Thursday, March 07, 2013

Iowa Survey discovers Ordovician impact crater

The Iowa Geological and Water Survey, in partnership with the U.S. Geological Survey,  have found evidence for a 3-mile meteor crater under the city of Decorah, Iowa, that appears to have been formed in the Ordovician by a 200-meter wide meteorite.   [Right, 3-dimensional view of Decorah, Iowa and the Upper Iowa River. Scene is looking due north. Credit, USGS]

[Below, maps showing electro-magnetic, well data and aggregate results over the crater. Credit, USGS]

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