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Full-Text Articles in Stratigraphy

The Broadwater Formation (Pliocene) Of Nebraska And Southeastern Wyoming, Robert F. Diffendal Jr., James B. Swinehart Dec 2023

The Broadwater Formation (Pliocene) Of Nebraska And Southeastern Wyoming, Robert F. Diffendal Jr., James B. Swinehart

Robert F. Diffendal, Jr., Publications

The Broadwater Formation, initially defined in 1945, is a Pliocene-aged coarse-grained alluvial deposit in Nebraska and southeastern Wyoming. It is characterized by a complex stratigraphic history and debated geologic interpretations. The formation is a rich resource of groundwater for the citizens of Nebraska and the Central Great Plains. We aim to synthesize and redefine the Broadwater Formation, shedding light on its distribution, geological characteristics, and paleoenvironmental significance. While historical hypotheses on Broadwater Formation paleovalley trajectories suggested northwest-southeast trending valleys, later investigations proposed wind-driven erosional patterns to explain the unique topographic features observed. The Broadwater is divided into an unnamed Upper …


Fossils On The Floor Mosaics In The Rotunda Of The Nebraska State Capitol Second Edition, Robert F. Diffendal Jr. Jun 2022

Fossils On The Floor Mosaics In The Rotunda Of The Nebraska State Capitol Second Edition, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The idea for this project arose during a field trip to the Nebraska State Capitol led by my long-time friend and colleague, Joe Hannibal, of the Cleveland Museum of Natural History, during the Geological Society of America’s North-Central Section Meeting in Lincoln, Nebraska, on Saturday, April 26, 2014. One of Joe’s interests is historical buildings and their building stones. He put together a very useful guidebook to the building and its decorative stones (Hannibal, 2014) that we used on our tour.

One of the many places that we visited was the State Capitol Archives, located in the basement, where the …


Rock Glen Wildlife Area: A Landscape History, Gerry Steinauer, Robert Diffendal Jr. Mar 2021

Rock Glen Wildlife Area: A Landscape History, Gerry Steinauer, Robert Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Nestled in the hills of southern Jefferson County, Rock Glen Wildlife Management Area, as its name implies, is a rocky land shaped by ancient geological forces, among them, meandering tropical rivers and grinding glacial ice. Euro-American settlers in the region arrived to a picturesque scene: rolling hills cloaked in tallgrass prairie fingered by glens, narrow valleys and canyons, filled with sprawling bur oaks. Too rocky to plow, southern Jefferson County has survived as an island of prairie amidst a sea of cropland. Settlement was not kind to the land. Fire suppression allowed eastern red cedars and other trees to spread, …


Tributes To Rick Edwards Upon His Retirement, Robert F. Diffendal Jr., Michael Farrell, Michael David Forsberg, Maurice Godfrey, John J. Janovy Jr., Katie Nieland, Linda Pratt, Rebecca S Wingo, David J. Wishart, George E. Wolf, Peter Longo, John R. Wunder Oct 2020

Tributes To Rick Edwards Upon His Retirement, Robert F. Diffendal Jr., Michael Farrell, Michael David Forsberg, Maurice Godfrey, John J. Janovy Jr., Katie Nieland, Linda Pratt, Rebecca S Wingo, David J. Wishart, George E. Wolf, Peter Longo, John R. Wunder

Robert F. Diffendal, Jr., Publications

I understand that you will be retiring from UNL in August. I wanted to express my sadness that you will be leaving the Center for Great Plains Studies, but am glad that you will now be able to perhaps enjoy life even more without having to do the administrative tasks that go with being the director of any organization. (RFD)


Hydrogeology And Geology Of The Lower North And South Platte Rivers Of Nebraska: Nebraska Geological Society Field Trip 2020, Douglas R. Hallum, Paul R. Hanson, Shane Tucker, Robert F. Diffendal Jr. Jan 2020

Hydrogeology And Geology Of The Lower North And South Platte Rivers Of Nebraska: Nebraska Geological Society Field Trip 2020, Douglas R. Hallum, Paul R. Hanson, Shane Tucker, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

