23 research outputs found
Review of \u3ci\u3eGreat Plains Geology\u3c/i\u3e by Robert F. Diffendal
No full textProfessor Robert Diffendal Jr\u27s little guidebook to the Great Plains of the USA makes for a fascinating read for an Englishman like me, who has never been there (but wants to). As he says in the article opposite, they rarely correspond to the impression most people have of them. For example, they are not just flat plains with cowboys herding longhorn cattle as you might imagine from the movies (in fact, they probably rarely were). Rather, it is clear from the guide that they can provide a visitor with an interesting mixture of geology, palaeontology, ecotourism and archaeology. In addition, they cover a vast area, including parts of southern Canada and northern Mexico. In fact for me, they consist of an unimaginably large area and the author spends a certain amount of time just trying to define them
The Sidney Gravel and Kimball Formation, Supposed Parts of the Ogallala Group (Neogene), Are Not Objectively Mappable Units
No full textIn the 1930s. G. L. Lueninghoener and A. L. Lugn prepared geologic maps of several counties. including Kimball and Cheyenne in the southern Nebraska Panhandle. for the Nebraska Geological Survey. Rock units designated as the Kimball Formation and the underlying Sidney Gravel were shown on these maps. Studies by Swinehart (1974). Breyer (1975; 1981). and Diffendal (1985) demonstrated that these units could not be defined in several areas in western Nebraska. Results of this study show clearly that the Kimball Formation and Sidney Gravel cannot be traced for more than a few kilometers from their type areas. The Kimball Formation does not have a base that can be traced with confidence away from the type area south of Kimball. No gravel sheet (Sidney Gravel) occurs at this locality beneath the Kimball. Furthermore. at least the lower two of the three gravel lithologies supposedly typical of the formation occur repeatedly throughout the Ogallala sequence. The discontinuous remnant sand and gravel at the type exposure of the Sidney Gravel have the characteristics of the material originally described by Lugn (1939a). To the north. across an intermittent stream. the lower of two sand and gravel bed sequences separated by caliche sandstones is at the same elevation as the type Sidney and could be the same unit. Farther to the north and east of the type exposure. several sand and gravel bed sequences are laterally and vertically discontinuous. Each one could be equivalent to the original Sidney. but none can be traced back to the type area. Complex geometries and possible post-Ogallala deformation also make correlations questionable. Arbitrarily designating rocks as part of the Kimball Formation if they occur high in a local section. as Lueninghoener and Lugn did. is poor practice. Designating any sand and gravel in the Ogallala sequence as the Sidney or always assigning the stratigraphically highest sand and gravel observed at each exposure in the southern Panhandle to the Sidney has resulted in miscorrelations. The formations as originally defined are not mappable. Usage of the terms should be abandoned. and the term Ash Hollow Formation should be used in their place
Ecoregions of Nebraska and Kansas
No full textEcoregions 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 that ecological regions can be identified through the analysis of the patterns of biotic and abiotic phenomena that reflect differences in ecosystem quality and integrity (Wiken, 1986; Omernik, 1987, 1995). These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I and level II divide the North American continent into 15 and 52 regions, respectively (Commission for Environmental Cooperation Working Group 1997). At level III, the continental United States contains 104 regions (United States Environmental Protection Agency [US EPA], 2000). However, depending on the objectives of a particular project, ecoregions may be aggregated within levels of the hierarchy for data analysis and interpretation. Explanations of the methods used to define the US EPA’s ecoregions are given in Omernik (1995), Griffith and others (1994), and Gallant and others (1989).
Albers equal area projection; Standard parallels 38° N and 42° N
PRINCIPAL AUTHORS: Shannen S. Chapman (Dynamac Corporation), James M. Omernik (US EPA), Jerry A. Freeouf (USFS), Donald G. Huggins (KBS), James R. McCauley (KGS), Craig C. Freeman (KBS), Gerry Steinauer (NGPC), Robert T. Angelo (KDHE), and Richard L. Schlepp (USDA, NRCS). COLLABORATORS AND CONTRIBUTORS: Steven R. Walker (NDEQ), Kenneth R. Bazata (NDEQ), Sharon W. Waltman (USDA, NRCS-National Soil Survey Center [NSSC]), William J. Waltman (USDA, NRCS-NSSC), Roger Kanable (USDA, NRCS), Steven C. Schainost (NGPC), Craig Engelhard (USDA, NRCS), James W. Merchant (Center for Advanced Land Management Information Technologies [CALMIT], University of Nebraska, Lincoln [UNL]), Virginia L. McGuire (USGS), Chris Mammoliti (KDWP), James L. Stubbendieck (UNL), David A. Mortensen (UNL), Thomas Wardle (Nebraska Forest Service), David T. Lewis (UNL), Robert F. Diffendal Jr. (Nebraska Conservation and Survey Division-Nebraska Geological Survey) and Jeffrey A. Comstock (OAO Corporation). This project was partially supported by funds from the U.S. Environmental Protection Agency’s Office of Water, Biological Criteria Program.
