Sioux Quartzite, Sioux Falls, South Dakota

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay

What better place to see the middle Precambrian Sioux Quartzite than siouxfalls, South Dakota? Excellent exposures are preserved in Falls Park.

Sioux Falls, South Dakota Below: general views of the park
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Weathered joints in the quartzite.
Sioux Falls, South Dakota Left and below: the upper falls area.
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Left and below: the circular marks are probably percussion marks created when fast-moving water slammed large rocks into the quartzite.
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Left and below: This sort of fluting and polishing looks a lot like wind abrasion, but here it is clearly due to running water.
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Left and below: Lower Falls Area
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Left and below: In pioneer days the falls were tapped for water power, as similar falls were in many places, but unlike the wholesale industrial vandalism that destroyed St. Anthony Falls on the Mississippi, here only a part of the water was diverted and the falls were left largely undamaged. Ruins of the mills are preserved in the park.
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Left: part of a sluice that once carried water to the mills.
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Left and below: Views of outcrop face
Sioux Falls, South Dakota Sioux Falls, South Dakota
Sioux Falls, South Dakota Cross-bedding in Sioux Quartzite
Sioux Falls, South Dakota Ripple marks in Sioux Quartzite
Sioux Falls, South Dakota Railroad cut in Sioux Quartzite adjacent to Falls Park.
Sioux Falls, South Dakota Looking north across the broad valley of the Big Sioux River. The Big Sioux River cut downward through soft Pleistocene and Cretaceous deposits until it encountered the resistant Sioux Quartzite.

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Created 14 July 2003, Last Update 06 June 2020