Replicated stalagmite records revealed orbital and millennial-scale hydroclimate changes in arid central Asia across the MIS 5 stadial-interstadial transition
- 1School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
- 2MOE Key Laboratory of Western China’s Environmental Systems, Lanzhou University, Lanzhou 730000, China
- 3Earth Observatory of Singapore and Asian School of Environment, Nanyang Technological University, Singapore 639798
- 4High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei 10617 Taiwan
- 5Institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an 710049, China
- 6Center for Climate Physics, Institute for Basic Science, Busan 46241, South Korea
- 7Department of Atmospheric Science, Yunnan University, Kunming 650500, China
- 8Chongqing Key Laboratory of Karst Environment & School of Geographical Sciences, Southwest University, Chongqing 400715, China
- 9Group of Alpine Paleoecology and Human Adaptation, State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
Hydroclimate in arid central Asia (ACA) exhibited unique variability due to the dominance of mid-latitude westerlies over the Holocene, yet ACA climate variations during the last interglacial (Marine Isotope Stage (MIS) 5) remain elusive. Here, we present stable isotopes and trace elemental ratios of two coeval stalagmites in Xinjiang (northwest China), to address the orbital and millennial-scale climate shifts of ACA during MIS 5. The isotopic records of Baluk Cave (42°26' N, 84°44' E), spanning from 101.9 ka to 78.3 ka BP (before 1950 CE), show distinctly negative δ18O and δ13C values in the interstadials (i.e., MIS 5a and 5c), relative to the values in the stadial (MIS 5b). Such variations well correspond to the element data (X/Ca, X=Mg, Sr, and Ba), which exhibit values relatively higher in 5c and 5a compared with the 5b. These jointly suggest a key role of precession in orbital-scale climate evolution in ACA, closely following the insolation changes in warm-season (May to September) at 50°N.
Specifically, the X/Ca ratios suggested relatively dry climate in 5c and 5a while wetter climate in 5b, supporting a ‘warm/dry and cold/wet’ pattern in ACA during the last interglacial. This pattern is further supported by the simulated precipitation variation using the CESM general circulation model. Moreover, the millennial-scale climate shift across the MIS 5b/5a transition is evidenced by depleted isotopic values in Baluk Cave (i.e., ~2.5‰ in δ18O and ~1.9‰ in δ13C), initiating at 87.2±0.5 ka BP and terminating at 84.1±0.4 ka BP. The onset and termination of this millennial event in ACA are comparable with those recorded by speleothems in eastern China and northern India, and with changes in northern hemispheric temperature, atmospheric methane and CO2 concentrations as inferred by the bi-polar ice cores. Our multi-proxy study suggests a close coupling between the large-scale westerly jet circulation, as suggested by δ18O, and local effective moisture in ACA, as documented by X/Ca, on orbital and millennial- scales.
How to cite: Liu, X., Wang, X., Shen, C.-C., Li, H., Ruan, J., Liu, G., Yang, Y., and Chen, F.: Replicated stalagmite records revealed orbital and millennial-scale hydroclimate changes in arid central Asia across the MIS 5 stadial-interstadial transition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21523, https://doi.org/10.5194/egusphere-egu24-21523, 2024.
Comments on the supplementary material
AC: Author Comment | CC: Community Comment | Report abuse