Late Quaternary Variations in the South American Monsoon System as Inferred by Speleothems-New Perspectives Using the SISAL Database

Author(s)

Deininger, Michael ^[1] ; Ward, Brittany Marie ^[2] ; Novello, Valdir F. ^[3] ; Cruz, Francisco W. ^[3]

Affiliation

^[1] Johannes Gutenberg Univ Mainz, Inst Geosci, JJ Becher Weg 21, D-55128 Mainz - Germany

^[2] Univ Waikato, Fac Sci & Engn, Private Bag 3105, Hamilton 3240 - New Zealand

^[3] Univ Sao Paulo, Inst Geosci, Rua Lago 562, BR-05508080 Sao Paulo - Brazil

• Document type: Review article
• Source: QUATERNARY; v. 2, n. 1 MAR 2019.
• Web of Science Citations: 6

Abstract

Here we present an overview of speleothem delta O-18 records from South America, most of which are available in the Speleothem Isotopes Synthesis and Analysis (SISAL\_v1) database. South American tropical and subtropical speleothem delta O-18 time series are primarily interpreted to reflect changes in precipitation amount, the amount effect, and consequently history of convection intensity variability of convergence zones such as the Intertropical Convergence Zone (ITCZ) and the South America Monsoon System (SAMS). We investigate past hydroclimate scenarios in South America related to the South American Monsoon System in three different time periods: Late Pleistocene, Holocene, and the last two millennia. Precession driven summertime insolation is the main driver of convective variability over the continent during the last 120 kyrs (from present day to 120 kyrs BP), including the Holocene. However, there is a dipole between speleothem delta O-18 records from western and eastern South America. Records located in the central region of Brazil are weakly affected by insolation-driven variability, and instead are more susceptible to the variability associated with the South Atlantic Convergence Zone (SACZ). Cold episodic events in the Northern Hemisphere, such as Heinrich and Bond Events, and the Little Ice Age, increase the convective activity of the SAMS, resulting in increased precipitation amount in South America. (AU)

• FAPESP's process: 16/15807-5 - Paleoclimate and paleoenvironmental reconstructions over the last glacial period in the mid-west Brazil
• Grantee: Valdir Felipe Novello
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 13/50297-0 - Dimensions US-BIOTA São Paulo: a multidisciplinary framework for biodiversity prediction in the Brazilian Atlantic forest hotspot
• Grantee: Cristina Yumi Miyaki
• Support type: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 18/12285-3 - Modelling karst system and its relevance for paleoclimate reconstruction of Brazil
• Grantee: Valdir Felipe Novello
• Support type: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 17/50085-3 - PIRE: climate research education in the Americas using tree-ring speleothem examples (PIRE-CREATE)
• Grantee: Francisco William da Cruz Junior
• Support type: Research Projects - Thematic Grants