Digital Commons Network^™

Dune Fields: Mid-Latitudes, J. Sun, Daniel R. Muhs

United States Geological Survey: Staff Publications

Large dune fields, or sand seas, are landscapes often thought to be found only in deserts beneath the great, subtropical high-pressure zones, where subsiding air suppresses rainfall. Dune fields are also quite common in mid-latitude regions, to the north and south of subtropical deserts (Fig. 1). Two major characteristics distinguish many mid-latitude dune fields from the sand seas of lower latitudes. One difference is that many of those in mid-latitudes are in semiarid, rather than arid climates, and therefore are not presently active. In this article, ‘active’ refers to eolian sand bodies that are not covered with vegetation, and where …

Kinematics Of The Nicaraguan Forearc From Gps Geodesy, Henry L. Turner, Peter Lafemina, Armando Saballos, Glen S. Mattioli, Pamela E. Jansma, Timothy H. Dixon

School of Geosciences Faculty and Staff Publications

Campaign GPS data from a network in the Nicaraguan forearc show a strong component of arc-parallel motion indicating northwest translation of a nearly rigid forearc sliver. Our measured mean velocity for forearc sites of 15.1 mm yr⁻¹ agrees well with the arc-parallel sliver motion predicted previously by DeMets (2001) derived from closure constraints on oblique convergence between the Cocos and Caribbean plates. The lack of a northeasterly oriented arc-normal component of motion in forearc velocities indicates that there are complexities involved beyond a simple interpretation of sliver motion being driven by oblique convergence. The forearc is reasonably well-fit by …

Observation Of Glacial Isostatic Adjustment In “Stable” North America With Gps, Giovanni F. Sella, Seth Stein, Timothy H. Dixon, Michael Craymer, Thomas S. James, Stephane Mazzotti, Roy K. Dokka

School of Geosciences Faculty and Staff Publications

Motions of three hundred and sixty Global Positioning System (GPS) sites in Canada and the United States yield a detailed image of the vertical and horizontal velocity fields within the nominally stable interior of the North American plate. By far the strongest signal is the effect of glacial isostatic adjustment (GIA) due to ice mass unloading during deglaciation. Vertical velocities show present-day uplift (∼10 mm/yr) near Hudson Bay, the site of thickest ice at the last glacial maximum. The uplift rates generally decrease with distance from Hudson Bay and change to subsidence (1–2 mm/yr) south of the Great Lakes. The …

Cenozoic Extensional Processes And Tectonics In The Northern Rocky Mountains: Southwest Montana And Eastern Idaho, Susanne U. Janecke

Geosciences Faculty Publications

No abstract provided.

Pleistocene Brawley And Ocotillo Formations: Evidence For Initial Strike-Slip Deformation Along The San Felipe And San Jacinto Fault Zones, Southern California, S. M. Kirby, Susanne U. Janecke, R. J. Dorsey, B. A. Housen, K. Mcdougall, V. Langenheim, A. Steely

Geosciences Faculty Publications

We examine the Pleistocene tectonic reorganization of the Pacific–North American plate boundary in the Salton Trough of southern California with an integrated approach that includes basin analysis, magnetostratigraphy, and geologic mapping of upper Pliocene to Pleistocene sedimentary rocks in the San Felipe Hills. These deposits preserve the earliest sedimentary record of movement on the San Felipe and San Jacinto fault zones that replaced and deactivated the late Cenozoic West Salton detachment fault. Sandstone and mudstone of the Brawley Formation accumulated between ∼1.1 and ∼0.6–0.5 Ma in a delta on the margin of an arid Pleistocene lake, which received sediment from …

Grand Canyon Reveals Nautiloid Mass Kill Event (Faith & Science Update), John T. Baldwin

Perspective Digest

No abstract provided.