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 …


Fun In A Kansas Salt Mine, Robert F. Diffendal Jr. Apr 2019

Fun In A Kansas Salt Mine, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Most people probably do not know that salt deposits hundreds of feet thick lie buried beneath large parts of western Kansas, western Oklahoma and a small part of the northeastern Texas Panhandle. Native Americans and early European explorers found that where the salt deposits came near the land surface (for, example north of Hutchinson, Kansas) salt is dissolved by ground water and increases the salinity of rivers, streams, springs and ponds. This salty water was used as a salt source by these peoples. The Hutchinson Salt, a 275 million-year-old Middle Permian deposit, was discovered in an exploratory drill hole in …


Geologic Mapping Of Nebraska: Old Rocks, New Maps, Fresh Insights, R. Matthew Joeckel, Robert F. Diffendal Jr., P. R. Hanson, Jesse T. Korus Oct 2018

Geologic Mapping Of Nebraska: Old Rocks, New Maps, Fresh Insights, R. Matthew Joeckel, Robert F. Diffendal Jr., P. R. Hanson, Jesse T. Korus

Robert F. Diffendal, Jr., Publications

Geologic mapping in Nebraska and environs is an ongoing endeavor that has spanned more than 170 years, involved dozens of scientists, and evolved through many changes. Digital mapping has risen to dominance in the state only since 1996. Geologic mapping in Nebraska today concentrates on surficial mapping, which emphasizes materials exposed at the land surface and their relationships with landforms, and which is particularly relevant because non- bedrock geologic materials (regolith) lie at the surface across at least 87% of the state. Moreover, surfi cial geologic maps assist the understanding of groundwater and sand and gravel resources, to name a …


Review Of The Ends Of The World: Volcanic Apocalypses, Lethal Oceans, And Our Quest To Understand Earth's Past Mass Extinctions, By Peter Brannen, Robert F. Diffendal Jr. Jan 2018

Review Of The Ends Of The World: Volcanic Apocalypses, Lethal Oceans, And Our Quest To Understand Earth's Past Mass Extinctions, By Peter Brannen, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

In his new best-selling book, Peter Brannen, award-winning science writer, takes you on a fascinating trip through the run-up to the end of the Cretaceous extinction event and the K-Pg (Cretaceous/Paleogene) boundary, formerly called the K-T (Cretaceous/Tertiary) boundary.

Brannen interviewed many scientists who studied these events and went on field trips with them to major Cretaceous sites and to those where earlier and later extinction events happened. He presents clear explanations of what is known and not known about all of these events in a largely error-free book. Brannen details the other four big extinction events in geologic history: the …


Great Plains Geology: My Personal Journey, Robert F. Diffendal Jr. Jul 2017

Great Plains Geology: My Personal Journey, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

In 2014 my good friend and former boss, Richard (Rick) Edwards, Director of the University of Nebraska's Center for Great Plains Studies asked me to consider writing a small book about the geology of the Great Plains as part of a series of books exploring many aspects of this marvelous place. I thought his request over and told Rick that I would give it a try. The series is being published by the University of Nebraska Press, the first completed book of which is Great Plains Indians written by my colleague David Wishart.

I wrote up an outline of my …


Nebraska, Usa: Wonderful Fossils, Natural History Museums And Public Art Depicting Fossils, Robert F. Diffendal Jr. Jan 2017

Nebraska, Usa: Wonderful Fossils, Natural History Museums And Public Art Depicting Fossils, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Nebraska is known by vertebrate palaeontologists as the place in North America where there is a very complete Cenozoic geologic record of mammalian evolution over the last thirty-five million years or so. All you have to do is visit any of the many major natural history museums in the USA and in many countries around the world, including the UK, to see fossil skulls, articulated skeletons and large slabs of rock containing bones of fossil mammals from Nebraska to verify this assertion. Nebraska is also the site of Cretaceous rocks containing the oldest known Cretaceous fossil flower and many other …


The University Of Nebraska State Museum, Robert F. Diffendal Jr. Jun 2014

The University Of Nebraska State Museum, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

I first walked through the doors of Morrill Hall on the main or City Campus of the University of Nebraska on a day late in August of 1962 and thought that I had entered paleontology heaven. Morrill Hall then housed the University of Nebraska State Museum (UNSM). most of the Geology Department, and some other parts of university units. I was a new graduate student hoping to pursue research in invertebrate paleontology in the Department of Geology and was on my way to see the department chairman for the first time. When I entered the building I walked through a …