Reverse side and supplementary 1-page versions are attached
I TABLE OF CONTENT Executive Summary and Policy Implications..............1
No full text(3011763-5926 This series contains research reports, written by or in cooperation with staff members of the Statisticdl Research Division, whose content may be of interest to the general statistical research corn munity. The views reflected inthesereports are not necessarily those of the Census Bureau nor do they necessarily represent Census Bu-eau statistical policy or practice. Inquiries may be addressedtothe author(s) or the SRD Report Serie
Review of \u3ci\u3eA Garden of Marvels\u3c/i\u3e: \u3ci\u3eHow We Discovered that Flowers Have Sex, Leaves Eat Air, and Other Secrets of Plants\u3c/i\u3e, by Ruth Kassinger
No full textUntil I read Kassinger’s book I clearly did not have the historical perspective necessary to appreciate the incredible lives of plants and how botanists have come to their present understandings of same. Kassinger, a gardener by avocation, cut out most of the jargon, defined terms that she does use, and wrote simple and compelling tales of the histories of discoveries about the various parts of plants and how those parts work together for the benefit of the plant and, ultimately, for our benefit.
[This] is a book that any gardener or other interested person with a modest background in plant biology can understand. It covers all plants, so even the “rots and spots” guys on Backyard Farmer and their fans will find something of interest here. Kassinger’s book is great fun. So much so that I decided to read it a second time. One can’t give an author a much greater compliment than that
Geologic Map Showing Configuration of the Bedrock Surface, North Platte, 1 ° x 2 ° Quadrangle, Nebraska
No full textThe map area, in west-central Nebraska, is largely covered by surficial deposits of eolian sand, loess, and alluvium ranging in age from Holocene to Pliocene. Holocene and late Pleistocene(?) eolian sand, as much as 300 ft (91 m) thick, covers most of the area north of the North Platte and Platte Rivers, and also covers a small area south of those rivers. The Peoria Loess of Quaternary age overlies most of the remaining upland north of the Platte River in southwestern Logan, northeastern Lincoln, and much of western Custer and extreme northwestern Dawson Counties. Loess also mantles the divide between the North and South Platte Rivers and most of the upland south of the South Platte River in Keith, Lincoln, and Perkins Counties. Holocene alluvium underlies the valleys of the rivers and their larger tributaries. Older alluvium of Pleistocene and Pliocene age occurs beneath loess on the divide between the North and South Platte Rivers, beneath eolian sand along the north side of the North Platte River valley, and along the Dismal and Middle Loup Rivers. Rocks of the Miocene Ogallala Group crop out principally along the south side of the North Platte River valley and on either side of the South Platte River, and locally in roadcuts and along other stream valleys. The Ogallala is present beneath the surficial deposits throughout the quadrangle except in two local areas. The Arikaree Group (Miocene and Oligocene) underlies the Ogallala over much of western Nebraska but no outcrops were recognized in the quadrangle. However, Arikaree deposits have been recognized in drill holes near the Grant County-Arthur County line in the northwestern part of the map area. The Oligocene Brule Formation of the White River Group unconformably underlies the Ogallala Group in outcrops in the quadrangle. Exposures of the Brule are confined to tributary streams along the south side of the North Platte River from Kingsley Dam eastward for about 2 mi (1.2 km). The Brule in the quadrangle conforms to the expanded definition of the formation in western Nebraska by Swinehart and others (1985). Data on the depth to bedrock and the thickness of the Ogallala Group are from logs of drill holes and irrigation wells in the data collections of the Conservation and Survey Division, University of Nebraska-Lincoln. Additional geologic data were derived from maps and reports listed in the Selected References and from the unpublished soil survey of Keith County (S.A. Scheinost, unpub. data, 1991). J.B. Swinehart, research geologist, Nebraska Geological Survey, collaborated with the author in preparation of the bedrock contour map.
