News Release, Kansas Geological Survey, June 15, 1999
The map shows the age and the type of rock at the earth's surface. Geologic maps are used in urban planning, construction, and environmental projects, including the building of roads, bridges, houses, and other structures. The map also shows towns, rivers, lakes, roads, and a variety of other man-made features.
The new map was drawn by Survey geologist James McCauley. Geologic maps of Wyandotte County have been published in the past. This new map reflects current thinking about the area's geology, current names for rock formations, and an updated depiction of the area's highways and roads.
According to the map, much of eastern Wyandotte County, particularly the area north of the Kansas River, is blanketed by a layer of silty soil called loess. That soil was deposited during the Pleistocene Period, when glaciers had moved into northeastern Kansas, about 600,000 years ago. Areas bordering the Kansas River and other streams are also covered by recently deposited sand, gravel, and other materials.
Hills in the western part of the county are covered by glacial drift--the cobbles, boulders, and other rock debris that was carried by the glaciers. Boulders of hard, red rock called Sioux quartzite are a particularly recognizable component of glacial drift.
Rocks in much of the rest of the county were deposited during the Pennsylvanian Period of geologic history, about 300 million years ago. Most of these rocks are limestones and shales, deposited by shallow seas that covered the area. In other places, sandstones and coals are found, the sandstones deposited in the channels of ancient rivers and the coals at the bottom of swamps.
"Wyandotte County is heavily urbanized, part of an area where large amounts of construction and expansion continue to take place," said McCauley. "That's why it's important to have information about the area's bedrock geology."
The new map is drawn in full-color at a scale of 1:50,000 so that one inch on the map equals about 0.8 miles of actual distance.
Copies of the new map are available from the Kansas Geological Survey, 1930 Constant Ave., Lawrence, KS 66047 (or call 785-864-3965). The cost is $15.00 plus $4.00 postage and handling. Kansas residents should add 6.9% sales tax.