What are Geologic Maps?

Unlike a road map which focuses on the locations of roads and cities a geologic map shows the distribution of materials at or near the Earth’s surface. Rock types or unconsolidated materials are generally grouped into map units and depicted using different colors. Geologic maps show information collected manually in the field by walking the Keweenaw landscape. To the trained eye, these maps help to explain the series of geologic events that led to the present-day distribution of rocks and other earth materials.

What can I learn using these maps?

To the trained eye, these maps help to explain the series of geologic events that led to the present-day distribution of rocks and other earth materials. A geological map shows the type of intact, solid bedrock at or near the earth's surface. These maps generally include rock descriptions, age relationships (stratigraphic sequence), major and minor structural data (folds and faults), and other information. As you are out and about in the Copper Country keep an eye out for Keweenaw Geoheritage signs. This project, developed by Dr. Bill Rose, and Dr. Erika Vye, highlights the many amazing Geoheritage sites around the Keweenaw. ​

Tips & Tools for Reading these maps

The 2001 Cannon & Nicholson Geologic Map with map unit descriptions, an explanation of map symbols and cross sections can be downloaded for free from the National Geologic Map Database. ​

Other Resources

• Keweenaw Geoheritage
• Introduction to Geologic Mapping - National Cooperative Geologic Mapping Program
• How to read a geologic map - Wisconsin Geological and Natural History Survey
• Geologic Timeline of the Keweenaw - National Park Service
• REPORT: GEOLOGIC MAP OF THE KEWEENAW PENINSULA AND ADJACENT AREA, MICHIGAN By: William F. Cannon and Suzanne W. Nicholson