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Baraboo Quartzite is a Precambrian

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

Hanson, G. F.
''Geology of the Barabou District, Wisconsin''
, The University of Wisconsin Extension, 1970, Information Circular 14 of

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...

, found in the region of

Baraboo Baraboo is a city in the Midwest and the county seat of Sauk County, Wisconsin, United States. The largest city in the county, Baraboo is the principal city of the Baraboo Micropolitan Statistical Area. Its 2020 population was 12,556. It is situ ...

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

. While pure quartzite is usually white or gray, Baraboo Quartzite is typically dark purple to maroon in color, due to the presence of

iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...

( hematite) and other impurities. 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 Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of ch ...

). Specimens of Baraboo quartzite may also display

ripple marks In geology, ripple marks are sedimentary structures (i.e., bedforms of the lower flow regime) and indicate agitation by water ( current or waves) or wind. Defining ripple cross-laminae and asymmetric ripples * ''Current ripple marks'', ''u ...

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 Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...

compression within

orogenic belts Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...

Uses

Quartzite is a decorative stone and may be used to cover walls, as roofing tiles, as flooring, and stairsteps. Crushed quartzite is sometimes used in road construction. Baraboo Quartzite is commonly mined for use as railroad ballast.

Occurrences

Formations of quartzite can be found throughout the Baraboo Hills in south-central Wisconsin. Many notable formations can be seen in Devil's Lake State Park.Geology by Lightplane
Geology.wisc.edu (1923-07-13). Retrieved on 2011-06-05. Image:Devil'sDoorway.JPG, Devil's Doorway rock formation at Devil's Lake State Park Image:TheDevilsDoorway.jpg, Chimney Rock Image:Devils Lake Boulders.jpg, Boulder field on Eastern bluff at Devil's Lake

References

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External links

* ttps://web.archive.org/web/20070630053203/http://www.uwmc.uwc.edu/geography/baraboo/baraboo.htm A Geologic Tour of the Baraboo Ranges
Devil's Lake Geologic History

Quartzite formations Geologic formations of Wisconsin Precambrian United States