Contribution Of High Turbidity To Tidal Dynamics In A Curved Channel In Zhoushan Islands, China, Li Li, Fangzhou Shen, Zhiguo He, Gangfeng Ma, Jiachen Wang, Kailong Huangfu

Civil & Environmental Engineering Faculty Publications

The curved tidal channel, Luotou Deep-water Navigational Channel, is the main channel of the Ningbo Zhoushan Port, which is ranked first in the world. Tidal dynamics in the channel are spatially and temporally asymmetric. In this study, the three-dimensional tidal dynamics in the channel were analyzed using field data and simulated using FVCOM. The results show that the tides in the channel flood/ebb along the northern/southern bank near the bottom/surface layer and these asymmetries are due to the imbalanced Coriolis force, centrifugal force, sea-level gradient, and density gradient. Residual current velocity peaks (0.7 m/s) in the middle of the channel …

Quantifying Chemical Erosion In The Lithologically-Heterogenous Appalachian Valley And Ridge, Amelia Jayne Zanoni

Graduate Theses, Dissertations, and Problem Reports (ETD)

Quantifying chemical erosion in the lithologically-heterogenous Appalachian Valley and Ridge

Amelia J. Zanoni

The interplay between physical and chemical erosion is well understood in landscapes underlain by a uniform rock type, but many regions are underlain by a mixture of rock types with varying erosion resistance and solubility. We used measurements of stream-water chemistry to estimate chemical erosion rates in the Appalachian Valley and Ridge, a region where the mechanisms of lithologic control over topography are poorly understood. Newly acquired stream water samples were collected from 51 locations across the research area during the Fall of 2023. The sampled waters …

(Non-) Recovery Of An Agricultural Stream From Straightening And Dredging, Aras Anderson Mann

Graduate Theses, Dissertations, and Problem Reports (ETD)

In recent history, natural, meandering streams have been straightened and dredged to reduce flooding. While this practice can be effective in reducing flooding locally, it often results in the degradation of stream water quality and aquatic ecosystems. A straighter channel inherently increases the stream gradient, which could increase flow velocity, shear stress, and potentially downstream sediment yield. Studies have shown that straightened, channelized streams often begin to return to a meandering pattern 35-50 years post-channelization. Yet cross-sectional surveys and air photo analysis of the stream reach in this study, Deckers Creek, indicate little to no observable trend of the stream …

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, 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, 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, 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 …

Modeling The Peak Ground Acceleration And Assessing The Economic Loss And Casualty Due To Potential Earthquakes Of Various Magnitudes In The New Madrid Seismic Zone, Mahmud Afroz

Graduate Theses and Dissertations

The New Madrid Seismic Zone (NMSZ) is one of the active tectonic zones capable of producing big earthquakes in the southcentral USA. The objective of this study was to assess the economic losses and casualties that might be caused by various magnitudes of seismic events in the NMSZ. The manifestation is the estimation for each magnitude which is using the Peak Ground Acceleration (PGA) that might occur during an earthquake. It is calculated using an attenuation function that correlates the intensity of local ground movement, the earthquake magnitude, and the distance from its epicenter. The assessment of casualties was conducted …

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, Jo De Waele

International Journal of Speleology

No abstract provided.

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, 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 …

New Insights Into The Tectonic Framework & Geologic Features Of The Bengal Basin, Bangladesh, Shahriar Bin Shahid

Masters Theses & Specialist Projects

In this research, high-resolution SRTM-based NASA Digital Elevation Models (DEM) data and published literature have used to gain new insights regarding South-east Asian surficial geology, fluvial geomorphology, and tectonics, focusing on the Bengal Basin. Seismic databased discovery of shallow, down-warping and >30 km thick Indian crust challenges prior knowledge of crustal origin, which was thought to be oceanic rather than continental in origin due to high-angle subduction. Furthermore, the collapse of the Indian passive margin beneath the Shillong Plateau may have formed a 20 km thick Surma Basin on top and has led to substantial earthquake risks. To update the …

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, 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., 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), 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), 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, 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, 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 …