Global ETD Search

101	Quantitative Ecological and Taphonomic Patterns in Late Cenozoic Mollusk-Dominated Marine Fossil Assemblages Barbour Wood, Susan L. 27 June 2006 (has links) Applications in paleontological research are far from being limited to taxonomic collection and identification. Nor is such research limited to working solely on fossil data. Actualistic paleontology is the study of modern or recent organisms and processes to better understand those of the past. The bulk of this body of research falls under the category of actualistic paleontology, and examines geochronological methods and error biases in dating biological specimens ranging in age from modern to thousands of years old. Although such methods are arguably not perfect, error rates of ± a few hundred to few thousand years can be extremely important when considering ecological relationships among both Holocene taxa and time-averaged paleocommunities, but quite diminished when considering implications on more traditional dating techniques for ancient strata. Regardless, understanding implications of time resolution is important in analyses of and comparisons between any biological dataset. The following chapters are united by quantitative and statistical management of data with varying levels of temporal resolution, and represent four manuscripts that either are in press or soon to be submitted for publication. / Ph. D. radiocarbon dating brachiopods Bouchardia mollusks Semele Holocene Quaternary Brazil Ubatuba Bay reservoir age taphonomy time averaging Atlantic Coastal Plain Miocene Pliocene Eastover Cobham Bay Yorktown Sunken Meadow aspartic Amino acid racemization paleoecology gradient ordination
102	名古屋大学における14C-AMS 研究の黎明期(1980-1990) NAKAMURA, Toshio, 中村, 俊夫 03 1900 (has links) 第23回名古屋大学年代測定総合研究センターシンポジウム平成22(2010)年度報告宇宙線生成核種放射性炭素年代測定放射性炭素超高感度質量分析加速器質量分析 cosmogenic nuclide Radiocarbon dating Radiocarbon Ultra-sensitive mass spectrometer AMS
103	縄文時代の急激な環境変動期における生態系復原と人間の適応 : 八戸・上北地域におけるボーリングコアの14C年代測定 Nakamura, Toshio, Sei-ichiro, Tsuji, Matsumoto, Yui, Hitoki, Eri, 中村, 俊夫, 辻, 誠一郎, 松本, 優衣, 一木, 絵理 03 1900 (has links) 名古屋大学年代測定総合研究センターシンポジウム報告十和田中掫テフラ上北平野完新世堆積物縄文海進放射性炭素年代測定 Towada Chuseri tephra (To-Cu) Kamikita plain Holocene sediments Jomon Transgression radiocarbon dating
104	Morphodynamics of a bedrock confined estuary and delta: The Skeena River Estuary Wild, Amanda Lily 07 December 2020 (has links) Bedrock islands add variation to the estuarine system that results in deviations from typical unconfined estuarine sediment transport patterns. Limited literature exists regarding the dynamics of seabed morphology, delta formation, sediment divergence patterns, and sedimentary facies classifications of non-fjordic bedrock confined systems. Such knowledge is critical to address coastal management concerns adequately. This research presents insights from the Skeena Estuary, a macrotidal estuary in northwestern Canada with a high fluvial sediment input (21.2-25.5 Mtyr-1). Descriptions on sub-environments, stratification, and sediment accumulation within the Skeena Estuary utilize HydroTrend model outputs of riverine sediment and discharge, Natural Resources Canada radiocarbon-dated sediment cores and grain size samples, and acoustic Doppler current profiler and conductivity-temperature-depth measurements from three field campaigns. Research findings delineate a fragmented delta structure with elongated mudflats and select areas of slope instability. Variations from well-mixed water circulation to lateral stratification, govern the slack tide flow transition and sediment transport pathways within seaward and landward passages of the estuary. Fostering a comprehensive understanding of bedrock confined estuary and delta systems has implications for the assessment of coastal management strategies, the productivity of ecological habitats, and the impacts of climate change within coastal areas. / Graduate Estuary Skeena Geomorphology Oceanography Morphodynamics Delta ADCP Stratification Bedrock Suspended Sediment Watershed Discharge Macrotidal Fjard Chronostratigraphy HydroTrend Sediment Core Bathymetry Grain size distribution Sedimentation Partially Mixed Estuary Bedrock Confined Estuary River Rivers of British Columbia Radiocarbon Dating of Sediments Ebb Tide Flood Tide Slack Tide
105	Carbon Dating of Agricultural Soils and Further Understanding the Transport of CO2 Gas Using Isotopes Zal, David 22 August 2023 (has links) CO2 is a greenhouse gas which is significantly emitted by agricultural soils through the decomposition of plant residue and soil organic carbon. Carbon isotopes can be used in determining the source of the CO2, origin of the carbon, and the age of the CO2 emissions. This study investigates the transport of CO2 gas through agricultural soils using carbon isotopes 14C and 13C to complement concentration and production rate measurements in two comparative agricultural settings in Eastern Ontario, one of which has been modified by clearing and dredging of the adjacent riparian zone and one left undredged. Traditional radiocarbon dating measures time through loss by decay, while recent dating