NOAA/WDS Paleoclimatology - South China Sea Terrigenous Grain Size, Mineral Component and Mass Accumulation Rate Data over the last 1.1 Million Years

Glacial-to-interglacial variations in East Asian summer and winter monsoon are widely ascribed to orbital and global ice-sheet forcing. The relative impact of orbital and millennial-scale factors, however, remains controversial. To constrain the differential response of seasonal monsoon winds we present paired records of siliciclastic grain sizes, pollen, minerals, and geochemical tracers obtained from high-sedimentation rate deposits at ODP Site 1144, northern South China Sea. Accordingly, loess-style dust supply of winter monsoon was predominant and fluvial input reduced during peak glacials and Heinrich stadials over the last 900 kyr, while fluvial mud earmarked interglacials and initial parts of glacial stages since the Mid-Pleistocene Transition as result of enhanced summer monsoon. Before, more limited northern-Hemisphere ice sheets during glacial stages 24–32 led to ongoing humidity over Eastern Asia. Altogether, changes in seasonal monsoon rather reflect a redistribution of insolation energy among various climate subsystems than direct orbital and northern-ice-sheet forcing.