The Chinese loess perspective on Marine Isotope Stage 11 as an extreme interglacial

Abstract

Loess/paleosol sequences have proven to be excellent paleoclimate archives of the past 2.5 million years. Furthermore, the magnetic susceptibility signal of these formations in the Central Loess Plateau of China shows a high degree of similarity with the marine isotope signal, and the enhanced magnetic susceptibility of each paleosol has been correlated to one or more interglacial marine isotope stages (MIS). If MIS 11 was the longest and warmest interglacial of the past 500 ka, then it should have produced the most highly-developed paleosol in the terrestrial record. In the Chinese sequence, S 5 is the most prominent paleosol, and it is generally assumed to represent the terrestrial climatic optimum for the past 1.2 Ma. However, the peak in magnetic susceptibility in S 5 , which is also the highest value in the entire section, is usually correlated to MIS 13, and not MIS 11. Paleosol S4, which has been correlated to MIS11, does not stand out in most of the properties that are associated with the intensity of pedogenesis, such as magnetic susceptibility enhancement, soil thickness, the depth of decalcification, or particle size. Comparison of the degree of soil development of S 1 -S 5 pedocomplexes of Jiaodao and other Chinese loess/paleosol sections does not confirm the unusual duration, warmth or stability of the S 4 soil-forming interval. However, it does confirm that S 5 (especially S 5-1 ) represents the period of either prolonged or most intense pedogenesis within the studied time interval. This raises questions about interpretation of marine and terrestrial paleoclimate proxies and the validity of their correlation to each other and orbital variations.