Scale = 1:250,000 North Latitude: 42° 0\u27 0 N (42.0000) South Latitude: 41° 0\u27 0 N (41.0000) East Longitude: 100° 0\u27 0 W (-100.0000) West Longitude: 102° 0\u27 0 W (-102.0000
Intramolecular [4+2] cycloadditions of conjugated ynones and related species ; Studies directed toward the total systhesis of glycinoeclepin A
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2002.Includes bibliographical references.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.The intramolecular [4 + 2] cycloaddition reactions of c,-alkynyl carbonyl compounds are described. This reaction, the first heterocyclic variant of the enyne cycloaddition reaction, affords a product with a dihydroisobenzofuran ring system. For this reaction, we propose a mechanism in which a highly strained heterocyclic allene intermediate undergoes an unusual rearrangement leading to a 3-furfuryl carbene. A 1,2-C-H insertion then produces the polycyclic furan product. A detailed analysis of the scope and mechanism of this reaction is presented. The synthetic utility of the method for the synthesis of complex organic molecules is illustrated by two sequences demonstraing further transformations of the dihydroisobenzofuran products. A two-step formal benzannulation process generates a tetrahydroanthracene derivative. Ozonolysis of a 7-oxabicycloheptene derivative prepared from a dihydroisobenzofuran affords a product that contains the core oxabicyclo[6.2.1]undecane ring system of eleutherobin and the sarcodictyin family of natural products. Glycinoeclepin A is the natural hatching stimulus agent of the soybean cystnematode. A new strategy for the synthesis of an advanced A-ring intermediate in the total synthesis of this important compound is presented. This strategy provides the key A-ring enyne intermediate in seven steps from 2,2-dimethylcyclohexanedione, utilizing a novel acid-catalyzed cyclization reaction of a hydroxy enedione.by Jason Michael Diffendal.Ph.D
Field Guide to the Geology of the Harlan County Lake Area, Harlan County, Nebraska, with a History of Events Leading to Construction of Harlan County Dam
No full textThe year 2002 will mark the fiftieth anniversary of completion of the Harlan County Dam and Multi-Purpose Reservoir. This seems a good time to write about the history of and reasons for building the dam, the effects of the dam and reservoir on the Republican River valley, and the geologic features seen along the shores of the lake and areas nearby. As many junior authors helped produced this educational circular, they are listed in the table of contents. All other sections were written by the senior author.
Includes July 2016 update: Addendum of photographs showing fault traces on drought-exposed lake bottom. Cretaceous Niobrara Chalk Formation and the younger Pierre Shale are also shown. Table of Contents Introduction 1 Location 1 Republican River Floods 1 The Republican River Flood of 1935 - D R Mohlman 1 Cautionary Notes (sidebar) 1 Events After the Flood Leading to Creation of Harlan County Lake 9 Stormer Ford Dog Town (sidebar) 10 Water 10 Surface Water Hydrology - S Summerside 10 Shoreline Springs and Seeps - F: E Harvey and K J Warren 12 Introduction 12 Using Water Chemistry to Identify Spring and Seep Origin 1 2 Geology 15 General Conditions Leading to Good Exposures 15 Stratigraphy of Unconsolidated Sediments and Rock Strata 15 Cretaceous System - Upper Cretaceous Series 15 Niobrara Formation - Smoky Hill Chalk Member 15 Pierre Shale 15 Tertiary System - Miocene Series 16 Ogallala Group -Ash Hollow Formation 16 Quaternary System - Pleistocene Series 16 Crete (?) Formation (Sands and Gravels) 1 6 Loveland Loess 16 Gliman Canyon Formation 16 Peoria and Bignell Loesses 16 Quaternary System - Holocene (Recent) Series 1 6 Unnamed Fluvial, Eolian, and Colluvial Deposits 16 Paleontology of the Various Formations 16 Plants 16 Invertebrates - R K Pabian 17 Cretaceous Marine Fossils 17 Niobrara Formation 17 Foraminifers 17 Post-Devonian Stromatoporoids 1 9 Mollusks 19 Bivalves 19 Ammonites 19 Pierre Shale Formation 19 Bivalves 19 Ammonites 19 Quaternary - Pleistocene (Ice Age) Invertebrate Fossils 19 Vertebrate Fossils - R G Corner 24 Late Cretaceous Fossils 24 Niobrara Formation 24 Niobrara Fishes 24 Niobrara Mosasaurs 29 Pierre Shale Formation 30 Protosphyvaena gladius: Giant Mystery Fish 30 Pierre Mosasaurs 32 Late Miocene Ogallala Group 32 Bone Cove I Fauna 32 Bone Cove II Fauna 32 Quaternary - Pleistocene (Ice Age) 33 Crete (?) Sands and Gravels 33 Gilman Canyon Formation 33 Peoria Loess 35 Late Pleistocene Fauna 35 Late Pleistocene Environments 37 Geologic Processes Affecting the Strata 37 Modem and Ancient Landslides 37 Modern Landslides D A Eversoll 37 Ancient Landslides - D A Eversoll and R F Diffendal, Jr 39 Geologic Structures 41 Introduction and Previous Work 41 Angular Unconformities 45 Joints 45 Faults and Folds 45 Ancient Landscapes (Paleotopography) 50 Quaternary River Terraces 50 Concluding Remarks 50 References Cited 51 Glossary Keywords: flooding 1930s, vertebrate fossils, earthquake faults, landslides, groundwater qualit
BUREAU OF THE CENSUS STATISTICAL RESEARCH DIVISION REPORT SERIES
No full textThis series contains research reports, written by or in cooperation with staff members of the Statistical Research Division, whose content may be of interest to the general statistical research community. The views reflected in these reports are not necessarily those of the Census Bureau nor do they necessarily represent Census Bureau statistical policy or practice. Inquiries may be addressed to the author(s) or the SED Report Series Coordinator, Statistica
Anatomy of sea-level change over the last glacial cycle as preserved in a buried river valley, offshore Burdekin Delta, northeastern Australia
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