Geology Commons^™

Quantifying The Effect Of Topographic Slope On Lava Flow Thickness: A First Step To Improve Lava Flow Volume Estimation Methods, Steven R. Rizo

USF Tampa Graduate Theses and Dissertations

The volume of lava flows provide important information on the magnitude of volcanic eruptions, and accurate volumes are necessary to produce reliable models of lava flow emplacement or constrain the internal structure of volcanoes. The most accurate lava flow volumes are obtainable when the topography before and after an eruption are both known, but information for the topography before lava flow emplacement is absent in non-historic lava flows. To calculate the volume of non-historic lava flows, this pre-emplacement topography needs to be reconstructed. Common methods for this include using inverse distance-weighted averages or global polynomial interpolation methods, but these can …

Signal Propagation, Provenance, And Climate Records In The Indus Submarine Canyon Since The Last Deglacial, Yuting Li

LSU Doctoral Dissertations

The Monsoon is one of the most powerful climatic phenomena on Earth and controls environments in South Asia. Erosion and weathering patterns are influenced by monsoon variations and can be reconstructed through marine sediment records. However, such reconstruction is based on the assumption that such sediments are representative of the onshore basins from which they are sourced. Debate continues regarding the degree to which storage and recycling homogenize short-term variations in sediment compositions. The Indus Submarine Canyon links the river mouth and the deep-water fan of the Indus drainage system. Determining how sediment fluxes through this canyon is important if …

The Wildcat Creek Tuff, Eastern Oregon: Co-Eruption Of Crystal-Poor Rhyolite And Fe-Rich Andesite With Implication For Mafic Underpinnings To Voluminous A-Type Rhyolites, Hillarie Jaye Sales

Dissertations and Theses

The Wildcat Creek Tuff is a thin (~3-12 m), rhyolite to andesitic ash-flow tuff with a minimal extent of 1500 km² in Malheur county, eastern Oregon. The previously undated tuff yielded a single crystal, anorthoclase ⁴⁰Ar/³⁹Ar age of 15.49±0.02 Ma and thus is closely related to mafic and silicic volcanism of the Columbia River Province. The tuff texturally stands out by its high proportion of co-mingled mafic inclusions appearing as dark, scoriaceous, and phenocryst-poor fragments, and their proportion dictate bulk tuff compositions ranging from rhyolite (74% SiO2) to andesite (59% SiO₂). Glass analyses confirm …

Irrigated Agriculture And Future Climate Change Effects On Groundwater Recharge, Northern High Plains Aquifer, Usa, Zachary H. Lauffenburger, Jason J. Gurdak, Chris Hobza, Duane Woodward

United States Geological Survey: Staff Publications

Understanding the controls of agriculture and climate change on recharge rates is critically important to develop appropriate sustainable management plans for groundwater resources and coupled irrigated agricultural systems. In this study, several physical (total potential (ψT) time series) and chemical tracer and dating (3H, Cl−, Br−, CFCs, SF6, and 3H/3He) methods were used to quantify diffuse recharge rates beneath two rangeland sites and irrigation recharge rates beneath two irrigated corn sites along an east-west (wet-dry) transect of the northern High Plains aquifer, Platte River Basin, central Nebraska. The field-based recharge estimates and historical climate were used to calibrate site-specific Hydrus-1D …

Humans Thrived In South Africa Through The Toba Eruption About 74,000 Years Ago, Eugene I. Smith, Zenobia Jacobs, Racheal Johnsen, Minghua Ren, Erich C. Fisher, Simen Oestmo, Jayne Wilkins, Jacob A. Harris, Panagiotis Karkanas, Shelby Fitch, Amber Ciravolo, Deborah Keenan, Naomi Cleghorn, Christine S. Lane, Thalassa Matthews, Curtis W. Marean

Geoscience Faculty Research

Approximately 74 thousand years ago (ka), the Toba caldera erupted in Sumatra. Since the magnitude of this eruption was first established, its effects on climate, environment and humans have been debated1. Here we describe the discovery of microscopic glass shards characteristic of the Youngest Toba Tuff—ashfall from the Toba eruption—in two archaeological sites on the south coast of South Africa, a region in which there is evidence for early human behavioural complexity. An independently derived dating model supports a date of approximately 74 ka for the sediments containing the Youngest Toba Tuff glass shards. By defining the input of shards …