Some Reflections On Our Experiences At Sun Yat-Sen University Since 1985, Robert F. Diffendal Jr., Anne P. Diffendal Jan 2014

Some Reflections On Our Experiences At Sun Yat-Sen University Since 1985, Robert F. Diffendal Jr., Anne P. Diffendal

Robert F. Diffendal, Jr., Publications

Professor Zhang Ke, Chairman of the Department of Earth Sciences at Sun Yat-sen University, has asked us to write about some of our memories from our several visits to Sun Yat-sen University, as part of the 2014 celebration of the 90th anniversary of the founding of the university and the creation of the department. We are very pleased to do so and to include with our written comments copies of some photographs that we have taken during these visits. We have gone back through our notes, books, tourist maps, photo files, and other information that we have kept as souvenirs …


Ashfall Tephra In The Ogallala Group Of The Great Plains: Characteristics And Significance, Michael E. Perkins, Robert F. Diffendal Jr., Michael R. Voorhies, Barbara P. Nash, Bruce E. Bailey Jan 2014

Ashfall Tephra In The Ogallala Group Of The Great Plains: Characteristics And Significance, Michael E. Perkins, Robert F. Diffendal Jr., Michael R. Voorhies, Barbara P. Nash, Bruce E. Bailey

Robert F. Diffendal, Jr., Publications

The Miocene Ogallala Group blankets the Great Plains east of the Rocky Mountains. This sheet of largely fluvial deposits, lying downwind of major silicic volcanic fields to the west, was ideally located to receive and preserve tephra from these fields. This investigation brings modern methods of tephrochronlogy to bear on the age and identity of Ogallala tephra. Results indicate that ~40 separate tephra layers, ranging in age from ~16.5–5.0 Ma, in the Ogallala. Most tephra came from Yellowstone hotspot sources. The relative frequency of hotspot tephra in the Ogallala matches that in more proximal regions to the west with peak …


Geologic Observations Along The Steamboat Trace Trail, Markers 16-20, In The Vicinity Of Peru, Nemaha County, Nebraska (Including On The Indian Cave Sandstone), Robert F. Diffendal Jr. Oct 2012

Geologic Observations Along The Steamboat Trace Trail, Markers 16-20, In The Vicinity Of Peru, Nemaha County, Nebraska (Including On The Indian Cave Sandstone), Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

This section of the Steamboat Trace Trail from markers 16 through 20 (Figure 1) offers especially good examples of geologic features in this part of Nebraska (Figure 2). These include: The Missouri River, its valley, river cuts into the valley side, tributaries to the river, and flood control structures; Sites of active and potential landslides; Wind-deposited silts (called loess by geologists and soil scientists); Glacial deposits; Bedrock exposures of ancient sandstone, shale, conglomerate, and limestone; Fossils of ocean- and land-dwelling plants and animals; Coal deposits.


Pamphlet To Accompany Geologic Map Gmc-34: Geologic Map Of The O’Neill 1º X 2º Quadrangle, Nebraska, With Configuration Maps Of Surfaces Of Formations, Robert F. Diffendal Jr., Michael R. Voorhies, E. Jane Voorhies, H. E. Lagarry, C. L. Timperley, M. E. Perkins Jan 2008

Pamphlet To Accompany Geologic Map Gmc-34: Geologic Map Of The O’Neill 1º X 2º Quadrangle, Nebraska, With Configuration Maps Of Surfaces Of Formations, Robert F. Diffendal Jr., Michael R. Voorhies, E. Jane Voorhies, H. E. Lagarry, C. L. Timperley, M. E. Perkins

Robert F. Diffendal, Jr., Publications

This map is necessarily generalized. It is based primarily on data from 7.5’ surficial geologic quadrangle maps of the map area prepared by the authors principally from 1991 to 2000, from Voorhies (unpublished data, 1974), as well as data from test-hole drilling done across the quadrangle by the Conservation and Survey Division, University of Nebraska, and its cooperators over many years since the 1930s. For more detailed information, consult the geologic data files of the Conservation and Survey Division, School of Natural Resources, University of Nebraska-Lincoln. The quadrangle is mostly covered by vegetation and Holocene sediments. Limited good exposures of …


