Palynological data confirm the occurrence of forest on the Loess Plateau of central China during the Middle Quaternary (MIS13)

Abstract

The Loess paleosol sequence S5SS1 (top layer of S5 paleosol layers; marine isotope stage (MIS) 13) has been extensively studied because it is the most developed paleosol layer among all Quaternary soils in the China loess and represents the greatest humidity since the past 2.5 Ma. The question of whether forests occurred on the Loess Plateau tablelands when these paleosols were deposited is still a controversial scientific issue. This research provides a quantitative reconstruction of the past climate and forest cover between 544 and 480 ka based on a high-resolution pollen record together with magnetic susceptibility (χfd) and L*a*b* color parameters. Results suggest that the Luochuan area (central Loess Plateau) was sparsely covered by temperate deciduous forest under warm and humid conditions with a strong East Asian summer monsoon. The precipitation and woody cover during 544 and 531 ka were similar to those today and much greater than modern from 531 to 480 ka. Our findings are supported by paleosol profile research and modern vegetation studies. This study confirms that MIS 13 was a warm and humid period and that sparse forest developed on the tablelands of the central Loess Plateau, which provides new thinking on the ecosystem restoration program of the Loess Plateau.