Different precipitation patterns across tropical South America during Heinrich and Dansgaard-Oeschger stadials

Author(s)

Zhang, Yancheng ^[1] ; Chiessi, Cristiano M. ^[2] ; Mulitza, Stefan ^[1] ; Sawakuchi, Andre O. ^[3] ; Haeggi, Christoph ^[1] ; Zabel, Matthias ^[1] ; Portilho-Ramos, Rodrigo C. ^[3] ; Schefuss, Enno ^[1] ; Crivellari, Stefano ^[3] ; Wefer, Gerold ^[1]

Affiliation

^[1] Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen - Germany

^[2] Univ Sao Paulo, Sch Arts Sci & Humanities, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Inst Geosci, Sao Paulo - Brazil

• Document type: Journal article
• Source: QUATERNARY SCIENCE REVIEWS; v. 177, p. 1-9, DEC 1 2017.
• Web of Science Citations: 11

Abstract

Detailed knowledge about tropical South American precipitation patterns during Heinrich (H) and Dansgaard-Oeschger (DO) stadials provides relevant insights into the possible evolution of Amazonian hydroclimate under future climate change. Sediment core GeoB16224-1 (ca. 7 degrees N), raised from a site in the continental slope off French Guiana in western equatorial Atlantic under the influence of the Amazon River discharge, documents the impacts of H and DO stadials on both inorganic (i.e., Fe/Ca record) and organic (i.e., alkenone C-37 concentration and C-37/C-38 ratio) geochemistry between 41 and 13 ka BP. Our results show millennial-scale covariations of increased Fe/Ca values with decreased C37 concentration and C37/C38 ratios during H and DO stadials. Comparing our high temporal resolution data with previously published records from ca. 17 degrees N to 4 degrees S, we are able to differentiate the influence of H and DO stadials upon tropical South American precipitation. We find that records under the influence of the South American summer monsoon (e.g., western Amazon) and the northern edge of the Intertropical Convergence Zone (ITCZ) (e.g., northernmost South America) exhibit strong climate shifts during both H and DO stadials, but regions under the influence of the southern edge of the ITCZ (e.g., northeastern Brazil) experience a weaker reaction during DO stadials than during H stadials. (C) 2017 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 12/17517-3 - Response of the Western Atlantic Ocean to changes in the Atlantic meridional overturning circulation: from millennial to seasonal variability
• Grantee: Cristiano Mazur Chiessi
• Support Opportunities: Research Program on Global Climate Change - Young Investigators
• FAPESP's process: 11/06609-1 - Provenance, transport and storage of sediments in Amazon rivers
• Grantee: André Oliveira Sawakuchi
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/50260-6 - Structure and evolution of the Amazonian biota and its environment: an integrative approach
• Grantee: Lúcia Garcez Lohmann
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants