An integrated approach to relate Holocene climatic, hydrological, morphological and vegetation changes in the southeastern Amazon region

作者：Felix Guimares Jose Tasso; Li**oa Cohen Marcelo Cancela; Castor Alves Igor Charles; Castor Alves Igor Charles; Smith Clarisse Beltro; Ruiz Pessenda Luiz Carlos; Behling Hermann

来源：Vegetation History and Archaeobotany, 2013, 22(3): 185-198.

DOI：10.1007/s00334-012-0374-y

• Holocene
• Palynology
• Amazon rain forest
• Wetland development
• Sedimentary facies
• Siliciclastic and organic matter sources

The geomorphological analysis of the river Tocantins alluvial area was carried out by remote sensing techniques, jointly with studies of sedimentary facies, mineralogy and geochemistry, pollen and spores, C and N isotopes data and radiocarbon dating of a sediment core from a floodplain lake, near the river Tocantins in the southeastern Amazon region. The aim was to identify and discuss the relationship between the main geomorphological processes and climatic factors, as well as their influence on vegetation patterns. The data indicate three phases of sediment and organic matter accumulation associated with vegetation changes during the Holocene: in Phase 1 (%26gt; 7760 +/- A 80 cal yrs b.p.), the channel was gradually being disconnected from its main course, accumulating organic matter from terrestrial woody plants; in Phase 2 (%26gt; 7760 +/- A 80 to 5145 +/- A 175 cal yrs b.p.), the very low energy flows allowed the deposition of autochthonous organic mud from suspension. Herbaceous vegetation and a Mauritia palm-swamp dominated the study area, followed by an increase in the contribution of freshwater dissolved organic carbon (DOC) to the lake; Phase 3 (5145 +/- A 175 cal yrs b.p. until present) records the expansion of ferns and arboreal plants, and greater freshwater organic matter input into the lake with anoxic water conditions. The development of the studied lake occurred by geomorphological changes and the filling process of an abandoned channel according to hydrodynamics and vegetation changes which were probably influenced by climatic changes during the Holocene.

• 出版日期2013-5