Each of these sedimentary rock layers has been named after towns, creeks, or other nearby landmarks the names are based on the locations where each rock layer was first found and described by geologists. Shales represent times when mud was deposited on the ocean floor. The limestones represent periods when the region's surface was covered by shallow, tropical oceans which teemed with life. The surface was covered by water most of the time. The limestone and shale beds were deposited during the Permian Period of geologic history, about 280 million years ago. Tougher limestones and flints cap the tops of the hills. The hills themselves are created by a process called differential erosion. The shales form steep slopes between the benches. Many of the limestone layers create notable benches on the hillsides. The alternating beds of limestone and shale produce terraced hillsides. Flint Hills RECAs mission statement is to provide a Safe, Reliable, & Affordable Power Supply while maintaining the Cooperative as a Valuable Business. It is harder and more erosion resistant than the shales which are usually gray or tan. Limestone ranges in color from nearly white to brown. The layers of chert may have formed as the silica material recrystallized, chemically replacing the limestone.Ī cross section of the Flint Hill geologic layers.Ĭourtesy of Kansas Geological Survey Differential Erosion The remains fell to the ocean floor, then migrated together as the limestone formed. Others theorize flint may form from the remains of marine organisms rich in silica. Some geologists believe flint nodules precipitated from volcanic ash which hardened in the cracks of limestone. Fusulinids can be seen in many of the limestone blocks used for building on the preserve.įlint, a type of chert, can occur within limestone as roughly spherical concentrations (nodules) or less commonly as layers (laminated). When they died, their skeletons were preserved in the lime mud of the ocean floor. These one-celled animals floated in the warm tropical water. Particularly abundant in some limestones are fusulinids - fossils shaped like wheat grains. Most of the marine fossils found here are invertebrates - animals without backbones: Corals, clams, snails, bryozoans (colonies of animals resembling sea fans), sea urchins, crinoids (a stalked animal that is distantly related to the starfish and sea urchin), and clam-like animals called brachiopods. The limestone and shale sediments seen in the Flint Hills show us a cross section of a different landscape long ago. This site provides a single location for land managers conducting prescribed burns in the Flint. Clay and mud deposits lithified into shale. Welcome to the Kansas Flint Hills Smoke Management Website. The harder calcium carbonate accumulated and lithified into limestone. As these organisms died, they sank to the sea floor where the organic parts decayed. These creatures took calcium carbonate (CaCO3) out of the water and secreted it, forming shells or skeletons. The shallow warm seas supported enormous populations of invertebrates, fish, amphibians and plants. Courtesy of Kansas Geological Survey Lithify and Fossilize
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