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Upper Peninsula Geological Repository


Melanie Humphrey

The Upper Peninsula Geological Repository (UPGR) is located in Michigan's Upper Peninsula near the Sawyer International Airport in Gwinn, Michigan. The collection is enclosed within in a 44,000 square foot warehouse at the former K.I. Sawyer Air Force Base and holds drill core and cuttings with an emphasis on Northern Peninsula Geology. Drill core samples are obtained by using specialized drilling tools which allow for discrete intact samples to be brought back up to the surface for geologic evaluation. Drill cuttings samples are fragments of rock which are returned to the surface during the drilling process. The purpose of the UPGR collection is to act as a "rock library" and make the collected material available to researchers and industry for geologic study. Some aspects of this study, may include:

  • Mineral resource exploration and development
  • Addressing issues related to water quality
  • Contributing to research on climate change
  • Enhancing the ability to identify geological hazards
  • Supporting research of unconventional energy sources

About the UPGR

  • General Information


  • In addition to the UPGR facility, the Michigan Geological Repository for Research and Education (MGRRE) at the Western Michigan University, in Kalamazoo, Michigan, includes drill core and cuttings with an emphasis on Southern Peninsula geology.

    The Department of Environment, Great Lakes, and Energy (EGLE), Oil, Gas, and Minerals Division (OGMD) moved into the new UPGR facility in the fall of 2020. Located in Michigan’s Upper Peninsula near the Sawyer International Airport in Gwinn, the collection is enclosed within in a 44,000 square foot warehouse at the former K.I. Sawyer Air Force Base. The samples were previously stored in two separate buildings that were in a state of disrepair and at maximum capacity. The new UPGR facility has significantly more space that will allow for expansion of the collection and offers greatly improved amenities in a more modern safe environment. Most core and cuttings are classified as non-confidential and are open and available for viewing. The core storage inventory consists primarily of rock core drilled during mineral exploration on private and state mineral leases. The collection also includes a small number of rock cuttings, chips, and hand samples. It is hoped that the UPGR collection will lead to increased overall geological knowledge and allow informed decisions involving all aspects of our society from agriculture to energy to minerals to drinking water and to remediation

    History and Available Core

    Two large acquisitions of mineral exploration and mine core are from the M.A. Hanna-Groveland collection and the U.S. Bureau of Mines-Michigan collection obtained in 1989. The M.A. Hanna- Groveland collection consists of cores from many cross sections of the old Groveland open-pit iron mine and core from numerous iron exploration projects. The U.S. Bureau of Mines-Michigan collection consists of thousands of boxes of Michigan exploration and mine core formerly housed at the U.S. Bureau of Mines Repository at Minneapolis, Minnesota.

    Acquisitions in 1993 included exploration drill core from Marquette and Iron Counties donated by Kerr McGee Corp. and Callahan Mining Corp. The collection also includes exploration drill core from Baraga basin exploration and core from the western syncline project along with pulps, second splits, assays and numerous soil and outcrop samples. '

    The collection also includes the core from the deepest all-cored mineral well drilled by AMOCO Production Company. This was a 7,238 foot hole that was drilled in late 1987 to learn more about the Mid-continent Rift. It was located southeast of Munising, near Wetmore, in Alger County in the Upper Peninsula. The hole ended in Precambrian aged Portage Lake Volcanics of Keweenawan time.

    Core and drill cuttings are required to be submitted from State mineral exploration leases. We also encourage donations of drill core and cuttings from Michigan projects drilled on private lands. Additional cores expand the coverage of our open-file collection and help increase the knowledge of the state's geology.

    The OGMD's metallic mine and data collection is also stored at the repository. This includes thousands of surface and underground maps from early to more recent mines from the western one-half of the Upper Peninsula. Reports and other miscellaneous information is also available from this same area. This collection helps in the understanding of the geology and mineral resource potential of the state, as well as being an aid to public safety and land use planning. It is a record of potential mine subsidence areas of the state which should be avoided when construction is planned.