The Himalaya Tibetan plateau uplift and the onset of seasonal Indian monsoon rainfall

After decades of research, there is still no consensus in the scientific community about the Indian Summer Monsoon evolution during the early stages. Here, we present new records from IODP Site U1471 with a refined magnetostratigraphy-based chronology spanning the past 12.5 to 9.5 million years. Based on Fe/K and magnetic susceptibility records, we show that strong Indian monsoon rainfall occurred during a period of aridification in central Asia, which suggests that the Himalaya-Tibetan Plateau uplift was the mechanism that drove and modulated the Indian monsoon. At about 11 Ma, the emergence of a long eccentricity signal in the Indian monsoon rainfall record hints that the Himalaya-Tibetan Plateau reached a sufficient height to increase climate seasonality. Moreover, the deposition of the Red Clay Formation in the eastern Chinese Loess Plateau and the onset of Oman margin upwelling highlight that the period encompassed one of the major steps towards modern monsoon conditions.