Model of wetland development of the Amapá coast during the late Holocene

Anais da Academia Brasileira de Ciências

José T.f. Guimarães²  Marcelo C.l. Cohen²  Marlon C. França²  Rúben J. Lara¹  Hermann Behling¹ 

[1] ,Universidade Federal do Pará Laboratório de Dinâmica Costeira Belém PA ,Brasil

关键词: Amazon river;    climatic changes;    mangrove;    palynology;    sea-level;    rio Amazonas;    mudanças climáticas;    manguezal;    palinologia;    nível do mar;   

DOI  :  10.1590/S0001-37652010000200021

来源: SciELO

【 摘 要 】

The modern vegetation types, sedimentary sequences, pollen records and radiocarbon dating obtained from three sediment cores from Calçoene Coastal Plain were used to provide a palaeoecological history during the late Holocene of Amapá coastal wetland according to flood regime, sea-level and climatic changes. Based on these records, four phases of vegetation development are presented and they probably reflect the interaction between the flow energy to the sediment accumulation and the brackish/freshwater influence in the vegetation. This work suggests interchanges among time periods characterized by marine and fluvial influence. The longitudinal profile did not reveal the occurrence of mangrove in the sediment deposited around 2100 yr B.P. During the second phase, the mud progressively filled the depressions and tidal channels. The mangrove probably started its development on the channel edge, and the herbaceous field on the elevated sectors. The third phase is characterized by the interruption of mangrove development and the increase of "várzea" vegetation that may be due to the decrease in porewater salinity related to a decrease in marine water influence. The last phase is represented by the mangrove and "várzea" increase. The correlation between current patterns of geobotanical unit distribution and palaeovegetation indicates that mangrove and "várzea" forests are migrating over the herbaceous field on the topographically highest part of the studied coast, which can be related to a relative sea-level rise.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License