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Scanning Electron Microscopic Study Of Quartz Sand Surface Features, Ash Hollow Formation, Ogallala Group, Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.
Scanning Electron Microscopic Study Of Quartz Sand Surface Features, Ash Hollow Formation, Ogallala Group, Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.
School of Natural Resources: Faculty Publications
In field studies of the late Tertiary Ash Hollow Formation of the Ogallala Group in western Nebraska the alluvial deposits are composed of large volumes of sand and gravel up to large cobbles. Because the current understanding of the climate of the region at the time of deposition does not provide for a source for deposits of this character, a scanning electron microscopic study of the surface features on the quartz sand grains from these sediments was undertaken. Nine samples, collected from locations in Banner, Morrill and Keith Counties, were examined to see if they had one or more of …
Plate Tectonics, Space, Geologic Time, And The Great Plains: A Primer For Non-Geologists, Robert F. Diffendal Jr.
Plate Tectonics, Space, Geologic Time, And The Great Plains: A Primer For Non-Geologists, Robert F. Diffendal Jr.
School of Natural Resources: Faculty Publications
For most Americans, "The Great Plains" evokes images of grasslands, dust storms, prairie fires, Native Americans on horseback, cowboys and wheat lands, and perhaps flat valleys crossed by braided rivers carrying a heavy load of sand and gravel, extremes of weather, and a climate typified by an alternation of droughts and wetter periods. Geologists picture such general images, too, but they also see radical changes in the landscape over periods expressed in millions rather than hundreds of years. Geologically speaking, human activities on the Great Plains are too recent to have much of a place in the broad geologic history …
Late Paleozoic Cyclic Sedimentation In Southeastern Nebraska: A Field Guide, Roger K. Pabian, Robert F. Diffendal Jr.
Late Paleozoic Cyclic Sedimentation In Southeastern Nebraska: A Field Guide, Roger K. Pabian, Robert F. Diffendal Jr.
School of Natural Resources: Faculty Publications
People studying and collecting sedimentary rocks, minerals, and fossils in eastern Nebraska often find that locating rock exposures can be difficult. Most of the rolling hills in the eastern sixth of the state are underlain by thick, interlayered, glacial deposits, loess (windblown silt), and alluvium (stream-deposited sediments) of very young geologic age. These sediments cover the bedrock in most of that area. Natural exposures and human excavations of bedrock are mostly confined to the sides and floors of stream valleys. However, in the southeasternmost counties of the state, the younger sediment cover is commonly thin or absent. Pawnee and Richardson …