When Eastern India Oscillated Between Desert Versus Savannah-Dominated Vegetation

Coralie Zorzi, Stéphanie Desprat, Charlotte Clément, Kaustubh Thirumalai, Dulce Oliviera, Krishnamurthy Anupama, Srinivasan Prasad, Philippe Martinez

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

During the last glacial period, the tropical hydrological cycle exhibited large variability across orbital and millennial timescales. However, the response of the Indian summer monsoon (ISM), its related impact on terrestrial ecosystems, and associated forcing mechanisms remain controversial. Here we present a marine record of pollen-inferred vegetation changes suggesting that eastern India shifted from woody-savanna mosaics during Marine Isotopic Stage 3 to grasslands during the Last Glacial Maximum resulting from large-scale drying. Our data shows that ISM maximum is in phase with obliquity and precession maxima suggesting a dominant role of the Indian Ocean interhemispheric temperature gradient on glacial ISM variability. Persistent and abrupt dryland expansions of varying magnitude suggest rapid-scale onset of aridity during Heinrich Stadial events and during the Toba eruption. We propose that the amplitude of ISM drought events are initiated by high latitude and volcanic forcings, although modulated by precession.

Original languageEnglish (US)
Article numbere2022GL099417
JournalGeophysical Research Letters
Volume49
Issue number16
DOIs
StatePublished - Aug 28 2022

Keywords

  • Heinrich Stadials
  • Indian summer monsoon
  • last glacial period
  • millennial and orbital variations
  • pollen analysis

ASJC Scopus subject areas

  • Geophysics
  • General Earth and Planetary Sciences

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