Holocenic proxies of sedimentary organic matter and the evolution of Lake Arari-Amazon Region

Auteur(s) et Affiliation(s)

SMITH, C.B.

Lab. of Coastal Dynamics, Federal Univ. of Pará, Belém, Bresil

COHEN, M.C.L.

Lab. of Coastal Dynamics, Federal Univ. of Pará, Belém, Bresil

Fac. of Oceanography, Federal Univ. of Pará, Belém, Bresil

PESSENDA, L.C.R.

Univ. of São Paulo, São Paulo, Bresil

FRANÇA, M.C.

Lab. of Coastal Dynamics, Federal Univ. of Pará, Belém, Bresil

GUIMARÃES, J.T.F.

Lab. of Coastal Dynamics, Federal Univ. of Pará, Belém, Bresil

Description :
Four sediment cores were sampled from Lake Arari, located on Marajó Island at the mouth of the Amazon River in Northern Brazil. The island's vegetation cover is composed mainly of Amazon coastal forest, herbaceous and varzea vegetation. The integration of data on sedimentary structures, pollen, carbon and nitrogen isotope records, C/N ratios and radiocarbon ages allowed the identification of changes in vegetation and the sources of organic matter accumulated in the lake during the Holocene. This study identified an influence between marine and freshwater with 3 development stages of Lake Arari : presence of mangroves during the lagoon phase; then, the mangroves were replaced by herbaceous vegetation with the increase in freshwater river discharge; finally, Lake Arari was established in association with the expansion of herbaceous vegetation and the dominance of freshwater algae.

Type de document :
Article de périodique

Source :
Catena (Giessen), issn : 0341-8162, 2012, vol. 90, n°. 1, p. 26-38, nombre de pages : 13, Références bibliographiques : 2 p.

Date :
2012

Editeur :
Pays édition : Allemagne, Cremlingen-Destedt, Catena

Langue :
Anglais