Western Nebraska

J.S. and S.W. Aber

Table of contents
Introduction Nebraska Sand Hills
White River Badlands References

Introduction

Nebraska is ranked 15th in state size (total area), 38th in human population, and 43rd in population density (US Census 2015). Population density is especially low in the west, where there is a lot of land and few people. Once upon a time, long ago, we lived in Chadron in the northwestern corner of Nebraska. Since then we have visited several times and led Emporia State University (ESU) geology field trips in the western portion of the state.

In 2010 and again in 2015, we had opportunities to conduct kite aerial photography (KAP) in the Nebraska Sand Hills and at Toadstool Geologic Park in the White River Badlands. Western Nebraska usually has ample sun and wind for kite aerial photography. We utilized primarily rokkaku and delta kites with various radio-controlled and autoKAP camera rigs.

Nebraska Sand Hills

The Nebraska Sand Hills (NSH) region covers most of north-central Nebraska and extends a short distance into South Dakota. The NSH stretches roughly 265 miles (~425 km) east-west and covers approximately 19,300 square miles (~50,000 km2). This is by far the largest area of sand dunes in North or South America (Bleed and Flowerday 1990), bigger than New Hampshire and Vermont together, and one of the largest areas of native prairie in the Great Plains (Labedz 1990). Most of the dunes are now stabilized by prairie grass, and lakes abound in many swales between dunes.

Panoramic overview of lakes and dunes near Valentine, Nebraska. Small blow-out dunes cover larger transverse dunes, and lakes occupy the troughs between large dunes. Assembled from two wide-angle shots.

The NSH has been described as resembling a vast sea with gigantic waves frozen in place and is comparable to other great sand seas in Africa, Arabia, Asia, and Australia. The region remains sparsely populated. Cattle ranching and hay production are the primary land uses based on lush prairie grass and abundant surface water and shallow ground water. In spite of its austere nature, the NSH has become a destination for ecotourism including hunting, fishing, and bird watching.

Cattle grazing on lush meadow grass (left), and a white-faced ibis
(Plegadis chihi) wades in shallow water searching for food (right).

Sand dunes are well-organized into distinct patterns that reflect prevailing wind and sand supply. In general, large dunes occupy the central and northern portions. Lesser dunes are common toward the south and east, and small blow-out dunes are found throughout and around the margins of the sand hills. The dunes are relatively young landscape features and have been active during the past several millennia, most importantly some 8000 to 5000 years ago, again from about 3000 to 1500 years ago, and most recently ca. AD 900-1300 during the Medieval climatic optimum (Swinehart 1990; Schmeisser McKean et al. 2015).

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Nebraska Sand Hills KAP
Lakeside vicinity, Sheridan County, western sand hills region. Left: lakes occupy troughs between large dunes with sparse grass cover. Right: close-up shot of lake nearly filled with emergent vegetation and large dunes in the background.
Lakeside vicinity. Left: maroon and gold colors in the lake are results of micro-organisms that thrive in hypersaline water (see title image). Right: lake in foreground has algae and sediment that color the water shades of green.
Overviews of Smith Lake State Wildlife Management Area looking toward the west (left) and north (right) with kite flyers on right side. Sheridan County, western sand hills region. This fresh-water lake is popular for fishing and camping.
Left: Smith Lake is fed by Pine Creek that drains through a broad valley with numerous lakes. View toward southeast. Right: line of cedar (juniper) trees meandering across small blow-out dunes south of Smith Lake. Trees were planted presumably to form a windbreak.
Steverson Lake overview (left) and close-up shot of inlet creek and delta (right). Part of the Cottonwood-Steverson State Wildlife Management Area, western Cherry County, north-central sand hills region.
Overviews of Dewey Lake toward the west (left) and southeast (right). One of several fresh-water lakes that occupy troughs between large dunes. Near Valentine, Cherry County, north-central sand hills region.

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White River Badlands

The White River Badlands (WRB) terrain is situated between the Pine Ridge in Nebraska and the Black Hills in South Dakota. The White River and its tributaries have cut deeply into the northern margin of the Pine Ridge and exposed underlying bedrock of the White River Group, including the Brule and Chadron formations. This bedrock consists of poorly consolidated mudstone and sandstone layers that have eroded into badlands. Toadstool Geologic Park is one such place, located near Crawford in Sioux County, where unusual erosional forms resemble giant toadstools. Erosion is rapid as demonstrated by collapse of pedestals and pillars during the past few decades.

Large toadstool block of sandstone supported by a narrow pillar of mudstone as it appeared in 1978. The same block, broken and partly collapsed in 2015. Mudstone is worn away by rain and wind, and freezing breaks up sandstone.

The WRB is famous for yielding many vertebrate fossils, especially mammals, as well as fresh-water fish, amphibian, reptile and bird species. These fossils were preserved in strata laid down by streams draining away from the Rocky Mountains during the late Eocene and early Oligocene epochs, approximately 40-30 million years ago (Stoffer 2003; GSA Timescale 2012). However, collecting vertebrate fossils is prohibited in the Oglala National Grassland which includes Toadstool Geologic Park. A small campground area allows easy access to the park.

Nearly whole skull of a fossil oreodont exposed in mudstone of the Chadron Formation. Oreodonts were herbivores similar to modern sheep and goats that populated the lush prairie wetlands. Pocket watch is about 2 inches (~5 cm) in diameter.


Toadstool Geologic Park KAP
Overview of White River Badlands (left), which here expose poorly consolidated mudstone and sandstone of the Chadron Formation. Right: close-up view of highly meandering stream channel incised into the prairie surface.
Escarpment formed by sandstone in the Brule Formation. Overview (left) with the Pine Ridge in the far left background. Close-up shot (right) reveals intricate patterns of gully erosion on steep slopes of the escarpment. Sandstone of the Brule Formation is more resistant to erosion compared with mudstone of the Chadron Formation.
Close-up shots show erosional details in the Chadron Formation (left) and a cluster of large, collapsed toadstools (right). Note people on the gravel path in both of these views.
Left: small campground and picnic area with kite flyers on right side. Right: international ESU students from China, Yuanyuan Zhou (left) and Zhilin Li, test the Canon S70 autoKAP rig prior to flight. Note leather gloves to handle kite line.

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References

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All text and imagery © by J.S. and S.W. Aber.
Last update Dec. 2015.