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Articles 211 - 240 of 1754

Full-Text Articles in Geology

Interpretation Of Hydrogeologic Data To Support Groundwater Management, Bazile Groundwater Management Area, Northeast Nebraska, 2019—A Case Demonstration Of The Nebraska Geocloud, Christopher M. Hobza, Gregory V. Steele Dec 2020

Interpretation Of Hydrogeologic Data To Support Groundwater Management, Bazile Groundwater Management Area, Northeast Nebraska, 2019—A Case Demonstration Of The Nebraska Geocloud, Christopher M. Hobza, Gregory V. Steele

United States Geological Survey: Publications

Nitrate, age tracer, and continuous groundwater-level data were interpreted in conjunction with airborne electromagnetic (AEM) survey data to understand the movement of nitrate within the Bazile Groundwater Management Area (BGMA) in northeastern Nebraska. Previously published age tracer data and nitrate data indicated vertical stratification of groundwater quality. Younger groundwater sampled within shallow parts of the aquifer had higher concentrations of nitrate, with 70 percent exceeding the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter. In contrast, groundwater sampled from deeper parts of the aquifer indicated that nitrate concentrations were less than 2 milligrams per liter and …


Sediment Provenance Of Tsunami Deposits: Implications For Assessing The Relative Intensity Of Paleotsunamis From The Sendai Coastline Of Japan, Tiffany Otai Dec 2020

Sediment Provenance Of Tsunami Deposits: Implications For Assessing The Relative Intensity Of Paleotsunamis From The Sendai Coastline Of Japan, Tiffany Otai

Master's Theses

The 2011 Tohoku tsunami impacted the northeastern coast of Japan and caused unexpected damages due to the underestimation of this type of hazard. Of particular importance is the fact that geologic evidence for a predecessor event, the Jogan tsunami (CE 869), could have forecasted the severity of the 2011 Tohoku event. While the timing of tsunamis is important for effective hazard mitigation, outside of the 2011 Tohoku event, the intensity of past tsunamis remains unclear. To understand paleotsunami intensity, it is important to document characteristics of modern analogues like the 2011 event. This study utilizes surface distributions of foraminifera from …


Exploring Sediment Compaction In Experimental Deltas: Towards A Meso-Scale Understanding Of Coastal Subsidence Patterns, Samuel Mason Zapp Dec 2020

Exploring Sediment Compaction In Experimental Deltas: Towards A Meso-Scale Understanding Of Coastal Subsidence Patterns, Samuel Mason Zapp

Graduate Theses and Dissertations

Subsidence in low elevation coastal areas has been extensively researched through direct field measurement, numerical modelling, and stratigraphic reconstruction of ancient sediment deposits. Here I present the first investigation of subsidence due to sediment compaction and consolidation in two laboratory scale river delta experiments. Compactional subsidence rates have never been thoroughly quantified in the experimental setting, though this mechanism is found to be a primary creator of total relative sea level rise which will likely cause coastlines to retreat in the coming years. Spatial and temporal trends in subsidence rates in the experimental setting may elucidate behavior which cannot be …


The Role Of Eolian-Fluvial Interactions And Dune Dams In Landscape Change, Late Pleistocene-Holocene, Mojave Desert, Usa, Mark R. Sweeney, Eric V. Mcdonald, Lucas P. Chabela, Paul R. Hanson Nov 2020

The Role Of Eolian-Fluvial Interactions And Dune Dams In Landscape Change, Late Pleistocene-Holocene, Mojave Desert, Usa, Mark R. Sweeney, Eric V. Mcdonald, Lucas P. Chabela, Paul R. Hanson

School of Natural Resources: Faculty Publications

The formation of the Kelso Dunes in the eastern Mojave Desert, California, was a landscape-changing event triggered by an increase in sediment supply that followed the incision of Afton Canyon by the Mojave River ca. 25 ka. Eastward migration of sand dunes occurred along a well-defined eolian trans­port corridor. Dunes temporarily blocked washes resulting in substantial aggradation of eolian and fluvial sediments. Stratigraphic exposures reveal numerous fining-up sequences with interbedded eolian sands that provide evidence of dune dams and subsequent aggradation. Luminescence ages reveal that dune blocking and aggradation correspond to a regional pulse of alluvial fan sedimentation that occurred …


