Magnetic Properties of the Ganzi Loess and their Implications for Precipitation History in the Eastern Tibetan Plateau since the Last Interglacial

Loess deposits are widely distributed in the eastern Tibetan Plateau (TP), which are valuable archives for retrieving the environmental history related to the Indian Summer Monsoon (ISM). Based on a detailed environmental magnetism analysis of the Ganzi loess sequence that has occurred since the Last Interglacial, we reconstructed the past rainfall history over the last glacial cycle by using multiple magnetic parameters. Our results reveal that the pedogenic process dominated the magnetic enhancement, and magnetic parameters can be used to indicate the past precipitation. The reconstructed precipitation from Ganzi loess shows that rainfall history related to the ISM in the eastern TP has varied dramatically, and the wettest periods over the last glacial cycle occurred during the Last Interglacial and the Holocene. The orbital forcing, global ice volume, atmospheric CO₂, and internal climate forcing have controlled the changes of the ISM at the glacial-interglacial timescale.