Origin of increased terrigenous supply to the NE South American continental margin during Heinrich Stadial 1 and the Younger Dryas

Author(s)

Zhang, Yancheng ^[1] ; Chiessi, Cristiano M. ^[2] ; Mulitza, Stefan ^[1] ; Zabel, Matthias ^[1] ; Trindade, Ricardo I. F. ^[3] ; Hollanda, Maria Helena B. M. ^[4] ; Dantas, Elton L. ^[5] ; Govin, Aline ^[1] ; Tiedemann, Ralf ^[6] ; Wefer, Gerold ^[1]

Affiliation

^[1] Univ Bremen, MARUM Ctr Marine Environm Sci, D-28359 Bremen - Germany

^[2] Univ Sao Paulo, Sch Arts Sci & Humanities, BR-05508 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, BR-05508 Sao Paulo - Brazil

^[4] Univ Sao Paulo, Inst Geosci, BR-05508 Sao Paulo - Brazil

^[5] Univ Brasilia, Inst Geosci, BR-70910900 Brasilia, DF - Brazil

^[6] Alfred Wegener Inst Polar & Marine Res, Bremerhaven - Germany

• Document type: Journal article
• Source: Earth and Planetary Science Letters; v. 432, p. 493-500, DEC 15 2015.
• Web of Science Citations: 19

Abstract

We investigate the redistribution of terrigenous materials in the northeastern (NE) South American continental margin during slowdown events of the Atlantic Meridional Overturning Circulation (AMOC). The compilation of stratigraphic data from 108 marine sediment cores collected across the western tropical Atlantic shows an extreme rise in sedimentation rates off the Parnaiba River mouth (about 2 degrees S) during Heinrich Stadial 1 (HS1,18-15 ka). Sediment core GeoB16206-1, raised offshore the Parnaiba River mouth, documents relatively constant Nd-143/Nd-144 values (expressed as epsilon(Nd(0))) throughout the last 30 ka. Whereas the homogeneous epsilon(Nd(0)) data support the input of fluvial sediments by the Parnaiba River from the same source area directly onshore, the increases in Fe/Ca, Al/Si and Rb/Sr during HS1 indicate a marked intensification of fluvial erosion in the Parnaiba River drainage basin. In contrast, the epsilon(Nd(0)) values from sediment core GeoB16224-1 collected off French Guiana (about 7 degrees N) suggest Amazon-sourced materials within the last 30 ka. We attribute the extremely high volume of terrigenous sediments deposited offshore the Parnaiba River mouth during HS1 to (i) an enhanced precipitation in the catchment region and (ii) a reduced North Brazil Current, which are both associated with a weakened AMOC. (C) 2015 Elsevier B.V. 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