LAWRENCE — A new full-color geologic map of Dickinson County showing rocks that transition from the Flint Hills to the Smoky Hills as well as the broad Smoky Hill River valley and adjacent sand hills is available from the Kansas Geological Survey, based at the University of Kansas.
Surficial geologic maps highlight the type and age of rock layers and unconsolidated sediments found on the surface or immediately below the vegetation and soil. The map also has a three-dimensional quality that accentuates the area’s topography.
“As the first detailed geologic map of Dickinson County, this is an important addition to the Survey’s decades-long geologic mapping effort,” said Survey Interim Director Rex Buchanan.
Mapped by now-retired Survey geologist James McCauley, the county’s surface geology is dominated by limestone and shale layers that range in age from Permian to Cretaceous.
The Permian rocks were formed from deposits in shallow seas that rose and receded across the area more than 275 million years ago. Sandstones in the Cretaceous-age Dakota and Kiowa formations in western Dickinson County formed near the edge of shallow seas in delta-type settings about 100 million years ago. These sandstones, in the Smoky Hills, offer the most noticeable relief in the county.
In more recent geologic time during the Glacial Age, the Smoky Hill River was diverted from a southward path to the Arkansas River to its current route through Dickinson County toward the Kansas River. Although glaciers did not descend into the county during that time, streams fed by melting glaciers eroded land surfaces and deposited clay, silt, sand and gravel in the Smoky Hill River floodplain.
Dunes built of fine-grained sand blown out of the floodplain and now covered with grass are visible north of the river between Abilene and Solomon and near Detroit. Rainwater captured in the dunes recharges groundwater in the floodplain, the main source of municipal water for Abilene and Solomon.
Natural resources in the county that have been extracted for commercial use include limestone for building stone, road aggregate, and rip-rap and sand and gravel for road aggregate. Dickinson County produced 8,590 barrels of oil from 29 wells in 2013, the most recent year for which complete data is available. The county ranked 83rd out of the 91 oil-producing counties in the state.
"This map shows the geology that underpins the diversity of landscapes and natural resources, highlighting each of the distinctive regions in Dickinson County," Buchanan said.
In addition to geologic and hydrologic characteristics, the map includes towns, roads (from interstate highways to unimproved roadways), elevation contours at 10-meter intervals, and township and range boundaries.
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 emphasize the landscape's topography. The map is at a scale of 1:50,000 so that 1 inch on the map equals about 3/4 mile of actual distance.
Besides the map, the 51" x 54" sheet contains an illustrated rock column, which shows the order in which the rock units were deposited over time, and a description of each unit.
Copies of the Dickinson County map are available from the Kansas Geological Survey at 1930 Constant Ave., Lawrence, KS 66047-3724 (phone 785-864-3965, email firstname.lastname@example.org) and at 4150 W. Monroe St., Wichita, KS 67209-2640 (phone 316-943-2343, email email@example.com).
The cost is $15 plus shipping and handling. Inquire about shipping and handling charges and, for Kansas residents, sales tax. More information about county geologic maps and other KGS products is available at the Survey's website (www.kgs.ku.edu).