The work of John Bluemle PhD

7-THE BADLANDS – PART ONE

If asked what he or she knows about North Dakota’s geology, an average resident will likely mention the badlands first. That’s true too of visitors, many of whom come to the state to see our best-known natural feature, the scenic badlands along the Little Missouri River.

Little Missouri River

Fig. 7-A. View upstream (to the south) of the Little Missouri River in Billings and Golden Valley counties about three miles north of Bullion Butte. Photo: 7-8-2010.

The badlands landscape is a rugged and hilly one, best viewed from above, looking down on the hills, not up at them, as we usually view buttes. From the rim of the “breaks,” the point where we descend into the badlands, an intricately eroded landscape of sparsely wooded ridges, bluffs, buttes, and pinnacles lies before us. Black veins of lignite coal may be seen eroding out of the steep badlands slopes. Reddish bands of clinker add vivid colors to the area. Pieces of petrified wood, as well as fossil stumps and logs, litter the surface. Behind us stretch rolling plains, interrupted only by occasional buttes.

Bullion Creek Badlands, Golden Valley County

Fig. 7-B. Bullion Creek Formation badlands, four miles north of Bullion Butte in Golden Valley County. Castellated sandstone structures, resulting in towering or battlement shapes, can be seen at the top of the butte. Such structures are examples of one of many kinds of badlands erosion. Photo: 8-7-2011.

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The American Indians, who inhabited the area when the European settlers arrived, referred to badlands as “mako sica,” (“land bad”). Early French explorers translated and added to this, referring to “les mauvais terrers a’ traverser” (“bad land to travel across”).

Bullion Creek badlands, Billings County

Fig. 7-C. Tertiary Bullion Creek Formation badlands along the Little Missouri River, Billings County. This view is to the north, along the East River Road about five miles north of the South Unit of Theodore Roosevelt National Park. The snow shows the erosion patterns in the south-facing bluffs in the distance beyond the river, which is at the base of the bluffs. Photo :1-15-2010.

 

 

 

 

General Alfred Sully, preparing to cross the badlands in August of 1864, described them as “hell with the fires burned out.” Theodore Roosevelt, who lived for a while in the Little Missouri Badlands in the 1880s, described them as “fantastically beautiful.” I prefer TR’s description.

Age of the Badlands Materials

Badlands topography is found in several places on the plains of the U.S. and Canada. The best-known badlands in the United States are the extensive “Big Badlands,” along the White River in western South Dakota. Near Dickinson we have the “South Heart Badlands” (known also as the “Little Badlands”) where we find layers of sedimentary rock, equivalent (same materials, same geologic age) in part to those in South Dakota’s Big Badlands. The South Heart Badlands are an erosional remnant of what was once a large butte or group of buttes. The South Heart Badlands are carved mainly from strata of Eocene and Oligocene age, ranging between 55 and 25 million years old. The youngest beds belong to the Miocene Arikaree Formation sandstone (22 million years old), which caps some badlands buttes.

South Heart Badlands

Fig. 7-D. South Heart Badlands about six miles south of South Heart, Stark County. Photo 9-24-2009..

North Dakota’s Little Missouri Badlands extend from near the Little Missouri River’s headwaters in Wyoming near Devils Tower to the point where the Little Missouri River joins the Missouri River in western North Dakota. The materials being eroded in these, our most extensive area of badlands, are much older than those in the South Heart Badlands.

The oldest materials in the badlands are in the southwest corner of the state, near Marmarth, where Cretaceous-age Hell Creek Formation beds (about 65 million years old) have been carved into badlands. The dark and somber, gray and purple beds of the Hell Creek Formation contain dinosaur fossils. Small patches of badlands, carved from the Hell Creek formation can also be seen along State Highway 1806 between Huff and Fort Rice in Morton County.

badlands

Fig. 7-E. This badlands topography is located about three miles northeast of Marmarth in Slope County. The materials are Cretaceous in age, about 65 million years old. In contrast to the badlands farther north, which are shades of light brown, these older beds are darker, tending to be purple and gray. They contain dinosaur fossils. Photo 10-22-2009.

