Baraboo Quartzite

{{short description|Precambrian geological formation in Wisconsin}}

File:UebAcdaGd-SK9vW6nM2QCULqQL3QhhIb8NilCSySX2I.jpg

File:Baraboo Quartzite.jpg

Baraboo Quartzite is a Precambrian geological formationHanson, G. F., [http://wisconsingeologicalsurvey.org/pdfs/IC14.pdf Geology of the Barabou District, Wisconsin] {{webarchive |url=https://web.archive.org/web/20140222184825/http://wisconsingeologicalsurvey.org/pdfs/IC14.pdf |date=February 22, 2014 }}, The University of Wisconsin Extension, 1970, Information Circular 14 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.{{cite web|url=http://www.uwmc.uwc.edu/geography/baraboo/quartz.htm |title=Baraboo Quartzite |last=Montgomery |first=Keith |accessdate=2013-10-14 |url-status=dead |archiveurl=https://web.archive.org/web/20100920231236/http://www.uwmc.uwc.edu/geography/baraboo/quartz.htm |archivedate=2010-09-20 }} 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). 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.

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