@inproceedings{fdi:010095085,
  title = {{P}aleoriver discharge controlled by precession cycle in the {N}orth {A}frica over the past 240,000 years : relationship to sapropel formation [r{\'e}sum{\'e}]},
  author = {{T}achikawa, {K}. and {B}eny, {F}. and {V}idal, {L}. and {G}uihou, {A}. and {S}onzogni, {C}. and {C}onrod, {S}. and {P}ratiwi, {A}. and {D}eschamps, {P}ierre and {S}chultz, {H}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he sedimentary sequence of the eastern {M}editerranean is often marked by organic-rich layers called sapropels. {S}apropel formation was mainly caused by excess freshwater input and the subsequent reduction of ventilation due to an enhanced {A}frican monsoon combined with deglacial water input. {H}owever, the paleoriver discharge from the {N}orth {A}frica under interglacial and glacial boundary conditions and its impact on the sapropel formation has not been fully clarified yet. {W}e obtained an {N}d isotopic composition ({EN}d) record of the detrital fraction as well as a grain size indicator of a marine sediment core from the eastern side of the {G}ulf of {S}irte to reconstruct the reactivation of {L}ibyan fluvial fossil systems for the past 240,000 years. {T}he {EN}d record showed a systematic increase from a baseline of -12 to -9 to -8 for sapropels {S}1 to {S}9, including the glacial sapropel {S}6. {T}his {EN}d shift was synchronous with barium enrichment and depleted planktonic foraminiferal oxygen and carbon isotopic compositions that marked the sapropels. {B}ased on a new {EN}d map of source regions in {N}orth {A}frica, the higher {EN}d values can be explained by preferential weathering of volcanic fields and soils and increased river discharge under both interglacial and glacial conditions. {T}he grain size indicator showed an increase in fine river particles relative to coarse atmospheric dust when detrital {EN}d was higher, supporting this interpretation. {T}hese observations are consistent with the available detrital {EN}d records, suggesting that the higher isotopic signals during sapropel formation are a basin-wide feature in the {G}ulf of {S}irte. {T}he hydrological cycle in the study area was estimated to be more sensitive to precessional forcing than to high-latitude climate conditions, being consistent with previous modelling studies.},
  keywords = {{AFRIQUE} {DU} {NORD} ; {MEDITERRANEE}},
  numero = {},
  pages = {{EGU}25--7994 [1 ]},
  booktitle = {},
  year = {2025},
  DOI = {10.5194/egusphere-egu25-7994},
  URL = {https://www.documentation.ird.fr/hor/fdi:010095085},
}