Geologic Framework And Groundwater Occurrence (Kimball County, Nebraska), Robert F. Diffendal Jr. Jan 2005

Geologic Framework And Groundwater Occurrence (Kimball County, Nebraska), Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Geologic Framework

All of Kimball County is part of the Cheyenne Tablelands, a largely constructional part of the High Plains underlain primarily by sediments transported from the Rocky Mountains and deposited on the developing tablelands. Quaternary fluvial erosion cut away parts of the tablelands producing the valleys of Lodgepole Creek and its tributaries. The oldest rocks exposed in Kimball County belong to the upper part of the Brule Formation, youngest formation of the White River Group of rocks. The Brule Formation is Oligocene in age and was deposited from about 35 to 29 million years ago. The Brule Formation underlies …


Keith County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 51, Robert F. Diffendal Jr., James W. Goeke Apr 2004

Keith County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 51, Robert F. Diffendal Jr., James W. Goeke

Robert F. Diffendal, Jr., Publications

In 1930, the Conservation and Survey Division (CSD) of the University of Nebraska and the U.S. Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in the county under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.

The maps in this report show the locations of all test holes drilled in the county since 1934.

Present techniques of …


Geomorphic And Environmental Change Around A Large, Aging Reservoir: Lake C. W. Mcconaughy, Western Nebraska, Usa, R. Matthew Joeckel, Robert F. Diffendal Jr. Feb 2004

Geomorphic And Environmental Change Around A Large, Aging Reservoir: Lake C. W. Mcconaughy, Western Nebraska, Usa, R. Matthew Joeckel, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Lake C. W. McConaughy, a 63-year-old manmade reservoir in the North Platte Valley of western Nebraska, is the largest standing body of water in the state. From the time that Kingsley Dam was completed in 1941 until the present day (2004), many geomorphic and environmental changes have occurred along the shores and within the North Platte Valley. Erosion on the southeastern shoreline of the lake had been perceived as a problem for landowners and managers for at least three decades, but the full scale of erosion was revealed only after a cumulative 18-m drawdown in lake level: bedrock platforms, extending …


Southeast Nebraska Geology: Field Trip 3, Roger K. Pabian, Robert F. Diffendal, Jr. Jr., Darwin R. Boardman Ii Jun 2003

Southeast Nebraska Geology: Field Trip 3, Roger K. Pabian, Robert F. Diffendal, Jr. Jr., Darwin R. Boardman Ii

Robert F. Diffendal, Jr., Publications

The purpose of this trip is to familiarize you with the latest Pennsylvanian and earliest Permian rocks that are exposed in extreme southeastern Nebraska. You will see eight exposures of these rocks and will have ample opportunity to collect lithologic samples, as well as samples for both macro- and micro-fossils. The stops have been selected to show you examples of several different environments that existed in southeastern Nebraska in the late Paleozoic. These include subaerial deposits with paleosols, nearshore and offshore marine clastic and carbonate sequences. Each stop is covered in detail in the handouts that have been furnished to …


Ashfall Historic Park: Field Trip 5, Robert F. Diffendal Jr. Jun 2003

Ashfall Historic Park: Field Trip 5, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Ashfall Fossill Beds: A State Historical Park. Brochure. Nebraska Game and Parks Commission and University of Nebraska State Museum

Research Reports, 1978. Projects: A Miocene Rhinoceros Herd Buried in Volcanic Ash. Grant Recipient: Michael R. Voorhies, Division of Vertebrate Paleontology, University of Nebraska State Museum, Lincoln, Nebraska.

Geologic Framework of the Niobrara River Drainage Basin and Adjacent Areas in South Dakota Generally East of the 100th Meridian West Longitude and West of the Missouri River Robert F. Diffendal, Jr. and Michael R. Voorhies. Nebraska Geological Survey Report of Investigations, number 9.


Ecoregions Of Nebraska And Kansas, Robert F. Diffendal Jr. Jan 2001

Ecoregions Of Nebraska And Kansas, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources; they are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. Ecoregions are directly applicable to the immediate needs of state agencies, including the development of biological criteria and water quality standards, and the establishment of management goals for nonpoint-source pollution. They are also relevant to integrated ecosystem management, an ultimate goal of most federal and state resource management agencies. The approach used to compile this map is based on the premise …


Arthur County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 3, Robert F. Diffendal Jr., James W. Goeke Sep 2000

Arthur County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 3, Robert F. Diffendal Jr., James W. Goeke

Robert F. Diffendal, Jr., Publications

In 1930, the Conservation and Survey Division (CSD) of the University of Nebraska and the United States Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in Arthur County under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.

