The paleoceanography of the Bering Sea during the last glacial cycle

• Main Author: Cook, Mea S. (Mea Young Sohn)
• Other Authors: Lloyd D. Keigwin., Woods Hole Oceanographic Institution., Joint Program in Oceanography, Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences., Massachusetts Institute of Technology. Department of Ocean Engineering
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology 2006
• Subjects: Joint Program in Oceanography; Earth; Atmospheric; and Planetary Sciences; Woods Hole Oceanographic Institution; Paleoceanography Bering Sea; Marine sediments; Bering Sea; Greenland; Bowers; Umnak Plateau
• Online Access: http://hdl.handle.net/1721.1/34271

Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2006. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Includes bibliographical references (leaves 117-126). 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 Umnak Plateau, there were episodic occurrences of diagenetic carbonate minerals with very low 13C (-22.4%), high 18O (6.5%), and high [Mg]/[Ca], which seem associated with sulfate reduction of organic matter and possibly anaerobic oxidation of methane. The episodes lasted less than 1000 years and were spaced about 1000 years apart. During MIS3 at 55-20 ky BP in a core from 2209m water depth on Bowers Ridge, N. pachyderma (s.) and Uvigerina 18O and 13C show no coherent variability on millennial time scales. Bering Sea sediments are dysoxic or laminated during the deglaciation. A high sedimentationrate core (200 cm/ky) from 1132m on the Bering Slope is laminated during the Blling warm phase, Allerd warm phase, and early Holocene, where the ages of lithological transitions agree with the ages of those climate events in Greenland (GISP2) to well within the uncertainty of the age models. The subsurface distribution of radiocarbon was estimated from a compilation of published and unpublished North Pacic benthic-planktonic 14C measurements (475{2700 m water depth). There was no consistent change in 14C probles between the present and the Last Glacial Maximum, Blling-Allerd, or the Younger Dryas cold phase. N. pachyderma (s.) 18O in the Bering Slope core decreases rapidly (in less than 220 y) by 0.7-0.8h at the onset of the Blling and ...