Geology and Landforms
1.2 billion years ago the island was formed when a rift opened up in Earth’s crust. About 10,000 years ago, the island was under miles of ice but the glaciers began to move away, forming Isle Royale’s topography.
Isle Royale’s bedrock is made of basalt, sandstone, and conglomerates. Greenstone Ridge runs the length of the whole island and is made of basalt. It is believed to be part of the largest lava flow on Earth that runs from Kansas and into Canada. There are multiple lakes and inlets on Isle Royale, including Lake Desor and Siskiwit Lake. In the past copper was mined on Isle Royale. |