Geology of Kansas
Rock that crops out in the US state of Kansas was formed during the Phanerozoic eon, which consists of three geologic eras: the Paleozoic, Mesozoic and Cenozoic.
[2] Pennsylvanian rocks consist predominantly of alternating marine and non-marine shales and limestones with some sandstone, coal, chert, and conglomerate.
The Cretaceous in Kansas was an open ocean or sea environment dominated by microscopic marine plants and animals that floated or swam near the surface of this ancient water body.
Paleogene to Neogene rocks in Kansas consist of river silt, sand, freshwater limestones, and some volcanic ash derived from eruptions in the western United States.
Over 60 million years of erosion, the Rocky Mountains created a wedge of material extending to the Flint Hills of eastern Kansas.
The Quaternary Period in western Kansas was very similar to the Neogene, continual erosion of the Rocky Mountains deposited additional sediments.
[4] Mississippian limestones and cherts of the Ozark Plateau are exposed in extreme southeastern Kansas in Cherokee County.
The cuestas are a region of east to southeast facing escarpments (50 to 200 feet [15 to 61 m] high) formed on resistant limestone units which dip gently to the west and northwest.
[11][12][13] The Red Hills cover a section of southern Kansas in Clark, Comanche, and Barber counties along the Oklahoma border.
Rocks outcropping in the area include the sandstones of the Dakota Formation, the Greenhorn Limestone, and the thick Niobrara Chalk.
The tectonic uplift of the Rocky Mountains during the Cenozoic resulted in erosion and deposition of vast quantities of non-marine sediments eastward across the High Plains.
The Ogallala Formation consists of a large wedge of unconsolidated sands and silts that is a significant aquifer under the plains.
In the southwest corner of the state in Morton County rocks of Jurassic age outcrop along the Cimarron River.
[20] The Wellington-McPherson Lowlands of south-central Kansas in Sumner, Sedgwick, Harvey and McPherson counties is underlain by fluvial sediments deposited in the ancestral Arkansas River valley during the Pleistocene Epoch one to two million years ago.
A significant area of sand dunes occur on the south side of the plain formed by the prevailing winds from the glaciers to the north during the Pleistocene.
[21] The subsurface geology of Kansas consists of several sequences of sedimentary strata deposited on the Pre-Cambrian basement of the North American Craton.
[22] The Nemaha uplift is a deep fault zone which runs diagonally across east Kansas and extends from just south of Omaha, Nebraska to Oklahoma City.
Some fifty miles to the west the southernmost extension of the Proterozoic Midcontinent Rift System extends into northeastern Kansas.
The igneous and metamorphic rocks of this orogenic zone are considered to be an extension of the 1.7 Ga fold belt exposed in Colorado and Wyoming.