Integrated Geophysical Data Processing And Interpretation Of Crustal Structure In Ethiopia With Emphasis On The Ogaden Basin And Adjacent Areas, Ketsela Tadesse

Open Access Theses & Dissertations

The combined effects of magmatism and stretching due to asthenosphere upwelling modifies the crustal structure of the Earth as seen in the Ethiopian rift and adjacent areas. The Ethiopian rift provides unique opportunities to understand the nature of rifted crust and the intensity of its modification by magmatic processes. I used geological and geophysical data to conduct an integrated study in and around the Ethiopian rift including the northern Kenyan rift and the northern part of the Kenyan dome. New gravity, controlled source seismic, and teleseismic data from the EAGLE (Ethiopia-Afar Geoscientific Lithospheric Experiment) were used as additional constraints in …

Biogeography And The Cambrian Radiation Of Arachnomorph Arthropods, Jonathan R. Hendricks, Bruce S. Lieberman

Faculty Publications

Biogeographic patterns in primarily Cambrian arachnomorph taxa are investigated using a recently constructed phylogenetic hypothesis in order to explore the biogeographic context of the Cambrian radiation. A modified version of Brooks Parsimony Analysis is employed to elucidate patterns of vicariance and geodispersal in taxa from six regions (Laurentia, Baltica, Siberia, Australia, Africa and China). Well resolved vicariance and geodispersal trees are very similar and reconstruct Laurentia and China as sister areas. This close area relationship between Laurentia and China provides extensive evidence for congruent vicariance and range expansion in Cambrian arachnomorphs, while data from trilobites do not show this pattern. …

Speleothems As Indicators Of Wet And Dry Periods, Ian John Fairchild, Emily Anne Mcmillan

International Journal of Speleology

Calcareous speleothems provide a record of dripwater composition which in turn is a function of climatic conditions. The historical focus of speleothem palaeoclimate studies has been on the derivation of palaeotemperatures through oxygen isotope studies. However, it is now realized that water availability is a more generally important control on their characteristics. Growth rate and growth morphology in principle should give rise to recognizable changes at low flow. However, accidental plumbing effects during aquifer evolution, can also lead to variations in water supply and it is not easy to distinguish these effects. In areas where there is a strong amount …

The Fate Of Nitrogren Fixed By Diazotrophs In The Ocean, Margaret R. Mulholland

OES Faculty Publications

While we now know that N₂ fixation is a significant source of new nitrogen (N) in the marine environment, little is known about the fate of this N (and associated C), despite the importance of diazotrophs to global carbon and nutrient cycles. Specifically, does N fixed during N₂ fixation fuel autotrophic or heterotrophic growth and thus facilitate carbon (C) export from the euphotic zone, or does it contribute primarily to bacterial productivity and respiration in the euphotic zone? For Trichodesmium, the diazotroph we know the most about, the transfer of recently fixed N₂ (and C) appears …

Interactions Between Structures In The Appalachian And Ouachita Foreland Beneath The Gulf Coastal Plain, Donald Matthew Surles

University of Kentucky Doctoral Dissertations

In Alabama, the Paleozoic Appalachian thrust belt plunges southwest beneath the Mesozoic-Cenozoic Gulf Coastal Plain. In Arkansas, the Paleozoic Ouachita thrust belt plunges southeast beneath the Coastal Plain. The strikes of the exposed thrust belts suggest an intersection beneath the Coastal Plain. Well data and seismic reflection profiles confirm the strike and intersection of the thrust belts, and provide information to determine the structure and general stratigraphy of each thrust belt. In east-central Mississippi, the Appalachian thrust belt curves from the regional northeast trace to westward at the intersection with the southeastern terminus of the Ouachita thrust belt, to northwest …

Gis-Based Integration Of Swat And Remm For Estimating Water Quality Benefits Of Riparian Buffers In Agricultural Watersheds, Y. Liu, Wanhong Yang, Xixi Wang

Civil & Environmental Engineering Faculty Publications

The Soil and Water Assessment Tool (SWAT) is a process-based, watershed-scale model with a hydrologic response unit (HRU) as the basic computation element, which makes it difficult to accurately represent riparian buffers using their physical parameters (e.g., vegetation structure). On the other hand, the field-scale Riparian Ecosystem Management Model (REMM) provides the opportunity to consider details of hydrologic processes within a riparian buffer zone. However, the runoff and its associated constituents from the upland area that is hydraulically connected to the riparian buffer zone must be provided as inputs into REMM. The rationale proposed here is that the integration of …

Co2 Control Of Trichodesmium N-2 Fixation, Photosynthesis, Growth Rates, And Elemental Ratios: Implications For Past, Present, And Future Ocean Biogeochemistry, D. A. Hutchins, F.-X. Fu, Y. Zhang, M. E. Warner, Y. Feng, K. Portune, P. W. Bernhardt, M. R. Mulholland