The maps in this report show the locations of all test holes drilled in the county since 1934.

Present techniques …


Keith County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 51, Robert F. Diffendal Jr., James W. Goeke Jul 2000

Keith County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 51, Robert F. Diffendal Jr., James W. Goeke

Robert F. Diffendal, Jr., Publications

In 1930, the Conservation and Survey Division (CSD) of the University of Nebraska and the U.S. Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in the county under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.

The maps in this report show the locations of all test holes drilled in the county since 1934 (Figure la–d).

Present …


Earth In Four Dimensions: Development Of The Ideas Of Geologic Time And History, Robert F. Diffendal Jr. Oct 1999

Earth In Four Dimensions: Development Of The Ideas Of Geologic Time And History, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Changes in ideas and in technology can come about as slow incremental modifications, as well as by major paradigm shifts. In the case of the development of the ideas of geologic history and time, I will try to present these changes broadly and then look at how some of these have affected interpretation of Nebraska geology. Changes of view on three fronts were important in the development of geologic history and time concepts.

First is the question of the nature of time. Is time cyclic or is it linear? The Greco-Oriental cultures had a world view based on cosmic cycles, …


Cheyenne County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 17, Robert F. Diffendal Jr. Apr 1999

Cheyenne County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 17, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

In 1930, the Conservation and Survey Division (CSD) of the University of Nebraska and the United States Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test-holes drilled in the county under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies. Also included are logs of test-holes drilled by cooperators with the South Platte Natural Resources District.

The maps in this report …


Deuel County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 25, Robert F. Diffendal Jr. Mar 1999

Deuel County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 25, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

In 1930, the Conservation and Survey Division (CSD) of the University of Nebraska and the United States Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in the county under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.

The map in this report shows the location of all test holes drilled in the county since 1942.

Present techniques …


Geology And Ground Water, Garden County, Nebraska, Robert F. Diffendal Jr. Jan 1999

Geology And Ground Water, Garden County, Nebraska, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

All of Garden County (Nebraska) is underlain by the Brule Formation. This formation is tightly cemented and yields sufficient water to wells only in areas where the siltstone has been fractured. In most places the Brule Formation forms an impermeable seal that prevents water from moving downward from the overlying aquifers. The Arikaree Group is unimportant as an aquifer in the county, but the younger Ash Hollow Formation is important, particularly beneath the Cheyenne Tableland. Most, if not all, of the domestic and livestock wells on the tableland tap this aquifer. The thickness of the Ash Hollow Formation is 100 …


Antelope County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 2, Sue Olafsen Lackey, Frank A. Smith, Robert F. Diffendal Jr. Oct 1998

Antelope County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 2, Sue Olafsen Lackey, Frank A. Smith, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

In 1930, the Conservation and Survey Division of the University of Nebraska and the United States Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in the county under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.

The map in this report shows the location of all test holes drilled in the county since 1930.

Present techniques of …


Holt County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 45, Sue Olafsen Lackey, Frank A. Smith, Robert F. Diffendal Jr. Sep 1998

Holt County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 45, Sue Olafsen Lackey, Frank A. Smith, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

In 1930, the Conservation and Survey Division of the University of Nebraska and the United States Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in Holt County, Nebraska, under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.

The map in this report shows the location of all test holes drilled in Holt County, Nebraska from 1944 to …


Geology Of The Ponca Creek And Keya Paha River Drainage Basins In Nebraska, Robert F. Diffendal Jr. Sep 1997

Geology Of The Ponca Creek And Keya Paha River Drainage Basins In Nebraska, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The geology of the study area has been investigated many times over more than a century. Interested readers are directed to the report by Diffendal and Voorhies (1994), which gives a more detailed overview of the results of the investigations and lists most of the more important reports about the area’s geology.

The names of the sedimentary rock strata and unlithified sediments exposed in and underlying all or parts of the study area are shown in Table V.I. These formations range in age from more than 85 million years to sediments being deposited today by winds, water, and downslope movements …