North Dakota

White Butte
       7 ½’ quadrangle: Amidon, ND
       Slope County
       Private land
       Chalky Buttes, North Dakota Badlands br>

Sedimentary
3,506 ft 1,069 m


White Butte viewed from the east. (1997)


View north from summit. (TBT, 1997)

Bedrock: Chadron Formation, White River Group

Tertiary (Oligocene)

The "dazzling white", gravel-bearing sandstone that caps White Butte has been informally called the Chalky Buttes member of the Chadron Formation. Thin conglomerate layers include clasts of chert, petrified wood, granite, rhyolite, and distinctive quartz-latite porphyry believed to have been eroded from the Beartooth Mountains. The sandstone is stained yellow by limonite toward the base, where it unconformably overlies the clay and silty claystone of the Amidon member. Geologists speculate that an ancestral Yellowstone River deposited these alluvial materials when it flowed south-southeast through Slope County, in a deep valley it had eroded into the older units below, much as the modern Missouri River is cutting into older rocks today north of Bismarck. The Chadron Formation has yielded titanotherium fossils near Rhame, southwest of the highpoint. (See Cenozoic titanotheres in the Jesse Hyde lantern slide collection, Case Western Reserve Geology department website.)

Surficial Geology: Pleistocene glaciation did not reach quite this far south in the state. Erosion along tributaries of the Little Missouri River has formed the typical badland topography of western North Dakota: buttes capped by sandstone overlie more easily eroded clays.

Soil Series: Badland/Cabbert complex: Shallow, light brown silt-loam soils over shallow bedrock, commonly gullied, suitable for carefully managed rangeland or wildlife habitat. Where the clay-rich Amidon member is exposed without vegetation and soil cover on the lower slopes of White Butte, the surface is covered by slippery clay which dries out to a "popcorn" texture (see photo below).

Additional Photos:


Popcorn texture in clays. Gypsum concretions in foreground.

Selected References:

  • Hoganson, John W., 1986, Oligocene stratigraphy of North Dakota in Clausen, Eric and Allen J. Kihm, Tertiary and upper Cretaceous of south-central and western North Dakota: North Dakota Geological Society, 1986 Field Trip, p.36-40.
  • Hoganson, John W., 1986, Oligocene stratigraphy of North Dakota in Clausen, Eric and Allen J. Kihm, Tertiary and upper Cretaceous of south-central and western North Dakota: North Dakota Geological Society, 1986 Field Trip, p.36-40.
  • Moore, G.W., R.E. Merlin and R.C. Kepferle, 1956, Preliminary geologic map of the Chalky Buttes area, Slope County, North Dakota: U.S. Geological Survey Coal Investigations Map C-38, 1:31,680.
  • Thompson, K.W., 1978, Soil Survey of Slope County, North Dakota: U.S. Soil Conservation Service.
  • 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.

Other suggested sources of information:


*You are viewing pages printed from http://www.unh.edu/
These pages appear differently when viewed online.

If you are the owner of this site and you would like to print the page as it appears online, please refer to the file "QuickStart.html" for instructions.