The grain size endmembers of Tengchongbeihai wetland sediments over the past 46 ka

 Here, we present a grain size end-member analysis for Tengchongbeihai wetland sediments from southwestern China to investigate the paleo-hydroclimate changes since the late MIS3. The overall low fine silt (EM2) content before ~16.5 cal ka BP resulted from weak catchment erosion indicating weak ISM during cold glacial while the increasing trend thereafter indicates the ISM strengthened during the last deglaciation and Holocene. Such an orbital ISM evolution resembles to the insolation gradient between 25°N and 25°S during the boreal summer periods, which implies the transequatorial insolation difference could be an alternative explanation for the orbital scale low latitude hydroclimate changes. The striking peaks of coarse component (EM3) around ~12, 16, 24, 29, 32 and 39 cal ka BP were related to significant water level descending indicating the millennial ISM collapse corresponding to the YD and Heinrich events. However, the absence of sawtooth feature as the NGRIP δ18O and the well correspondence to the Indian Ocean sea surface temperatures (SSTs) of the ISM collapses evidence the complementary role of low latitude climate for the North Atlantic climate on the millennial scale hydroclimate variabilities.