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Structural Evolution Of The Kilombero Rift Basin In Central Tanzania, A. H. Mruma

Tanzania Journal of Science

Detailed geological and structural investigations at the northwestern scarp of the Cenozoic Kilombero Rift allow the drawing of its structural evolution and establishment of stress conditions that prevailed at the different deformational episodes at this rift zone. The structure, where the northwestern scarp of the Cenozoic Kilombero Rift System is located, starts by ductile deformation of granitic and gabbroic rock masses leading to the formation gneissic fabric and b-mineral lineation in the rocks. This deformation is of Precambrian age (most probably a Pan African deformation) and its kinematics are characterized by 320˚/20˚ tectonic transport direction (λ1). Later the area was …

Engineering Geological Mapping Of Dar Es Salaam City, Tanzania, K. A. Msindai

Tanzania Journal of Science

Engineering geological mapping of Dar es Salaam city in Tanzania has been carried out using desk studies supplemented by field reconnaissance as well as limited laboratory tests. Desk studies involved interpretation of medium to large-scale topographical maps, Landsat imagery and sequential aerial photographs from 1953-1990. These studies also evaluated small to medium scale geological, pedological maps together with ground water data from 50 boreholes. Two basic maps were prepared, namely, geomorphological and geological map depicts the spatial extent of the Neogene geological formations. Three distinct sandstone terraces could be distinguished in Dar es Salaam region at 0-15 m and 30 …

Energy‐Constrained Open‐System Magmatic Processes 3. Energy‐Constrained Recharge, Assimilation, And Fractional Crystallization (Ec‐Rafc), Frank J. Spera, Wendy A. Bohrson

All Faculty Scholarship for the College of the Sciences

Geochemical data for igneous rock suites provide conclusive evidence for the occurrence of open‐system processes within thermally and compositionally evolving magma bodies. The most significant processes include magma Recharge (with possible enclave formation and magma mixing), Assimilation of anatectic melt derived from wallrock partial melting and formation of cumulates by Fractional Crystallization (RAFC). In this study, we extend the Energetically Constrained Assimilation and Fractional Crystallization (EC‐AFC) model [Spera and Bohrson, 2001; Bohrson and Spera, 2001] to include the addition of compositionally and thermally distinct recharge melt during simultaneous assimilation and fractional crystallization. Energy‐Constrained Recharge, Assimilation, and Fractional …

Lake-Catchment Interactions With Climate In The Low Arctic Of Southern West Greenland, N. John Anderson, Sherilyn C. Fritz, Christopher E. Gibson, Bent Hasholt, Melanie J. Leng

Department of Earth and Atmospheric Sciences: Faculty Publications

Arctic hydrology plays a central role in the earth’s heat balance and ocean circulation (Vörösmarty et al. 2001). Future changes associated with human influence on the climate system are also predicted to cause major changes in the energy and hydrologic mass balance of Arctic catchments. Climate change will likely affect permafrost and snowmelt, which dominate Arctic hydrology and control the chemistry of surface runoff (and hence streams and lakes) as water percolates through the active layer. However, the controls and dynamic impact of snowmelt are poorly understood, because this critical timeframe is often missed by sampling programs. In the Søndre …

Seasonal Biogeochemistry And Mineral Cycling Of The Middle Rio Grande Alluvial Aquifer, New Mexico, David Stewart Vinson

Earth and Planetary Sciences ETDs

The Rio Grande in central New Mexico flows through a semi-arid, historically aggrading Quaternary rift basin. Flow regulation measures include dams, irrigation diversions, levees, and bank stabilization. These have caused severe impairment including incision, lowered water tables, and less overbank flooding; disrupted groundwater - surface water interactions; altered seasonal organic carbon dynamics; and declining native biota. Previously dynamic flowpaths in the shallow alluvial aquifer (hyporheic corridor) have become are less reversible due to parallel drain ditches with lower beds than the river. These ditches impose relatively static hydraulic gradients on the alluvial aquifer that force water to flow from the …

Depth-Varying Constitutive Properties Observed In An Isothermal Glacier, H. P. Marshall, Joel T. Harper, W. Tad Pfeffer, Neil Humphrey

