Geology of Minnesota

Geology of Minnesota. Mankato Region. , This marker is located near the big bend of the Minnesota River directly opposite the mouth of the Blue Earth River. The abandoned channel east of it is the former course of the LeSueur before it joined the Blue Earth. Most of the broad valley of the Minnesota was carved out of bedrock prior to the last glacier which came from the northwest and partially filled the valley with debris. After the glacier melted, the river re-established itself in the old valley. The name "Glacial River Warren" is applied to the stage when it carried enormous volumes of meltwater from Glacial Lake Agassiz which for a long time occupied the Red River Valley region. , The rocks exposed in this road cut are from bottom to top – Jordan sandstone, Blue Earth siltstone, Oneota dolomite (Mankato quarry rock) and glacial drift of two ages. The lowest rock is about 500 million years old and the upper drift at least 10,000 years., ~~~~~~, Erected by the Geological Society of Minnesota , In memory of Alger R. Syme, past president and mentor , in cooperation with the Department of Highways , State of Minnesota.