OES Faculty Publications

Diazotrophic marine cyanobacteria in the genus Trichodesmium contribute a large fraction of the new nitrogen entering the oligotrophic oceans, but little is known about how they respond to shifts in global change variables such as carbon dioxide (CO₂) and temperature. We compared Trichodesmium dinitrogen (N₂) and CO₂ fixation rates during steady-state growth under past, current, and future CO₂ scenarios, and at two relevant temperatures. At projected CO₂ levels of year 2100 (76 Pa, 750 ppm), N₂ fixation rates of Pacific and Atlantic isolates increased 35-100%, and CO₂ fixation rates increased 15-128% …

Light Environment And Seasonal Dynamics Of Microalgae In The Annual Sea Ice At Terra Nova Bay, Ross Sea, Antarctica, L. Lazzara, I. Nardello, C. Ermanni, O. Mangoni, V. Saggiomo

OES Faculty Publications

We investigated the physical conditions of the Spring pack ice environment at Terra Nova Bay to understand their influence on the structure and physiology of sympagic microalgae. Bio-optical methods were used to study the availability and spectral quality of solar radiation, both inside and underneath the ice cover. Pack ice thickness was around 2.5 m, with a temperature between -2 and -7°C. On average, only 1.4% of surface PAR penetrated to the bottom ice and less than 0.6% below platelet ice level. Surface UV-B radiation under the bottom ice was 0.2-0.4%. Biomass concentrations up to 2400 mg Chl a m- …

An Investigation Of Lead And Other Metal Contaminants In The Sediments Of Clearwater Lake, Missouri, Gary W. Krizanich

Doctoral Dissertations

"The purpose of this investigation is to characterize the spatial and temporal distribution and concentration of trace metals in sediments of Clearwater Lake. Understanding how trace metals are released to and transported in aquatic environments is important to the overall understanding of the impacts of mining on the natural environment. The main focus of this research will be on historic sedimentation within Clearwater Lake, which may act as a sink where mining related trace metals are stored. Because of their high preservation rates in basins, sediments can provide detailed chronostratigraphic histories of trace metal inputs in lakes. Sediment records can …

Incipient Continental Rifting: Insights From The Okavango Rift Zone, Northwestern Botswana, Baraka D. Kinabo

Doctoral Dissertations

"In this dissertation aeromagnetic, gravity, and Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) data from the Okavango Rift Zone in northwest Botswana are used to map the distribution of rift and basement structures. The distribution of these structures provide useful insights into the early stages of continental rifting. The objectives of this study are (1) assessing the role of pre-existing structures on rift basin development, (2) characterizing the geometry of the nascent rift basins, (3) documenting fault growth and propagation patterns, and (4) investigating the border fault development"--Abstract, page iv.

Impacts Of Acid Mine Drainage On Carbon Cycling In Receiving Streams, Ernest W. Fonyuy

Doctoral Dissertations

"Field and laboratory investigations of acid mine drainage (AMD) contaminated and uncontaminated waters were conducted in order to determine and model processes and reaction mechanisms that control dissolved inorganic carbon (DIC) transformation and shifts in isotope ratio of DIC (Δ¹³C_DIC). The results show that AMD caused variable pH changes, overall decreases in Fe²⁺, alkalinity, and DIC, and increases in (Δ¹³C_DIC) in receiving streams. AMD caused more than 50 to > 98% seasonal DIC loss in stream water through CO₂ degassing. High DIC losses corresponded to high Fe²⁺ and lower or no HCO₃⁻ in the water samples, because …

Assessment Of The Source And Transformation Of Nitrate In The Cedar River Watershed By Using Stable Isotopes Of Nitrogen, Sushil Gautam

Dissertations and Theses @ UNI

Stable isotopes of nitrogen were used to assess the source and fate of nitrate in the Cedar River Watershed, Iowa. Ground water samples from 20 private wells and surface water samples from 10 sites in the Cedar River and its tributaries were collected. A total of 90 samples were collected during the growing season from May through September 2006. In 35% of the wells, nitrate concentration exceeded the U.S. Environmental Protection Agency's recommended maximum contaminant level (MCL) of 45 mg/1 (as NO3-) for drinking purposes. Eight (8) out of 10 samples exceeded MCL for nitrate in the first set of …

