“The Sioux Quartzite”
(Note: any text in italics has been taken from the official SDSHS records.)
Marker Text
The Sioux Quartzite, deposited more than a billion years ago, is among the oldest rock exposed in South Dakota. The quartzite and associated pipestone deposits were known to white men as early as 1822, but the American Indian used pipestone centuries earlier to make ornaments and utensils.
The Sioux Quartzite consists of thick beds of silica-cemented quartz sandstone, the grains of which were deposited and rounded by wave action in the floor of an ancient continental sea. This fact is illustrated by laminations and ripple marks preserved in the quartzite. The density of the rock resulting from the cementation and compaction makes it very resistant to erosion as shown by the falls at this site; the Big Sioux River has been flowing in its present course here for about 10,000 years.
In Pioneer Days this rock was the principal building and paving material in this area. At the present time its use as an aggregate in concrete construction makes the Sioux Quartzite an important natural resource of Eastern South Dakota.
Location
Minnehaha County, SD115/Philip Ave - south edge of Falls Park in Sioux Falls (2006)