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Showing 1 to 20 of 49 for “"Paleoecological"”.
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Spatial variability in modern brachiopod assemblages: paleoecological and geochemical implications
… This work investigates geochemical and paleoecological patterns in modern brachiopod faunas which may serve as analogues for ancient brachiopod assemblages. The paleoclimatic utility of delta18O in the phosphatic phase of lingulid brachiopod shells requires valve secretion in equilibrium …
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Paleoecological Analyses of the Late Holocene Dry Period in the Northwestern Great Basin, Nevada
During the Pleistocene the Great Basin was filled by endorheic lakes that receded greatly during the Holocene. Several proxy records provide extensive evidence that the basin has gone through periods of amelioration from low precipitation followed by a return to dry conditions through the Holocene. …
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North American and Greenland modern pollen data for multi-scale paleoecological and paleoclimatic applications
The status of the modern pollen network in North America and Greenland is presented by assembling a database for use in quantitative calibration studies and paleoenvironmental reconstructions. The geo-referenced database includes 4569 samples from all regions of the continent. The database includes …
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Novel disturbance regimes in the Arctic: paleoecological perspectives on fire and thermo-erosion from Alaskan tundra
… disturbance. I overcome these challenges with paleoecological techniques to examine these disturbance processes over a broad range of scenarios, which is vital given the novel climate and vegetation settings predicted for the future. The main questions of my dissertation research are: Chapter 2 …
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Paleoenvironmental, paleoecological and thermal metamorphism implications on the organic petrography and organic geochemistry of Tertiary Tanjung Enim coal, South Sumatra Basin, Indonesia
Organic petrography and organic geochemistry studies have been conducted on Tertiary age coals from Tanjung Enim, South Sumatra Basin, Indonesia. The coals are of subbituminous rank (vitrinite/huminite reflectance, VRr, = 0.35 - 0.46%). In this area, the coals were also locally intruded by …
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Palynology of the Springfield Coal of the Illinois Basin (Middle Pennsylvanian) with quantitative comparison of spore floras and coal-ball peats and implications for paleoecological studies
… how quantitative spore floras can be used in paleoecological interpretations of Pennsylvanian-age coals. Laterally extensive sampling of spore profiles also was designed to evaluate lateral and vertical floristic variation related to proximity to contemporaneous paleochannels, overbank …
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Mechanistic underpinnings of lacustrine brGDGT production, and proteomic vertebrate taxonomic identification of phrynosomatid lizards and arvicoline rodents
… is enhanced and informed by paleoecology. Paleoecological analyses on issues such as species distribution, extinction and generation, and the impacts of climatic shifts on biotic systems serve to inform our understanding of these same issues today and into the future. Accuracy in …
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Paleoenvironmental Reconstruction of the Late Cretaceous Eastern Gulf Coastal Plain in Georgia and Alabama
… of Georgia and Alabama using paleobotanical, paleoecological and geochemical methods in order to evaluate the Late Cretaceous climate of the Southeastern United States, and to add to the body of paleoclimate data for that time. Paleobotanical analysis indicates a terrestrial mean annual …
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Fish and Reptile Remains From the Late Eocene, Crow Creek Local Fauna, St. Francis County, Arkansas
… Eocene deposits of Arkansas for the first time. Paleoecological conditions evidenced by the vertebrate remains indicate deposition occurred under hyposaline conditions adjacent to warm marine waters. This is in agreement with earlier studies of associated molluscan remains and sporomorphs found …
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Analysis of deposition, erosion, and landscape stability during the late Quaternary using multi-proxy evidence from Owl Creek, Central Texas, USA.
… buried soils provide a record of changes in paleoecological and paleo-alluvial conditions spanning ~14 ky. Morphological and geochemical differences between buried soils reflect changes in landscape attributable to climate, with a distinct 5‰ increase in δ13C values of soil organic matter …
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Non-Ranid Anurans of the Mio-Pliocene Gray Fossil Site, Tennessee
… frog). Occurrence of these Anura support a paleoecological environment described as warm, moist, and wooded.</p>
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Paleontology and Paleoecology of the Nada Member of the Borden Formation (Lower Mississippian) in Eastern Kentucky
… the end of the time of Nada deposition.Community paleoecological study was carried out with the application of the concepts of community components, tiering, and guilds. Biotic interactions were represented in the Nada fauna by the platyceratid-crinoid, the platyceratid-tabulate coral, and the …
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Variability within the 10-year pollen rain of a seasonal neotropical forest
… climatic variability, while also suggesting that paleoecological interpretations of modern pollen assemblages need to adjust for skewed short-term variability in pollen influx from neighboring pollen taxa.
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Carbon Accumulation Rates Over the Holocene in Flow Country Peatlands and the Direct Comparison of Open and Afforested Peatland Carbon Stocks Using Tephrochronology
… as well as improving the accuracy of our paleoecological carbon accumulation estimates. The ubiquitous nature of some of these tephra suggest this study could be replicated across the north of Scotland. Along with the chronology, carbon content and bulk density data were then used to …
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Multiproxy Analyses of Past Vegetation, Climate, and Sediment Dynamics in Hudson River Wetlands
… to major environmental changes. We expand paleoecological records in the freshwater section of the estuary to understand regional ecological changes as prior studies are restricted to the lower portion of the Hudson. An estuary-wide study of wetland and delta sediments across various …
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The winds of change: A study of post-glacial dispersal in pacific-northwest conifers
… and climate of putative refugia, we need paleoecological data from strategically selected sites. To infer past demographic events related to glacial refugia and post-glacial migration pathways, population genomic analysis is emerging as an important novel tool. Paleorecords are key to …
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Responses of a shallow-water ecosystem to the early Paleogene greenhouse environmental conditions : evolution of Larger Foraminifera and coral communities from the Northern Tethys
… I focused on sedimentological analysis and paleoecological study of benthic assemblages. During the Late Paleocene-earliest Eocene, sedimentation occurred on a shallow-water carbonate ramp system characterized by enhanced nutrient levels. LF represent the common constituent of the benthic …
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An investigation of terrestrial arthropod herbivory in Pennsylvanian peat forests revealed by coprolites from coal balls
… 1 introduces the significance of coprolites as paleoecological proxies, outlining their potential to reconstruct complex food web interactions in Pennsylvanian peat swamp ecosystems. Chapter 2 presents a comprehensive review of the cellulose acetate peel method, offering updated protocols for …
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The Effects of Snowmelt Percolation on Stratified Pollen Records: A Cooler Study
<p>Temperate valley glaciers may contain unique paleoecological records with the possibility of very high-resolution pollen analysis. However, little is known about the effects of meltwater percolation on pollen found in snow and glacial ice. Previous studies have suggested that pollen is …
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Geochemical Approaches to Paleobiology, Paleoclimatology, and Chronostratigraphy of the Cretaceous Cloverly Formation
… mid-late Albian in age, warranting revision of paleoecological comparisons with other late-Early Cretaceous nonmarine deposits. I examine the ecohydrology and paleoenvironment of a local Cloverly fossil assemblage by analyzing the 18O of biogenic phosphates from a large set of vertebrate …
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