Geosciences Faculty Publications

Detailed three-dimensional in-situ measurements of deformation at depth are used to examine the rheology of a 6 x 10⁶ m³ block of temperate glacier ice. Assuming that the viscosity of this ice is primarily dependent on stress, the relationship between inferred stress and measurements of strain-rate above about 115 m depth suggest a constitutive relationship with a stress exponent n about 1. Deformation below 115 m is described by a non-linear flow law with a power exponent of approximately 3-4. A sharp transition between the two flow regimes is likely caused by a change in the dominant mechanism …

Measuring Surface Chemical Properties Of Soil Using Flow Calorimetry, R. D. Rhue, Chip Appel, Nadine Kabengi

Earth and Soil Sciences

Flow calorimetry, which is ideally suited for measuring reactions occurring at the liquid/solid interface, has been used to study the surface chemistry of many types of solids, but little use of it has been made in the study of surface reactions of soils. The purpose of this study was to demonstrate the application of flow calorimetry to the study of two fundamental soil chemical processes, namely cation exchange and phosphate sorption. Surface horizon samples of a Typic Acrorthox and a Typic Tropohumult from Puerto Rico, a strong acid cation exchange resin (Dowex 50W-8), and an amorphous Al(OH)₃ were used. …

Heats Of K/Ca And K/Pb Exchange In Two Tropical Soils As Measured By Flow Calorimetry, Chip Appel, Dean Rhue, Lena Ma, Bill Reve

Earth and Soil Sciences

Flow calorimetry can provide useful information about surface chemical reactions in soils that cannot be obtained readily by other methods. When flow calorimetry is conducted over a range of surface coverages, different sorption heats can be calculated to yield information about how binding energies vary with coverage, i.e., surface heterogeneity. The purpose of this study was to determine heats of exchange for K/Ca and K/Pb systems using flow calorimetry and to evaluate the degree of surface heterogeneity with respect to cation exchange. Surface horizon samples from a Typic Acrorthox and Typic Tropohumult from Puerto Rico were used. Lead was adsorbed …

The Role Of Climate In Modern Water Planning And Related Decisions: Nebraska Case Study, Donna L. Woudenberg

Open Access Master's Theses (through 2010)

Climate and weather play an integral role in the planning and decision-making processes for those involved in agricultural and natural resource fields. This project was conducted to determine whether climate and weather data are being efficiently and effectively used in these processes.

A survey was mailed to those who work in water-related fields in Nebraska and post-survey interviews were conducted to obtain greater detail. Survey results were analyzed in the following three ways: as a whole; stratified by respondent’s agency; and stratified by the educational background of respondents. It was found that climate and weather data are more likely to …

Analysis Of Integrated Farming Systems In Eastern Nebraska, Lori A. Hoagland

School of Natural Resources: Dissertations, Theses, and Student Research

Agroecosystems in the U.S. are beset with social, ecological and environmental problems as large industrial farming methods are edging out small family-sized farms and replacing ecological services provided by biodiversity with synthetic inputs and practices. While many of the benefits of smaller diversified or integrated farming systems are well known, farm producers need a concrete model that shows how integration is possible and with what crops. The objective of this study was to investigate some of these supplemental farm activities, and identify and evaluate whether they were compatible given the time and resource constraints of a typical eastern Nebraska farm. …

Provenance Of Sand In Periglacial Sand Wedges And Sheet Sand, Northeastern Nebraska, Usa, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

Sand-wedge polygons on upland surfaces beneath thin loess in northeastern Nebraska record existence of permafrost around the margin of the Wisconsinan glacier at its maximum advance. Strong unidirectional wind not only kept the upland surfaces free of snow, allowing frost to penetrate deeply and thermal contraction cracks to develop, but also dessicated the surface material so that frost action and sublimation of pore ice could loosen surface material. The strong NW-SE winds deflated soils from upland surfaces, made ventifacts of the cobbles in the lag that remained and created fields of yardangs oriented NW-SE. Sand derived from the soils and …

Geoelectrical Response Of An Aged Lnapl Plume: Implications For Monitoring Natural Attenuation, Douglas D. Werkema Jr.

