Millennial paleoclimate variations on the Central Tibetan Plateau during MIS4-MIS2 inferred from a sediment core based RPI chronology

Lakes on the Tibetan Plateau, highly sensitive to environmental changes, play a key role in paleoclimatic studies. However, dating limitations often constrain investigations to periods before the Last Glacial Maximum (LGM). Relative paleointensity (RPI) of lake sediments offers a valuable means of developing high-resolution chronological frameworks during the Brunhes Chron. This study presents an RPI record from a lacustrine sediment core (NMC2020-1A) from Nam Co, Tibetan Plateau (TP), based on normalization of natural remanent magnetization (NRM) by anhysteretic remanent magnetization (ARM) over 20-60 mT demagnetization range using the slope method. Rock magnetic analyses indicate pseudo-single domain (PSD (≈vortex) magnetite as the dominant magnetic mineral. Five age control points were identified by correlating the RPI record with the PISO-1500 paleointensity stack. An age model for the 38.71-10.8 m upper section of the core has been established, covering 78 to 25 ka. The environmental magnetic parameter κARM/κ exhibits a clear precession cycle, highlighting the sensitivity of environmental changes on the TP to variations in solar radiation. Furthermore, comparisons of the κARM/κ ratio at the millennial scale with stalagmite and Greenland ice core records demonstrate the influence of high-latitude abrupt climate shifts on the climate of the TP.