Spatiotemporal Variations of Riverine Discharge Within the Amazon Basin During the Late Holocene Coincide With Extratropical Temperature Anomalies

Author(s):Show less -

Bertassoli, Jr., D. J. ^[1] ; Sawakuchi, A. O. ^[1] ; Chiessi, C. M. ^[2] ; Schefuss, E. ^[3] ; Hartmann, G. A. ^[4] ; Haeggi, C. ^{[5, 3]} ; Cruz, F. W. ^[1] ; Zabel, M. ^[3] ; McGlue, M. M. ^[6] ; Santos, R. A. ^[1] ; Pupim, F. N. ^[7]

Affiliation

^[1] Univ Sao Paulo, Inst Geosci, Sao Paulo - Brazil

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

^[3] Bremen Univ, MARUM Ctr Marine Environm Sci, Bremen - Germany

^[4] Univ Estadual Campinas, Inst Geosci, Campinas, SP - Brazil

^[5] Univ Southern Calif, Dept Earth Sci, Los Angeles, CA - USA

^[6] Univ Kentucky, Dept Earth & Environm Sci, Lexington, KY - USA

^[7] Univ Fed Sao Paulo, Dept Environm Sci, Diadema - Brazil

• Document type: Journal article
• Source: Geophysical Research Letters; v. 46, n. 15, p. 9013-9022, AUG 16 2019.
• Web of Science Citations: 0

Abstract

Late Holocene hydroclimate variations have been extensively recognized in Amazonia, but the effects of such changes on riverine discharge within the Amazon lowlands are still poorly understood. We investigated a sediment core covering circa 4,000 to 300 cal yr BP collected in the lower valley of the Xingu River (Xingu Ria) in an area under the influence of the Amazon River. Our results indicate a decrease in precipitation in the Amazon lowlands throughout the studied period and reduced input of coarser and potassium-rich Amazon River sediments to the confluence from about 2,600 to 1,400 cal yr BP. We suggest that lower temperatures in the extratropical Southern Hemisphere weakened the South American Summer Monsoon and led to a decrease in the water discharge of the Amazon River during this period. Plain Language Summary The variability of the Amazon River water discharge over the last millennia is still poorly understood. Sediments deposited in the lower valley of the Xingu River, a major eastern tributary of the Amazon River, allowed for the identification of a decrease in rainfall over the Amazon lowlands throughout the last 4,000 years. Changes in the relative input of Amazon and Xingu sediments in an area affected by both rivers indicate that the water discharge of the Amazon River decreased from about 2,600 to 1,400 years ago. We suggest that anomalously low temperatures in the Southern Hemisphere led to drier conditions in Amazonia during this period. (AU)

• FAPESP's process: 16/11141-2 - Hydrologic variability and sediment supply of the Xingu and Tapajós rivers: Climate change and anthropogenic impacts in eastern Amazon rivers during Holocene
• Grantee: Dailson José Bertassoli Junior
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/25735-4 - Organic geochemistry analysis to reconstruct hydroclimate changes across eastern and western Amazon during the last 4,000 years
• Grantee: Dailson José Bertassoli Junior
• Support type: Scholarships abroad - Research Internship - Doctorate
• 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
• FAPESP's process: 14/23334-4 - Coupling Optically Stimulated Luminescence (OSL) and Terrestrial Cosmogenic Nuclides (TCN) analysis to reconstruct changes in the Amazonian fluvial system in the Late Cenozoic (<5 Ma)
• Grantee: Fabiano Do Nascimento Pupim
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 16/02656-9 - The response of sedimentary dynamics of the Xingu and Tapajós rivers to climate changes and hydropower dams: risks for biodiversity conservation and energy production in Amazonia
• Grantee: André Oliveira Sawakuchi
• Support type: Research Program on Global Climate Change - Regular Grants