Tracking millennial-scale Holocene glacial advance and retreat using osmium isotopes: Insights from the Greenland ice sheet

QUATERNARY SCIENCE REVIEWS

卷:138

Article

Rooney, Alan D.^1,2  Selby, David²  Lloyd, Jeremy M.³  Roberts, David H.³  Lueckge, Andreas⁴  Sageman, Bradley B.⁵  Prouty, Nancy G.⁶ 

[1] Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA

[2] Univ Durham, Dept Earth Sci, Durham DH1 3LE, England

[3] Univ Durham, Dept Geog, Durham DH1 3LE, England

[4] Bundesanstalt Geowissensch & Rohstoffe, Stilleweg 2, D-30655 Hannover, Germany

[5] Northwestern Univ, Dept Earth & Planetary Sci, 1850 Campus Dr, Evanston, IL USA

[6] US Geol Survey, Pacific Coastal & Marine Sci Ctr, 400 Nat Bridges Dr, Santa Cruz, CA 95060 USA

关键词: Greenland ice sheet;    Osmium;    Holocene;    Ocean-ice interaction;   

DOI  :  10.1016/j.quascirev.2016.02.021

来源: Elsevier

【 摘 要 】

High-resolution Os isotope stratigraphy can aid in reconstructing Pleistocene ice sheet fluctuation and elucidating the role of local and regional weathering fluxes on the marine Os residence time. This paper presents new Os isotope data from ocean cores adjacent to the West Greenland ice sheet that have excellent chronological controls. Cores MSM-520 and DA00-06 represent distal to proximal sites adjacent to two West Greenland ice streams. Core MSM-520 has a steadily decreasing Os signal over the last 10 kyr (Os-187/Os-188 = 1.35-0.81). In contrast, Os isotopes from core DA00-06 (proximal to the calving front of Jakobshavn Isbr) highlight four stages of ice stream retreat and advance over the past 10 kyr (Os-187/Os-188 = 2.31; 1.68; 2.09; 1.47). Our high-resolution chemostratigraphic records provide vital benchmarks for ice-sheet modelers as we attempt to better constrain the future response of major ice sheets to climate change. Variations in Os isotope composition from sediment and macro-algae (seaweed) sourced from regional and global settings serve to emphasize the overwhelming effect weathering sources have on seawater Os isotope composition. Further, these findings demonstrate that the residence time of Os is shorter than previous estimates of similar to 10(4) yr. (C) 2016 The Authors. Published by Elsevier Ltd.

【 授权许可】

Free