A mid-Holocene climate reconstruction for eastern South America
- 1Instituto Oceanográfico, Universidade de São Paulo, São Paulo, Brazil
- 2Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, Brazil
- 3IRD UMR 226 Institut des Sciences de l'Evolution, IRD CNRS UM2, Montpellier, France
- 4IRD UMR 7159 Laboratoire d'Océanographie et du Climat: Expérimentations et approches numériques, Bondy, France
Abstract. The mid-Holocene (6000 calibrated years before present) is a key period in palaeoclimatology because incoming summer insolation was lower than during the late Holocene in the Southern Hemisphere, whereas the opposite happened in the Northern Hemisphere. However, the effects of the decreased austral summer insolation over South American climate have been poorly discussed by palaeodata syntheses. In addition, only a few of the regional studies have characterised the mid-Holocene climate in South America through a multiproxy approach. Here, we present a multiproxy compilation of mid-Holocene palaeoclimate data for eastern South America. We compiled 120 palaeoclimatological datasets, which were published in 84 different papers. The palaeodata analysed here suggest a water deficit scenario in the majority of eastern South America during the mid-Holocene if compared to the late Holocene, with the exception of northeastern Brazil. Low mid-Holocene austral summer insolation caused a reduced land–sea temperature contrast and hence a weakened South American monsoon system circulation. This scenario is represented by a decrease in precipitation over the South Atlantic Convergence Zone area, saltier conditions along the South American continental margin, and lower lake levels.