is based on matching measurements with the atmospheric 14CO2 signal (F14C) generated by nuclear bomb testing in the 1950s and 1960s. CO2 emissions were analyzed from soil core sections together with soil-probe gas samples and surface flux chamber samples collected from the study area. Soil cores were collected from 0- 90 cm at 7.5 cm increments and placed into IsoJar® microcosms for a period of one month. CO2 in-growth was monitored to provide production rates and samples for 14C and 13C analysis. The radiocarbon data for the microcosms showed that values increase with depth from the current fraction modern value of 1.00 F14C at the surface to an attenuated peak of 1.04 F14C at a depth of 30 to 40 cm and then decrease to values below 1.00 F14C. The data collected from the soil-probe gas showed a significant depletion in comparison to the microcosms and the surface chambers. The soil cores were subsequently analyzed by a selective leach oxidation protocol to sample decreasingly labile solid organic carbon. This involved placing the weighed soil samples into MilliQ water for 24 hours, before being passed through two sieves, 63 microns and 0.45 microns. The DOC leachate was collected and analyzed for 14C and 13C. The two solid soil fractions were then dried, treated with HCl to remove carbonate and then oxidized under vacuum with 5% H2O2 yielding CO2 and residual soil carbon for 14C and 13C. The radiocarbon analysis of these variously labile fractions, together with the microcosm and soil probe measurements, demonstrate that surface emissions at both sites are greatly dominated by CO2 from recently-sequestered labile organic carbon from the upper 30 cm with minor contribution from earlier, bomb-pulse carbon or from deeper pre-bomb carbon. No significant difference in age of emissions between the dredged and undredged sites was found. Carbon dating Soil Organic Carbon Recalcitrant Carbon Green House Gases Fraction modern carbon Dissolved Organic Carbon C13 C14 Carbonate weathering Organic carbon Depth profile Agriculture Fields Agriculture Soil C3 C4 Carbon 13 Carbon 14 Radiocarbon Dating Dating of agriculture soils Carbon pool Carbon pool separation Recalcitrant Carbon
106	Postglazialer Anstieg des Meeresspiegels, Paläoklima und Hydrographie, aufgezeichnet in Sedimenten der Bermuda inshore waters / Postglacial rise of sea level, palaeoclimate and hydrography, recorded in sediments of the Bermuda inshore waters Vollbrecht, Rüdiger Dr. 13 January 1997 (has links) No description available. 550 Geowissenschaften Mathematics and Computer Science Postglazial Meeresspiegel Paläoklima Hydrography Bermuda Sedimente Pleistozän Holozän Quartär Seen Küste Laminite Solarzyklen Sonnenzyklen marin lakustrin Geologie Karbonate Böden Karst Torf Isotopen-Geochemie Altersbestimmung Fazies Paläökologie postglacial sea level palaeoclimate paleoclimate hydrography Bermuda sediments Pleistocene Holocene Quaternary inshore waters lakes laminites solar cycles lacustrine marine geology carbonates soil karst peat isotope geochemistry radiocarbon dating facies palaeoecology paleoecology 38.48 Marine Geologie 38.41 Sedimentation 38.82 Klimatologie 38.19 Historische Geologie: Sonstiges 38.32 Geochemie 38.88 Regionale Hydrologie 38.47 Moore 38.90 Ozeanologie Ozeanographie VAT 250 Litorale Sedimente VCA 520 Quartärgeologie VDI 210 Pleistozän VDI 220 Holozän VEW 200 Karibischer Raum VEZ 130 Inselgruppen TWC 600 Paläoklimatologie VKB 380 Sedimente bestimmter Regionen VKB 378 Rhytmite VKB 376 Organogene Sedimentgesteine VKB 340 Fazieskunde VKB 333 Sonstige Sedimentationsprozesse VKB 332 Sedimentationsbedingungen UHA 700 Marine Geologie (Küsten Watt Inselbildung etc.) UHA 440 Schwankungen
107	Aspects of ancient Near Eastern chronology (c. 1600-700 BC) Furlong, Pierce James January 2007 (has links) (PDF) The chronology of the Late Bronze and Early Iron Age Near East is currently a topic of intense scholarly debate. The conventional/orthodox chronology for this period has been assembled over the past one-two centuries using information from King-lists, royal annals and administrative documents, primarily those from the Great Kingdoms of Egypt, Assyria and Babylonia. This major enterprise has resulted in what can best be described as an extremely complex but little understood jigsaw puzzle composed of a multiplicity of loosely connected data. I argue in my thesis that this conventional chronology is fundamentally wrong, and that Egyptian New Kingdom (Memphite) dates should be lowered by 200 years to match historical actuality. This chronological adjustment is achieved in two stages: first, the removal of precisely 85 years of absolute Assyrian chronology from between the reigns of Shalmaneser II and Ashur-dan II; and second, the downward displacement of Egyptian Memphite dates relative to LBA Assyrian chronology by a further 115 years. Moreover, I rely upon Kuhnian epistemology to structure this alternate chronology so as to make it methodologically superior to the conventional chronology in terms of historical accuracy, precision, consistency and testability.

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