Geochemical evidence of the 8.2ka event and other Holocene environmental changes recorded in paleolagoon sediments, southeastern Brazil

The paleoclimatic record of Juréia Paleolagoon, coastal southeastern Brazil, includes cyclic and gradual changes with different intensities and frequencies through geological time, and it is controlled by astronomical, geophysical, and geological phenomena. These variations are not due to one single cause, but they result from the interaction of several factors, which act at different temporal and spatial scales. Here, we describe paleoenvironmental evidence regarding climatic and sea level changes from the last 9400calyr BP at the Juréia Paleolagoon — one of the main groups of protected South Atlantic ecosystems. Geochemical evidences were used to identify anomalies from multi-proxy analyses of a paleolagoon sediment core. The anomalies of centennial scale were correlated to climate and transgression–regression cycles from the Holocene period. Decadal scale anomalous oscillations in the Quaternary paleolagoon sediments occur between 9400 and 7500calyr BP, correlated with long- and short-term natural events, which generated high sedimentation rates, mainly between 8385 and 8375calyr BP (10cm/yr). Our results suggest that a modern-day short-duration North Atlantic climatic event, such as the 8.2ka event, could affect the environmental equilibrium in South America and intensify the South American Summer Monsoon.