Interdecadal climate variability identified in aeolian deposits in southern Santa Catarina, Brazil

Abstract

Changes have occurred to the patterns of surface morphology in coastal aeolian deposits in a chrono-correlated way in different geographical areas at different time scales. These changes can be recognized and associated with meso and large-scale climatic events, thus establishing a teleconnection. In the present study, surface and subsurface data, combined with Optically Stimulated Luminescence (OSL) dating, allowed us to establish the evolutionary chronology and the environmental context of aeolian features that cover a stretch of the Holocene coastal barrier in the southern coast of Santa Catarina, Brazil. According to geophysical and geochronological data and geomorphological indicators, the section shows regressive coastal line behavior (progradational pattern). The sedimentary cover of this Holocene coastal barrier, so far dominated by active dunes, began to change after the 1930s. The subsequent decades were marked by a significant increase in vegetation, fixing the precipitation crests of the transgressive sand sheets (TSS). This increase in vegetation cover over the last century results from climatic variability associated with the Pacific Decadal Oscillation.