Dissertations

The geoelectric stratigraphy at a site impacted with light non-aqueous phase liquids (LNAPLs) is investigated for its link to natural biodegradation, its contribution to the conductive model for aged (i.e. mature) LNAPL contaminated sites, and the relationship to the natural hydrologic regime. The highest conductivities (lowest resistivities) were observed in portions o f soils where LNAPL was in residual and free phase. Corroborating evidence from bacteria enumeration from soil close to the vertical resistivity probe (VRP) installations show orders-of-magnitude increase in both heterotrophic and oil degrading microbes at the depths where the conductivity was at a maximum. The coincidence o …

Integrated Geophysical Examination Of A Former Refinery Site, Carson City, Michigan, Kennedy Opiyo Mwanda

Masters Theses

Integrated geophysical surveys, including electromagnetic (EM-31), magnetic, dc resistivity, and ground penetrating radar (GPR) methods and soil borings were used to investigate part of a former refinery site in Carson City, Michigan, which has more than a 50-year history of hydrocarbon contamination.

Although not readily evident on the magnetic anomaly maps, the EM-31 conductivity map clearly revealed many sections of buried pipes of various lengths and orientations. Also evident on the EM maps are extensive near surface conductivity anomalies. Soil borings in zones of anomalous conductivities to the west suggest the presence of shallow clays with pooled hydrocarbons at depths …

Inorganic And Organic Chemistry Of The Former Lakeside Refinery In Kalamazoo, Michigan, Kurt W. Carlson

Masters Theses

The focus of this investigation of the Lakeside Refinery site is the inorganic geochemistry because previous investigations concerned organics and heavy metals. Because little nitrate is in native groundwater, high dissolved ammonia immediately downgradient from a petroleum body suggests the source is the petroleum and/or associated byproducts. Iron reduction is most prominent immediately upgradient from the known and measurable petroleum while manganese reduction occurs mostly downgradient. Sulfate reduction occurs mostly towards the southern portion of the light petroleum LNAPL. Based on concentrations of nitrate, manganese, iron and sulfate along a groundwater flow path, there appears to be a sequential use …

Determining The Mobility Of Metals Through Coal Combustion Byproducts In Surface Impoundments By Analyzing Leachate From Modified Saturated Hydraulic Conductivity Tests, Michael Joseph Trofinoff

Theses and Dissertations

Surface impoundments are used extensively throughout the utility industry to store the combustion byproducts, or ash, from coal-fired generating facilities. Following combustion, the metals, naturally contained within coal at low concentrations, may become highly concentrated within the ash. These combustion byproducts are then piped out in a water-ash slurry to the surface impoundments where the ash weathers to- a clay- like substance after approximately 10 years. It is feared that these metals that are contained within the ash could possibly leach into the ground and contaminate the local groundwater. Utilizing a open column percolation test to determine the hydraulic conductivity …

News From Cart, Michael A. Krol, Julia Stakhnevich

Bridgewater Review

No abstract provided.

Microbial Community Structure In Hydrocarbon Impacted Sediment Associated With Anomalous Geophysical Signatures, Joseph W. Duris

Masters Theses

The Crystal Refinery is a former refinery site in Carson City Michigan that has had historic releases of refined and unrefined crude oil dating back to the late 1940's. The contamination of soil with light non-aqueous phase liquids (LNAPL) has had a dynamic impact on the subsurface environment in adjacent Carson City Park. Very little is known about the complex interactions between microbial communities, geochemistry and geophysics. In order to investigate possible connections between these parameters a multidisciplinary study was undertaken to investigate the hypothesis that the degradation of LNAPL by resident microbial communities causes a local increase in organic …

Seafloor Characterization From Spatial Variation Of Multibeam Backscatter Vs."Best Estimated" Grazing Angle, Tianhang Hou, Larry A. Mayer, Christian De Moustier, Barbara J. Kraft

Center for Coastal and Ocean Mapping

Backscatter vs. grazing angle, which can be extracted from multibeam backscatter data, depends on characteristics of the multibeam system and the angular responses of backscatter that are characteristic of different seafloor properties, such as sediment hardness and roughness. Changes in backscatter vs. grazing angle that are contributed by the multibeam system normally remain fixed over both space and time. Therefore, they can readily be determined and removed from backscatter data. The component of backscatter vs. grazing angle due to the properties of sediments varies from location to location, as the sediment changes. The sediment component of variability can be inferred …

Geochemical And Isotopic Characteristics Associated With High Conductivities In A Shallow Hydrocarbon-Contaminated Aquifier, Franklyn D. Legall

