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Please use this identifier to cite or link to this item: http://hdl.handle.net/11299/59441

Title: Minnesota at a Glance Geologic Time
Authors: Southwick, D.L.
Lusardi, B.A.
Keywords: geology
geologic time
Minnesota Geological Survey
age
Issue Date: 1997
Publisher: Minnesota Geological Survey
Series/Report no.: Minnesota at a Glance
Geologic Time
Abstract: Rocks brought back from the moon by astronauts are about 4,500 million years old. Many meteors that fall to Earth are about 4,500 million years old also. Because the moon, the earth, and the meteors probably formed at the same time, when the entire solar system formed, we can logically conclude that the earth itself is about 4,500 million years old even though no earthly rock that old has yet been found. Minnesota is host to some of the oldest rocks on earth. Parts of the Morton Gneiss (pronounced "nice") in western Minnesota have been dated at 3,600 million years before present. Rocks as old or older than these are rare on earth because geologic processes on and within our active planet tend to recycle old rocks and produce younger ones. Only in Minnesota, northwestern Canada, Greenland, Siberia, South Africa, and Australia have remnants of very old rocks been preserved.
Description: Short summary of geologic time and age dating of rocks in Minnesota.
URI: http://purl.umn.edu/59441
Appears in Collections:Miscellaneous Publications

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