Glacier Inventories And Change In Glacier National Park, Melissa Carrie Brett

Dissertations and Theses

Glacier National Park, in northwestern Montana, is a unique and awe-inspiring national treasure that is often used by the media and public-at-large as a window into the effects of climate change. An updated inventory of glaciers and perennial snowfields (G&PS) in the Park, along with an assessment of their change over time, is essential to understanding the role that glaciers are playing in the environment of this Park. Nine inventories between 1966 and 2015 were compiled to assess area changes of G&PS. Over that 49-year period, total area changed by nearly -34 ± 11% between 1966 and 2015. Volume change, …

Fire-Induced Mineralogical Changes In Midwest Tallgrass Prairie Soils, Lacey Legrand

UNO Student Research and Creative Activity Fair

Tallgrass prairies are productive ecosystems that historically covered a large part of the Midwest and in the past were subjected to frequent, natural fire regimes. Today prairie remnants are often managed by ecological burns. Glacier Creek Preserve is a restored prairie in Omaha, Nebraska that includes randomized research plots established in 1978 to study the effects of burning on vegetation and provides a controlled field environment to investigate the effects of fire on soils. The purpose of this study is to compare soil mineralogy in long-term burned and unburned plots to answer the question: “Does prescribed burning induce mineralogical changes …

The Island Of Amsterdamøya: A Key Site For Studying Past Climate In The Arctic Archipelago Of Svalbard, Jostein Bakke, Nicholas Balascio, Willem G.M. Van Der Bilt, Raymond Bradley, William J. D' Andrea, Marthe Gjerde, Sædís Ólafsdóttir, Torgeir Røthe, Greg De Wet

Geosciences: Faculty Publications

This paper introduces a series of articles assembled in a special issue that explore Holocene climate evolution, as recorded in lakes on the Island of Amsterdamøya on the westernmost fringe of the Arctic Svalbard archipelago. Due to its location near the interface of oceanic and atmospheric systems sourced from Arctic and Atlantic regions, Amsterdamøya is a key site for recording the terrestrial response to marine and atmospheric changes. We employed multi-proxy approaches on lake sediments, integrating physical, biogeochemical, and isotopic analyses to infer past changes in temperature, precipitation, and glacier activity. The results comprise a series of quantitative Holocene-length paleoclimate …

Holocene Glacier Activity Reconstructed From Proglacial Lake Gjøavatnet On Amsterdamøya, Nw Svalbard, Gregory A. De Wet, Nicholas L. Balascio, William J. D'Andrea, Jostein Bakke, Raymond S. Bradley, Bianca Perren

Geosciences: Faculty Publications

Well-dated and highly resolved paleoclimate records from high latitudes allow for a better understanding of past climate change. Lake sediments are excellent archives of environmental change, and can record processes occurring within the catchment, such as the growth or demise of an upstream glacier. Here we present a Holocene-length, multi-proxy lake sediment record from proglacial lake Gjøavatnet on the island of Amsterdamøya, northwest Svalbard. Today, Gjøavatnet receives meltwater from the Annabreen glacier and contains a record of changes in glacier activity linked to regional climate conditions. We measured changes in organic matter content, dry bulk density, bulk carbon isotopes, elemental …

Platy Galena From The Viburnum Trend, Southeast Missouri: Character, Mine Distribution, Paragenetic Position, Trace Element Content, Nature Of Twinning, And Conditions Of Formation, Richard D. Hagni

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Viburnum Trend of southeast Missouri is one of the world’s largest producers of lead. The lead occurs as galena, predominantly in two crystallographic forms, octahedrons and cubes. Many studies have shown that octahedral galena is paragentically early, the more abundant of the two crystal forms, and is commonly modified in the cube. Those studies also have shown that the cubic form is paragenetically later, less abundant than the octahedrons, and may exhibit minor octahedral modifications. Viburnum Trend galena crystals that exhibit a platy form have received almost no study. The reason for their lack of study is the rarity …

Landscapes From The Waves—Marine Terraces Of California, Marjorie Schulz, Corey Lawrence, Daniel R. Muhs, Carol Prentice, Sam Flanagan

United States Geological Survey: Publications

M any coastlines around the world have stair-step landforms, known as marine terraces. Marine terraces make up a large part of coastal California’s landscape—from San Diego to Crescent City. Find out how these landscapes form, why marine terraces are of interest to scientists, and where you can explore these landscapes.