Dissertations

In-situ vertical resistivity probes (VRPs) deployed at a hydrocarboncontaminated site in SW Michigan showed high soil conductivities within the contaminated zone. Within this zone, different phases of hydrocarbon impact were recognized, namely, zones with residual and dissolved phase hydrocarbons (RDH) and zones where these phases coexist with free product (RDFH). Bulk soil conductivities were highest ( 12 to 30 mS/m) in the zone with RDFH compared to the RDH zone (10 to 25 mS/m). Groundwater chemistry and stable carbon isotope data from closely spaced vertical samples within the anomalous conductive zones were used to provide evidence for biodegradation and to …

Interactive Learning Tools: Animating Statics, Nancy Hubing, David B. Oglesby, Timothy A. Philpot, Vikas Yellamraju, Richard H. Hall, Ralph E. Flori

Business and Information Technology Faculty Research & Creative Works

Computer-Based Modules for Engineering Instruction Must Be Concise, Flexible, Educational and Engaging in Order to Effectively Supplement Traditional Classroom Teaching Tools. a Computer Example that Takes More Time Than a Chalkboard Presentation is Not Likely to Be Useful in Today's Engineering Classroom. Flexible Navigation is Necessary So that the Instructor Can Quickly and Easily Respond to Student Questions. Useful Modules Must Also Improve Problem-Solving Skills or Clarify Troublesome Concepts in Order to Be Considered Worthy of Inclusion in the Limited Class Time Available. Finally, and Perhaps Most Importantly, Effective Computer-Based Modules Must Meet the Challenge of Holding the Student's Attention. …

Upper Spokane River Model: Boundary Conditions And Model Setup, 2001, Spencer Slominski, Robert Leslie Annear, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:

• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam for 2001 based on the calibration conducted for 1991 and 2000 data sets, (Annear et al, 2001).

• Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen …

The Polarising Effects In Sintered Kaolin, Fm D'Ujanga, Y Kaahwa, L Atteraas

Tanzania Journal of Science

The polarizing effects in sintered kaolin samples were analysed in terms of the sample density (or porosity) using direct current (dc) techniques. More porous samples exhibited higher polarizing effects than the less porous ones. The conduction carriers in kaolin samples at room temperature were found to be mainly electrons, with ionic conduction being enhanced by the moisture content with the pores. The influence of the uniaxial pressure and particle-size on the compacted and sintered density of the ceramic have been studied, and a density-pressure relationship before- and after-sintering conditions obtained

Studies On Benthic Denitrification In The Chwaka Bay Mangrove Sediments, Zanzibar, Sm Mahommed, Rw Johnstone

Tanzania Journal of Science

Denitrification was measured at three sites in a narrow tidal creek in the Chwaka mangrove ecosystem. Denitrification arising from water column nitrate (Dw) was low (< 0.1μM Nm-2h-1) and there was little spatial and seasonal variation in Dw rates in the creek. Coupled nitrification-denitrification (Dn) was found to be low, but within the range measured in other mangrove sediments. Average values ranged from 0.01 to 0.45 μM Nm-2h-1 and showed strong spatial variations. The low denitrifcation rates observed in the creek were possibly as a result of the low availability of NO3 and high C:N values of the organic matter in the sediment. Spatial variations in denitrification rates were due to variations in concentration levels of organic matter and possibly to disproportionate competition for inorganic nitrogen between denitrifiers and benthic autotrophs among sites. There were no seasonal differences in denitrification rates. Results from the present study suggest that sediment denitrification does not play a major role as a sink for N in this ecosystem

Interpretation Of Refelction Seismic Data From The Usangu Basin, East African Rift System, Ei Mbede

Tanzania Journal of Science

Reflection seismic data collected by AMOCO Tanzania Oil Company in the 80s, are herin used to correlate the main Usangu Basin parameters to those estimated from outcrop, gravity and aeromagnetic data. The seismic data are further used to constrain the geometry of crustal extension in this south-western sector of the East African Rift System (EARS) in Tanzania. Three distinct sedimentary packages on top of the basement reflector are interpreted and correlated to the Permo-Carboniferous Karoo rocks, the Jurassic/Cretaceous and Miocene Red Sandstone Group and Miocene to recent Lake Beds in the adjacent Rukwa basin, where the ages of the sedimentary …

Comparison Of Various Methods For Estimating Wave Incident Angles In The Nearshore Zone, As Ngusaru

