Narrator: Last summer during a guided walk on the importance of mosquitoes and blackflies, Ranger Karl Larson made a couple of important discoveries. One, while mosquitoes and blackflies are important for several reasons, guided walks highlighting their importance aren’t popular with visitors. And two, the Keweenaw has a rich geologic history that can’t be ignored.
Hello, my name is ranger Karl Larson. I am interpreter for the Keweenaw National Historical Park in Calumet, MI. After I healed up from my fall, I discovered that the Keweenaw has a rich geoheritage. What is geoheritage? I am glad I made you ask that. Geoheritage is the term used to describe features of geodiversity that are important to people, communities, or cultural groups. Wait a second…what is geodiversity? Another great question. Geodiversity is the variety of earth materials, forms and processes that constitute and shape the Earth, either the whole or a specific part. Relevant materials include rocks, minerals, sediments, fossils, soils and water. Here in the Keweenaw we have all of those relevant materials. Some are better represented than others, but they do all exist to some degree. I am just going to briefly describe our main relevant materials or geoelements as the following episodes will focus on them. The five are Lava, Sandstone, Fault, Glaciers, and Lake. Our story for the Keweenaw begins 1.1 billion years ago as told by the geologists who read the rocks. There was a rift tearing apart a supercontinent. Lava filled the crack. Sand was deposited in the low lying areas, two faults thrust up the lava layers. Now zoom ahead nearly a billion years. Glaciers scraped the surface and then Lake Superior is filled with the melted glaciers. And we’re back to the present. Simple, right? Well, that was an ultra-quick super-simplified trip from a billion years ago to now. I hope you will join me as I tell the story from my recent travels in the National Park Service issued time machine as we look closer at these events in later episodes.
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An introduction to geoheritage and its application to the Keweenaw Peninsula. Five major components make up the Keweenaw’s geologic past. Ranger Karl explains how volcanic lava, sandstone, faults, glaciers, and a Great Lake combined to create the Keweenaw Peninsula, home to the world’s largest source of pure metallic copper. How have these components been important to shaping the area and the lives of the people who live here? That’s geoheritage.
Produced by: Karl Larson
Written by: Karl Larson
Last updated: January 21, 2023