Radiological Identification Of Near‐Surface Mineralogical Deposits Using Low‐Altitude Unmanned Aerial Vehicle, Peter G. Martin, Dean T. Connor, Natalia Estrada, Adel El-Turke, David Megson-Smith, Chris P. Jones, David K. Kreamer, Thomas B. Scott Oct 2020

Radiological Identification Of Near‐Surface Mineralogical Deposits Using Low‐Altitude Unmanned Aerial Vehicle, Peter G. Martin, Dean T. Connor, Natalia Estrada, Adel El-Turke, David Megson-Smith, Chris P. Jones, David K. Kreamer, Thomas B. Scott

Geoscience Faculty Research

An ever‐increasing global population and unabating technological growth have resulted in a relentless appetite for mineral resources, namely rare earth elements, fuel minerals and those utilised in electronics applications, with the price of such species continuing to climb. In contrast to more established large‐scale and high‐cost exploration methodologies, this work details the application of novel multi‐rotor unmanned aerial vehicles equipped with miniaturised radiation detectors for the objective of undertaking resource exploration at lower costs, with greater autonomy and at considerably enhanced higher spatial resolutions; utilizing the ore material’s inherent low levels of characteristic radioactivity. As we demonstrate at the former …


Impacts Of Land-Use Change On The Menominee River In Jo Daviess County, Illinois, Preston J. Konop Oct 2020

Impacts Of Land-Use Change On The Menominee River In Jo Daviess County, Illinois, Preston J. Konop

Theses and Dissertations

This study addresses land-use changes in Jo Daviess County, Illinois, and their effects on the Menominee River. The Menominee River flows north to south through Jo Daviess County, and southern Grant County, Wisconsin. Many of the surrounding properties are agricultural and have undergone developmental and land-use changes that may affect the flood flashiness of the Menominee River. The concern with increasing flood flashiness of the Menominee River include more frequent flooding events, undercutting of riverbanks, and increased amounts of sediment transport from upstream locations into the Mississippi River. Increases in impermeable surfaces have led to greater amounts of runoff during …


The Multidisciplinary Enrichment Of Undergraduate Environmental Geology Students From International Summer Programs. Case Study: Summer 2019 3mugis, Russia, Ruslana Baker, Malek Shami, Nazrul I. Khandaker, Stanley Schleifer Oct 2020

The Multidisciplinary Enrichment Of Undergraduate Environmental Geology Students From International Summer Programs. Case Study: Summer 2019 3mugis, Russia, Ruslana Baker, Malek Shami, Nazrul I. Khandaker, Stanley Schleifer

Publications and Research

Hosted by the People’s Friendly University of Russia (RUDN), the Modeling, Monitoring, and Managing of Urban Green Infrastructure (3MUGIS) summer program was organized by the collaboration of the New York City Urban Soil Institute (NYC-USI), City University of New York – Brooklyn College, and under the auspices of the International Union of Soil Sciences (IUSS). The program consisted of one-week lecture sessions and two-weeks of fieldwork across five bioclimatic zones, ranging from the sub-arctic tundra of the Kola Peninsula to the Southern Steps of Rostov, Black Sea. Faculty and guest lecturers included scientists with various expertise from Germany, USA, Russia, …


The Urban Heat Island Effect And Its Impact On The Climate And Landscape Of Phoenix, Arizona, Gurwinder Sahota, Nazrul I. Khandaker, Ali Zarine, Malek Shami Oct 2020

The Urban Heat Island Effect And Its Impact On The Climate And Landscape Of Phoenix, Arizona, Gurwinder Sahota, Nazrul I. Khandaker, Ali Zarine, Malek Shami

Publications and Research

This paper examines the impact of the urban heat island effect on the climate and landscape of Phoenix, Arizona. Urbanization is quickly becoming the most influential environmental factor because of the exponential growth in the human population coupled with industrialization, modernization, and commercialization, which has become the allure of urban centers worldwide. While urbanization offers numerous advantages, it comes at the cost of altering the environment by replacing permeable natural soils and vegetation with impermeable urban surfaces, such as pavements, buildings, and other such structures. This impervious modification results in absorption of solar energy that is taken up by the …


Using Tidal Analysis To Examine Lake-Aquifer Connectivity On A Modern Carbonate Platform, Ronald A. Knoll Oct 2020

Using Tidal Analysis To Examine Lake-Aquifer Connectivity On A Modern Carbonate Platform, Ronald A. Knoll

USF Tampa Graduate Theses and Dissertations

Lake-aquifer connectivity on carbonate platforms is governed by basin morphology which is influenced by diagenetic and depositional processes. Both these processes cause aquifer permeability to vary significantly with scale of measurement (i.e., pore-scale, well-scale, and regional-scale). Because coastal aquifers are well-known to have tidally controlled water level fluctuations, inland lakes may be used to expand the areal measurement of permeability and establish a link between well-scale and regional scale connectivity in the aquifer. To evaluate the impact of lake basin morphology on aquifer connectivity, water level fluctuations were collected at high temporal resolution in the ocean and twenty-four surface water …


The Use Of Green Pond Conglomerate As Building Stone In Morris County, New Jersey, Gregory A. Pope Oct 2020

The Use Of Green Pond Conglomerate As Building Stone In Morris County, New Jersey, Gregory A. Pope

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Green Pond Conglomerate (GPC) is a maroon colored quartzite with white quartz pebbles, a classic “puddingstone”. GPC derives from a NW-SW-trending sliver of Paleozoic sediments, the “Green Pond Outlier”, surrounded by older metamorphic and igneous rocks of Morris and Passaic Counties. Buildings, retaining walls, field fences, and monuments incorporate the durable and attractive stone, in a distinct geographic area of Morris County. Several instances of structures completely constructed or faced with GPC occur in and around Morristown, limited to affluent houses and one prominent church. In these cases, GPC stones were dressed and faced, a labor-intensive effort. Elsewhere in the …


Bubble Trail And Folia In Cenote Zapote, Mexico: Petrographic Evidence For Abiotic Precipitation Driven By Co2 Degassing Below The Water Table, Rafael López-Martínez, Fernando Gázquez, José M. Calaforra, Philippe Audra, Jean Y. Bigot, Teresa Pi Puig, Rocío J. Alcántara-Hernández, Ángel Navarro, Philippe Crochet, Liliana Corona Martínez, Raquel Daza Brunet Oct 2020

Bubble Trail And Folia In Cenote Zapote, Mexico: Petrographic Evidence For Abiotic Precipitation Driven By Co2 Degassing Below The Water Table, Rafael López-Martínez, Fernando Gázquez, José M. Calaforra, Philippe Audra, Jean Y. Bigot, Teresa Pi Puig, Rocío J. Alcántara-Hernández, Ángel Navarro, Philippe Crochet, Liliana Corona Martínez, Raquel Daza Brunet

International Journal of Speleology

Folia are speleothems that resemble bells, inverted cups, or bracket fungi, and whose origins are still controversial. Cenote Zapote (an underwater cave) in the Yucatán Peninsula (México), is home to some of the largest folia reported to date. These speleothems are currently growing in an active underwater system, meaning this site offers an excellent opportunity to constrain the different formation models proposed for folia, which have traditionally relied on inactive examples. In Cenote Zapote, folia are closely related to bubble trails and cupolas, suggesting an underwater CO2-degassing process. In thin section, they display a succession of columnar-open and …


Tributes To Rick Edwards Upon His Retirement, Robert F. Diffendal Jr., Michael Farrell, Michael David Forsberg, Maurice Godfrey, John J. Janovy Jr., Katie Nieland, Linda Pratt, Rebecca S Wingo, David J. Wishart, George E. Wolf, Peter Longo, John R. Wunder Oct 2020

Tributes To Rick Edwards Upon His Retirement, Robert F. Diffendal Jr., Michael Farrell, Michael David Forsberg, Maurice Godfrey, John J. Janovy Jr., Katie Nieland, Linda Pratt, Rebecca S Wingo, David J. Wishart, George E. Wolf, Peter Longo, John R. Wunder

Robert F. Diffendal, Jr., Publications

I understand that you will be retiring from UNL in August. I wanted to express my sadness that you will be leaving the Center for Great Plains Studies, but am glad that you will now be able to perhaps enjoy life even more without having to do the administrative tasks that go with being the director of any organization. (RFD)


Evolution Of The Magnolia Growth Fault: An Evaluation Of Cenozoic Activity, Plaquemines Parish, Southeastern Louisiana, Jared S. Bullock Aug 2020

Evolution Of The Magnolia Growth Fault: An Evaluation Of Cenozoic Activity, Plaquemines Parish, Southeastern Louisiana, Jared S. Bullock

LSU New Orleans Theses and Dissertations

A geologic investigation of the Lake Hermitage area west of the Mississippi River in Plaquemines Parish, Louisiana suggests an active, regional growth fault has caused rapid local subsidence. The Magnolia growth fault is a down-to-the-south, deep-seated listric fault bounded to the west and east by two salt diapirs. Evidence from 3D seismic data, well logs, and biostratigraphy, in addition to local geomorphology, suggests the fault has been active since the Miocene and is causing submergence of wetlands on the hanging wall side. To investigate whether a correlation exists between deep-seated growth faults and subsidence at this location, near-surface data including …


Geology, Soils And Climate Of The Margaret River Wine Region, Peter J. Tille, Angela Stuart-Street, Peter S. Gardiner Aug 2020

Geology, Soils And Climate Of The Margaret River Wine Region, Peter J. Tille, Angela Stuart-Street, Peter S. Gardiner

All other publications

This report is an extract from the broader description and analysis of the Geology, soils and climate of Western Australia's wine regions. It expands on the brief descriptions in the second edition of 'Viticulture' (Coombe & Dry 2004) concerning the soils and landscapes of Western Australia’s main wine growing regions. We have tailored this report extract to the specific needs of the Margaret River wine region. It contains local soil names and soil-landscape zones and systems maps.

The wine industry recognises the importance of giving customers an understanding of the vines’ environment and how that may influence wine character …


Geomorphic History Of The Grand Staircase Region Of The Colorado Plateau: Understanding Arroyo Cut-Fill Dynamics, Erosion Rates, And Wildfire, Kerry E. Riley Aug 2020

Geomorphic History Of The Grand Staircase Region Of The Colorado Plateau: Understanding Arroyo Cut-Fill Dynamics, Erosion Rates, And Wildfire, Kerry E. Riley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Most streams in the southwestern United States do not flow all year, and given their delicate balance of sediment and water flow, they are sensitive to climate change. At the turn of the 20th century, many streams in the Southwest rapidly incised into their floodplains, forming arroyos with a channel entrenched into near-vertical channel banks mostly composed of sand and mud. This dissertation investigates past changes in watersheds draining the Grand Staircase region in southern Utah with the goal of understanding how changes in climate and sediment influence these types of streams. Results show sediment supply is highly variable across …


Field Measurements Of Bed-Load Transport Distances Using Painted Sediment Tracers In An Urban Stream In The Missouri Ozarks, Kristen E. Breckenridge Aug 2020

Field Measurements Of Bed-Load Transport Distances Using Painted Sediment Tracers In An Urban Stream In The Missouri Ozarks, Kristen E. Breckenridge

Graduate Theses/Dissertations

Predictions of bed-load mobility and transport in stream channels are useful for restoration and management purposes. This study uses native gravel tracers to determine transport distances for bed-load in an urban stream in the Ozark Highlands. The objectives of this project are to: (i) determine downstream transport distances of painted tracers of different sizes over a range of flow conditions; (ii) evaluate the influence of channel morphology and thalweg location on transport; and (iii) compare field results to those predicted by mobility equations. The study site is located on South Creek, which drains Springfield, Missouri. The study reach is 132 …


Quaternary Shelf-Slope Development In The Northern Gulf Of Alaska From Combined Geophysical And Geomorphologic Analysis, Wesley A. Clary Jul 2020

Quaternary Shelf-Slope Development In The Northern Gulf Of Alaska From Combined Geophysical And Geomorphologic Analysis, Wesley A. Clary

Earth and Planetary Sciences ETDs

This dissertation follows the hybrid format as defined by the Office of Graduate Studies at the University of New Mexico. The three chapters defined herein were prepared as manuscripts to be submitted for publication in peer reviewed journals in the field of Earth sciences. A version of chapter 1 was published in Proceedings of the Integrated Ocean Drilling Program, 2017, Volume 41. Chapter 2 was submitted to Marine Geology in Feb 2020, and is under revision as of this date. A version of chapter 3 will be submitted to the Journal of Geophysical Research. In chapter 1, I …


Quantitative Analyses Of Cirques On The Faroe Islands: Evidence For Time Transgressive Glacier Occupation, Keyleigh N. Wallick, Sarah M. Principato Jul 2020

Quantitative Analyses Of Cirques On The Faroe Islands: Evidence For Time Transgressive Glacier Occupation, Keyleigh N. Wallick, Sarah M. Principato

Student Publications

This study presents the first analysis of ice‐free cirques on the Faroe Islands using a Geographical Information System (GIS) and the Automated Cirque Metric Extraction (ACME) tool. The length, width, area, circularity, mean aspect, mean slope, and elevation range, minimum, and maximum were calculated using ACME. Cirque distance to coastline was measured using ArcGIS. A total of 116 cirques were identified. Mean cirque length is 950 m and mean cirque width is 890 m. Average cirque area is 0.8 km2 and mean elevation is 386 m a.s.l. The modal orientation of the aspect of cirques is north‐northeast, with a vector …


Fluvial Geomorphic And Hydrologic Evolution And Climate Change Resilience In Young Volcanic Landscapes: Rhyolite Plateau And Lamar Valley, Yellowstone National Park, Benjamin Newell Burnett Jul 2020

Fluvial Geomorphic And Hydrologic Evolution And Climate Change Resilience In Young Volcanic Landscapes: Rhyolite Plateau And Lamar Valley, Yellowstone National Park, Benjamin Newell Burnett

Earth and Planetary Sciences ETDs

Quaternary volcanism associated with the last caldera cycle in Yellowstone National Park included emplacement of ash-flow tuffs, massive rhyolite flows ranging from 79 to 484 ka, and valley-filling basalts. This study examines (1) the evolution of spring hydrology with flow age on the Rhyolite Plateau, (2) initial development and evolution of stream networks on the rhyolite flows, and (3) the impact of the 630 ka caldera formation and volcanic flow emplacement on Lamar Valley incision rates.

Integrated stream networks formed within 79 kyr on the Rhyolite Plateau. Incision is focused on steep flow margins and knickpoints and is dependent on …


Response Of Transient Base Level Signals To Erodibility Contrasts In Bedrock Streams, Joshua A. Wolpert Jul 2020

Response Of Transient Base Level Signals To Erodibility Contrasts In Bedrock Streams, Joshua A. Wolpert

LSU Master's Theses

It has long been recognized that bedrock streams gradually adjust their slopes towards topographic steady state, an equilibrium state between rock uplift rate and erosion rate. Tectonic geomorphology studies often analyze stream profiles for clues of this adjustment, which can initiate from changes in tectonic and climatic forcings. The stream power incision model, the most widely utilized framework with which to interpret bedrock stream profiles, predicts that streams perturbed from topographic steady state by changes in bedrock erodibility or uplift rate adjust their slopes to return to topographic steady state through upstream propagating waves of incision, or knickpoints. Under the …


Environmental Influences On Tree-Driven Karst Bedrock Physical Weathering, Cole Robert Jimerson Jul 2020

Environmental Influences On Tree-Driven Karst Bedrock Physical Weathering, Cole Robert Jimerson

Graduate Theses and Dissertations

The role of tree roots as stressors that contribute to physical weathering processes and thus soil generation remains an open question in critical zone science. While evidence suggests roots may be able to damage rock by accessing pre-existing fractures, where they can expand due to water uptake or generate forces on rock in response to wind gusts, these processes have not been investigated in temperate karst regions until now. I monitored forces at the root-rock interface for an American elm and Hackberry tree between September 2019 and May 2020. I used piezoelectric force sensors to determine if differences in species, …


