@article{fdi:010053075,
  title = {{B}iogeochemical indicators of environmental changes from 50 {K}a to 10 {K}a in a humid region of the {B}razilian {A}mazon},
  author = {{C}ordeiro, {R}. {C}. and {T}urcq, {B}runo and {S}ifeddine, {A}bdelfettah and {L}acerda, {L}. {D}. and {S}ilva, {E}. {V}. and {G}ueiros, {B}. and {P}otty, {Y}. {P}. and {S}antelli, {R}. {E}. and {P}adua, {E}. {O}. and {P}atchinelam, {S}. {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e present a geochemical record of a 113.6-cm sediment core ({LFT} {V}) from {L}agoa da {P}ata, which is located in the forested upper {R}io {N}egro basin. {T}he record reveals significant changes in the environmental history of {A}mazonia during the late {Q}uaternary. {T}he results of biogeochemical analyses revealed three hydrological and climatic regimes from 50,000 to 10,000 cal yr {BP}. {T}he first phase, between 50,000 and 26,300 cal yr {BP}, was characterized by a relatively wet climate as suggested by relatively high total organic carbon ({TOC}) and chlorophyll derivate concentrations, indicating high productivity linked to a high lake level. {A} decrease of the {TOC} and chlorophyll derivate accumulation rates between 43,100 cal yr {BP} and 26,300 cal yr {BP} marks a decrease in the productivity linked to a reduced lake level, indicating a decrease in moisture at the end of this phase. {T}he second phase, between 26,300 and 15,300 cal yr {BP}, was characterized by a decrease in productivity, reaching a minimum at 21,950 cal yr {BP}, as indicated by a minima in sedimentary chlorophyll and {TOC} accumulation rates. {V}alues of delta {C}-13 increased by 5 parts per thousand in relation to the preceding phase, indicating an influence of the {C}-4 organic matter. {H}igh iron concentrations and accumulation rates, related to intense erosion of the lateritic crust in the watershed, were observed. {A}ll of the observations indicate a dry phase during this period. {A} third phase, from approximately 15,300 to 10,000 cal yr {BP}, was characterized by an increase in lacustrine productivity, as shown by an increased in {TOC} and chlorophyll derivate concentrations and accumulation rates. {T}hese increases likely correspond to a lake level rise due to a wetter climate. {C}rown {C}opyright (c) 2010 {P}ublished by {E}lsevier {B}.{V}. {A}ll rights reserved.},
  keywords = {{A}mazonia ; {L}ate {Q}uaternary ; {L}agoa da {P}ata ; {O}rganic elementary and ; isotopic composition ; {P}aleofire indicators ; {L}ithogenic metals ; {M}ercury},
  booktitle = {},
  journal = {{P}alaeogeography {P}alaeoclimatology {P}alaeoecology},
  volume = {299},
  numero = {3-4},
  pages = {426--436},
  ISSN = {0031-0182},
  year = {2011},
  DOI = {10.1016/j.palaeo.2010.11.021},
  URL = {https://www.documentation.ird.fr/hor/fdi:010053075},
}