A Tibetan lake sediment record of Holocene Indian summer monsoon variability

Broxton W. Bird, Pratigya J. Polisar, Yanbin Lei, Lonnie G. Thompson, Tandong Yao, Bruce P. Finney, Daniel J. Bain, David P. Pompeani, Byron A. Steinman

Research output: Contribution to journalArticlepeer-review

93 Scopus citations

Abstract

Sedimentological data and hydrogen isotopic measurements of leaf wax long-chain n-alkanes (δD wax ) from an alpine lake sediment archive on the southeastern Tibetan Plateau (Paru Co) provide a Holocene perspective of Indian summer monsoon (ISM) activity. The sedimentological data reflect variations in lake level and erosion related to local ISM rainfall over the Paru Co catchment, whereas δD wax reflects integrated, synoptic-scale ISM dynamics. Our results indicate that maximum ISM rainfall occurred between 10.1 and ~5.2ka, during which time there were five century-scale high and low lake stands. After 5.2 ka, the ISM trended toward drier conditions to the present, with the exception of a pluvial event centered at 0.9 ka. The Paru Co results share similarities with paleoclimate records from across the Tibetan Plateau, suggesting millennial-scale ISM dynamics were expressed coherently. These millennial variations largely track gradual decreases in orbital insolation, the southward migration of the Intertropical Convergence Zone (ITCZ), decreasing zonal Pacific sea surface temperature (SST) gradients and cooling surface air temperatures on the Tibetan Plateau. Centennial ISM and lake-level variability at Paru Co closely track reconstructed surface air temperatures on the Tibetan Plateau, but may also reflect Indian Ocean Dipole events, particularly during the early Holocene when ENSO variability was attenuated. Variations in the latitude of the ITCZ during the early and late Holocene also appear to have exerted an influence on centennial ISM rainfall.

Original languageEnglish (US)
Pages (from-to)92-102
Number of pages11
JournalEarth and Planetary Science Letters
Volume399
DOIs
StatePublished - Aug 1 2014

Keywords

  • Global change
  • Grain size
  • Lake levels
  • Leaf wax hydrogen isotopes
  • Paleoclimate

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