Occurrence and impact of the mega-South Atlantic Convergence Zone over the eastern South America during the last glacial period: a paleoceanographic approach

• Grant number: 16/10242-0
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): September 01, 2016
• Effective date (End): May 31, 2020
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal researcher: Cristiano Mazur Chiessi
• Grantee: Marília de Carvalho Campos Garcia
• Home Institution: Escola de Artes, Ciências e Humanidades (EACH). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 18/06790-7 - Variability of the Brazil Current and South American climate during the last glacial cycle: assessing sea-surface temperatures via Mg/Ca analyses and pulses of terrigenous sediments via X-ray fluorescence analyses, BE.EP.DR

Abstract

The Brazil Current (BC) plays a fundamental role in the distribution of energy between the hemispheres. It stores and redirects towards the mean latitudes of the Southern Hemisphere a significant portion of heat in periods of weakening of the Atlantic Meridional Overturning Circulation (AMOC). Additionally, the BC influences summer precipitation in a large sector of South America. Recently, anomalies so far unknown of the position and intensity of the South Atlantic Convergence Zone (SACZ) were described for the Heinrich Stadial (HS) 1 and termed "mega-SACZ". Such anomalies were associated to the weakening of the AMOC and had produced dramatic changes in South America climate. Since the HSs can, to some extent, be considered as past analogous of future conditions and that the reduction of up to 44% of the AMOC intensity is predicted to occur until the end of the century, a better understanding of the above described phenomenon is urgently required. This PhD project aims at reconstructing the oceanographic and climatic variability of the western South Atlantic near 10.5°S and of the adjacent portion of the continent during the last glacial and deglacial periods. Thus, we will be able to determine the occurrence and impact of the mega-SACZ over eastern South America during the last glacial period. We will investigate the marine sediment cores M125-95-2/3 collected at a site under the influence of the BC and subject to the delivery of terrigenous sediments from the São Francisco river drainage basin, located mainly under the influence of the SACZ. For this cores we will produce age models based on 14C ages, fluorescence X-ray analyses, oxygen and carbon stable isotope analyses, and Mg/Ca analyses.

Scientific publications

(5)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

CRIVELLARI, STEFANO; VIANA, PATRICIA JUNIA; CAMPOS, MARILIA DE CARVALHO; KUHNERT, HENNING; MACHADO LOPES, ALYNE BARROS; CRUZ, JR., FRANCISCO WILLIAM DA; CHIESSI, CRISTIANO MAZUR. Development and characterization of a new in-house reference material for stable carbon and oxygen isotopes analyses. Journal of Analytical Atomic Spectrometry, v. 36, n. 6, p. 1125-1134, JUN 1 2021. Web of Science Citations: 0.

PINHO, TAINA M. L.; CHIESSI, CRISTIANO M.; PORTILHO-RAMOS, RODRIGO C.; CAMPOS, MARILIA C.; CRIVELLARI, STEFANO; NASCIMENTO, RODRIGO A.; ALBUQUERQUE, ANA L. S.; BAHR, ANDRE; MULITZA, STEFAN. Meridional changes in the South Atlantic Subtropical Gyre during Heinrich Stadials. SCIENTIFIC REPORTS, v. 11, n. 1 MAY 3 2021. Web of Science Citations: 0.

CHIESSI, C. M.; MULITZA, S.; TANIGUCHI, N. K.; PRANGE, M.; CAMPOS, M. C.; HAEGGI, C.; SCHEFUSS, E.; PINHO, T. M. L.; FREDERICHS, T.; PORTILHO-RAMOS, R. C.; SOUSA, S. H. M.; CRIVELLARI, S.; CRUZ, F. W. Mid- to Late Holocene Contraction of the Intertropical Convergence Zone Over Northeastern South America. PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY, v. 36, n. 4 APR 2021. Web of Science Citations: 0.

CAMPOS, MARILIA C.; CHIESSI, CRISTIANO M.; VENANCIO, IGOR M.; PINHO, TAINA M. L.; CRIVELLARI, STEFANO; KUHNERT, HENNING; SCHMIEDL, GERHARD; DIAZ, RUT A.; ALBUQUERQUE, ANA LUIZA S.; PORTILHO-RAMOS, RODRIGO C.; BAHR, ANDRE; MULITZA, STEFAN. Constraining Millennial-Scale Changes in Northern Component Water Ventilation in the Western Tropical South Atlantic. PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY, v. 35, n. 7 JUL 2020. Web of Science Citations: 0.

CAMPOS, MARILIA C.; CHIESSI, CRISTIANO M.; PRANGE, MATTHIAS; MULITZA, STEFAN; KUHNERT, HENNING; PAUL, ANDRE; VENANCIO, IGOR M.; ALBUQUERQUE, ANA LUIZA S.; CRUZ, FRANCISCO W.; BAHR, ANDRE. A new mechanism for millennial scale positive precipitation anomalies over tropical South America. QUATERNARY SCIENCE REVIEWS, v. 225, DEC 1 2019. Web of Science Citations: 0.