Vegetation History and Archaeobotany

, Volume 23, Issue 5, pp 527–542

Inter-proxy evidence for the development of the Amazonian mangroves during the Holocene

  • Marlon C. França
  • Mariah I. Francisquini
  • Marcelo C. L. Cohen
  • Luiz C. R. Pessenda
Original Article

DOI: 10.1007/s00334-013-0420-4

Cite this article as:
França, M.C., Francisquini, M.I., Cohen, M.C.L. et al. Veget Hist Archaeobot (2014) 23: 527. doi:10.1007/s00334-013-0420-4

Abstract

The dynamics of mangrove forest on the island of Marajó (Ilha de Marajó) at the mouth of the river Amazon during the past ~7,500 cal. b.p. were studied using multiple proxies, including sedimentary facies, pollen, δ13C, δ15N and C/N ratio, related to 15 sediment samples by 14C dating. The results allow us to propose a scheme of palaeogeographical development, with changes in vegetation, hydrology and organic matter dynamics. Today, the interior of the island is occupied by várzea freshwater herbaceous vegetation, but during the early to middle Holocene, mangroves with accumulations of estuarine organic matter colonized the tidal mud flats. This spread of mangroves was caused by post-glacial sea-level rise, which combined with tectonic subsidence, produced a marine transgression. It is likely that the relatively greater marine influence at the studied area was favoured by reduced discharge from the river Amazon, which was itself caused by a dry period that occurred during the early and mid Holocene. During the late Holocene, there was a reduction of mangrove vegetation and the contribution of freshwater organic matter to the area was higher than during the early and mid Holocene. This suggests a decrease in marine influence during the late Holocene which led to a gradual migration of mangrove vegetation from the central region to the northeastern littoral zone of the island, and, consequently, its isolation since at least ~1,150 cal. b.p. This was probably a result of lower tidal water salinity caused by a wet period that resulted in greater river discharge during the late Holocene. This work details the contraction of mangrove forest from the northeastern part of the island of Marajó under the influence of Amazon climatic changes, chronologically and spatially. This allows us to propose a model of successive phases of sediment accumulation and vegetation change, according to the marine-freshwater influence gradient. As demonstrated by this work, the use of a combination of proxies is efficient for establishing a relationship between the changes in estuarine salinity gradient and depositional environment/vegetation.

Keywords

Amazon coastal area Holocene Isotopes Sea-level Vegetation Climate change 

Supplementary material

334_2013_420_MOESM1_ESM.doc (62 kb)
Supplementary material 1 (DOC 61 kb)
334_2013_420_MOESM2_ESM.doc (56 kb)
Supplementary material 2 (DOC 56 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Marlon C. França
    • 1
    • 2
  • Mariah I. Francisquini
    • 4
  • Marcelo C. L. Cohen
    • 1
    • 3
  • Luiz C. R. Pessenda
    • 4
  1. 1.Post-Graduate Program of Geology and Geochemistry, Laboratory of Coastal DynamicsFederal University of ParáBelémBrazil
  2. 2.Federal Institute of ParáBelémBrazil
  3. 3.Faculty of OceanographyFederal University of ParáBelémBrazil
  4. 4.14C LaboratoryUniversity of São PauloPiracicabaBrazil

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