7 ½’ X 15’ quad: Pine Bluffs SE, WY-NE-CO
Great High Plains
5,424 ft (1,653 m)
Caliche-cemented sandstone, algal limestone and shale, called by some geologists the Kimball Formation, but not considered a mappable unit by others. The heterogeneous sedimentary materials in the Ogallala Group were eroded from mountains farther west that had been elevated during the Laramide Orogeny. The sediments were deposited as a huge apron stretching eastward toward the Missouri River. Subsequent erosion separated the Ogallala from its source area in the Rockies, leaving a high plateau that gradually decreases in elevation toward the east. The Ogallala serves as an important aquifer throughout the Plains states and is recharged by precipitation and snowmelt in areas such as Panorama Point.
The Ogallala Formation is underlain by the White River Group, which contains a higher proportion of volcaniclastics, and is well exposed along Pine Bluffs, a long cliff that stretches parallel to the Nebraska-Wyoming border from three miles west of Panorama Point north to I-80 at the town of Pine Bluffs, Wyoming. Oil and gas are extracted from the still deeper Cretaceous sandstones and Permian limestones in Kimball County. The Permian rocks are at the base of the same sequence of rocks exposed at Texas’ highest point and also tapped for oil in New Mexico and west Texas.
Surficial Geology: Pleistocene glaciation did not extend into this area.
Soil Series: Canyon Complex: very shallow, grayish-brown, calcareous loamy soils developed under short grass prairie over weathered sandstone and limestone.
- Clocker, Lawrence F. and others, 1962, Soil Survey of Kimball County, Nebraska: US Soil Conservation Service.
- Diffendal, R.F., Jr., 1995, Review of the Ogallala and younger Neogene of Nebraska: things known and things not known: Geological Society of America Abstracts, v.27, no.3, p.47.
- Loeffler, Peter T., 1992, Paleozoic oil production in the northern Denver basin, Kleinholz field area, Kimball County, Nebraska: The Outcrop; newsletter of the Rocky Mountain Association of Geologists, v.41, no.7, p.4.
- Souders, Vernon L. and others, 1984, A geological section and survey of Cenozoic and uppermost Cretaceous rocks, westernmost Nebraska: Proceedings, Nebraska Academy of Sciences and Affiliated Sciences, v.94, p.49-50.
- Trimble, D. E., 1980, The Geologic Story of the Great Plains: A nontechnical description of the origin and evolution of the landscape of the Great Plains: U.S. Geological Survey Bulletin 1493.
- Ver Ploeg, A.J., 1998, Digital geological map of the Cheyenne 30’ X 60’ quadrangle, southeastern Wyoming, western Nebraska, and northern Colorado: Wyoming State Geological Survey, 1:100,000.
Other suggested sources of information: