Publications And Other Works By R. F. Diffendal, Jr., 2024 University of Nebraska-Lincoln
Publications And Other Works By R. F. Diffendal, Jr., Robert F. Diffendal Jr.
School of Natural Resources: Faculty Publications
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Updated March 2024
Fauna, Flora, And Land Cover Changes Over The Last Two Decades In The Mobile-Tensaw River Delta, 2024 University of South Alabama, Mobile, AL
Fauna, Flora, And Land Cover Changes Over The Last Two Decades In The Mobile-Tensaw River Delta, Gabriel De Oliveria, Steven R. Schultze, Guilherme Mataveli
Technical Reports
A technical report documenting ecosystem changes to the Mobile-Tensaw River Delta region due to urban expansion over approximately two decades (2001-2019).
Reverse Pseudo-Gours: A New Sub-Type Of Folia Observed In The Nerja Cave (Se Spain), 2023 Research Institute Nerja Cave and University of Malaga, Spain
Reverse Pseudo-Gours: A New Sub-Type Of Folia Observed In The Nerja Cave (Se Spain), Cristina Liñán Baena, Concepción Jiménez De Cisneros, Yolanda Del Rosal, Paolo Forti
International Journal of Speleology
A new sub-type of folia named “reverse pseudo-gour” has been observed and described in the Nerja Cave, southern Spain. It consists of fairly vertical, thin barriers (about 5 mm high and 2 mm thick) that develop on the underside of a sub-horizontal surface (shelfstone) and grow in the opposite direction to normal gours (rimstone dams), generating sinuous shapes. Their mineral composition is essentially calcium carbonate, although globular aggregates composed of clay and phosphate minerals have also been identified. The genesis and evolution of these reverse pseudo-gours occur just at the air-water interface and are controlled by (1) the sub-horizontality of …
Comparative Lineament And Geomorphic Analysis Of Chaotic Terrains And Noctis Labyrinthus, Mars, 2023 Stephen F Austin State University
Comparative Lineament And Geomorphic Analysis Of Chaotic Terrains And Noctis Labyrinthus, Mars, Sarah A. Walton
Electronic Theses and Dissertations
Noctis Labyrinthus (NL) is an extensional trough network connecting the Tharsis rise and Valles Marineris on Mars. Chaotic terrains are a group of polygonally-fractured surface features commonly associated with subsidence due to rapid fluid loss within the subsurface. Polygonal surface patterns are seen at both sites, where geometric topographic highs are bounded by low troughs. Lineaments, topography, and geomorphology of NL and chaotic terrains were analyzed to determine tectonics and fluid influence in the formation and evolution of both sites. NL shows preferential fracture patterns associated with regional extension. Lineaments within chaotic terrains do not show cumulative preferential trends but …
The Broadwater Formation (Pliocene) Of Nebraska And Southeastern Wyoming, 2023 University of Nebraska-Lincoln
The Broadwater Formation (Pliocene) Of Nebraska And Southeastern Wyoming, Robert F. Diffendal Jr., James B. Swinehart
Robert F. Diffendal, Jr., Publications
The Broadwater Formation, initially defined in 1945, is a Pliocene-aged coarse-grained alluvial deposit in Nebraska and southeastern Wyoming. It is characterized by a complex stratigraphic history and debated geologic interpretations. The formation is a rich resource of groundwater for the citizens of Nebraska and the Central Great Plains. We aim to synthesize and redefine the Broadwater Formation, shedding light on its distribution, geological characteristics, and paleoenvironmental significance. While historical hypotheses on Broadwater Formation paleovalley trajectories suggested northwest-southeast trending valleys, later investigations proposed wind-driven erosional patterns to explain the unique topographic features observed. The Broadwater is divided into an unnamed Upper …
The Tidal Prism, Viable Eelgrass Habitat, And The Effects Of Sea Level Rise In Morro Bay, 2023 California Polytechnic State University, San Luis Obispo
The Tidal Prism, Viable Eelgrass Habitat, And The Effects Of Sea Level Rise In Morro Bay, Kaden A. Caliendo
Master's Theses
The tidal prism, or the volume of water exchanged from the sea to an estuary from mean low to mean high tide, influences system hydrodynamics and ecological functioning. Since 1884, the tidal prism in Morro Bay, California has been estimated to be decreasing over time due to sedimentation from upstream practices. What is the current tidal prism in Morro Bay and how will that change with sea level rise? How will eelgrass respond to rising sea levels?
For this study, inexpensive tidal gauges were deployed at four locations in Morro Bay from March to August 2023 to measure spatially varying …
The Spatial And Temporal Distribution Of Large Rock Blocks And Control On Landscape Evolution In The Ozarks, 2023 University of Arkansas-Fayetteville
The Spatial And Temporal Distribution Of Large Rock Blocks And Control On Landscape Evolution In The Ozarks, Chelsea Moran
Graduate Theses and Dissertations
Geologists often use landscape form to infer landscape processes through time. While climate and tectonics shape geomorphic form, the potential range of spatial or temporal scales that can shape any specific landscape can render landscape process-form based hypotheses too general for consideration. Contributions by mathematical modeling have helped bridge the gap between inferring processes from form, notably in how sediment transport dynamics shape hillslopes. However, few models encapsulate the movement of large rock blocks ( >2 meters across) and their potential impact as hillslope sediment transport disruptors. The Upper Buffalo River watershed (BRW) in the Ozarks of northern Arkansas has …
Book Review: Australian Caves And Karst Systems, John Webb, Susan White, Garry K. Smith, 2023 Italian Institute of Speleology, Bologna
Book Review: Australian Caves And Karst Systems, John Webb, Susan White, Garry K. Smith, Jo De Waele
International Journal of Speleology
No abstract provided.
Seasonal Dynamics Of Karst Surface Dissolution Based On A Limestone Tables Experiment (Slovak Karst), 2023 Institute of Geography, University of P.J. Šafárik, Košice, Slovakia
Seasonal Dynamics Of Karst Surface Dissolution Based On A Limestone Tables Experiment (Slovak Karst), Alena Gessert, Zdenko Hochmuth
International Journal of Speleology
Chemical denudation in karst is the basic process of karst relief formation. However, it is influenced by many factors of varying intensity that depend on the climatic conditions and characteristics of each given location. Based on measurable results of weight loss of limestone tablets, we monitored the intensity of chemical denudation in two areas of the Slovak Karst, Silica Plateau and Jasov Plateau that are situated in the most developed karst plateau region of Slovakia. Both experimental sites are similar in terms of geographical conditions, thus comparable between them. In each locality, we placed three sets of standardized tablets at …
An Attempt To Identify Source Areas Of Clastic Deposits From Selected Caves Of The Prokletije Mountains (Montenegro): A Mineralogical And U-Series Geochemistry Approach, 2023 Adam Mickiewicz University, Poznań, Poland
An Attempt To Identify Source Areas Of Clastic Deposits From Selected Caves Of The Prokletije Mountains (Montenegro): A Mineralogical And U-Series Geochemistry Approach, Ditta Kicińska, Jacek Pawlak, Jacek Stienss
International Journal of Speleology
The Prokletije Mountains/Albanian Alps are the highest part of the Dinaric Mountains. Paradoxically, these mountains and their cave areas remain among the most enigmatic in Europe, having only recently become subjects of scientific research and cave exploration. This paper focuses on the Kolata and Greben massifs, where the highest, and thus the oldest, cave systems are located. Through the analysis of heavy mineral composition, the apatite-tourmaline index, and cluster analysis for mineralogical composition and uranium isotopic data, it becomes possible to identify the source areas for the cave clastic deposits. It also allow to distinguish multiple paleoflow directions, each corresponding …
Terrestrial Craters As Analogues For Degraded Craters On Titan, 2023 The University of Western Ontario
Terrestrial Craters As Analogues For Degraded Craters On Titan, Taylor M. Duncan
Electronic Thesis and Dissertation Repository
Besides Earth, Titan is the only planetary body in our Solar System to currently have flowing liquid on its surface. Previous works note that dendritic and rectangular stream networks are present on a global scale on Titan, but do not map networks in the vicinity of Titan’s impact craters: Selk and Sinlap. The objective of this work is to understand how stream networks form adjacent to Titan’s impact craters. This information will inform future missions to Titan (i.e., Dragonfly) about the fluvial morphology of streams near their landing site. I conduct an analogue study with the stream networks at three …
Investigating Mercer's Paradox: A 10be Chronology Of Moraines Deposited During The Last Glaciation At Soda Lake, Wind River Range, Wyoming, U.S.A., 2023 University of Maine
Investigating Mercer's Paradox: A 10be Chronology Of Moraines Deposited During The Last Glaciation At Soda Lake, Wind River Range, Wyoming, U.S.A., Lauren M. Woods
Electronic Theses and Dissertations
Here I use geomorphic mapping and 10Be surface-exposure dating to address the paradox that lies within the general understanding of the mechanisms driving ice-age climate and glacial cycles. The long-standing and widely accepted Murphy-Milankovitch hypothesis suggests glacial cycles are controlled by the local intensity of summer-time insolation. By this hypothesis, glacier maxima should be achieved at times of low insolation intensity and asynchronously between the polar hemispheres, a pattern which is inconsistent with the glacial geomorphic record. The 10Be chronology I have constructed of moraines at Soda Lake, Wind River Range, Wyoming, U.S.A. shows nine glacial advances to …
Seismic Analysis Of The Upper & Lower Falls Of The Yellowstone River, 2023 University of New Mexico
Seismic Analysis Of The Upper & Lower Falls Of The Yellowstone River, Loring Schaible
Earth and Planetary Sciences ETDs
Twelve years of concurrent hydrologic and continuous seismic data along with temporary seismic data demonstrate that the Upper and Lower Falls of the Grand Canyon of the Yellowstone River comprise a highly localized source of 0.5-5 Hz seismic energy that overwhelms anthropogenic contributions. In aggregate, seismic amplitude from 2008-2019 is linearly related to discharge with a correlation coefficient of 0.96. Repeated deviations from this linear relationship persist for 1-2 weeks prior to the date that Yellowstone Lake becomes clear of winter ice coverage. Seismic efficiency increases by ~50-250% during this period of ice-breakup, during which lake ice flows into the …
Predictive Modeling Of Cave Entrance Locations: Relationships Between Surface And Subsurface Morphology, 2023 University of Kentucky, Lexington, USA
Predictive Modeling Of Cave Entrance Locations: Relationships Between Surface And Subsurface Morphology, William Blitch, Adia R. Sovie, Benjamin W. Tobin
International Journal of Speleology
Cave entrances directly connect the surface and subsurface geomorphology in karst landscapes. Understanding the spatial distribution of these features can help identify areas on the landscape that are critical to flow in the karst groundwater system. Sinkholes and springs are major locations of inflow and outflow from the groundwater system, respectively, however not all sinkholes and springs are equally connected to the main conduit system. Predicting where on the landscape zones of high connectivity exist is a challenge because cave entrances are difficult to detect and imperfectly documented. Wildlife research has a similar issue of understanding the complexities of where …
Polygonal Faults In The Austin Chalk: Invariance Of Scale From Mud Cracks To Polygons With Implications Of Structural, Geomorphic And Isotopic Data On Polygonal Fault Geometry And Origin., 2023 Southern Methodist University
Polygonal Faults In The Austin Chalk: Invariance Of Scale From Mud Cracks To Polygons With Implications Of Structural, Geomorphic And Isotopic Data On Polygonal Fault Geometry And Origin., Kun Shang
Earth Sciences Theses and Dissertations
The Cretaceous Austin Chalk contains large numbers of fractures and normal faults whose orientations have been attributed to either regional stresses (e.g., the Balcones fault trend) or, by analogy with the mudrocks, to polygonal faulting resulting from compaction. In this study, we present geomorphic data, field study, and stable isotope data to support that the majority of these faults in North Texas are polygonal. Field-measured fault orientations suggest randomly distributed fault strikes, indicating a polygonal fault structure. Using geomorphologic data (topographic and DEM data) on stream orientations suggests that the polygonal fault patterns are best reflected in the headwater (1st …
Preliminary Data Of Potentially Hazardous Radon Concentrations In Modrič Cave (Croatia), 2023 Department of Geography, University of Zadar, Croatia
Preliminary Data Of Potentially Hazardous Radon Concentrations In Modrič Cave (Croatia), Robert Lončarić, Vanja Radolić, Maša Surić, Igor Miklavčić, Matea Šatalić, Dalibor Paar, Lukrecija Obšivač
International Journal of Speleology
Instigated by relatively high cave-air CO2 concentrations in Modrič Cave (Croatia) recorded for the purpose of speleothem-based paleoclimate research, we established preliminary monitoring of radon (222Rn) concentrations within the cave for a 4.5-year period (2018–2022). As radioactive geogenic gas, radon, which often correlates with cave-air CO2 concentrations, presents a potential health hazard in cases of longer exposure time in high concentration conditions. Since the Modrič Cave is open to tourists and long-term scientific research has been performed within, a safety assessment for radon concentrations was essential. The integrated measurements of radon concentrations were performed by passive …
4d Flow Pattern Of The Longest Cave In The Eastern Alps (Schönberg-Höhlensystem, Totes Gebirge), 2023 Natural History Museum, Vienna, Austria
4d Flow Pattern Of The Longest Cave In The Eastern Alps (Schönberg-Höhlensystem, Totes Gebirge), Lukas Plan, Eva Kaminsky, Pauline Oberender, Clemens Tenreiter, Maximilian Wimmer
International Journal of Speleology
The Schönberg-Höhlensystem (SBH) is not only the longest cave system in the Eastern Alps (length 156 km, depth 1061 m), but a significant proportion of the passages have developed on or just below two surfaces that dip 1.7° to the NE. These so-called "speleogenetic phases" are rarely developed in caves of the Northern Calcareous Alps and have not yet been confirmed by detailed morphological mapping. Furthermore, the deep parts of the cave offer the possibility to study the active epiphreatic zone for a distance of 1.6 km. Detailed morphological mapping shows that the main level at about 1500 m a.s.l. …
Downstream Gradients In Unit Stream Power Influence Log Jam Location And Process Domain, 2023 Dartmouth College
Downstream Gradients In Unit Stream Power Influence Log Jam Location And Process Domain, Eliza H. Malakoff
Dartmouth College Master’s Theses
Growing calls for the use of natural materials and processes to meet management goals have positioned artificial log jams as a compelling alternative to hard engineering instream and floodplain habitat. Deep uncertainties remain, however, about where and how wood should be placed to best mimic natural river processes. In this study, I test whether at-a-point or downstream gradients in unit stream power, an estimate of a river’s ability to do work, exert control over where and how log jams form. Using field observations of 360 log jams in New Hampshire and Vermont and an additional 320 previously published locations of …
Evaluating The Relationship Between Methane Seeps And Seafloor Geomorphology On The Northern Us Atlantic Margin, 2023 Mississippi State University
Evaluating The Relationship Between Methane Seeps And Seafloor Geomorphology On The Northern Us Atlantic Margin, Gabriel Hernandez
Theses and Dissertations
Methane seeps are a transport pathway for carbon from seafloor sediments to the marine environment with important implications for global biogeochemical cycling. Accordingly, there is substantial interest in better understanding the processes that control seep location and predicting the distribution of seeps with existing seafloor datasets. Visual evaluation of methane seeps, in multibeam sonar water column data, suggests a spatial relationship between seeps and specific seafloor morphologic features such as ridge crests. In this thesis, seafloor geomorphology at 1996 seep detection sites on the US Atlantic margin was quantitatively characterized by geomorphologic phonotype, bathymetric position index, slope, rugosity, and aspect …
Spot1356 Black Rock, 2023 University of New Orleans
Spot1356 Black Rock, Robert C. Mahon, Elizabeth J. Trower, Benjamin P. Smith, Tyler A. Lincoln, Juliana Olsen-Valdez, John S. Magyar, Cedric J. Hagen
2D Wave Spectral Data, South Arm, Great Salt Lake, Utah
Data in this folder are produced by a SoFarOcean Spotter wave buoy deployed along the south arm of the Great Salt Lake, near Antelope Island State Park from the period of July 13, 2021 through June 28, 2022, in relatively shallow water, approximately 1.6m.