Tibet forcing of mid-Pleistocene synchronous enhancement of East Asian winter and summer monsoons revealed by Chinese loess record

Abstract

The mid-Pleistocene transition (MPT) of the global climate system, marked by a shift of previously dominant 41-ka cycles to lately dominant 100-ka cycles roughly in the mid-Pleistocene, is one of the fundamental enigma in the Quaternary climate evolution. The process and origin of the MPT remain of persistent interest and conjecture. Here we present high-resolution astronomically tuned magnetic susceptibility (MS) and grain‐size records from a complete loess–paleosol sequence at Chaona on the central Chinese Loess Plateau. These two proxies are well-known sensitive indicators to the East Asian summer and winter monsoons, respectively. The records reveal a remarkable two-step simultaneous enhancement of the East Asian summer and winter monsoons at 0.9 Ma and 0.64 Ma, respectively, accompanied with an onset of a clear 100-ka cycle at 0.9 Ma and of a final, predominant 100-ka cycle starting at 0.64 Ma. The mid-Pleistocene stepwise rapid uplift of the Tibetan Plateau could be the mechanism driving the simultaneous enhancement of East Asian summer and winter monsoons and the shift of the periodicities during the MPT by complex positive feedbacks.

Variations in the Iron Mineralogy of a Loess Section in Tajikistan During the Mid‐Pleistocene and Late Pleistocene: Implications for the Climatic Evolution in Central Asia

“…Previous investigations have indicated that variations in the magnetic susceptibility of loess deposits dominated by lithogenic magnetite varied with changes in the attributes of the dust source area and the degree of wind sorting (e.g., Begét et al, ; Deng et al, ; Han et al, ). The persistent increase in χ CBD in the DK section suggests the dominant role of dust source, rather than wind sorting, in the Tajikistan loess.…”

Early–Middle Pleistocene transitions: Linking terrestrial and marine realms

“…Further modeling (Kutzbach et al, 1989) produced monsoonlike circulation with increasing uplift. Han et al (2012) studied a loess-paleosol sequence from the Chinese Loess Plateau which provides a sensitive record of the relative strengths of East Asian summer (loess) and winter (paleosol) monsoons. They found a simultaneous strengthening of summer and winter monsoons both at 0.9 Ma and 0.64 Ma along with a shift to ~100 kyr cyclicity.…”

Middle-Late Pleistocene Paleo-Climate and Paleo-Altimetry of the Centre of Tibetan Plateau Indicated by the Sporopollen Record of Well QZ-4

“…Meanwhile the Gonghe movement was started at 150 ka BP and persisted for about 50 ka ( Figure 6) [10,11]. Hence, many studies regard the Plateau uplift as a possible driving force for the simultaneous enhancement of East Asian winter and summer monsoons as well as for the Mid-Pleistocene transition occurrence [46,47]. However, some authors suggest that the mid-Pliocene climate changes in East Asia are unlikely to be a response to Plateau uplift [48].…”