Marine terraces result from the interaction of two geologic processes: uplift of the land surface and the natural rise and fall of sea level over hundreds of thousands of years. As sea level rises, waves move underwater sediment—sand and gravel—back and forth against bedrock, acting like sandpaper to hone bedrock …

Drivers Of Solar Radiation Variability In The Mcmurdo Dry Valleys, Antarctica, Maciej K. Obryk, Andrew G. Fountain, Peter T. Doran

Geology Faculty Publications and Presentations

Annually averaged solar radiation in the McMurdo Dry Valleys, Antarctica has varied by over 20 W m−2 during the past three decades; however, the drivers of this variability are unknown. Because small differences in radiation are important to water availability and ecosystem functioning in polar deserts, determining the causes are important to predictions of future desert processes. We examine the potential drivers of solar variability and systematically eliminate all but stratospheric sulfur dioxide. We argue that increases in stratospheric sulfur dioxide increase stratospheric aerosol optical depth and decrease solar intensity. Because of the polar location of the McMurdo Dry Valleys …

Lithofacies And Sequence Architecture Of The Upper Desert Creek Sequence (Middle Pennsylvanian, Paradox Formation) In The Greater Aneth Field, Southern Paradox Basin, Utah, Evan R. Gunnell

Theses and Dissertations

The Greater Aneth Buildup (GAB) is comprised of the 3rd-order middle Pennsylvanian (Desmoinesian) Desert Creek sequence of the Paradox Formation. A hierarchy of 4th- and 5th order, carbonate-dominated cycles comprise the Upper Desert Creek (UDC) 4th-order sequence. A SE to NW trending transect line, utilizing core and petrophysical data from six oil and gas wells (from SE to NW wells R-19, Q-16, O-16, J-15, K-430, E-313), revealed deposition of seven carbonate facies within four 5th-order parasequences in the UDC. While each of the seven carbonate facies are present across the transect line, the UDC parasequences are dominated by a shallow-water …

Fossils On The Floor In The Nebraska State Capitol: A Coloring And Activities Book, Robert F. Diffendal Jr.

Conservation and Survey Division: Faculty and Staff Publications

The Nebraska State Capitol is a wonderful place. This building is home to great treasures of art owned by the people of Nebraska. The floor of the Capitol Rotunda has beautiful works of art. Maybe you have seen this art. Small pieces of two kinds of rocks make pictures of people, their tools, the natural resources they used, and pictures of fossil animals and plants. These kinds of pictures are called mosaics [moe ZAY icks]. The animals and plants follow one another in a curved ribbon around the floor. In that ribbon of pictures are many kinds of fossil animals …

Paleo-Environmental Interpretations And Weathering Effects Of The Mowry Shale From Geochemical Analysis Of Outcrop Samples In The Western Margin Of The Wind River Basin Near Lander, Wyoming, Trevor Robinson Tuttle

Theses and Dissertations

The Cretaceous Mowry Shale is an organic-rich, siliceous marine shale, and as such is a known source rock in the Western United States. Studies have documented that total organic carbon (TOC) in the Wind River Basin, Wyoming increases to the southeast. These studies cover large areas with limited sample sets. In this study, over 250 samples were collected near Lander, Wyoming to address spatial heterogeneity of TOC within the Mowry Shale at a much finer scale than previously examined. Samples were collected along five vertical sections at three localities, and following correlation of the vertical sections, which was strongly aided …

Discovery Of Possible Paleotsunami Deposits In Pangandaran And Adipala, Java, Indonesia Using Grain Size, Xrd, And 14C Analyses, Kevin L. Stuart

