Earth Sciences Commons^™

Volcanological And Petrogenetic Characteristics Of Komatiites Of The 3.3 Ga Saw Mill Complex, Weltevreden Formation, Barberton Greenstone Belt, South Africa, Matthew Stephen Huber

LSU Master's Theses

The Saw Mill Complex (SMC) is a 1275 m thick layered komatiitic sequence in the 3.3 Ga Weltevreden Formation, uppermost stratigraphic unit of the Onverwacht Group in the northern part of the Barberton Greenstone Belt, South Africa. A series of ultramafic complexes in the Weltevreden Formation have been interpreted as layered ultramafic intrusions, consisting of thick, layered ultramafic units of peridotite, pyroxenite, dunite, and gabbro. However, recent work on the Pioneer complex of the Weltevreden Formation has demonstrated an extrusive origin of komatiites and tuffs. The Weltevreden Formation has been less studied than other Onverwacht Group units. It is likely …

Metamorphic Rocks In The Sawtooth Mountains, Idaho, Usa: A Window Into The Precambrian Basement Of Southwest Laurentia, Kyle Michael Metz

LSU Master's Theses

The western North American craton consists of a mosaic of Precambrian basement terranes that developed through episodes of microcontinent collision and magmatic arc accretion. Defining the extent and boundaries of these terranes is critical to deciphering the Precambrian development of Laurentia. The poorly exposed Selway terrane occurs between the Archean Wyoming province and the Neoproterozoic rifted margin of Laurentia. A rare exposure of Precambrian metamorphic rocks, the Sawtooth Metamorphic Complex (SMC), crops out over 33 km2 in the Sawtooth Mountains of Idaho, USA, and potentially provides a window into the deep crust of the region. Field mapping, petrographic analyses, and …

Speciation Of Heavy Metals In Disturbed And Undisturbed Sediments From Atchafalaya Bay, Houma Navigation Canal, And Southwest Pass, Louisiana, Amanda Jo Zimmerman

LSU Master's Theses

In coastal Louisiana it is common to use dredge spoil to build marshland that has been lost due to a variety of factors. Under various conditions such as deposition in a drained oxygenated environment, metals in the spoil can become more bioavailable posing a threat to the ecosystem. This study compares metal availability in natural and dredged sediments to determine what changes occur in nature. Forty four samples from three locations, Atchafalaya Delta, Houma Navigation Canal, and Southwest Pass, were analyzed for 13 common elements with known or potentially harmful health effects; Al, As, Ba, Be, Cd, Cr, Co, Cu, …

Burrow Morphology Of The Bahamian Land Crab Gecarcinus Lateralis, Koji Seike, H. Allen Curran

Geosciences: Faculty Publications

Abstract from 2010 Workshop on Crustacean Bioturbation — Fossil and Recent held in Lepe, Spain.

Editors: Jordi M. deGibert, Fernando Muñiz, Eduardo Mayoral, Zain Belaústegui

Implementing Deep Drainage To Reduce Salinity In The Date Creek Catchment, South West Western Australia, Derk Bakker, John P. Collins, Justin Hardy

Resource management technical reports

No abstract provided.

Women In Glaciology, An Historical Perspective, Christina L. Hulbe, Weili Wang, Simon Ommanney

Geology Faculty Publications and Presentations

Women's history in glaciology extends as far back in time as the discipline itself, although their contributions to the scientific discourse have for all of that history been constrained by the sociopolitical contexts of the times. The first Journal of Glaciology paper authored by a woman appeared in 1948, within a year of the founding of the Journal, but it was not until the 1980s that women produced more than a few percent of Journal and Annals of Glaciology papers. Here international perspectives on women's participation in the sciences are presented in order to establish an economic and sociopolitical context …

Grounding-Line Basal Melt Rates Determined Using Radar-Derived Internal Stratigraphy, Ginny Catania, Christina L. Hulbe, Howard Conway

Geology Faculty Publications and Presentations

We use ice-penetrating radar data across grounding lines of Siple Dome and Roosevelt Island, Antarctica, to measure the spatial pattern, magnitude and duration of sub-ice-shelf melting at these locations. Stratigraphic layers across the grounding line show, in places, a large-amplitude downwarp at, or slightly downstream of, the grounding line due to sub-ice-shelf basal melting. Localized downwarping indicates that melting is transient; melt rates, or the grounding line position, have changed within a few hundred years in order to produce the observed stratigraphy. Elsewhere, no meltrelated stratigraphic signature is preserved. In part, heterogeneity in the amount of sub-ice-shelf melt is due …

