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News Release, Kansas Geological Survey, July 9, 2008

Maps of Tallgrass Prairie National Preserve Now Available

LAWRENCE--A new geologic map of the unique Tallgrass Prairie National Preserve in the Kansas Flint Hills is now available from the Kansas Geological Survey, based at the University of Kansas.

The preserve is the only National Park System unit devoted to the North America's tallgrass prairie ecosystem, which once covered 140 million acres from Kansas to Indiana and Canada to Texas. Less than 4% of the prairie remains today, much of that in the Kansas Flint Hills.

A private/public partnership between The Nature Conservancy and the National Park Service, the Tallgrass Prairie National Preserve encompasses 10,894 acres in Chase County. It also receives support from the Kansas Park Trust.

"Understanding the geology and water resources of this rare natural grassland is essential when it comes to making long-term decisions about how to use and sustain its natural resources," said Robert Sawin, Survey geologist and the map's author. "Land-use activities on the preserve, such as grazing and recreation, are changing and will continue to change in the future."

A companion map to the geologic map shows water-bearing rock formations and springs.

The rocks at the preserve and the surrounding Flint Hills were deposited about 300 million years ago by fluctuating shallow seas that covered the region. Limestone layers deposited by the seas and interspersed with harder chert--also called flint--form hillside benches and cap hilltops.

Hills and rocky soil limited crop farming in the Flint Hills, leading to the preservation of much of the Flint Hill's grasslands.

Drawn in full-color to differentiate rock layers, the computer-generated geologic map depicts the age and type of bedrock at the surface or just beneath the soil and vegetation. Shaded relief gives the map a three-dimensional look and accentuates the topography within the preserve, which varies in elevation from about 1,500 feet at its highest point to 1,200 feet in the Fox Creek valley.

In addition to rock units and relief, the map includes trails, preserve boundaries, pasture boundaries, highways, ponds and streams, and elevation contours at 10-foot intervals.

Both the geologic map and the companion map showing the preserve's water-bearing rocks are highly detailed at a scale of 1:12,000. One inch on each map is equal to 1,000 feet of actual distance. Besides a map, each 37" x 47" sheet features a graphically illustrated rock column describing the rock units shown on the map and two generalized cross sections.

The cross sections depict vertical slices of surface and subsurface rocks along two lines--one running north to south and the other east to west. They graphically illustrate the layers of underground rocks and highlight the elevation differences within the preserve.

The geologic map is also available in a more compact 19" x 24" size for fieldwork and hiking. It is at a scale of 1:24,000, the same scale as the popular 7.5' U.S. Geological Survey map series.

An interactive electronic version of the geologic map has been developed through a partnership between the Kansas Geological Survey and National Park Service. It can be viewed at

Copies of the Surficial Geology of the Tallgrass Prairie National Preserve map and the Water-Bearing Units of the Tallgrass Prairie National Preserve map are available from the Kansas Geological Survey, 1930 Constant Ave., Lawrence, KS 66047-3724 (785-864-3965). The large-format 1:12,000-scale geologic map and water-bearing map are each $20. The smaller 1:24,000-scale geologic map is $10. Call for shipping and handling charges and, for Kansas residents, sales tax.

More information about the maps and other KGS products is available at the Survey's website (

Story by Cathy Evans, (785) 864-2195.
For more information, contact Robert Sawin, (785) 864-2099

Kansas Geological Survey, Public Outreach