Understanding The Middle Miocene Climatic Optimum: Evaluation Of Deuterium Values (Δd) Related To Precipitation And Temperature,
2013
Bryant University
Understanding The Middle Miocene Climatic Optimum: Evaluation Of Deuterium Values (Δd) Related To Precipitation And Temperature, Colin Gannon
Honors Projects in Science and Technology
The Middle Miocene Climate Optimum was a unique warming period in the Earth’s geologic history, when a high global mean annual temperature was accompanied by a relatively low global CO2 concentration. Hydrogen isotopic signals (specifically molecular δD, the ratio of deuterium to hydrogen) from lipids of fossils and sediments offer intrinsic insights into precipitation of ancient climates. Using samples collected from known Middle Miocene deposits, we measured δD of n-alkanes extracted from well-preserved plant and sediment samples from varying latitudes across the Northern Hemisphere, and then analyzed the data through a zonally averaged precipitation and evaporation climate model. The reduced …
Paleoecology Of Nebraska’S Ungulates During The Eocene–Oligocene Climate Transition,
2013
University of Nebraska-Lincoln
Paleoecology Of Nebraska’S Ungulates During The Eocene–Oligocene Climate Transition, Grant S. Boardman
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
The White River Group (WRG) preserves the Eocene-Oligocene climate transition (EOCT), an interval of global cooling and drying during the onset of Antarctic glaciation. In the Great Plains, a shift from forested conditions to drier woodland-savanna biomes is hypothesized to have occurred at this time. I test this hypothesis through the analyses of several paleoenvironmental proxies on the teeth of 12 WRG ungulate species: stable carbon and oxygen isotopes from tooth enamel, and mesowear and microwear texture. The EOCT shift toward more open habitats and lower vegetation density under drying climates should have resulted in an increase in mean carbon …
Preliminary Groundwater Level Changes At Selected Sites In Nebraska Following The Drought Of 2012,
2013
University of Nebraska - Lincoln
Preliminary Groundwater Level Changes At Selected Sites In Nebraska Following The Drought Of 2012, Aaron R. Young, Mark E. Burbach, Leslie M. Howard
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Recently Described Vulture One Of Several New Avian Species From The Ashfall Fossil Beds,
2013
University of Nebraska - Lincoln
Recently Described Vulture One Of Several New Avian Species From The Ashfall Fossil Beds, Rick E. Otto
University of Nebraska State Museum: Programs Information
Several species of fossil bird are known from the Ashfall Fossil Beds. As of publication date, all represent previously undescribed species. In 2012, ornithologists Zhang, Feduccia and James described a vulture from isolated remains recovered from the Ashfall site in 1979. Similar in morphology to the Palm-nut Vulture (Gypohierax) of Africa, the relationship to the Ashfall vulture is unclear, and may represent an example of convergent evolution. The fossil vulture was designated Anchigyps voorhiesiin honor of paleontologist Michael Voorhies.
Microbially Induced Sedimentary Structures Recording An Ancient Ecosystem In The Ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia,
2013
Old Dominion University
Microbially Induced Sedimentary Structures Recording An Ancient Ecosystem In The Ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia, Nora Noffke, Daniel Christian, David Wacey, Robert M. Hazen
OES Faculty Publications
Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse communities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2 billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia. Outcrop mapping at the meter to …
Stromatolites And Miss—Differences Between Relatives,
2013
Old Dominion University
Stromatolites And Miss—Differences Between Relatives, N. Noffke, S. M. Awramik
OES Faculty Publications
Benthic microorganisms form highly organized communities called “biofilms.” A biofilm consists of the individual cells plus their extracellular polymeric substances (EPS). In marine and non-marine environments, benthic microbial communities interact with the physical sediment dynamics and other factors in the environment in order to survive. This interaction can produce distinctive sedimentary structures called microbialites. Binding, biostabilization, baffling, and trapping of sediment particles by microorganisms result in the formation of microbially induced sedimentary structures (MISS); however, if carbonate precipitation occurs in EPS, and these processes happen in a repetitive manner, a multilayered build-up can form—stromatolites. Stromatolites and MISS are first found …