However, the main area of  the Little Missouri Badlands is that which has been carved largely from the Paleocene Bullion Creek and Sentinel Butte formations, which were deposited  between 58 and 56 million years ago. The beds that have been eroded into these badlands are too young for dinosaur fossils; the dinosaurs were already extinct when they were deposited.

Between 70 and 40 million years ago, a major mountain-building event known as the Laramide Orogeny (orogeny = “mountain forming”) formed the Rocky Mountains in Montana and Wyoming. As the mountains rose, they were attacked by intense erosion, providing sediment to eastward-flowing rivers and streams. The rivers delivered the eroded sediment to western North Dakota’s coastal plain, an area that could be likened to today’s Mississippi River Delta (central North Dakota was an inland sea at that time). Sediment from the eroding mountains accumulated into thick layers of soft, poorly lithified siltstone, claystone, and sandstone: materials that were deposited on river floodplains and in swamps in what is now western North Dakota. These are the sediments we see exposed today in the Little Missouri Badlands.

In addition to the stream-transported sediments, clouds of volcanic ash, blown eastward from the rising Rocky Mountains during the Laramide Orogeny, collected in layers that were later weathered to clays ( “bentonite”). When wet, the clay absorbs water and swells, and it can become slippery when wet so don’t try walking or driving on it. When the beds dry, they assume a surface  texture, similar in appearance and consistency to popcorn, with colors ranging from white to bluish-gray or black.

Why the Badlands Formed

South Heart Badlands

Fig. 7-F. The dark-gray to black mound-like hills are examples of topography of the South Heart Member of the Eocene Chadron Formation in the South Heart Badlands south of the town of South Heart, Stark County. The material is a clay that forms a popcorn-like surface when it is dry. When wet, it is sticky and slippery. The clay is a weathering product of volcanic ash. Photo 9-24-2009

Even though the layers of sedimentary rock exposed in North Dakota’s Little Missouri Badlands range from Cretaceous through Eocene in age (65 to 50 million years old), the badlands themselves–the hills and valleys we see today–are not nearly that old. Before a glacier diverted it, the Little Missouri River flowed northward through a broad, smooth valley, joining the early Yellowstone River in northern Williams County. The Little Missouri and Yellowstone rivers came together near Alamo (about 30 miles north of Williston) in a place now buried beneath 400 feet of glacial deposits. From there, the combined Yellowstone-Little Missouri River flowed northeastward into Canada.

The diversion of the Little Missouri River, away from its route to the north, probably happened sometime prior to the deposition of a volcanic ash bed on the glacial sediment blocking the channel (the ash was deposited as a result of a volcanic eruption in the area of Yellowstone Park 640,000 years ago). It is possible, though, that an earlier glacier might have diverted the river – the 640,000-year figure is a minimum date; erosion of the badlands may have begun as early as 3.5 million years ago.

Since it was diverted by glacial ice, the Little Missouri River has flowed over a shorter and steeper route than it did prior to its diversion. That part of the river’s route today, from the point where it makes its sharp turn toward the east in the area of the North Unit of Theodore Roosevelt National Park, is east rather than north as it had been before a glacier diverted it. When the river assumed its new, shorter route toward the Gulf of Mexico, it began a vigorous erosion cycle, cutting down more rapidly and deeply and sculpting badlands topography. The badlands then, are an indirect result of glacial activity, even though the only conspicuous direct evidence of glaciation remaining in the area is an occasional glacial erratic on the upland in northern McKenzie County.

Sentinel Butte badlands; Theodore Roosevelt Park

Fig. 7-G. Badlands carved from the Tertiary-age Sentinel Butte Formation in the North Unit of Theodore Roosevelt National Park. Notice that certain beds can be followed across the entire vista, although they may be discontinuous, eroded away in places. An example is the bluish gray layer that forms the surface of many table-like pedestals. This layer is a bentonitic clay, a weathered volcanic ash deposit. The layers shown here are slightly younger than are those exposed in the South Unit of the park. Total relief here, from valley floor to upland surface, is about 500 feet. Photo: 10-24-2009

 

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