The Baraboo Range is a

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimpose ...

located in

Columbia Columbia may refer to: * Columbia (personification), the historical female national personification of the United States, and a poetic name for America Places North America Natural features * Columbia Plateau, a geologic and geographic region i ...

and Sauk Counties,

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 ...

. It consists of highly eroded

Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of th ...

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...

. It is about long and varies from 5 to in width. The

Wisconsin River The Wisconsin River is a tributary of the Mississippi River in the U.S. state of Wisconsin. At approximately 430 miles (692 km) long, it is the state's longest river. The river's name, first recorded in 1673 by Jacques Marquette as "Meskous ...

, previously traveling in a north to south direction, turns to the east just north of the range before making its turn to the west towards the

Upper Mississippi River The Upper Mississippi River is the portion of the Mississippi River upstream of St. Louis, Missouri, United States, at the confluence of its main tributary, the Missouri River. History In terms of geologic and hydrographic history, the Upper ...

. The eastern end of the range was glaciated during the

Wisconsinian glaciation The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cord ...

, while the western half was not, and consequently, marks the eastern boundary of Wisconsin's

Driftless Area The Driftless Area, a topographical and cultural region in the American Midwest, comprises southwestern Wisconsin, southeastern Minnesota, northeastern Iowa, and the extreme northwestern corner of Illinois. Never covered by ice during the las ...

. The city 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 sit ...

is in the center of the valley. The range was designated a

National Natural Landmark The National Natural Landmarks (NNL) Program recognizes and encourages the conservation of outstanding examples of the natural history of the United States. It is the only national natural areas program that identifies and recognizes the best ...

in 1980.

Geology

The range is an example of a buried mountain range exposed through erosion, to once again undergo the forces of surface erosion. The rocks are as much as 1.5 billion years old,Hanson, G. F.
''Geology of the Baraboo District, Wisconsin''
, The University of Wisconsin Extension, November 1970, Information Circular 14 among the oldest exposed rocks in North America, consisting mainly of gray to pink Baraboo Quartzite and red

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The miner ...

. The

Baraboo River The Baraboo River is a tributary of the Wisconsin River, about 70 mi (115 km) long, in south-central Wisconsin in the United States. Via the Wisconsin River, it is part of the watershed of the Mississippi River. The Baraboo River was ...

divides the range in half, flowing through Upper Narrows Gorge near Rock Springs and travels onto its confluence with the

downstream from

Portage Portage or portaging (Canada: ; ) is the practice of carrying water craft or cargo over land, either around an obstacle in a river, or between two bodies of water. A path where items are regularly carried between bodies of water is also called a ...

through the Lower Narrows. The Baraboos are composed of resistant

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 ...

) which has formed an erosional remnant or

Monadnock An inselberg or monadnock () is an isolated rock hill, knob, ridge, or small mountain that rises abruptly from a gently sloping or virtually level surrounding plain. In Southern Africa a similar formation of granite is known as a koppie, a ...

, resulting in

topographic prominence In topography, prominence (also referred to as autonomous height, relative height, and shoulder drop in US English, and drop or relative height in British English) measures the height of a mountain or hill's summit relative to the lowest contou ...

. The mountains may have formed as long ago as the late Precambrian. These formations were buried by

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ...

sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...

and are still being uncovered by the erosion of the softer, overlying rocks. Devil's Lake, the centerpiece of Devil's Lake State Park, was formed from

terminal moraine A terminal moraine, also called end moraine, is a type of moraine that forms at the terminal (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed by the front edge ...

s blocking access to its outlet, creating what is today an

endorheic lake An endorheic lake (also called a sink lake or terminal lake) is a collection of water within an endorheic basin, or sink, with no evident outlet. Endorheic lakes are generally saline as a result of being unable to get rid of solutes left in the l ...

(i.e., a lake lacking a surface outlet to the world's oceans).

References

* Steven Dutch
Devil's Lake
Retrieved July 27, 2007 (With map)

Retrieved July 27, 2007
Baraboo Range Protection Plan
Sauk County, Retrieved July 27, 2007

Wisconsin Department of Natural Resources The Wisconsin Department of Natural Resources (WDNR) is a government agency of the U.S. state of Wisconsin charged with conserving and managing Wisconsin's natural resources. The Wisconsin Natural Resources Board has the authority to set policy ...

, Retrieved July 27, 2007 * Keith Montgomery
The Baraboo Ranges and Devil's Lake Gorge: A Geologic Tour
Retrieved April 30, 2019

External links

* {{authority control Driftless Area Landforms of Columbia County, Wisconsin Landforms of Sauk County, Wisconsin Geology of Wisconsin Inselbergs of North America Mountain ranges of Wisconsin National Natural Landmarks in Wisconsin