DID SEA-LEVEL CHANGES AFFECT THE BRAZILIAN AMAZON FOREST DURING THE HOLOCENE?

Autor(es)

Araujo Silva, Mayra Nina ^[1] ; Cohen, Marcelo C. L. ^[1] ; Rossetti, Dilce F. ^[2] ; Pessenda, Luiz C. R. ^[3]

Afiliação do(s) autor(es)

^[1] Fed Univ Para, Grad Program Geol & Geochem, Ave Perimentral 2651, BR-66077530 Belem, PA - Brazil

^[2] Natl Space Res Inst INPE, Rua Astronautas 1758, CP 515, BR-12245970 Sao Jose Dos Campos, SP - Brazil

^[3] Univ Sao Paulo, Lab 14C, Ave Centenario 303, BR-13400000 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: RADIOCARBON; v. 60, n. 1, p. 91-112, FEB 2018.
• Citações Web of Science: 0

Resumo

In order to contribute to the discussion of Holocene climate changes, four sediment cores were collected from the northern Brazilian Amazonia lowland. These cores were studied through pollen analysis and sedimentary features, and the results were discussed within a chronological framework provided by radiocarbon dating. The cores were sampled from fluvial terraces representative of channel, floodplain/lake and crevasse splay deposits formed since the mid-Holocene. The pollen samples derive from floodplain/lake deposits and the pollen grains are mainly composed by families Moraccae, Euphorbiaceae, Caesalpiniaceae, Fabaceae, Rubiaceae, Melastomataceae, Combretaceae, Sapindaceae, Poaceae, Cyperaceae, Aizoaceae, Apiaceae and genus Sebastiana. The pollen data suggest no significant vegetation changes in the study area for the past 4808-4886 cal yr BP. This led to proposing stable climatic conditions since at least the middle Holocene. Such a finding is contrary to the occurrence of a dry period during the middle Holocene. The stabilization of the relative sea level about 6000 cal yr BP along the northern Brazilian littoral may have influenced the water table, and favored the establishment and maintenance of Amazonian lowland forest during the mid- and late Holocene. In addition, this process may have attenuated the impact of that dry period in areas under most fluvial influence. (AU)

• Processo FAPESP: 13/50475-5 - Mapping Amazonian biodiversity at multiple scales by integrating geology and ecology
• Beneficiário: Dilce de Fátima Rossetti
• Modalidade de apoio: Auxílio à Pesquisa - Regular