Theses and Dissertations

Grain size, ¹⁴C age, and X-ray diffraction (XRD) analyses of sediments indicate possible tsunami deposits on the southern coast of Java near Pangandaran and Adipala. Previous studies that have described known recent and paleotsunami deposits were used for comparison. Fining-upward grain size trends, interbedded sand and mud, sediment composition, and trends in heavy mineral abundances are among the characteristics used for tsunami deposit identification. At Batu Kalde, an archaeological site south of Pangandaran, a layer of aragonitic sand with marine fossils was found atop a layer of archaeological fragments at an elevation of ~2-5 m. It is likely this …

Experimental Study Of Gravitational Mixing Of Supercritical Co2, Dennis L. Newell, J. William Carey, Scott N. Backhaus, Peter Lichtner

Geosciences Faculty Publications

CO₂ injection into saline aquifers for sequestration will initially result in buoyant supercritical (sc)CO₂ trapped beneath the caprock seal. During this period, there is risk of CO₂ migration out of the reservoir along wellbore defects or fracture zones. Dissolution of the scCO₂ plume into brine results in solubility trapping and reduces this risk, but based on diffusion alone, this mechanism could take thousands of years. Gravitational (density-induced) mixing of CO₂-saturated brine is shown to significantly accelerate this process in computational studies, but few experimental efforts have confirmed the phenomenon. Here, constant-pressure, 3-dimensional bench-scale experiments …

Spectrally Based Bathymetric Mapping Of A Dynamic, Sandbedded Channel: Niobrara River, Nebraska, Usa, E. Dilbone, C.J. Legleiter, J.S. Alexander, B. Mcelroy

United States Geological Survey: Staff Publications

Methods for spectrally based mapping of river bathymetry have been developed and tested in clear‐flowing, gravel‐bed channels, with limited application to turbid, sandbed rivers. This study used hyperspectral images and field surveys from the dynamic, sandy Niobrara River to evaluate three depth retrieval methods. The first regressionbased approach, optimal band ratio analysis (OBRA), paired in situ depth measurements with image pixel values to estimate depth. The second approach used ground‐based field spectra to calibrate an OBRA relationship. The third technique, image‐to‐depth quantile transformation (IDQT), estimated depth by linking the cumulative distribution function (CDF) of depth to the CDF of an …

Evidence For Cyclical Fractional Crystallization, Recharge, And Assimilation In Basalts Of The Kimama Drill Core, Central Snake River Plain, Idaho: 5.5-Million-Years Of Petrogenesis In A Mid-Crustal Sill Complex, Katherine E. Potter, John W. Shervais, Eric H. Christiansen, Scott K. Vetter

Geosciences Faculty Publications

Basalts erupted in the Snake River Plain of central Idaho and sampled in the Kimama drill core link eruptive processes to the construction of mafic intrusions over 5.5 Ma. Cyclic variations in basalt composition reveal temporal chemical heterogeneity related to fractional crystallization and the assimilation of previously-intruded mafic sills. A range of compositional types are identified within 1,912 m of continuous drill core: Snake River olivine tholeiite (SROT), low K SROT, high Fe-Ti, and evolved and high K-Fe lavas similar to those erupted at Craters of the Moon National Monument. Detailed lithologic and geophysical logs document 432 flow units comprising …

Phytoforensics: Trees As Bioindicators Of Potential Indoor Exposure Via Vapor Intrusion, Jordan L. Wilson, V. A. Samaranayake, Matt A. Limmer, Joel G. Burken

United States Geological Survey: Staff Publications

Human exposure to volatile organic compounds (VOCs) via vapor intrusion (VI) is an emerging public health concern with notable detrimental impacts on public health. Phytoforensics, plant sampling to semi-quantitatively delineate subsurface contamination, provides a potential non-invasive screening approach to detect VI potential, and plant sampling is effective and also time- and cost-efficient. Existing VI assessment methods are time- and resourceintensive, invasive, and require access into residential and commercial buildings to drill holes through basement slabs to install sampling ports or require substantial equipment to install groundwater or soil vapor sampling outside the home. Tree-core samples collected in 2 days at …