Crystal Queer: Fracturing The Binaries Of Matter, Creation, And Landscape, Sarah Knight May 2020

Crystal Queer: Fracturing The Binaries Of Matter, Creation, And Landscape, Sarah Knight

Graduate School of Art Theses

In this thesis, I compile a series of fragments consisting an analysis of my artwork in the gendered contexts of landscape, self-identity, mythology, and philosophy. I develop my concept of a “queer mark” in my art that serves as a form of queering, a disruption of visual and conceptual cohesion. I form a picture of how our contemporary selves are influenced by our gendered understanding of the landscape through the analysis of philosophical, artistic, and mythological concepts of creation. I see my sculptures as an atlas to an alternative means of understanding identity, a queering of these historical and exclusionary …


Characterization Of Surface Karst Using Lidar And Field Traverses, Fort Hood Military Installation, Coryell County, Texas, Heather Jaclyn Dailey May 2020

Characterization Of Surface Karst Using Lidar And Field Traverses, Fort Hood Military Installation, Coryell County, Texas, Heather Jaclyn Dailey

Electronic Theses and Dissertations

The Fort Hood Military Installation is a karst landscape that has been significantly altered for training exercises that include heavy vehicle maneuvers and simulated combat. Traditional karst surveys are often time-consuming and require extensive field analyses to adequately characterize large areas. Bias is given to areas that are most easily accessible and false negatives are common. Previous studies conducted in the eastern and western portion of the base have understated the abundance and spatial distribution of karst, particularly in the western portion.

This study used field traverses and 0.5-meter Light Detection and Ranging (LiDAR) data to characterize surface karst depressions, …


Spatial Analysis Of Soil Creep Rates On Mount Sequoyah, Fayetteville Arkansas, Amy Suzanne Morris May 2020

Spatial Analysis Of Soil Creep Rates On Mount Sequoyah, Fayetteville Arkansas, Amy Suzanne Morris

Graduate Theses and Dissertations

Mount Sequoyah in Fayetteville, Arkansas, is a part of the Boston Mountains, which are considered a deeply dissected plateau. The area is prone to mass wasting, which is the general downslope movement of sediments, soils, and rock through different processes that cause instabilities along a hillslope, and in its soil and loose rubble mantle. For this study, we looked at soil creep, which is the small-scale movement of soil downhill because of gravity, wetting and drying cycles, and heating and cooling cycles.

By measuring the tilt of utility poles, we determined multiple causes of soil creep. The variables that are …


411— Analysis Of Hillslope Stability, Harriman, Tennessee, Walter Hennings, Anthony Wagman Apr 2020

411— Analysis Of Hillslope Stability, Harriman, Tennessee, Walter Hennings, Anthony Wagman

GREAT Day Posters

We seek to conduct a hillslope safety analysis of a hill located in Roane County, Tennessee, composed of the Gilpin-Petros soils. This unit is composed primarily of residuum from sandstone, siltstone, and shale. The stability of the hill was assessed using a one-dimensional infinite slope-stability model. This model was used to calculate the factor of safety under both dry and wet conditions based on a set of assumptions derived from soil lithology and hydrologic parameters. Simulations in ArcGIS show that under dry conditions, the slope is unconditionally stable at all locations. Under conditions of sufficiently heavy rainfall (>9 inches …


An Analysis Of The Reactivation Potential Of A Deep-Seated Landslide In The Oregon Coast Range Under Varying Hydrologic Conditions With Seismic Triggering, Emily E. Smoot Apr 2020

An Analysis Of The Reactivation Potential Of A Deep-Seated Landslide In The Oregon Coast Range Under Varying Hydrologic Conditions With Seismic Triggering, Emily E. Smoot

