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Last Deglacial Arctic to Pacific Transgressions via the Bering Strait: Implications for Climate, Meltwater Source, Ecosystems and Southern Ocean Wind Strength
Nwaodua, Emmanuel C

2013, PHD, Kent State University, College of Arts and Sciences / Department of Geology.
The main goal of this research is to provide physical evidence of reverse flow(s), from the Arctic to the North Pacific Ocean, after the Last Glacial Maximum (LGM). This is primarily essential to studies concerned with understanding how the fluctuations in strength of the Southern Ocean Wind (SOW), in conjunction with an open Bering Strait, alter the direction of water flow through the Bering Strait.

Visible and Near Infrared (VNIR) derivative spectroscopy; quotient normalization and varimax rotated principal component analysis of diffuse spectral reflectance (DSR) measurements from 234 surface core samples and 2 piston cores, in addition to the USGS spectral library, were used to extract and identify these lithological compositions (in order of importance) within the study location. These compositions are chlorite + muscovite; goethite + phycoerythrin + phycocyanin; smectite; calcite+dolomite; and illite + Chlorophyll a. The Geostatistical tool, kriging, was utilized in creating the sedimentary maps of all the components. These maps were used to determine these components' modern spatial patterns. This aided in the evaluation and downcore interpretation of the component most suited for this study.

The illite in illite + Chlorophyll a assemblage was deemed to be the appropriate water mass tracer for a reverse flow from the Arctic into the North Pacific; this is because of its prominence and abundance in the Mackenzie River drainage basin and on the west Arctic Sea shelf. The illite denotes these periods of meltwater pulses (MWP): MWP 1A, ~14,600 and 13,800 Cal yrs. BP, separated by the Older Dryas; MWP 1B, ~11,000-9,200 Cal yrs. BP; and MWP 1C, ~8,000 Cal yrs. BP. The timing of these pulses along with previously published data on the Bering Sea shelf and the North Pacific Ocean enabled these deductions: 1) the initial opening of the Bering Strait and the flow direction after the LGM; 2) the source of these meltwater pulses and the mechanism that might drive them through the Strait; 3) the impact of these pulses on climate change; and 4) the effect of these pulses on the Bering Sea shelf ecosystem.

Joseph Ortiz (Advisor)
Alison Smith (Committee Member)
Elizabeth Griffith (Committee Member)
John Portman (Committee Member)
185 p.

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Nwaodua, E. (2013). Last Deglacial Arctic to Pacific Transgressions via the Bering Strait: Implications for Climate, Meltwater Source, Ecosystems and Southern Ocean Wind Strength . (Electronic Thesis or Dissertation). Retrieved from https://etd.ohiolink.edu/

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Nwaodua, Emmanuel. "Last Deglacial Arctic to Pacific Transgressions via the Bering Strait: Implications for Climate, Meltwater Source, Ecosystems and Southern Ocean Wind Strength ." Electronic Thesis or Dissertation. Kent State University, 2013. OhioLINK Electronic Theses and Dissertations Center. 17 Jul 2018.

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Nwaodua, Emmanuel "Last Deglacial Arctic to Pacific Transgressions via the Bering Strait: Implications for Climate, Meltwater Source, Ecosystems and Southern Ocean Wind Strength ." Electronic Thesis or Dissertation. Kent State University, 2013. https://etd.ohiolink.edu/

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