Diatom Stratigraphy Defining Ice Sheet Grounding Chronology, Ross Sea, Antarctica, Juan Manuel Chow

LSU Doctoral Dissertations

Evidence of Antarctic ice sheet behavior and paleoenvironment is often approached from proxy records because there is a dearth of direct records from Antarctica itself. The studies presented here seek to augment our knowledge of translations of the West Antarctic Ice Sheet’s (WAIS) marine termination based on direct biostratigraphic evidence. Diatom analyses were conducted from two areas of Ross Sea, Antarctica. In the first study, diatoms were used to constrain the age of diamictons from five seismic units in the Eastern Basin and thus expand our knowledge of WAIS behavior during the Southern Hemisphere Last Glacial Maximum (LGM). All five …

Oxidation Of Reduced Sulfur Compounds: A Triple-Oxygen-Isotope Perspective, Issaku E. Kohl

LSU Doctoral Dissertations

The Earth’s geochemical evolution is recorded in the rocks that compose its lithosphere. Specifically, sulfate minerals have been identified as being repositories of information concerning the past hydrosphere, atmosphere and biosphere. This is due to the non-labile nature of SO42- and its ability to store a record of the oxidative reactions and oxygen sources involved in its formation. Microbial dissimilatory sulfate reduction (MDSR) and sulfide oxidation cause oxygen from H2O and O2 to be trapped to varying degrees in ambient, dissolved SO42-. In order to better interpret the H2O and O2 signals in SO42-, we must deepen our understanding of …

Reservoir Analysis Of The Clinton Interval In Stark And Summit Counties, Ohio, Dominick Andrew Wytovich

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The characteristics of a sandstone reservoir of Silurian age (the "Clinton interval") were analyzed using 382 geophysical well logs from the Dominion Gas storage field located in Stark and Summit Counties, Ohio. These sandstones have long been identified by the informal drillers' terms, White, Red, and Stray Clinton. Gamma ray logs were used to analyze the distribution of net stand thickness and its relation to initial production through the construction of isopach and net sand isolith maps. I constructed eight cross sections to identify and correlate the tops of three prominent sandstones and two marine flooding surfaces to evaluate reservoir …

Augmented Reality Navigation Interfaces Improve Human Performance In End-Effector Controlled Telerobotics, Keshav Chintamani

Wayne State University Dissertations

On the International Space Station (ISS) and space shuttles, the National Aeronautics and Space Administration (NASA) has used robotic manipulators extensively to perform payload handling and maintenance tasks. Teleoperating robots require expert skills and optimal performance is crucial to mission completion and crew safety. Degradation in performance is observed when manual control is mediated through remote camera views, resulting in poor end-effector navigation quality and extended task completion times. This thesis explores the application of three-dimensional augmented reality (AR) interfaces specifically designed to improve human performance during end-effector controlled teleoperations. A modular telerobotic test bed was developed for this purpose …

Plains Co2 Reduction (Pcor) Partnership Atlas, Wesley D. Peck, Katherine K. Anagnost, Barry W. Botnen, Lisa S. Botnen, Daniel J. Daly, Charles D. Gorecki, Megan M. Grove, John A. Harju, Melanie D. Jensen, Michael L. Jones, Steven A. Smith, James A. Sorensen, Edward N. Steadman, Stephanie L. Wolfe, Andrea T. Mcnemar, John T. Litynski, Sean I. Plasynski

EERC Maps and Infographics

The Plains CO₂ Reduction (PCOR) Partnership Atlas, revised 3rd edition, introduces global climate change and a regional profile of CO₂ sources and potential sinks across central North America. Carbon storage offers a promising set of technologies through which CO₂ can be stored for long periods of time.

