Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 44 for “"paleoceanography"”.
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Late Paleogene (Eocene to Oligocene) paleoceanography of the northern North Atlantic
Seismic stratigraphic evidence from the western and northern North Atlantic indicates that a major change in abyssal circulation occurred in the latest Eocene to earliest Oligocene. In the northern North Atlantic, the widely-distributed reflector R4 correlates with an unconformity that can be …
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The paleoceanography of the Bering Sea during the last glacial cycle
In this thesis, I present high-resolution stable-isotope and planktonic-fauna records from Bering Sea sediment cores, spanning the time period from 50,000 years ago to the present. During Marine Isotope Stage 3 (MIS3) at 30-20 ky BP (kiloyears before present) in a core from 1467m water depth near …
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Late Paleogene (Eocene to Oligocene) paleoceanography of the northern North Atlantic
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1983.
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The paleoceanography of the Bering Sea during the last glacial cycle
In this thesis, I present high-resolution stable-isotope and planktonic-fauna records from Bering Sea sediment cores, spanning the time period from 50,000 years ago to the present. During Marine Isotope Stage 3 (MIS3) at 30-20 ky BP (kiloyears before present) in a core from 1467m water depth near …
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LATE MIOCENE AND PLIOCENE PALEOCEANOGRAPHY OF THE LOW LATITUDE NORTHERN HEMISPHERE AND ITS IMPLICATIONS FOR FUTURE CLIMATE CHANGE
The late Neogene represents an exceptionally dynamic period in Earth history during which the Northern Hemisphere has transitioned from a warmer, more equable climate to a cooler, more transient state characterized by waxing and waning continental ice sheets. While geographical distal, the tropical …
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Dinoflagellate cyst record and paleoceanography through the Pliocene–Pleistocene transition at ODP Site 1143, southern South China Sea
Palynological analysis of 72 samples from Ocean Drilling Program (ODP) Site 1143, southern South China Sea, spanning a 2.90–2.41 Ma interval across the Pliocene–Pleistocene boundary, reveals a well preserved and relatively diverse dinoflagellate cyst (dinocyst) record. Generally, the cysts of …
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Ordovician paleoceanography: Stable isotope and carbon-sulfur-iron evidence from the Caradocian Trenton Group, Mohawk Valley, New York
Oxygen isotope evidence from Caradocian Trenton Group brachiopods in the Mohawk Valley of New York suggests that Caradocian oceans were salinity-stratified and dominated at depth by warm, saline waters. $\delta\sp{18}$O values of these brachiopods, which lived on the eastern continental slope of …
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Paleoceanography across the Pliocene–Pleistocene transition in the southern Bering Sea: dinoflagellate cysts and acritarchs from IODP Site U1341
The latest Pliocene–earliest Pleistocene (2.828 Ma to 2.401 Ma) interval from Integrated Ocean Drilling Program Site U1341, Bowers Ridge, southern Bering Sea, northern North Pacific has been analyzed for dinoflagellate cysts, acritarchs and other palynomorphs. Based on 86 samples, with a spacing …
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Western Pacific paleoceanography across the Early–Middle Pleistocene boundary (~773 ka, Marine Isotope Stage 19): Dinoflagellate cysts of the Chiba composite section, Japan.
The Chiba composite section, central Boso Peninsular, Japan, is a candidate Global Boundary Stratotype Section and Point for the Early–Middle Pleistocene Subseries boundary. This well-exposed, continuous and expanded marine silty sedimentary succession has a detailed paleomagnetic record and an …
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Central North Atlantic (IODP Site U1313) paleoceanography based on a high-resolution dinoflagellate cyst record across the Early–Middle Pleistocene boundary (Marine Isotope Stages 20–18, ~810–741 ka)
A dinoflagellate cyst (dinocyst) study of 102 samples from Integrated Ocean Drilling Program Site U1313 in the central North Atlantic Ocean represents the most detailed dinocyst record yet available for Marine Isotope Stage (MIS) 19, which spans the Lower–Middle Pleistocene boundary. A published …
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BIOSTRATIGRAPHIC AND PALEOCEANOGRAPHIC RECONSTRUCTION OF THE LATE MIOCENE IN BAJA CALIFORNIA AND TRES MARIAS ISLANDS, MEXICO
… provided enough samples to reconstruct the paleoceanography of the study area at two time intervals. The first one at 10 m.y.a., shows the intense development of a paleo-El Nino Current, producing high percentages of warm water radiolarians in all the basins. However, Arroyo Tiburon might …
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Constraining circulation changes through the last deglaciation with deep-sea coral radiocarbon and sedimentary 231Pa/230Th
Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean’s role in climate change over the last deglaciation. I present a new method for rapid radiocarbon analyses as a …
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Constraining circulation changes through the last deglaciation with deep-sea coral radiocarbon and sedimentary ²³¹Pa/²³⁰Th
Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean's role in climate change over the last deglaciation. I present a new method for rapid radiocarbon analyses as a …
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Deep-marine depositional systems of the western North Atlantic: Insights into climate and passive-margin evolution
… a unique, long-term record of paleoclimate, paleoceanography, and tectonics affecting the basin in question. Whereas deep-marine strata may be used to answer myriad of questions regarding the evolution and development of Earth systems, this dissertation narrowly targets two distinct aspects …
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Antarctica's Geologic and Ice Sheet History from Isotopic Sedimentary Provenance Studies
… samples. Chapter 2 is published in the journal Paleoceanography, and chapters 3 and 4 are to be submitted to Earth and Planetary Sciences and Paleoclimatology, Palaeoecology & Paleoceanography, respectively. In Chapter 2, I demonstrated that (1) four main sectors between the Ross Sea and Prydz …
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Cenozoic deep-water agglutinated foraminifera in the North Atlantic
… in the North Atlantic, and their utility for paleoceanography. Towards this end, spade core samples from a 3912 m deep station in the Panama Basin were studied to determine abundance and microhabitat partitioning among living agglutinated foraminiferal populations and the preservation of dead …
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Paleoceanographic variability on a millennial scale: a high resolution record of the latest deglaciation from the Blake Outer Ridge, western North Atlantic
Strong temporal and geographic variabilty in paleocirculation during the latest deglaciation is demonstrated for the Blake Outer Ridge, Western North Atlantic. Cores KNR140-2 GGC-39 from 2975 meters and GGC-40 from 2924 meters show correlative oscillations in Cibicidoides and Uvigerina abundances, …
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An organic geochemical approach to problems of glacial-interglacial climatic variability
The concentration and carbon isotopic composition (δ13C) of sedimentary organic carbon (Corg), N/C ratios, and terrigenous and marine δ13C-Corg end-members form a basis from which to address problems of Late Quaternary glacial-interglacial climatic variability in a 208.7 m hydraulic piston core …
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An inverse modeling approach to investigate deep ocean ventilation from radiocarbon records
The goal of this project is to investigate the relationship between paleoceanographic radiocarbon records and the ventilation history of deep oceanic basins during the last 40 kyrs. Deep ocean ventilation changes, especially changes in Atlantic meridional overturning circulation (AMOC), are often …
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Marine carbonate accumulation during the greenhouse climate of the Eocene
… mechanism. As this study and multiple others in paleoceanography utilize bulk sediment carbon isotope (δ13C) records in Cenozoic chemostratigraphy; it is crucial to deconvolute the isotope signal of marine bulk sediments. Pelagic carbonates are ensemble of different components of varying …
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