Primary Pristine And Altered Iron Sulfides In Cm And Cr Carbonaceous Chondrites: Insights Into Nebular And Parent Body Processes, Sheryl A. Singerling

Earth and Planetary Sciences ETDs

This work presents our detailed investigation of textures and major, minor, and trace element compositions of iron sulfides in CM and CR carbonaceous chondrites using scanning electron microscopy (SEM), electron probe microanalysis (EPMA), transmission electron microscopy (TEM) from focused ion beam-prepared (FIB) sections, and synchrotron X-ray fluorescence (SXRF) microanalysis. This study represents the first attempt to link micro- to nano-scale textural and chemical characteristics of CM and CR chondrite primary iron sulfides and their alteration products.

The objectives of our studies included determining: 1) if primary sulfides are present in the least-altered CM and CR chondrites, and if so, 2) …

Gps Vertical Land Motion Corrections To Sea-Level Rise Estimates In The Pacific Northwest, Jean-Philippe Montillet, Timothy I. Melbourne, Walter M. Szeliga

All Faculty Scholarship for the College of the Sciences

We construct coastal Pacific Northwest profiles of vertical land motion (VLM) known to bias long-term tide-gauge measurements of sea-level rise (SLR) and use them to estimate absolute sea-level rise with respect to Earth’s center of mass. Multidecade GPS measurements at 47 coastal stations along the Cascadia subduction zone show VLM varies regionally but smoothly along the Pacific coast and inland Puget Sound with rates ranging from +4.9 to –1.2 mm/yr. Puget Sound VLM is characterized by uniform subsidence at relatively slow rates of +0.1 to –0.3 mm/yr. Uplift rates of 4.5 mm/yr persist along the western Olympic Peninsula of northwestern …

Natural And Anthropogenic Impacts On Sediment Dynamics And Preservation In Contrasting Mississippi Deltaic Coastal Environments, Jiaze Wang

LSU Doctoral Dissertations

Deltas worldwide share the same sinking problem in face of pressure from natural and anthropogenic activities. Many restoration strategies are being planned or have been implemented in the coasts around the world. However, many conventional hard structure constructions are energy-intensive. There are also associated uncertainties and limitations on the effectiveness and sustainability of these restoration plans. Soft or ecological engineering strategies normally take advantage of or mimic the coastal system self-response and feedbacks to natural and anthropogenic activities. The successful implementation of soft strategies relies on process-based studies on the change of complex coastal system. In addition, post-implementation monitoring work …

Highway Construction Or Stream Destruction: A Water Quality Analysis In The Black Warrior Basin, Walker County, Alabama, Cayla Baughn

Mahurin Honors College Capstone Experience/Thesis Projects

In 2012, residents along Freeman Branch Creek in Eldridge, Alabama observed unusual orange discoloration along the stream and on stream vegetation; an unprecendented black veneer coating pebbles along the streambed; and life in the stream seemed to have vanished. Freeman Branch Creek is located in Walker County, Alabama, which is known for its production of coal and natural gas from the underlying Pennsylvanian-aged Pottsville Formation, which is the uppermost geologic layer within the the Black Warrior Basin. Concerns for environmental safety related to intensive mining operations include the concern that shallow aquifers will be contaminated by mining in deep reservoir …

Global Seawater Redox Trends During The Late Devonian Mass Extinction Detected Using U Isotopes Of Marine Carbonates, David Allen White

Earth and Planetary Sciences ETDs

The Late Devonian extinction ranks as one of the ‘big five’ Phanerozoic extinctions affecting up to 80% of marine species and occurred during five distinct pulses spanning /or widespread marine anoxia. We test the marine anoxia hypothesis by analyzing uranium isotopes (δ²³⁸U) across a ~7 My interval of well-dated Upper Devonian marine carbonates from the Devil’s Gate Limestone in Nevada, USA.

