An integrated analysis of palynofacies and diatoms in the Jucurucu River valley, northeastern Brazil: Holocene paleoenvironmental changes

Autor(es)

Lorente, Flavio Lima ; Castro, Darcilea Ferreira ; Francisquini, Mariah Izar ; Ruiz Pessenda, Luiz Carlos ; Fontes, Neuza Araujo ; Lisboa Cohen, Marcelo Cancela ; Bendassolli, Jose Albertino ; Piccolo, Marisa de Cassia ; Macario, Kita

• Tipo de documento: Artigo Científico
• Fonte: Journal of South American Earth Sciences; v. 103, p. 11-pg., 2020-11-01.

Resumo

This study demonstrates the usefulness of palynofacies as a tool for characterizing the origin, transport, and settling of particulate organic matter preserved in fluvial plain sediments and its integration with diatoms for inferring past depositional environments. Palynofacies, diatoms, and organic geochemistry (S, C/S) data from a sediment core (PR07) collected from the Jucurucu River valley in coastal southern Bahia, northeastern Brazil were used to better understand ecosystem changes that occurred in the region during the last similar to 7.5k years. Elemental values (S: 0.15-5.9%; C/S: 0.12-41.5) suggest marine and fluvial influences in the valley during the Holocene, and organic matter was derived from freshwater and marine phytoplankton. The presence of heterolithic deposits, brackish/marine diatoms, predominance of amorphous group, non-opaque phytoclasts, pyrite crystals, and marine microfossils suggests that a tidal flat formed during a mid-Holocene sea-level highstand. A fluvial plain developed in the last 5k years, due to marine regression and an increase in fluvial sediment supply to the region. (AU)

• Processo FAPESP: 11/00995-7 - Estudos paleoambientais interdisciplinares na costa do Espírito Santo
• Beneficiário: Luiz Carlos Ruiz Pessenda
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático
• Processo FAPESP: 15/05111-0 - Reconstituição paleoambiental (nível relativo marinho, vegetação e clima) da costa Sul da Bahia com base em indicadores biológicos e isotópicos
• Beneficiário: Flávio Lima Lorente
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado