Cook County Gunflint Trail Collection
Cook County naturally requires two geological trips: one along US 61 which follows the shore of Lake Superior and reveals exposures of the North Shore Volcanic Group, the Duluth Complex formations, and the terraces of Glacial Lake Duluth; the other along Co 12, the Gunflint Trial.
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The roadcuts and outcrops along the Gunflint Trail are the inspiration for this collection. Precambrian rock is the underlying bedrock of Cook County. The Gunflint Trail courses over extrusive and intrusive rock; till deposits; then the coarse-grained, dark-colored igneous rocks of the Duluth Complex; ending with exposures of the light-colored granitic rocks of the Lower Precambrian Saganaga Batholith. This variation in bedrock structure and composition makes the trail geologically diverse and scenic. Scour by streams and glaciers have produced a unique landscape, a region of diverse geomorphic environments. This stunning collection is defined by the course of the trail. Each specimen is a rich expression of the region’s diverse geologic history. It captures the beauty for which the region is known. Saganaga tonalite, the light-colored granitic rock, is the cornerstone of the collection. Rainy lobe glacial till, metabasalt, graywacke slate, and two varieties of gabbro complete the collection. This collection is useful to non-professionals who simply wish to learn more about the geology of the county. It is not intended to be a one-stop, comprehensive collection. It is useful to anyone with an interest in earth science or the county. |
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since May, 2006.