Multiproxy analysis (phytoliths, stable isotopes, and C/N) as indicators of paleoenvironmental changes in a Cerrado Site, Southern Brazil

Abstract

Cerrado vegetation is associated with the semi-humid climate of the Central Brazil highlands. The presence of this vegetation in small and sparse areas in Parana, Southern Brazil, can be associated with its past climate conditions. Paleoenvironmental changes of Cerrado vegetation in the Campo Mourao region (24o06’S - 52o23’W) are discussed in this study. The environmental changes were characterized using proxy data that includes stable isotopes and phytolith analyses in peaty sediments. Two drill cores obtained in alluvial plains were analyzed. Results were compared with the isotopic record (δ 13 C) from a trench in the Cerrado Ecological Station. Based on the results, we can infer that in ~48,800±270 yrs BP, the vegetation was mainly composed of grasses and at ~42,280 cal yrs BP a wetter climate allowed the expansion of arboreal vegetation. During the Middle Holocene (~7280 cal yrs BP), a drier period is also reported. Current climatic conditions (wet) were established since ~3280 cal yrs BP, after which the data suggests the expansion of subtropical forests over the Cerrado.