Three-Dimensional Hydrostratigraphy Of The Firth, Nebraska Area: Results From Helicopter Electromagnetic (Hem) Mapping In The Eastern Nebraska Water Resources Assessment (Enwra),
2013
University of Nebraska-Lincoln
Three-Dimensional Hydrostratigraphy Of The Firth, Nebraska Area: Results From Helicopter Electromagnetic (Hem) Mapping In The Eastern Nebraska Water Resources Assessment (Enwra), Jesse T. Korus, R. Matthew Joeckel, Dana Divine
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Three-Dimensional Hydrostratigrapy Of The Swedeburg, Nebraska Area: Results From Helicopter Electromagnetic (Hem) Mapping For The Eastern Nebraska Water Resources Assessment (Enwra),
2013
University of Nebraska-Lincoln
Three-Dimensional Hydrostratigrapy Of The Swedeburg, Nebraska Area: Results From Helicopter Electromagnetic (Hem) Mapping For The Eastern Nebraska Water Resources Assessment (Enwra), Dana Divine, Jesse T. Korus
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Morphometric Analysis Of Dinosaur Tracks From Southwest Arkansas,
2013
University of Arkansas, Fayetteville
Morphometric Analysis Of Dinosaur Tracks From Southwest Arkansas, R. Shell, Stephen K. Boss
Journal of the Arkansas Academy of Science
Dinosaur trackways were discovered in Cretaceous De Queen Limestone strata in Howard County, Arkansas, in June 2011. Multiple trackways with variably sized tridactyl tracks were exposed in a commercial quarry, suggesting multiple theropod species or adult and juvenile tracks of a single species. Results of morphometric analyses of 32 plaster casts from selected trackways are reported in an effort to identify the specific track-making dinosaurs and differentiate large and small tracks. Track measurements included length and width of each track, the lengths and widths of each digit impression, and the angular spread (divarication) between digit impressions. Twenty-nine plaster casts were …
Tree-Ring Evidence Of North Pacific Volcanically Forced Cooling And Forcing Of The Pacific Decadal Oscillation (Pdo),
2013
The College of Wooster
Tree-Ring Evidence Of North Pacific Volcanically Forced Cooling And Forcing Of The Pacific Decadal Oscillation (Pdo), Lauren Vargo
Senior Independent Study Theses
Two large undocumented volcanic eruptions in 1698/9 and 1809 have been previously identified in ice cores as sulfate peaks, and in tree-ring latewood density data as low-density rings. These eruptions can also be recognized using tree-ring width data, and can be identified in the tree-ring record as narrow rings for several consecutive years. The first part of this study uses tree-ring width data from the Gulf of Alaska to provide further evidence that these eruptions occurred. The two eruptions also provide a natural experiment for investigating the effects large volcanic eruptions have on North Pacific climate, including the Pacific Decadal …
Saturated Thickness Of The Unconfined Portions Of The High Plains Aquifer,
2013
University of Nebraska - Lincoln
Saturated Thickness Of The Unconfined Portions Of The High Plains Aquifer, Conservation And Survey Division
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
The Groundwater Atlas Of Nebraska,
2013
University of Nebraska - Lincoln
The Groundwater Atlas Of Nebraska, Jesse T. Korus, Leslie M. Howard, Aaron R. Young, Dana P. Divine, Mark E. Burbach, J. Michael Jess, Douglas R. Hallum, R.F. Diffendal, Jr., R.M. Joeckel
Conservation and Survey Division: Faculty and Staff Publications
Groundwater has long been important to inhabitants of Nebraska. Native Americans in the Great Plains erected their villages near water sources. Early explorers from Europe and pioneers heading west following river valleys depended on ample freshwater in the Nebraska Territory for drinking water and livestock supplies. These Europeans, however, considered the Nebraska Territory part of “The Great American Desert” and few people had an idea of the vast groundwater resource in Nebraska.
