Department or Program

Geology

Abstract

While the cold Younger Dryas (YD; 12.9-11.6 ka BP) and warm early Holocene (beginning 11.5 ka BP) have been well-observed at several locations in the Northeast Pacific, little work has been done off the coast of Oregon. In an effort to better understand variations in hypoxia and productivity in this region during these time periods, this high-resolution paleoceanographic study examined a sediment core collected along the Oregon Margin at a depth of 360 m. Methods included geochemical analyses of authigenic (xs) trace metals (xsRe, xsMo), as well as carbon and nitrogen contents and their associated stable isotopes. A 14C- and 210Pb-dated age model noted two separate sections of the core (0-0.9 ka BP; 9.8 to 13.0 ka BP); the interim period likely corresponds to a slab lost due to seismic activity. xsRe and xsMo increases in the Early Holocene suggests low oxygen conditions during this time period. Likewise, total organic carbon, δ13C, and δ15N enrichment may suggest high productivity. These observations may be explained by increased upwelling and/or an intensification of the oxygen minimum zone along the Oregon Margin. These results suggest high levels of hypoxia and productivity into the early Holocene relative to the Younger Dryas, likely as a result of increased upwelling and/or an intensification of the oxygen minimum zone along the Oregon Margin. As these occurrences were observed during the early Holocene warming, it is likely that, in our current warming climate, the system may be susceptible to similar widespread events of hypoxia.

Level of Access

Restricted: Campus/Bates Community Only Access

First Advisor

Beverly Johnson

Date of Graduation

Spring 5-2013

Degree Name

Bachelor of Science

Number of Pages

58

Components of Thesis

Thesis text (58 p.)

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