@article{fdi:010055681,
  title = {{T}he oxygen isotopic composition of phytolith assemblages from tropical rainforest soil tops ({Q}ueensland, {A}ustralia) : validation of a new paleoenvironmental tool},
  author = {{A}lexandre, {A}. and {C}respin, {J}. and {S}ylvestre, {F}lorence and {S}onzogni, {C}. and {H}ilbert, {D}. {W}.},
  editor = {},
  language = {{ENG}},
  abstract = {{P}hytoliths are micrometric particles of amorphous silica that form inside or between the cells of higher plant tissues throughout the life of a plant. {W}ith plant decay, phytoliths are either incorporated into soils or exported to sediments via regional watersheds. {P}hytolith morphological assemblages are increasingly used as proxy of grassland diversity and tree cover density in inter-tropical areas. {H}ere, we investigate whether, along altitudinal gradients in northeast {Q}ueensland ({A}ustralia), changes in the delta {O}-18 signature of soil top phytolith assemblages reflect changes in mean annual temperature ({MAT}) and in the oxygen isotopic composition of precipitation (delta {O}-18(precipitation)), as predicted by equilibrium temperature coefficients previously published for silica. {O}xygen isotopic analyses were performed on 16 phytolith samples, after controlled isotopic exchange ({CIE}), using the {IR} {L}aser-{H}eating {F}luorination {T}echnique. {L}ong-term mean annual precipitation ({MAP}) and {MAT} values at the sampled sites were calculated by the {ANUCLIM} software. delta {O}-18(precipitation) estimates were calculated using the {B}owen and {W}ilkinson (2002) model, slightly modified. {A}n empirical temperature-dependant relationship was obtained: {D}elta {O}-18(wood phytolith-precipitation) (% vs. {VSMOW}) = -0.4 (+/- 0.2) t (degrees {C}) + 46 (+/- 3) ({R}-2 = 0.4, p < 0.05; n = 12). {D}espite the various unknowns introduced when estimating delta {O}-18(precipitation) values and the large uncertainties on delta {O}-18(wood phytolith) values, the temperature coefficient (-0.4 +/- 0.2% parts per thousand f {C}-1) is in the range of values previously obtained for natural quartz, fresh and sedimentary diatoms and harvested grass phytoliths (from -0.2 to -0.5% ffi {C}-1). {T}he consistency supports the reliability of ffi delta {O}-18(wood phytolith) signatures for recording relative changes in mean annual delta {O}-18(soil water) values (which are assumed to be equivalent to the weighted annual delta {O}-18(precipitation) values in rainforests environments) and {MAT}, provided these changes were several % and/or several ffi {C} in magnitude.},
  keywords = {},
  booktitle = {},
  journal = {{C}limate of the {P}ast},
  volume = {8},
  numero = {1},
  pages = {307--324},
  ISSN = {1814-9324},
  year = {2012},
  DOI = {10.5194/cp-8-307-2012},
  URL = {https://www.documentation.ird.fr/hor/fdi:010055681},
}