DOI: 10.1016/j.palaeo.2014.03.017
论文题名: A mineralogical and organic geochemical overview of the effects of Holocene changes in Amazon River flow on three floodplain lakes
作者: Moreira L.S. ; Moreira-Turcq P. ; Kim J.H. ; Turcq B. ; Cordeiro R.C. ; Caquineau S. ; Mandengo-Yogo M. ; Sinninghe Damsté J.S.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2014
卷: 415 起始页码: 152
结束页码: 164
语种: 英语
英文关键词: Amazonian floodplain lakes
; Glycerol dialkyl glycerol tetraethers
; Holocene
; Sedimentary organic matter
英文摘要: A synthesis of the impacts of the Amazon River hydrological changes on the sedimentation process of organic matter (OM) in three different floodplain lakes (Santa Ninha, Maracá, and Comprido lakes) is presented in this study. Today the Santa Ninha and Maracá lakes are directly and permanently connected with the main channel of the Amazon River, in contrast to Comprido Lake, which is indirectly and periodically influenced by the Amazon River due to its greater distance from the main channel. All three lake sediment records showed a reduced river inflow due to dry climatic conditions during the early and middle Holocene followed by an increased fluvial input during the wetter late Holocene. In Santa Ninha and Maraca Lakes, the reduced river inflow period was recorded by sediments with a low abundance of smectite (on average ~20wt.%), a clay mineral mainly transported by the fluvial system, high total organic carbon (TOC) contents (on average ~8.2wt.%), and a predominantly acidic soil OM input evidenced by high concentrations (on average 180μggTOC-1) of branched glycerol dialkyl glycerol tetraethers (GDGT). During the late Holocene, a higher smectite abundance (on average ~43 wt.%) and a lower TOC content (on average ~1.4 wt.%) pointed to greater dilution by riverine lithogenic matter. This change was accompanied by a proportional increase in the aquatically produced crenarchaeol, suggesting a higher lake water level. In Comprido Lake, a sedimentation gap occurred during the early and middle Holocene. The wetter late Holocene, since 3000calyears BP, was characterized by high TOC values (on average ~9wt.%) and a sharp increase in soil OM input as recorded by an increase in branched GDGT concentrations (on average ~81μggTOC-1), but the smectite content was low (on average ~14%). This combination suggests that the soil OM input to Comprido Lake from the local catchment area became dominant during the wet-climate late Holocene due to the large distance of the lake from the Amazon River main channel. Consequently, our study shows that the sedimentation processes of OM in Amazonian floodplain lakes were strongly influenced by variations in the hydrodynamic regime of the Amazon River during the Holocene. However, the impacts of the variations on the three floodplain lakes were different depending on the distance of each lake from the main channel of the Amazon River. © 2014 Elsevier B.V. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69178
Appears in Collections: 过去全球变化的重建
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作者单位: Departamento de Geoquímica, Universidade Federal Fluminense (UFF), Niterói, Brazil; Institut de Recherche pour Développement (IRD)-GET (Géosciences Environment Toulouse), Bondy, France; NIOZ Royal Netherlands Institute for Sea Research, AB Den Burg, Netherlands; Inst. de Recherche pour Développement (IRD)-LOCEAN (Lab. d'Océanographie et du Climat), Bondy, France
Recommended Citation:
Moreira L.S.,Moreira-Turcq P.,Kim J.H.,et al. A mineralogical and organic geochemical overview of the effects of Holocene changes in Amazon River flow on three floodplain lakes[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2014-01-01,415