Tanzania Journal of Science

Five different methods were examined for their suitability in estimating the inshore wave incident angles on a nearshore zone with a complex topography. Visual observation provided preliminary estimates. Two frequency independent methods and one frequency dependent method based on current meter measurements were examined. Another frequency dependent method based on collocated bottom pressure and current meter measurements was also examined. The results from all the methods provided a reasonably consistent estimate of the inshore wave incident angles. The frequency independent methods gave exactly the same results while the frequency dependent methods had a 5% relative error among themselves. Between frequency …

Tectonic Setting Of Gabbroic Rocks In The Western Part Of The Lupa Gold Field, South-West Tanzania, Sr Mnali

Tanzania Journal of Science

There is a pronounced occurrence of gabbroic rocks in the western part of the Lupa gold field, SW Tanzania. These rocks occur in the peripheral part around the Saza-Chuya granodiorite with which it makes a gradiational, unchilled contact. The rocks have been altered or metamorphosed to low-grade greenschist facies as indicated by the presence of secondary epidote, penninite, chlorite, sericite and calcite. The majority of major-element oxides show scattered variation trends against immobile elements such as Zr, indicating some degree of element mobility during post-crystallization processes of alteration or metamorphism. Major-trace-element data show that the gabbroic rocks in the study …

A 700-Year Record Of Atmospheric Circulation Developed From The Law Dome Ice Core, East Antarctica, Joseph M. Souney Jr, Paul A. Mayewski, Ian D. Goodwin, David Meeker, Vin Morgan, Mark Aj Curran, Tas D. Van Ommen, Anne S. Palmer

All Materials

A 700-year, high-resolution, multivariate ice core record from Dome Summit South (DSS) (66°46′S, 112°48′E; 1370 m), Law Dome, is used to investigate sea level pressure (SLP) variability in the region of East Antarctica. Empirical orthogonal function (EOF) analysis reveals that the first EOF (LDEOF1) of the combined glaciochemical, oxygen isotope ratio, and accumulation rate record from DSS represents most of the variability in sea salt seen in the record. LDEOF1 is positively correlated (at least 95% confidence level) to instrumental June mean SLP across most of East Antarctica. Over the last 700 years, LDEOF1 levels at Law Dome were the …

Selectivities Of K/Ca And K/Pb Exchange In Two Tropical Soils, C. S. Appel, L. Q. Ma, R. D. Rhue, W. Reve

Earth and Soil Sciences

Measurement of cation selectivity in soils provides important information about the affinity and binding strength of a particular cation on soil surfaces. Gaines-Thomas (KGT) selectivity coefficients were determined for a variety of K/Ca and K/Pb ratios on an Oxisol and Ultisol soil from Puerto Rico. The calculated KGT values indicated a preference for K+ over Ca2+ or Pb2+. The selectivity for Pb2+ was significantly greater than that for Ca2+ due to the larger hydrated charge density of Pb2+ relative to that of Ca2+. The patterns of selectivity were independent of metal type. The selectivity of the Oxisol for Ca2+ or …

Enhancement Of Wind-Driven Upwelling And Downwelling By Alongshore Bathymetric Variability, James M. Pringle

Earth Sciences

Steady wind-driven flow along a shelf of changing width is described with a frictional barotropic model valid in the limit of small Rossby and Burger number. In these limits, an alongshore wind drives enhanced onshelf transport in a coastal ocean if the shelf widens downwind, and the change in shelf width only affects the flow in the direction of Kelvin wave propagation ("downwave'') from the change in shelf width. There is enhanced onshore transport of cold, nutrient-laden bottom water if the winds favor upwelling and the shelf narrows in the direction of Kelvin wave propagation. This enhanced transport extends a …

Soils Of Mississippi County, Arkansas, J. M. Mckimmey, B. Dixon, H. D. Scott, C. M. Scarlat

AAES Research Reports and Research Bulletins

Along with air and water, soil contributes essential processes to the natural order of global cycles. With the exception of edibles from the sea, virtually everything we, and most other land-based animals, eat is derived from soil. Soil is a storage medium of essential minerals and nutrients for fulfilling our agricultural and nutritional needs. Humans work the soil to provide the basics of food, clothing, and shelter. We also use the soil as a medium to store and discard our waste. Virtually everything we do is in some way connected to soil