Mid- to Late Holocene (5200–980 cal YR BP) paleoenvironmental dynamics in the Ilha Grande, Brazil, assessed by terrestrial and marine microfossils

Abstract

Ilha Grande is a Brazilian island that has a high vegetal biodiversity with a well-documented prehistoric human occupation but has few paleoenvironmental studies developed in this area. In view of this, multiproxy analysis of lagoonal sediments including radiocarbon dating were carried out on a 139 cm-long continental sediment core. The aim of our study was to recognise and explain environmental dynamics in this region during the Holocene (∼5200 cal yr BP). The palynomorphs indicate the continuous presence of Atlantic Forest under humid conditions during the last Holocene sea-level highstand, after 5200 cal yr BP. A phase of low palynomorph concentrations was followed by a marked increase in palynomorph accumulation and diversity which may be linked to the subsequent drop of the sea-level. Dinoflagellate cysts showed a higher accumulation at the base of the sediment core. The high accumulation of charcoal particles identified between approximately 3700 and 3000 cal years BP might indicate human activity related to the long-lasting bonfires kept burning by the inhabitants of the archaeological site of Ilhote do Leste.

Keywords:

• charcoal fragments
• ¹⁴C
• dinocysts
• pollen grains
• Ilha Grande
• sea-level

Acknowledgements

This study was sponsored by the Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). The authors are thankful to Instituto Estadual do Ambiente (INEA), for the research licence granted and for the support to the field work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Alex da Silva de Freitas

ALEX DA SILVA DE FREITAS graduated in Biological Sciences from the Universidade Federal do Rio de Janeiro (UFRJ) and Master’s degree and PhD in Ocean and Earth Dynamics from the Universidade Federal Fluminense (UFF).

Cintia Ferreira Barreto

CINTIA FERREIRA BARRETO graduated in History and Geography, Master in Geology from the Universidade Federal do Rio de Janeiro (UFRJ) and PhD. in Geology from Universidade Federal do Rio de Janeiro (UFRJ). She is currently working at Geology and Geophysics Department from Universidade Federal Fluminense (UFF).

Rafael Cuellar de Oliveira e Silva

RAFAEL CUELLAR DE OLIVEIRA E SILVA graduated from the Universidade Estadual do Rio de Janeiro - UERJ (2000). He holds a Masters (2015) and a PhD. (2021) in Marine Geology and Geophysics from the Universidade Federal Fluminense (UFF). He has experience in coastal geology and geomorphology; coastal evolution; shallow marine geophysics; coastal maritime navigation; sedimentological analysis; dating by C-14; digital mapping.

Gilberto Tavares de Macedo Dias

GILBERTO TAVARES DE MACEDO DIASAND graduated from the Universidade Federal do Rio de Janeiro (1972) and PhD. in Geology from L'Environnement - Université de Bordeaux I (1976). He is currently a Full Professor at Universidade Federal Fluminense. He has experience in marine geology and geophysics, with an emphasis on Environmental Geology, working mainly on the following topics: coastal evolution, environmental diagnosis and monitoring of coastal and oceanic areas, seismic and side-scan sonar surveys.

José Antônio Baptista Neto

JOSE ANTONIO BAPTISTA NETO graduated in Geography from the Universidade Federal Fluminense (UFF), Specialization and Master's degree in Geology and Geophysics from the Universidade Federal Fluminense and PhD in Geosciences - Queens University, Belfast. He is currently Professor of Universidade Federal Fluminense.