysical technology. The aircraft and crews being used are currently being flown out of the O'Neill Airport.

The geophysical survey will focus on the buried Spirit Lake tectonic zone, centered in the area between Sioux Fall sand Omaha. The region is thought to have potential for critical mineral deposits buried in the ancient Precambrian rocks deep beneath the glacial deposits and sedimentary rocks exposed near the surface.

The purpose of the geophysical survey is to better map the ancient Precambrian rocks at depth. The region was chosen in collaboration with the Iowa Geological Survey, Minnesota Geological Survey, Minnesota Department of Natural Resources, Minnesota Natural Resources Research Institute, Nebraska Conservation and Survey Division and the South Dakota Geological Survey.

Covering more than 105,000 square miles, the new geophysical survey will use the latest technological developments that will allow scientists to develop high-resolution three-dimensional representations of geology to depths of more than 3,200 feet, or one kilometer, below the surface.

The 3D models and maps produced from the survey will help understand the distribution of mineral and energy resources, as well as the potential for natural hazards. Data collected as part of this effort will be made public and used by the state agencies and the USGS to guide more detailed geologic mapping at local scales.

The airplane will fly along pre-planned flight paths relatively low to the ground at more than 300 feet (100 meters) above the surface. The ground clearance will be increased to about 1,000 feet (300+ meters) over populated areas in order to comply with FAA regulations. Flight line separation will be more than 600 feet (200 meters) throughout the survey area.

Instruments on the airplane will measure variations in the Earth's magnetic field and natural low-level radiation created by different rock types. This information will help researchers develop geologic maps in three dimensions.

The USGS is contracting with Sander Geophysics Ltd. and Dewberry to collect the geophysical data.

The scientific instruments on the airplane are completely passive with no emissions that pose a risk to humans, animals, or plant life. No photography or video data will be collected. The data collected will be made freely available to the public once complete. The aircraft will be flown by experienced pilots that are specially trained and approved for low-level flying. The companies work with the FAA to ensure flights are safe and in accordance with U.S. law. The surveys will be conducted during daylight hours only.

This survey fits into a broader effort by the USGS and many other state geological surveys, and other partners, including private companies, academics and state and federal agencies to modernize our understanding of the Nation's fundamental geologic framework and knowledge of mineral resources. This effort is known as the Earth Mapping Resources Initiative, and it includes airborne geophysical surveys like this one, geochemical reconnaissance surveys and geologic mapping projects.