Hydrogeology and Geology of the Lower North and South Platte Rivers of Nebraska (GB-37)

Hydrogeology and Geology of the Lower North and South Platte Rivers of Nebraska (GB-37). Guidebook for the Nebraska Geological Society Field Trip 2020, 8.5" x 11", 38 pp.

The 2020 Nebraska Geological Society field trip will visit central Nebraska, and explore the geology and hydrogeology of the upper Platte, Lower South Platte and Lower North Platte rivers. The field trip area consists of a roughly east-west strip of land, approximately 100 kilometers long, and generally less than 10 kilometers north and south of the Platte, North Platte and South Platte rivers' channels over most of the reach; from Brady, NE, upstream to Big Springs on the South Platte River and Lewellen on the North Platte River (Map 1). In addition to the river valleys, participants will observe alluvial fans along the valley margin, adjacent uplands consisting of variable bedrock strata, as well as loess, dune sand and gravel. This field excursion will examine these features with the goal of better understanding the region with respect to the aquifer and stratigraphic framework, hydrogeology, and water management challenges in the region.

Dozens of geologists have been mapping Nebraska since the mid-1800s, and since 1996 have transitioned from drawing paper maps to creating digital maps
(Joeckel et al., 2018). Many of the early maps and publications have also been subsequently digitized and made available through UNI:s Digital Commons, such as the Scottsbluff 1 ° by 2° quadrangle (Swinehart and Diffendal, 1997), and the North Platte 1 ° by 2° quadrangle (Diffendal, 1991) that form the geological basis for this tour. Another product of the geological work is the ability to engage students and geologists through field trips and field guides, this publication being just the most recent for this region. T. Mylan Stout and others ( 1971) published one of the earlier field trip guides covering a route from Sidney to Lincoln, including several stops that overlap with this trip. Stout's descriptions of the stratigraphic sections from Ash Hollow (Stop 5 B'), Brule Canyon and northeast of Ogallala (Stop 6 C, D, and E), and southeast of North Platte (Stop 7 F, G, and H) provide useful information and additional basis for this trip.