Propagation Of Long Fractures In The Ronne Ice Shelf Investigated Using A Numerical Model Of Fracture Propagation, Christina L. Hulbe, Christine Marie Ledoux, Kenneth M. Cruikshank

Geology Faculty Publications and Presentations

Long rifts near the front of the Ronne Ice Shelf, Antarctica, are observed to begin as fractures along the lateral boundaries of outlet streams feeding the shelf. These flaws eventually become the planes along which tabular icebergs calve. The fractures propagate laterally as they advect through the shelf, with orientations that can be explained by the glaciological stress field. Fracture length remains constrained over much of the advective path, and locations of crack tip arrest are observed to coincide with structural boundaries, such as suture zones between ice from adjacent outlet glaciers. Geomechanical principles and numerical models demonstrate that in …

Paleotsunami Inundation Of A Beach Ridge Plain: Cobble Ridge Overtopping And Interridge Valley Flooding In Seaside, Oregon, Usa, Curt D. Peterson, Harry M. Jol, Thomas Horning, Kenneth M. Cruikshank

Geology Faculty Publications and Presentations

The Seaside beach ridge plain was inundated by six paleotsunamis during the last ∼2500 years. Large runups (adjusted >10m in height) overtopped seawardmost cobble beach ridges (7m elevation) at ∼1.3 and ∼2.6 ka before present. Smaller paleotsunami (6−8m in height) likely entered the beach plain interior (4-5m elevation) through the paleo-Necanicum bay mouth. The AD 1700 Cascadia paleotsunami had a modest runup (6-7mheight), yet it locally inundated to 1.5 km landward distance. Bed shear stresses (100−3,300 dyne cm−2) are estimated for paleotsunami surges (0.5−2m depths) that flowed down slopes (0.002−0.017 gradient) on the landward side of the cobble beach ridges. …

Dimethylmercury Production In Freshwater Sediments, David C. Kelly

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Dimethylmercury (DMHg) has been examined almost exclusively in marine environments to date, plays an uncertain role in the global cycling of Hg, and is produced by a currently unknown mechanism in natural systems. We examined DMHg production in microcosms containing 100 cm3 of freshwater sediment sampled from 3 wetlands and a lake near Dayton, Ohio. DMHg was produced from all sediments analyzed, and found that production is increased significantly by the addition of inorganic Hg from ~0.1pM to ~10pM, its production is unaffected by autoclaving the sediment, and organic carbon additions had no discernible effect on production. Its total concentrations …

How The Growth Of The Frampton Fold Affected The Growth Of The Green Knoll Diapir, John A. Zinck

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The growth of structural features formed by the movement of the Louann Salt within the study area follows a fold-first model (Rowan et al., 2000), in which the formation of the Frampton Fold predates the formation of the Green Knoll Diapir. The Frampton Fold was formed during two growth episodes driven by movement of the Louann Salt within the study area. The folding and faulting resulting from these growth episodes created a conduit through which the autochthonous Louann Salt was extruded to the sea floor during the Pliocene. Following a depositional episode consisting of the early sequences of the Mississippi …

Functional Identification Of Microorganisms That Transform Mercury In Marine Sediments, Lisa Romas

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Monomethylmercury (MMHg) is the toxic form of mercury (Hg) that biomagnifies in food webs, and human exposure to MMHg occurs predominantly via consumption of fish. The primary source of MMHg to the marine environment is thought to be in situ sedimentary production by benthic microorganisms, namely sulfate-reducing bacteria (SRB). I collected sediments from the continental shelf (stations 2 and 6) and slope (station 9) of the NW Atlantic Ocean, and amended them with various inhibitor and promoter solutions to target specific functional groups capable of Hg transformations. I also added stable enriched Hg isotopes to quantify gross Hg methylation and …

Mercury Speciation In Temperate Tree Foliage, Melissa Danielle Tabatchnick

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Cycling of mercury (Hg) and monomethylmercury (MMHg) in forest ecosystems can affect exposures of terrestrial and aquatic wildlife within the watershed. Litterfall has been posited to be a major source of MMHg and total Hg to the forest floor; however, the origin of MMHg associated with tree foliage is largely unknown. I tested the hypothesis that leaf MMHg would be controlled by root uptake and thereby proportional to levels in soil. Fresh leaves and associated soil samples were sampled from nine tree species (deciduous and coniferous) at 30 locations spanning a 1145 km2 area in southwest Ohio, a region presumed …

Trace Metal Fluxes In Southwest Ohio Watersheds, Avani Naik

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Land-use and watershed characteristics affect the cycling and transport of trace metals in rivers. I investigated the influence of different land uses and water physicochemistry on loadings, partitioning, and speciation of Hg, Zn, Cr, Ni, V, Cd, Cu, and Pb in three contrasting watersheds near the Dayton, Ohio metropolitan area over a 13-month period; Wolf Creek (urban/residential), Holes Creek (urban/residential), and Little Miami River (agricultural). Metal concentrations were related positively to discharge in each stream. Dissolved organic ligands appear to influence trace-metal partitioning between filtered and particle phases, however, particle-associated metals were dominant in each site. Total Hg concentrations and …

