Organic and inorganic geochemical data of sediment cores XC-03 and XC-01-2, Xingu River, Amazon Basin

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.