The measured δ²³⁸U curve shows no co-variation with local anoxic facies, water-depth dependent facies changes, redox-sensitive metals, TOC, or diagnostic elemental ratios indicating the δ²³⁸U curve was not controlled by local depositional or …

Evidence Of The 1762 Arakan And Prior Earthquakes In The Northern Sunda Subduction, Dhiman Ranjan Mondal

Dissertations, Theses, and Capstone Projects

The objective of this dissertation is to understand the seismic hazard associated with Arakan segment of the northern Sunda subduction along SE Bangladesh. In order to do that, it is necessary to document geologic evidence for the 1762 Arakan earthquake and prior events, to help estimate the recurrence interval (repeat time) for that earthquake. Historical records described that the 1762 earthquake caused extensive damage along the Arakan segment of the Sunda subduction system. But the geologic evidence for the earthquake farther north is necessary to better understand its associated seismic hazard to the densely populated nation of Bangladesh. This dissertation …

Assessing Tsunami Risk In Southwest Java, Indonesia: Paleo-Tsunami Deposits And Inundation Modeling, Han Deng

Theses and Dissertations

Samples from 13 different sites along the south coast of West Java yield 7 candidate paleo-tsunami sands, which may represent 4 different paleo-tsunami events. Ages obtained from one deposit may document a tsunami and coastal subsidence from an earthquake in 1,053 AD. The tsunami deposit from this event is preserved in an uplifted marine terrace exposed at Panto Cape, Banten Province. We speculated that the terrace has been uplifted about 4.6 m to the present height of 2 m above sea level, since the 1053 AD event at a rate of 4.8 mm/a. This uplift is strong evidence that strain …

Siphons, Water Clocks, Cooling Coffee, And Leaking Capacitors: Classroom Activities And A Few Equations To Help Students Understand Radioactive Decay And Other Exponential Processes, John B. Brady

Geosciences: Faculty Publications

Although an understanding of radiometric dating is central to the preparation of every geologist, many students struggle with the concepts and mathematics of radioactive decay. Physical demonstrations and hands-on experiments can be used to good effect in addressing this teaching conundrum. Water, heat, and electrons all move or flow in response to generalized forces (gradients in pressure, temperature, and electrical potential) that may change because of the flow. Changes due to these flows are easy to monitor over time during simple experiments in the classroom. Some of these experiments can be modeled as exponential decay, analogous to the mathematics of …

Origin Of Last-Glacial Loess In The Western Yukon-Tanana Upland, Central Alaska, Usa, Daniel R. Muhs, Jeffrey S. Pigati, James R. Budahn, Gary L. Skipp, E Arthur Bettis Iii, Britta Jensen

United States Geological Survey: Staff Publications

Loess is widespread over Alaska, and its accumulation has traditionally been associated with glacial periods. Surprisingly, loess deposits securely dated to the last glacial period are rare in Alaska, and paleowind reconstructions for this time period are limited to inferences from dune orientations. We report a rare occurrence of loess deposits dating to the last glacial period, ~19 ka to ~12 ka, in the Yukon-Tanana Upland. Loess in this area is very coarse grained (abundant coarse silt), with decreases in particle size moving south of the Yukon River, implying that the drainage basin of this river was the main source. …

Southern Ocean Warming And Wilkes Land Ice Sheet Retreat During The Mid-Miocene, Francesca Sangiorgi, Peter K. Bijl, Sandra Passchier, Ulrich Salzmann, Stefan Schouten, Robert Mckay, Rosemary Cody, Jörg Pross, Tina Van De Flierdt, Steven M. Bohaty, Richard Levy, Trevor Williams, Carlota Escutia, Henk Brinkhuis

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Observations and model experiments highlight the importance of ocean heat in forcing ice sheet retreat during the present and geological past, but past ocean temperature data are virtually missing in ice sheet proximal locations. Here we document paleoceanographic conditions and the (in)stability of the Wilkes Land subglacial basin (East Antarctica) during the mid-Miocene (~17–13.4 million years ago) by studying sediment cores from offshore Adélie Coast. Inland retreat of the ice sheet, temperate vegetation, and warm oligotrophic waters characterise the mid-Miocene Climatic Optimum (MCO; 17–14.8 Ma). After the MCO, expansion of a marine-based ice sheet occurs, but remains sensitive to melting …