Transport Through Georeservoirs: Spatial Entropy In Hydraulic Properties, And Temporal Entropy In Residence Time Distributions, Lumeng Huang

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The general principle of maximum entropy can be used to guide the construction of flow and transport models parameters when are uncertain. The principle states that the model which maximizes the entropy should be chosen so that the full multiplicity or uncertainty is represented in the model outcomes.

In models for flow and transport through georeservoirs, the principle would commonly be applicable to the uncertainty in the model outcome for the time of travel through the system, in order to represent the full range of multiplicity in the distribution of residence times. Importantly, the model which maximizes the entropy in …

Estimating Permeability From The Grain-Size Distributions Of Natural Sediment, Lawrence Mastera

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Permeability, k, can be estimated using the Kozeny-Carman equation, given a grain-size distribution with any number of grain-size categories and the porosity of a sediment. A recursive method was developed to calculate the effective grain-size parameter, d, for sediment mixtures with more than three grain sizes. The method was tested on four sediment models of sand, gravelly sand, sandy gravel, and open-framework gravel created from grain-size distributions. The k estimated from the recursive method were consistent with physical measurements of k.

Inferring Lake Depth Using Diatom Assemblages In The Shallow, Seasonally Variable Lakes Of The Nebraska Sand Hills (Usa): Calibration, Validation, And Application Of A 69-Lake Training Set, Avery L. C. Shinneman, Danuta M. Bennett, Sherilyn C. Fritz, Jens Schmieder, Daniel R. Engstrom, Aris Efting, John Holz

Department of Earth and Atmospheric Sciences: Faculty Publications

The Nebraska Sand Hills are a distinctive eco-region in the semi-arid Great Plains of the western United States. The water table underlying the Sand Hills is part of the High Plains/ Ogallala aquifer, an important water resource for the central Great Plains. Lake levels are affected directly by fluctuations in the water table, which is recharged primarily by local precipitation and responds quickly to climatically induced changes in regional water balance. Instrumental records are available for only 50–100 years, and paleolimnological data provide important insights into the extremes and variability in moisture balance over longer time scales. A set of …

Displacements And Kinematics Of The February 1, 1944 Gerede Earthquake (North Anatolian Fault System, Turkey): Geodetic And Geological Constraints, Mehmet Emi̇n Ayhan, Ali̇ Koçyi̇ği̇t

Turkish Journal of Earth Sciences

The North Anatolian Fault System (NAFS) is an approximately 2-110-km-wide, 1600-km-long right-lateral intra-continental transform fault boundary between the Anatolian platelet and the Eurasian plate. The Gerede fault zone is one of the major active structures in the western section of the NAFS. It is a 1-9-km-wide, 325-km-long and ENE-trending dextral strike-slip fault zone, with a total accumulated offset since its initiation (Late Pliocene) of about 43 km. This offset indicates an average geological slip rate of 16.5 mm/yr. The 1 February 1944 Gerede earthquake occurred within the Gerede fault zone. Based on recent field geological mapping of the rupture traces …

Trace Metal Biogeochemistry In The Western North Pacific, Peter Lynn Morton

OES Theses and Dissertations

Dissolved and suspended particulate samples collected during the Intergovernmental Oceanographic Commission 2002 Contaminant Baseline Survey were analyzed to determine the surface and vertical distributions of Cd, Co, Cu, Mn, Ni Zn and Pb across the western and central North Pacific.

Dissolved trace metal concentrations were measured using a novel isotope dilution-ICP-MS method after extraction over an 8-hydroxyquinoline resin column and validated through the use of the SAFe consensus reference materials. Filtered suspended particulate matter was digested using an HCl/HNO3/HF mixture and analyzed by HR-ICP-MS to obtain total particulate concentrations for the trace metals and other tracer elements such as Al, …

Uranium-Series Dating Of Gypsum Speleothems: Methodology And Examples, Laura Sanna, Francisco Saez, Siri Simonsen, Silviu Constantin, José-Maria Calaforra, Paolo Forti, Stein-Erik Lauritzen