Trampling, Peeling And Nibbling Mussels: An Experimental Assessment Of Mechanical And Predatory Damage To Shells Of Mytilus Trossulus (Mollusca: Mytilidae), Carlos E. Cintra-Buenrostro

School of Earth, Environmental, & Marine Sciences Faculty Publications

Shell damage, if properly recognized, can provide information about biotic interactions between molluscs and their predators. However, it can be difficult to distinguish predatory damage from mechanical breakage, thus making interpretation of damaged modern and fossil shells problematic. To establish a clear-cut distinction between antemortem predatory crab damage and ante- and postmortem mechanical damage in Mytilus trossulus shells, a combined field and experimental approach was used. Mussels were exposed to predation by crabs, tumbled-live, tumbled-dead, and trampled. After 100 h of tumbling, live-collected mussel shells were abraded and disarticulated but not otherwise damaged. Eight percent of the dead-collected shells were …

Methane Potential Of Upper Fort Union Formation Sandstones, Campbell County, Wyoming, Michael J. Blackstone

Theses and Dissertations

Coalbed methane has been produced from the coalbeds of the Upper Fort Union Formation in the Powder River Basin for many years. The sandstones associated with these coals have also proven to be gas-charged, but industry has done little with the sandstones thus far. The purpose of this study is to determine the paleoenvironrnent responsible for the deposition of the coal and sandstone bodies in an attempt to locate gas-charged sandstone bodies in the Tongue River Member of the Fort Union Formation.

The 30-mile by 90-mile study area was chosen because of the presence of a decrease in thick coalbed …

Resolving Terrain Effects In Borehole Temperature Profiles, Shannon M. Heinle

Theses and Dissertations

The study of borehole paleoclimatology aids scientists in determining past climate changes and in understanding current climate trends. Accurate borehole temperature logs are necessary to obtain a useful temperature profile. However, as many climate workers have discovered, borehole temperature profiles can have many causes of inaccuracy. Uncertainties associated with borehole data include errors stemming from temperature measurement, depth measurement, thermophysical property measurements, and terrain effects. Terrain effects include topography, changes in land cover over time, direct and diffused sun radiation, and groundwater flow.

This study focused on specific terrain effects influencing borehole temperature profiles in the United States borehole dataset …

Shelf-Margin Delta Morphology As A Paleo Sea Level Indicator: Implications On Late Quaternary Relative Sea-Level Changes In The Northeast Gulf Of Mexico, Swati Ghoshal

LSU Doctoral Dissertations

A new technique to determine relative sea level history at siliciclastic settings is proposed in this dissertation. The clinoform break (defined as the topset-foreset transition point) of the modern Mississippi River Delta shows a direct relationship with sea level elevation. The analysis of Holocene lobes 8 and 9 belonging to the St. Bernard delta complex of the Mississippi Delta suggests that delta clinoforms can be significantly modified by post-abandonment processes, and hence a detailed stratigraphic evaluation is necessary to determine whether the clinoform geometry is a result of wave erosion or any other post-abandonment processes. The strategy was tested on …

Acadian Biospeleology: Composition And Ecology Of Cave Fauna Of Nova Scotia And Southern New Brunswick, Canada, Max Moseley

International Journal of Speleology

The vertebrate and invertebrate fauna, environment and habitats of caves and disused mines in Nova Scotia and southern New Brunswick are provisionally catalogued and described, based on field collections made over many years. The area was glaciated and the subterranean fauna consists of non-troglobites all of which have arrived and colonised the caves during or following final recession of the Pleistocene glaciers. The statistical composition of the fauna at the higher taxonomic level is similar to that in Ontario, but is less species rich and there are some notable ecological and other differences. Porcupine dung accumulations are an important habitat …

Bomb-Spike Dating Of A Mummified Baboon In Ludwig Cave, Namibia, Greg Hodgins, George A. Brook, Eugene Marais

