U of Minnesota Press, 1982 - 255 pages
Have you ever wondered how the Mississippi River was formed? Or why shark teeth have been found in the Iron Range of the Upper Midwest? Towering mountain ranges, explosive volcanoes, expansive glaciers, and long-extinct forms of both land and sea life were an important part of Minnesota's ancient history. Today the evidence of this remarkable heritage is revealed in the state's rocky outcroppings, stony soils, and thousands of lakes.
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Minnesotas Place in Geologic History
Early Precambrian Time 4500 to 2500 Million Years Ago
Middle Precambrian Time 2500 to 1600 Million Years Ago
Late Precambrian Time 1600 to 600 Million Years Ago
PostPrecambrian Time 600 to 2 Million Years Ago
The Quaternary Period 2 Million Years Ago to the Present
Nonmetals Fuels and Water
abundant advance basalt base basin bedrock beds belts beneath boundary called carbonate changes Chapter Complex contain cover Cretaceous deposits developed dikes drift Duluth early earth east eastern environment eroded erosion eventually exposed Falls fault Figure flows Formation formed fossils geologic geologists glacial Glacial Lake glacier grains granite Highway important indicate iron Lake Superior land Late lava layers limestone located lower major margins material melting Michigan Middle Precambrian million years ago minerals mining Minnesota Mississippi Moraine moved natural North North America northern Note older original outcrops Park Period places plant Plate Pleistocene Point Precambrian present probably quartz Quartzite Rainy Range region result River rocks sand sandstone sedimentary sediments shale Shore showing side southeastern streams surface thick types units upper Valley Vermilion volcanic weathering western Wisconsin zone