Groundwater-Level Changes In Nebraska - Spring 2012 To Spring 2013,
2013
University of Nebraska-Lincoln
Groundwater-Level Changes In Nebraska - Spring 2012 To Spring 2013, A. Young, M. E. Burbach, L. M. Howard
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Nebraska Statewide Groundwater-Level Monitoring Report 2013,
2013
University of Nebraska-Lincoln
Nebraska Statewide Groundwater-Level Monitoring Report 2013, A. R. Young, M. E. Burbach, L. M. Howard
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Field Guide For Nebraska Invasive Insects,
2013
University of Nebraska - Lincoln
Field Guide For Nebraska Invasive Insects, Nebraska Invasive Species Project
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
A History Of Place: Using Phytolith Analysis To Discern Holocene Vegetation Change On Sanak Island, Western Gulf Of Alaska,
2013
Antioch University - New England
A History Of Place: Using Phytolith Analysis To Discern Holocene Vegetation Change On Sanak Island, Western Gulf Of Alaska, Cricket C. Wilbur
Antioch University Dissertations & Theses
This study investigated a terrestrial climate proxy, phytoliths, as a complimentary approach to documenting the dynamics of present and past vegetation on Sanak Island, the largest island in a small island group in the eastern Aleutian archipelago, and as a new basis by which to interpret Holocene environmental variability in Alaska. A phytolith reference collection was established from 59 selected plant species of maritime tundra belonging to 27 families. The grass species and a sedge species produced abundant phytolith forms whereas the majority of dicotyledons in this study were trace producers of phytoliths. A paleoenvironmental reconstruction from fossil phytoliths recovered …
Ecology Of The Late Neogene Extinctions: Perspectives From The Plio-Pleistocene Of Florida,
2013
University of South Florida
Ecology Of The Late Neogene Extinctions: Perspectives From The Plio-Pleistocene Of Florida, Shubhabrata Paul
USF Tampa Graduate Theses and Dissertations
The ecological impact of past extinction events is one of the central issues in paleobiology. In face of present environmental changes, a better understanding of past extinctions will enable us to identify the magnitude of biodiversity crises and their underlying processes. The Late Neogene was a time of extraordinary climatic reorganization, including Northern Hemisphere glaciation, the rise of the Central American Isthmus, and associated changes in environmental conditions. Therefore, the Late Neogene extinctions of marine molluscs of South Florida present an ideal platform to examine the interaction between environmental changes and biotic response. In the present study, three different aspects …
Early Permian Seawater From The Delta18o Record Of Fossil Bivalves: Seasonality And A Latitudinal Gradient,
2012
Syracuse University
Early Permian Seawater From The Delta18o Record Of Fossil Bivalves: Seasonality And A Latitudinal Gradient, James Andrew Beard
Earth & Environmental Sciences - Theses
The transition from a glaciated world to one that was ice-free makes the early Permian a time interval that in many ways mirrors the present, and hence there is great interest in constraining paleoclimate conditions over that transition. A common method for estimating ancient temperatures uses the oxygen isotope composition of marine carbonate, but this approach becomes significantly more complicated prior to the Cretaceous due to uncertainties about diagenesis and the isotopic composition of seawater, which has been hypothesized to be more depleted than during the Cenozoic. I use stable isotope compositions of sequentially microsampled accretionary calcite from fossil bivalves …
Geologic Observations Along The Steamboat Trace Trail, Markers 16-20, In The Vicinity Of Peru, Nemaha County, Nebraska (Including On The Indian Cave Sandstone),
2012
University of Nebraska-Lincoln
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.
Late Holocene Sedimentation And Paleoenvironmental History For The Tidal Marshes Of The Potomac And Rappahannock Rivers, Tributaries To Chesapeake Bay,
2012
University of Mary Washington
Late Holocene Sedimentation And Paleoenvironmental History For The Tidal Marshes Of The Potomac And Rappahannock Rivers, Tributaries To Chesapeake Bay, Neil E. Tibert, J. Bradford Hubeny, Mark Abbott, Joseph M. Kiker, Lindsay J. Walker, Shawn Mckenzie
Virginia Journal of Science
Instrumental tide gauge records indicate that the modern rates of sea-level rise in the Chesapeake Bay more than double the global average of 1.2-1.5 mm yr-1. The primary objective for this study is to establish a relative depositional history for the tidal marshes of the Potomac and Rappahannock Rivers that will help us improve our understanding of processes that influence sedimentation in the proximal tributaries of Chesapeake Bay. Marsh cores were collected from Blandfield Point VA, Tappahannock VA, and Potomac Creek VA. The sedimentary facies include: 1) a lower unit of organic-poor, grey clay with fine sand and silt layers …
