Sioux Quartzite Boulder
This large boulder was carried to Kansas by a glacier several thousand feet thick about 700,000 years ago during the Pleistocene (Ice) Age. The boulder was plucked from a bedrock source, the nearest located in southeastern South Dakota or northwestern Kansas by glaciers.
This particular boulder is made of a rock known as Sioux quartzite. Quartzite is sandstone that has been subjected to heat and pressure, and has been cemented with silica. Sioux quartzite is almost 100% quartz, so it resists erosion. It weighs 10.4 tons.
Courtesy hmdb.org
