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Showing 1 to 20 of 224 for “"Lacustrine"”.
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U-Th Dating of lacustrine carbonates
… are prevalent in many modern and ancient lacustrine settings, but reconstructions of past lake levels or environments from such materials have been hindered by poor chronology. Uranium-thorium (U-Th) dating has the potential to fill a gap in current geochronological tools for such …
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Microbial-biogeochemical interactions in tropical lacustrine environments
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-05-01
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Lacustrine biogeochemistry of the McMurdo Dry Valleys, Antarctica.
Lacustrine biogeochemistry of the McMurdo Dry Valleys, Antarctica.
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Dating of fallout in lacustrine sediment in southwestern Utah
Sandy Cove is located in an area of southwestern Utah which received the highest fallout from Nevada Test Site (NTS) nuclear testing during the period 1951-1959. The reservoir was shown to have a constant sedimentation rate and to be relatively undisturbed. A 40 centimeter (cm) core taken from this …
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The biogeochemistry of methane isotopologues in marine and lacustrine sediments
… is herein applied to methane from marine and lacustrine sediments to test assumptions about prevailing mechanisms of its formation and consumption in these settings. This thesis describes 1) three studies about biogeochemical insights gained by quantifying the relative abundance of clumped …
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The Biogeochemistry of Methane Isotopologues in Marine and Lacustrine Sediments
… is herein applied to methane from marine and lacustrine sediments to test assumptions about prevailing mechanisms of its formation and consumption in these settings. This thesis describes 1) three studies about biogeochemical insights gained by quantifying the relative abundance of clumped …
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Turbulence In Low Energy Lacustrine Environments At The Sediment-Water Interface
… season (July through October) in a low energy lacustrine bottom boundary layer. Using these measurements, a turbulence chamber was developed for use in turbulent scalar flux studies. The chamber was characterized using particle image velocimetery (PIV), characterizing the near bed turbulence …
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Archives of climate variability on Kiritimati: lacustrine, aeolian and remote sensing perspectives
… variability are not limited to the scope of lacustrine records. Aeolian sedimentary archives are a less common approach to documenting tropical hydroclimate variability but given the profound impact of the ocean-atmosphere system on Kiritimati, aeolian archives provide a unique opportunity to …
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Analysis of biomarker candidates from plant lipid inputs into Galapagos lacustrine sediments
Paleoclimatological investigations into past precipitation and temperature patterns in regions of the tropical Pacific may be the key to resolving scientific disputes about the effects of global warming on the magnitude and frequency of the El Niño/Southern Oscillation (ENSO) phenomenon. Plant …
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Depositional constraints on lacustrine carbonates from the Winnemucca Dry Lake Basin, Nevada, USA
… Because of this high degree of variability in lacustrine depositional environments, lacustrine carbonate rocks exhibit large differences with respect to texture, morphology, and distribution within the lake basin. Lacustrine carbonate rocks are often important sedimentary archives of lake …
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Lacustrine Turbidites from Tropical African Lakes as Indicators of Hydrologic and Climatic Changes
… <p> To further evaluate the effectiveness of lacustrine hyperpycnites as indicators of tropical African hydroclimatic changes, a 65 k.y. record of extreme hydrologic events in equatorial West Africa was reconstructed, using flood-sourced turbidites, seismic and sedimentological lake-level …
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Paleoenvironmental reconstruction of late quaternary lacustrine sediments (Seibold Site) in southeastern North Dakota
… County, North Dakota, contains a late Quaternary lacustrine deposit with a spectaculary preserved and diverse biota; more than 150 species occur, of which the mollusks and fish are figured and discussed in detail in this study. The stratigraphic sequence, in ascending order, is a follows: 1) …
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Holocene guano influences on eutrophication and lacustrine ecology at Kettle Lake, North Dakota
… Coupling this with the sensitivity of grassland lacustrine ecosystems to moisture variability and ecological change, it will be crucial to understand the response of these systems to both future avian influence and climate variability. Here, I examine the influence of climate-forced avian …
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The biostratigraphy, palaeoecology and geochemistry of a long lacustrine sequence from NW Greece
Examination of an important new 319m core of lake sediment recovered from Ioannina in NW Greece has attempted to relate changes in the lake to variations in the regional climate of south-central Europe over the last 600,000 years. The site is known to have been extremely sensitive to past climatic …
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Analysis of Lacustrine Deposits of Custer Lookout and Leftor Butte, Stark County, North Dakota
… These units are commonly considered to be of lacustrine origin, although no specific paleoenvironmental analysis has been conducted. The purpose of this research was to determine if petrographic or other laboratory evidence supports a lacustrine origin for these units. Methods included …
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Lacustrine Deltaic Deposits of the Sandstone Tongue of the Wasatch Formation, Fossil Basin, Wyoming
… before rapidly thinning and grading into the lacustrine Green River Formation. Field observations. lateral correlation of measured sections. and construction of sandstone isolith and sandstone/mudstone ratio maps reveal that the sandstone units, for the most part. form notheasterly trending …
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Paragenesis of Lacustrine Microbialites in the Upper Wilkins Peak Member, Green River Formation, Wyoming
<p>Microbialites from the upper Wilkins Peak Member were investigated to determine their paragenesis and to help interpret lake chemistry. Two specific microbialite beds were analyzed that are associated with the “layered tuff”. Samples were collected from correlated sections along a NW to SE, 24 …
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Rock Physics Study of Lacustrine Shales and Applications in Geophysical Prediction of Sweet Spot
… extraction still pose challenges, especially in lacustrine shale environments. I conducted a comprehensive rock physics study and predicted sweet spots in the lacustrine shale reservoir in the Songliao Basin. First, I characterized the porosity, maturation, pore structure, and pore fluid phases …
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Lacustrine Sediment Record of Multiple Quaternary Lava Dams on the Owyhee River, Southeastern Oregon
<p>Multiple lava dams and correlating lakes impacted the Quaternary evolution of the Owyhee River. Sediment records from lava-dammed lakes were investigated to understand effects of the West Crater (WC) lava dam (~70 ka), the Saddle Butte 2 lava dam (~144 ka), and the Bogus Rim lava dam (~1.9 Ma). …
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Origin and Diagenesis of Lacustrine Sediments of the Late Oligocene Creede Formation, Southwestern Colorado
Vertically-zoned sequences of authigenic silicates in tuffs reflect alteration of silicic-intermediate vitric tuff within an elevated geothermal gradient (90$\sp\circ$-150$\sp\circ$C/km). The abundance of clinoptilolite - Al-smectite in drillcore CCM-2 is consistent with diagenetic waters having …
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