Anthós

Landslides can occur in many locations across the world and have the potential to be extremely destructive if failures occur near populated areas. Failures are most likely to occur on slopes that have already experienced numerous failures. This means they are a considerable hazard, and the risk involved with building in areas that have previously experienced landslides should be adequately understood. This study examines the reactivation potential of a deep-seated landslide located in the Oregon Coast Range. The analysis of this landslide included creating a map of the surface morphology and computing the factor of safety for the deposit using …


The Long-Term Outlook Of The Mississippi-Atchafalaya Bifurcation: A Convergence Of Engineering, Economics, And Deltaic Evolution, Thomas Mitchell Andrus Apr 2020

The Long-Term Outlook Of The Mississippi-Atchafalaya Bifurcation: A Convergence Of Engineering, Economics, And Deltaic Evolution, Thomas Mitchell Andrus

LSU Doctoral Dissertations

The most recent and currently active delta lobe of the Mississippi River (MR) is the Atchafalaya-Wax Lake lobe, which was initiated approximately 400 years ago as a result of MR stream capture by the Atchafalaya River (AR). This capture process accelerated in the early to mid-1900s but further progress was prevented by construction and operation of the Old River Control Structure (ORCS) Complex. Many recent studies indicate that MR system below the ORCS is on a retreating geologic trajectory due to contributing factors such as sea level rise, subsidence, faulting, and declining hydraulic stream power. Diversions along the Lower MR …


Cave Airflow Mechanism Of A Crevice-Type Cave: A Case Study From Czechia, Martin Kašing, Jan Lenart Apr 2020

Cave Airflow Mechanism Of A Crevice-Type Cave: A Case Study From Czechia, Martin Kašing, Jan Lenart

International Journal of Speleology

At present, crevice-type caves are investigated mainly by means of geomorphic and geophysical methods. Microclimatic research of this type of caves is underrepresented and is often limited to temperature and humidity measurement only. Yet, microclimatic research of such caves can significantly help in the management and conservation of caves, speleological exploration or analysis of speleothems. Being the first ever research of ventilation within a crevice-type cave, a complex analysis of cave ventilation was performed within the Velká Ondrášova Cave, a crevice-type cave in the Outer Western Carpathians, Czechia. Long-term temperature recording, airflow tracing within the cave, and a total of …


Quantifying Tekeze River Canyon Incision On The Ethiopian Plateau From Low-Temperature Apatite Thermochronology, Jacob Thomas Grigsby Apr 2020

Quantifying Tekeze River Canyon Incision On The Ethiopian Plateau From Low-Temperature Apatite Thermochronology, Jacob Thomas Grigsby

Masters Theses & Specialist Projects

The Ethiopian Plateau in East Africa features dynamic topography, deep river incision (~1.5 km), active tectonics, continental rifting, volcanic terrain and ~2 km of plateau uplift. Situated on the northwestern part of the Ethiopian Plateau, the Tekeze River is one of the two major rivers associated with incising and documenting the recent geologic history of the uplifted plateau landscape. The consequential Tekeze River incision into the uplifted Ethiopian Plateau is associated with the arrival and impingement of the Afar mantle plume as evidenced by the presence of thick sheets of Cenozoic flood basalts (~30 Ma). However, the Cenozoic to present-day …


Nebraska Statewide Groundwater-Level Monitoring Report 2019, Aaron R. Young, Mark E. Burbach, Leslie M. Howard, Sue Olafsen Lackey, Robert Matthew Joeckel Apr 2020

Nebraska Statewide Groundwater-Level Monitoring Report 2019, Aaron R. Young, Mark E. Burbach, Leslie M. Howard, Sue Olafsen Lackey, Robert Matthew Joeckel

Conservation and Survey Division: Faculty and Staff Publications

The term “groundwater” has come to be all but synonymous with Nebraska. Nearly three-quarters of the total volume of the High Plains Aquifer lies beneath the State. Groundwater maintains our streams, our ecosystems, our people, and our vitally important agricultural economy. Nebraska’s total groundwater resource is vast, yet it is also vulnerable to natural and anthropogenic changes, necessitating a long-term commitment to wise management through informed decision making. Monitoring, studying, and reporting form the essential basis for such management and, ultimately, for meeting the myriad challenges presented by change.

The personnel of the Conservation and Survey Division (CSD) are proud …