International Journal of Speleology

The analytical problems of dating gypsum speleothems with the U-series technique are reviewed. Gypsum speleothems are, in general, very low in U content, challenging the limits of detection methods. Various approaches to dissolving gypsum and isolation of actinides from the matrix include ion-pairing dissolution with magnesium salts and using nitric acid. The most precise dating technique is Thermal Ionization Mass Spectrometry (TIMS), combined with Fe(OH)₃ scavenging and anionic exchange chromatography. Less satisfactory, but much quicker, is direct retention of actinides from HNO₃ by means of TRU resin and MC-ICP-MS detection. We have tested these methods on gypsum speleothems …

Modern C, O, And H Isotope Composition Of Speleothem And Dripwater From Modrič Cave, Eastern Adriatic Coast (Croatia), Maša Surić, Zvjezdana Roller-Lutz, Magda Mandić, Ines Krajcar Bronić, Mladen Juračić

International Journal of Speleology

Modrič Cave is a shallow horizontal cave situated in the middle of the eastern Adriatic coast (Croatia). The cave entrance is located 120 m from the coast at an altitude of 32 m above sea level, and due to its position on the SW slope of the Dinaridic mountain range, a Mediterranean climatic influence is dominant. Due to the stable environmental conditions [(15.6 ± 0.1) °C] Modrič Cave was recognized as a potential site for detailed palaeoclimatic studies. Isotope analyses of modern carbonate speleothems, rain and dripwater were conducted in order to evaluate the isotopic equilibrium conditions. The δ18O composition …

Age Frequency Distribution And Revised Stable Isotope Curves For New Zealand Speleothems: Palaeoclimatic Implications, Paul W. Williams, Helen L. Neil, Jian-Xin Zhao

International Journal of Speleology

The occurrence of speleothems in New Zealand with reversed magnetism indicates that secondary calcite deposition in caves has occurred for more than 780 thousand years (ka). 394 uranium-series dates on 148 speleothems show that such deposition has taken place somewhere in the country with little interruption for more than 500 ka. A relative probability distribution of speleothem ages indicates that most growth occurred in mild, moist interglacial and interstadial intervals, a conclusion reinforced by comparing peaks and troughs in the distribution with time series curves of speleothem δ¹⁸O and δ¹³C values. The stable isotope time series …

A Methodology To Estimate The Future Extent Of Dryland Salinity In The Southwest Of Western Australia, Peter Caccetta, Robert Dunne, Richard J. George, Don J. Mcfarlane

Natural Resources Research Articles

In the southwestern agricultural region of Western Australia, the clearing of the original perennial vegetation for annual vegetation-based dryland agriculture has lead to rising saline groundwater levels. This has had effects such as reduced productivity of agricultural land, death of native vegetation, reduced stream water quality and infrastructure damage. These effects have been observed at many locations within the 18 million ha of cleared land. This has lead to efforts to quantify, in a spatially explicit way, the historical and likely future extent of the area affected, with the view to informing management decisions. This study was conducted to determine …

Zebulon Pike: Great American Explorer Or Climate Spy?, Merlin P. Lawson, Randall Cerveny, Cary Mock

Department of Earth and Atmospheric Sciences: Faculty Publications

Zebulon Pike is known in history books as one of America’s heroes—a great explorer whose adventures in the American West rivaled the Lewis and Clark Expedition and who became the namesake for Colorado’s Pike’s Peak. But what if the history books got it wrong, and Pike was actually not the hero everyone thinks he is? What if he was actually a spy carrying out a secret mission, or a scoundrel interested in overthrowing the American government and helping to carve a new empire out of the North American Southwest? Evidence from Pike’s famed expedition in 1806-1807 points to the possibility …

Collapse Of The Maya: Could Deforestation Have Contributed?, Robert Oglesby, Thomas L. Sever, William Saturno, David J. Erickson Iii, Jayanthi Srikishen

Department of Earth and Atmospheric Sciences: Faculty Publications

The collapse of the Maya civilization during the ninth century A.D. is a major conundrum in the history of mankind. This civilization reached a spectacular peak but then almost completely collapsed in the space of a few decades. While numerous explanations have been put forth to explain this collapse, in recent years, drought has gained favor. This is because water resources were a key for the Maya, especially to ensure their survival during the lengthy dry season that occurs where they lived. Natural drought is a known, recurring feature of this region, as evidenced by observational data, reconstructions of past …