International Journal of Speleology

In 1982 a mummified adult female baboon was discovered on a ledge in Ludwig Cave in Namibia. A toe bone was removed for dating in July 1995. AMS radiocarbon dating of bone collagen, tendon, and skin indicates a post-modern age. Application of the atomic bomb-spike calibration curve suggests death in late 1977 and an age at death of around 19 years. Baboons roost in the cave and the mummified female, along with a mummified juvenile male discovered in 2002 and three rotting corpses discovered in 1995, were probably chased by other baboons or by leopards down a ca. 6 m …

Eogenetic Karst, Glacioeustatic Cave Pools And Anchialine Environments On Mallorca Island: A Discussion Of Coastal Speleogenesis, Angel Ginés, Joaquín Ginés

International Journal of Speleology

Coastal karst is characterized by special geomorphologic and hydrodynamic conditions as well as by peculiar sedimentary, geochemical, and biospeleological environments. Generally, the more distinctive karstic features produced near the coastline are strongly influenced by sea-level changes, which generate a broad set of interactions between littoral processes and karst development. The glacioeustatic rises and falls of sea level affected the littoral karst in different ways, namely: vertical and horizontal shifts in the shoreline position, changes in elevation of the local water table, and vertical displacements of the halocline. Most eogenetic karsts have been subjected over long time spans to repeated changes …

The Polygenetic Caves Of Cuatro Ciénegas (Coahuila, Mexico): Morphology And Speleogenesis, Leonardo Piccini, Paolo Forti, Italo Giulivo, Marco Mecchia

International Journal of Speleology

The Cuatro Ciénegas area is renown worldwide for its thermal springs, which feed a unique ecosystem consisting of many pools, lakes and marshes. The pools also represent a very important water resource in a region characterized by scarce rainfalls. Field investigation has emphasized the role of karst in the hydrogeology of the area. Only few and restricted forms of surface karst are represented; caves are mainly relics of old speleogenetic phases of thermal and bathyphreatic water flow.

A Taxonomic Survey Of Lamp Flora (Algae And Cyanobacteria) In Electrically Lit Passages Within Mammoth Cave National Park, Kentucky, Thomas Smith, Rick Olson

International Journal of Speleology

A taxonomic survey of the lamp flora from electrically lit passages in Mammoth Cave, Mammoth Cave National Park, identified 28 species. Overall, cyanobacteria were dominant represented by 14 species (50% of the total), green algae had eight species (29%), and six diatoms species (21%) were present. There was not a correlation between species diversity and temperature, but there is a general trend of increasing diversity with warmer temperatures. There were two algal or cyanobacterial species identified in this study that overlapped with previous studies. There is a lack of continuity between previous studies only having one species identified in more …

Investigation Of A Possible Lead-Lag Relationship Between The Innuitian And Laurentide Ice Sheets, Arctic Canada, Paula Zimmerman

OES Theses and Dissertations

Peaks of iron-rich grains in Arctic Ocean sediment cores matched to the Laurentide and Innuitian Ice Sheets appear to show a lead-lag relationship during the Late Pleistocene when grain abundances are plotted against time and depth below sea floor. Cores from across the Arctic have been analyzed to determine if this is the case. Of the six IRD events identified, the Innuitian leads 68% of the time with 26% of events in all cores occurring simultaneously. The Innuitian seems to lead 33.3% of the time when peaks from the Innuitian and Laurentide occur within close proximity (less than 1 cm), …

Carbon Dioxide In The Atmosphere, Storm Project

Open Educational Resources

Objectives: Students learn the importance of carbon dioxide in the atmosphere.

National Science Education Standards: As a result of activities in grades 9-12, all students should develop abilities necessary to do scientific inquiry and understandings about scientific inquiry. As a result of their activities in grades 9-12, all students should develop understanding of matter, energy, and organization in living systems. As a result of their activities in grades 9-12, all students should develop an understanding of energy in the earth system and geochemical cycles.

Understanding Dispersion Models Using Computer Technology, Storm Project

Open Educational Resources

Objectives:

• Analyze dispersion models
• Use computer models to predict outcomes of various scenarios

9-12 NSES Standards:

• Standard A: Inquiry - Abilities necessary to do scientific inquiry and Understanding about scientific inquiry
• Standard E: Science and Technology - Abilities of technological design and Understanding about science and technology
• Standard F: Science in Personal and Social Perspectives - Personal and community health, Population growth, Natural resources, Environmental quality, Natural and human-induced hazards, Science and technology in local, national, and global challenges