News Release, Kansas Geological Survey, Feb. 17, 2009
LAWRENCE--The surface geology of Morton County in southwestern Kansas is featured on a new full-color map with a three-dimensional quality available from the Kansas Geological Survey, based at the University of Kansas.
Geologic maps show the type and age of rock layers found at the surface or immediately under the vegetation and soil. No map of Morton County has been produced since 1942.
"Having an accurate detailed map in digital form will be useful for land-use planning on all levels, for recreational planning, and for assessing future drought impact and other geologic hazards," said Bill Johnson, KU professor of geography who mapped the county with KU physical geography graduate students Terri Woodburn and Lisa Messinger.
The geology of Morton County, which borders Oklahoma and Colorado, has been affected by a number of factors, from the formation of the Rocky Mountains millions of years ago to the Dust Bowl in the 1930s.
"Morton County was the bull's eye of the Dust Bowl, and the large sand sea south of the Cimarron River was mobilized in a wholesale fashion," Johnson said. "It is now stabilized with only a few active areas, most notable during the recent drought early in this decade."
The water-bearing Ogallala Formation, made up of silt, sand, gravel and clay transported in by streams from the Rocky Mountains, crops out along the north side of the Cimarron River and up along the river's north fork. It underlies most of the county and is a major source of drinking water.
North of the Cimarron River valley the surface geology consists mainly of widespread loess, or wind-blown silt, punctuated by Ogallala and alluvial deposits along the streams and several intermittent lake deposits, also called playas or buffalo wallows.
Jurassic rocks at the surface in Kansas are limited to one small area of Morton County along the Cimarron River valley near Point of Rocks, a landmark on the Dry Route of the Santa Fe Trail. The route of the Trail accentuates how geology influences human activities.
"Using this map, one can easily see why the trail went where it did," Johnson said. "This remarkable historic feature is still evident in places, especially within the Cimarron National Grasslands in Morton County."
In addition to rock units and relief, the map shows towns, roads--from federal highways to unimproved roadways--ponds and streams, clay pits and limestone quarries, and elevation contours at 10-meter intervals.
Drawn in full-color to differentiate rock layers, the computer-generated geologic map features shaded relief to give the map its three-dimensional look and emphasizes the landscape's topography. The map is at a scale of 1:50,000 so that one inch on the map equals about 3/4 mile of actual distance.
Besides the map, the 47" x 38" sheet contains an illustrated rock column, which classifies each rock unit on the map, and a description of each unit.
Copies of the Morton County map are available from the Kansas Geological Survey, 1930 Constant Ave., Lawrence, KS 66047-3724 (or phone 785-864-3965, email firstname.lastname@example.org) and at 4150 Monroe Street, Wichita, Kansas, 67209, 316-943-2343. The cost is $15 plus shipping and handling. Inquire about 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 web site (www.kgs.ku.edu).