@article{fdi:010061180,
  title = {{T}he riverine silicon isotope composition of the {A}mazon {B}asin},
  author = {{H}ughes, {H}. {J}. and {S}ondag, {F}rancis and {S}antos, {R}. {V}. and {A}ndr{\'e}, {L}. and {C}ardinal, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e present here the first large-scale study of riverine silicon isotope signatures in the {A}mazon {B}asin. {T}he {A}mazon and five of its main tributaries were studied at different seasons of the annual hydrological cycle. {T}he delta {S}i-30 signature of the dissolved silicon ({DS}i) exported to the estuary (weighted for {DS}i flux) for the period considered is estimated at +0.92 parts per thousand. {A} river cross-section shows the homogeneity of the {A}mazon {R}iver regarding {DS}i concentration and isotope ratio. {T}he biogenic silica ({BS}i) concentration measured in surface water from all rivers is generally small compared to the {DS}i reservoir but large variations exist between rivers. {V}ery low isotope signatures were measured in the upper {R}io {N}egro (delta {S}i-30 = +0.05 +/- 0.06 parts per thousand), which we explain both by an equilibrium between clay formation and dissolution and by gibbsite formation. {T}he {S}i isotope fractionation in the {A}ndean tributaries and the {A}mazon main stem can be explained by clay formation and follow either a {R}ayleigh or a batch equilibrium fractionation model. {O}ur results also suggest that the formation of 2:1 clays induces a fractionation factor similar to that of kaolinite formation.},
  keywords = {{AMAZONE} {BASSIN} ; {AMAZONE} ; {RIO} {NEGRO} ; {ANDES} ; {AMAZONIE}},
  booktitle = {},
  journal = {{G}eochimica et {C}osmochimica {A}cta},
  volume = {121},
  numero = {},
  pages = {637--651},
  ISSN = {0016-7037},
  year = {2013},
  DOI = {10.1016/j.gca.2013.07.040},
  URL = {https://www.documentation.ird.fr/hor/fdi:010061180},
}