Citation
Karst and Shallow Carbonate Bedrock in Wisconsin

Material Information

Title:
Karst and Shallow Carbonate Bedrock in Wisconsin
Alternate Title:
Factsheet 02 | 2009
Creator:
Leila Gonzales ( suggested by )
U.S. Geological Survey
Publisher:
Wisconsin Geological and Natural History Survey
Publication Date:
Language:
English

Subjects

Subjects / Keywords:
Geology ( local )
Genre:
Map
serial ( sobekcm )

Notes

General Note:
Carbonate bedrock rock formations composed primarily of limestone or dolomite, underlie the southern third of Wisconsin in a V-shaped belt (see map on other side). These rocks are commonly fractured, with the fractures provid- ing primary pathways for ground- water movement. Carbonate rocks are soluble, and percolating surface water can enlarge fractures to form conduits, caves, and sinkholes that are the hallmarks of a karst system and its related karst landscape. In Wisconsin, karst landscapes are direct evidence of underlying shal- low, fractured carbonate bedrock. But the lack of classic karst features in a landscape does not mean that shallow fractured carbonate bedrock is absent, or that the groundwater is potentially any less vulnerable to contamination. Carbonate bedrock and groundwater contamination Carbonate formations are important aquifers in Wisconsin. These aquifers supply water for homes, farms, cities, industries, and other human uses as well as maintaining water levels in lakes and wetlands and flows in streams and springs. Carbonate aquifers are exceptionally vulnerable to contamination for two reasons: Groundwater flow in fractured rocks and karst systems can be extremely rapid-tens to hundreds of feet per day. Carbonate rocks are poor at filtering or otherwise removing contaminants Some site-specific questions to ask about carbonate aquifers Carbonate aquifers are particularly vulnerable where overlying soils are thin or absent. There are numerous examples of ground- water contamination of carbon- ate aquifers in such settings in Wisconsin. Consequently, land-use activities in areas of carbonate rock must be carefully managed to avoid the release of contaminants to groundwater. Types of questions to ask: Is carbonate bedrock present in the subsurface? How deeply is it buried? In other words, what is the thickness of the overlying material? What is the nature of the overlying material? For example, what is its origin, composition, grain size, etc? Water- and land-use management plans in areas with carbonate bed- rock should always address these sorts of questions as they seek to protect groundwater quantity and quality. For more information, contact Kenneth R. Bradbury, Ph.D. Wisconsin Geological and Natural History Survey 608.263.7921, krbradbu@wisc.edu
Restriction:
Open Access - Permission by Publisher
General Note:
See Extended description for more information.

Record Information

Source Institution:
University of South Florida Library
Holding Location:
University of South Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
K26-02162 ( USFLDC DOI )
k26.2162 ( USFLDC Handle )
19952 ( karstportal - original NodeID )

USFLDC Membership

Aggregations:
Karst Information Portal

Postcard Information

Format:
Serial

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Full Text
Description
Carbonate bedrock rock formations composed primarily of
limestone or dolomite, underlie the southern third of
Wisconsin in a V-shaped belt (see map on other side). These
rocks are commonly fractured, with the fractures provid- ing
primary pathways for ground- water movement. Carbonate rocks
are soluble, and percolating surface water can enlarge
fractures to form conduits, caves, and sinkholes that are the
hallmarks of a karst system and its related karst landscape.
In Wisconsin, karst landscapes are direct evidence of
underlying shal- low, fractured carbonate bedrock. But the
lack of classic karst features in a landscape does not mean
that shallow fractured carbonate bedrock is absent, or that
the groundwater is potentially any less vulnerable to
contamination.
Carbonate bedrock and groundwater
contamination
Carbonate formations are important aquifers in Wisconsin.
These aquifers supply water for homes, farms, cities,
industries, and other human uses as well as maintaining water
levels in lakes and wetlands and flows in streams and
springs. Carbonate aquifers are exceptionally vulnerable to
contamination for two reasons:
Groundwater flow in fractured rocks and karst systems
can be extremely rapid-tens to hundreds of feet per
day.
Carbonate rocks are poor at filtering or otherwise
removing contaminants
Some site-specific questions to ask about carbonate
aquifers
Carbonate aquifers are particularly vulnerable where
overlying soils are thin or absent. There are numerous
examples of ground- water contamination of carbon- ate
aquifers in such settings in Wisconsin. Consequently,
land-use activities in areas of carbonate rock must be
carefully managed to avoid the release of contaminants to
groundwater.
Types of questions to ask:
Is carbonate bedrock present in the subsurface?
How deeply is it buried? In other words, what is the
thickness of the overlying material?
What is the nature of the overlying material? For
example, what is its origin, composition, grain size,
etc?
Water- and land-use management plans in areas with
carbonate bed- rock should always address these sorts of
questions as they seek to protect groundwater quantity and
quality.
For more information, contact
Kenneth R. Bradbury, Ph.D.
Wisconsin Geological and Natural History
Survey
608.263.7921, krbradbu@wisc.edu



PAGE 1

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PAGE 2

Carbonate bedrock karst Carbonate bedrock and groundwater contamination Typical features of a karst sytem and landscape: Seepages, sinkholes, caves, fractures, springs, and stream sinks. Some site-speci!c questions to ask about carbonate aquifers For more information, contact Kenneth R. Bradbury, Ph.D. Wisconsin Geological and Natural History Survey 608.263.7921, krbradbu@wisc.edu Karst and shallow carbonate bedrock in Wisconsin Wisconsin Geological and Natural History Survey Factsheet 02 | 2009 Fracturing and bedding in an exposure of carbonate bedrock near Sturgeon Bay in Door County.