Timing and structure of Mega-SACZ events during Heinrich Stadial 1

Author(s):Show less -

Strikis, Nicolas M. ^[1] ; Chiessi, Cristiano M. ^[2] ; Cruz, Francisco W. ^[1] ; Vuille, Mathias ^[3] ; Cheng, Hai ^[4] ; de Souza Barreto, Eline A. ^[1] ; Mollenhauer, Gesine ^{[5, 6]} ; Kasten, Sabine ^{[5, 6]} ; Karmann, Ivo ^[1] ; Edwards, R. Lawrence ^[4] ; Pablo Bernal, Juan ^[7] ; Sales, Hamilton dos Reis ^[8]

Affiliation

^[1] Univ Sao Paulo, Inst Geociencias, BR-01498 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, Sao Paulo - Brazil

^[3] SUNY Albany, Dept Atmospher & Environm Sci, Albany, NY 12222 - USA

^[4] Univ Minnesota, Dept Earth Sci, Minneapolis, MN - USA

^[5] Univ Bremen, MARUM Ctr Marine Environm Sci, D-28359 Bremen - Germany

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

^[7] Univ Nacl Autonoma Mexico, Ctr Geociencias, Queretaro - Mexico

^[8] Inst Fed Educ Ciencia & Tecnol Norte Minas Gerais, Januaria - Brazil

• Document type: Journal article
• Source: Geophysical Research Letters; v. 42, n. 13, p. 5477-5484, JUL 16 2015.
• Web of Science Citations: 28

Abstract

A substantial strengthening of the South American monsoon system (SAMS) during Heinrich Stadials (HS) points toward decreased cross-equatorial heat transport as the main driver of monsoonal hydroclimate variability at millennial time scales. In order to better constrain the exact timing and internal structure of HS1 over tropical South America, we assessed two precisely dated speleothem records from central-eastern and northeastern Brazil in combination with two marine records of terrestrial organic and inorganic matter input into the western equatorial Atlantic. During HS1, we recognize at least two events of widespread intensification of the SAMS across the entire region influenced by the South Atlantic Convergence Zone (SACZ) at 16.11-14.69kyr B.P. and 18.1-16.66kyr B.P. (labeled as HS1a and HS1c, respectively), separated by a dry excursion from 16.66 to 16.11kyr B.P. (HS1b). In view of the spatial structure of precipitation anomalies, the widespread increase of monsoon precipitation over the SACZ domain was termed Mega-SACZ. (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: 12/01187-4 - A calibration study in Central Brazil caves: implications for the paleoclimate inferences from speleothem records
• Grantee: Ivo Karmann
• 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