News Release, Kansas Geological Survey, July 30, 2010
LAWRENCE--Rocks that hold clues to the state's diverse environmental and climatic past, including the rocks that make up the Flint Hills of eastern Kansas, are the subject of a new publication from the Kansas Geological Survey at the University of Kansas.
In "The Permian System of Kansas," Ron West, Keith Miller and Lynn Watney describe the many rock layers formed by a succession of ocean and terrestrial environments in the state between 300 million and 250 million years ago during the Permian Period.
West is Kansas State University professor emeritus, Miller is a research assistant professor at KSU and Watney is a geologist at the Kansas Geological Survey.
"A variety of depositional environments are preserved in the Permian rocks of Kansas, from shallow marine environments preserved in older fossiliferous limestones to semi-arid and arid environments recorded in younger red beds and evaporite deposits," West said.
Permian deposits are found at or below the surface in the western three-fourths of Kansas. The surface deposits range from layers of limestone and mudrocks in the Flint Hills to red mudrocks, siltstone, sandstone, gypsum and dolomite in the Red Hills of south-central Kansas to extensive underground salt beds.
Economic products associated with Permian deposits in Kansas include oil and gas, salt, gypsum, building stone, road and construction aggregate, and groundwater.
More than 27 trillion cubic feet of natural gas has been extracted from Permian rocks in southwest Kansas, the largest gas-producing area in the western hemisphere, and salt has been mined in central Kansas since the late 1800s.
During the Permian, Kansas was in the northern tropics with a tropical to dry subtropical climate. Although shallow seas often covered much of the area, sizable landmasses emerged when sea levels dropped.
"The different rock sequences reflect cycles that occurred over time and are the result, in part, of the global fluctuations between glacial and interglacial conditions," West said.
Invertebrate marine fossils, including single-celled shelled animals called fusulinids, corals, clams and ammonoids, and terrestrial fossils such as leaves and insects are among the relics used to define boundaries between rocks deposited by oceans, and those left behind in nonmarine times. Ancient soils called paleosols provide evidence of climate change in the Permian.
Horizontally rock layers of Permian age are most easily studied in their natural order when exposed by road or dam construction. Heavy flooding in 1993 resulted in a wide exposure of Permian strata at the Tuttle Creek Lake Spillway near Manhattan, providing a rare glimpse at the boundary between the Permian and older rock units in Kansas.
"The rocks exposed by the flood at the Tuttle Creek Lake Spillway is, from a scientific stand point, the most important Permian site in Kansas," West said. "The internationally recognized boundary between the Carboniferous rocks below and the Permian rocks above is well exposed at this site."
Drawing together information from a variety of sources, "The Permian System in Kansas" is the most complete resource available on the stratigraphy and history of Permian geology in Kansas. It includes more than 60 full-color photographs of Permian exposures with precise location information.
"The Permian System in Kansas" is available online at http://www.kgs.ku.edu/Publications/Bulletins/257/index.html.
A published version also is 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 $20 plus shipping and handling. Inquire about shipping and handling charges and, for Kansas residents, sales tax.
Information about all KGS publications and data is available at the Survey's web site (www.kgs.ku.edu).