Geological Society of America

T160 Paleoclimate, Paleoenvironments, and Paleoceanography of Northwestern North America (Posters)

Tuesday, 12 October 2021
9:00 AM - 1:00 PM
Exhibit Hall A

PALEOCEANOGRAPHIC PERSPECTIVES ON COLUMBIA RIVER DISCHARGE DURING THE HOLOCENE

Paper number: T160-6
Program: Technical Sessions
Time: 9:00 AM – 1:00 PM

Authors

Erin Gregory Presenting Author
Western Washington University, Bellingham, WA
Brendan Reilly
Scripps Institution of Oceanography, La Jolla, CA
Joseph Stoner
Oregon State University, Corvallis, OR
Alan Mix
Oregon State University, Corvallis, OR
Maureen H. Walczak
Oregon State University, Corvallis, OR
Camilo Ponton
Western Washington University, Bellingham, WA
June Padman
Oregon State University, Corvallis, OR
Andrew Ross
Oregon State University, Corvallis, OR
Katherine M. Stelling
Western Washington University, Bellingham, WA
Deepa Dwyer
Oregon State University, Corvallis, OR
Jonas Donnenfield
Oregon State University, Corvallis, OR

Abstract

The Columbia River is among the largest river systems in North America (fourth in terms of discharge). Its flow influences North Pacific climate and ecosystems, while serving as an essential resource for agriculture, hydropower, shipping, and fisheries. Future warming is expected to influence snowpack, seasonal precipitation, and both atmospheric and sea-surface temperatures, but model projections disagree about both the sign and magnitude of the effects, so the resulting impacts on seasonal and annual river flows remain uncertain. This study assesses past variations in sea-surface salinity from δ¹⁸O in planktonic foraminifera at a seasonal scale over the Holocene along the Oregon margin, to better understand the impact of warming on river flows. Newly collected marine sediment cores off the Columbia River record the influence of the freshwater plume near the sea surface. Core descriptions document a thick, bioturbated Holocene sediment package with Holocene sedimentation rates of 60-80 cm/kyr and abundant foraminifera, sufficient for developing a high-resolution (century-scale) record of changes in the Columbia Plume. δ¹⁸O analysis of several planktonic foraminifera species in the seasonal succession are expected to document seasonal-scale variation in the sea-surface salinity record related to changing freshwater flows during the late Pleistocene and Holocene.

Geological Society of America Abstracts with Programs. Vol. 53, No. 6

doi: 10.1130/abs/2021AM-368480

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