Geology Commons^™

Geochemistry And Mineralogy Of Late Quaternary Loess In The Upper Mississippi River Valley, Usa: Provenance And Correlation With Laurentide Ice Sheet History, Daniel R. Muhs, E. Arthur Bettis Iii, Gary L. Skipp

United States Geological Survey: Staff Publications

The midcontinent of North America contains some of the thickest and most extensive last-glacial loess deposits in the world, known as Peoria Loess. Peoria Loess of the upper Mississippi River valley region is thought to have had temporally varying glaciogenic sources resulting from inputs of sediment to the Mississippi River from different lobes of the Laurentide Ice Sheet. Here, we explore a new method of determining loess provenance using K/Rb and K/Ba values (in K-feldspars and micas) in loess from a number of different regions in North America. Results indicate that K/Rb and K/Ba values can distinguish loess originating from …

Maximum Depositional Age Of The Neoproterozoic Jacobsville Sandstone, Michigan: Implications For The Evolution Of The Midcontinent Rift: Reply, David H. Malone, Carol A. Stein, John P. Craddock, Jonas Kley, Seth Stein, John E. Malone

Faculty Publications - Geography, Geology, and the Environment

We thank T.J. Bornhorst (2018) for consideration of our work on the Jacobsville Sandstone in northern Michigan. We engaged in this research to advance understanding of the geology of the Lake Superior region. As we began this project, we were fascinated that little attention had been paid to refining the lithostratigraphic and chronostratigraphic understanding of the Jacobsville Sandstone; our work is ongoing. Since publication of Malone et al. (2016a), we have analyzed ~400 additional zircons from 3 Jacobsville Sandstone exposures in Ontario (Canada). We will collect and analyze Jacobsville subsurface occurrences in the next few months. Bornhorst’s comment questioned our …

Application Of Modern Foraminiferal Assemblages To Paleoenvironmental Reconstruction: Case Studies From Coastal And Shelf Environments, Christian Haller

USF Tampa Graduate Theses and Dissertations

The aim of paleoenvironmental studies is to reconstruct characteristics of the past environment from fossil assemblages preserved in sedimentary strata. Thus, studies of modern surface assemblages, quantitatively correlated to the environmental parameters, are required before reliable interpretations can be made. For this dissertation, two different techniques were applied in two case studies: a reconstruction making use of a benthic foraminiferal transfer function from the intertidal marshes in the eastern Mississippi Sound, Alabama/Mississippi, and a qualitative reconstruction of ocean current activity on the Western Australian shelf.

Modern salt-marsh foraminifera were collected from Grand Bay, Pascagoula, Fowl River, and Dauphin Island across …

Sh-Wave Seismic Reflection Imaging And Inversion: An Analysis Of Architectural And Physical Properties Of A Near-Surface Point-Bar, Nathan William Benton

LSU Master's Theses

Both architecture and physical properties of near-surface point-bar sediment packages have not be imaged or analyzed via SH-wave seismic reflection surveying, respectively. Point-bar architecture within near-surface environments characterized by conductive, saturated, and/or unconsolidated sediments cannot be well-imaged with other remote sensing methods compared to the SH-wave seismic reflection surveying method. The physical properties that distinguish different point-bar sediment packages are variably altered during early-stage diagenetic processes such as compaction and dewatering, thereby changing SH-wave seismic velocities and subsequently shear impedance of different sediment packages. This study accomplishes two objectives by acquiring, processing, and inverting seismic reflection data from two surveys …

Vertical Sediment Accretion In Jamaica Bay Wetlands, New York, Ryan Christopher Clarke

LSU Master's Theses

Over the last century, ~60% of the saltmarsh wetlands in Jamaica Bay (in the Gateway National Recreation Area of the Greater New York City region) have been converted to intertidal or subtidal unvegetated mudflats and projections suggest that all of Jamaica Bay’s saltmarsh wetlands may disappear within the next two decades. After landfall of Hurricane Sandy in 2012 and to better understand environmental controls on the maintenance of the remaining Jamaica Bay wetlands, cores were collected from twelve saltmarsh locations in the bay to study the chronology of wetland vertical accretion and mineral sediment accumulation. In association with the United …

