Baraboo Quartzite

A picture of a brecciated quartzite rock
A Baraboo Quartzite sample, in breccia form. The brecciated purple portions are quartzite, and the matrix is white quartz
A sample of Baraboo Quartzite.

Baraboo Quartzite is a Precambrian geological formation[1] of quartzite, found in the region of Baraboo, Wisconsin. While pure quartzite is usually white or gray, Baraboo Quartzite is typically dark purple to maroon in color, due to the presence of iron (hematite) and other impurities.[2] Baraboo Quartzite may display strata created by progressive deposition of layers of sand in the original sandstone from which the quartzite was formed (through metamorphism).[2] Specimens of Baraboo quartzite may also display ripple marks that appear visually similar to the patterns one might see in the sand at a beach. Ripples indicate that the sandstone from which the quartzite was metamorphosed was originally water-laid sediment.[2]

Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts.

  1. ^ Hanson, G. F., Geology of the Barabou District, Wisconsin Archived February 22, 2014, at the Wayback Machine, The University of Wisconsin Extension, 1970, Information Circular 14
  2. ^ a b c Montgomery, Keith. "Baraboo Quartzite". Archived from the original on 2010-09-20. Retrieved 2013-10-14.