The Hydroclimate Change on the Northeast Tibetan Plateau Recorded by Stalagmite from an Open Cave

The semi-arid region on the Northeast Tibetan Plateau is characterized by insufficient water resources, sparse vegetation coverage, and fragile ecology, making it highly vulnerable to hydroclimate change. However, the long-term hydroclimate changes in this region and the correlation with ecology change are unclear. Here, we present a highly resolved multi-proxy stalagmite record from an open cave (Yanwu Cave), Northeast Tibetan Plateau, for the past ~1300 years. The antiphased relationship between stalagmite isotope (δ¹⁸O and δ¹³C) records with trace elements (Sr/Ca, Mg/Ca, and Ba/Ca) from Yanwu Cave and regional stalagmite δ¹⁸O records indicate a significant influence of kinetic isotope effects on δ¹⁸O and δ¹³C. Utilizing the trace elements records, we reconstruct long-term hydroclimate change on the Northeast Tibetan Plateau. Our records suggest that the increased amplitude of decadal-scale hydroclimate variability during the Little Ice Age (LIA) increased the frequency of extreme climate events. Natural hydroclimatic conditions rather than human activity could have regulated regional vegetation composition change at the transition from Medieval Warm Period to LIA, although human activity has significantly enhanced over the past millennium.