Interseismic Coupling-Based Earthquake And Tsunami Scenarios For The Nankai Trough, Hannah Baranes, Jon D. Woodruff, John P. Loveless, M. Hyodo

Geosciences: Faculty Publications

Theoretical modeling and investigations of recent subduction zone earthquakes show that geodetic estimates of interseismic coupling and the spatial distribution of coseismic rupture are correlated. However, the utility of contemporary coupling in guiding construction of rupture scenarios has not been evaluated on the world’s most hazardous faults. Here we demonstrate methods for scaling coupling to slip to create rupture models for southwestern Japan’s Nankai Trough. Results show that coupling-based models produce distributions of ground surface deformation and tsunami inundation that are similar to historical and geologic records of the largest known Nankai earthquake in CE 1707 and to an independent, …

Topographic Control On Post-Lgm Groundings Of The West Antarctic Ice Sheet In The Whales Deep Basin, Eastern Ross Sea, Matthew Danielson

LSU Master's Theses

By the peak of the Last Glacial Maximum (LGM), the West Antarctic Ice Sheet (WAIS) had advanced to the outer continental shelf of eastern Ross Sea trough basins. During the post-LGM retreat, the WAIS paused several times within 75 km of the Whales Deep Basin (WDB) shelf edge. An overlapping stack of seven grounding zone wedges (GZWs) records the locations of these groundings. Here we used ~7500 km of seismic reflection data to map the subglacial unconformity that was eroded when WAIS was grounded at the shelf edge, i.e., prior to the deposition of the backstepping GZWs. With respect to …

Spatially Heterogeneous Post-Caledonian Burial And Exhumation Across The Scottish Highlands, Michelle L. Fame, James A. Spotila, Lewis A. Owen, Jason M. Dortch, David L. Shuster

Faculty, Staff, and Affiliated Publications--KGS

The postassembly, postrift evolution of passive margins is an essential element of global continental tectonics. Thermal and exhumational histories of passive margins are commonly attributed to a number of drivers, including uplift and erosional retreat of a rift-flank escarpment, intraplate fault reactivation, mantle-driven uplift, and erosional disequilibrium, yet in many cases, a specific factor may appear to dominate the history of a given passive margin. Here, we investigate the complex evolution of passive margins by quantifying exhumation patterns in western Scotland. We build upon the well-studied thermal evolution of the Scottish North Atlantic passive margin to test the importance of …

Geochemical Modeling Of Primary Morb Magmas: Implications For Parental Melting Regimes In Melt Lenses Along-Axis Of The Hess Deep Rift, Stephanie Michelle Drumm

USF Tampa Graduate Theses and Dissertations

The Hess Deep Rift in the East Pacific Rise is a mid-ocean ridge spreading center that produces melts which exhibit geochemical characteristics of evolved MORB. Using basaltic glass samples collected from multiple dive cruises that explored Hess Deep geology, volatile and chemical data were collected at USF using FTIR and EMPA, respectively. In addition, a data suite of samples of glass from Hess Deep were compiled from the EarthChem database. The intention was to use the data suite and models to compare the Hess Deep regime to analog models for mid-ocean ridge crystallization regimes and tectonic structures. The USF and …

The Stability Of Sand Waves In A Tidally-Influenced Shipping Channel, Tampa Bay, Florida, John Willis Gray

USF Tampa Graduate Theses and Dissertations

Tidally-influenced sandwaves are common coastal features present in various settings, including shipping channels. The main shipping channel in Tampa Bay under the Bob Graham Sunshine Skyway Bridge (a.k.a. the Skyway Bridge) contains such sandwave bedforms. Between the years 2000 and 2017, these bedforms have been surveyed with multibeam echosounders (MBES) on 21 occasions with ranging coverage and quality of returns. Surveys between 2000 and 2009 used a 300 kHz Kongsberg EM3000; surveys between 2015 and 2017 used a 400 kHz Reson Seabat 7125. For comparable surveys, bathymetry, backscatter, slope, curvature, planform curvature, and profile curvature maps were created and analyzed. …

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 …