Vegetation and climate changes during three interglacial periods represented in the Luochuan loess-paleosol section, on the Chinese Loess Plateau

摘要

Studies of vegetation successions related to climate changes during previous interglacial periods provide important insights into the mechanisms of climate change during the current interglacial and enable predictions of future climate impacts on ecosystems. The Chinese Loess Plateau (CLP), which is particularly sensitive to climate warming, presents an excellent site for such studies. However, few detailed records exist of vegetation and climate variations during interglacial periods on the CLP. This study obtained a series high resolution pollen records from the Luochuan loess-paleosol section on the CLP, and the paper discusses the vegetation and climate histories during three previous interglacial periods (MIS 9, MIS 7 and MIS 5). The Artemisia-Chenopodiaceae steppe vegetation that covered this area between 342 ka and 312 ka changed to Humulus-Chenopodiaceae steppe between 312 ka and 302 ka, and then reverted to Artemisia-Chenopodiaceae steppe after 302 ka. From 250 ka to 237 ka, the vegetation type remained Artemisia-Chenopodiaceae steppe, and then changed to Artemisia-Humulus steppe between 237 ka and 227 ka. Between 227 ka and 195 ka, the vegetation returned to Aremisia-Chenopodiaceae steppe. During MIS 5, vegetation of the study area changed from Pinus-Rosaceae-Chenopodiaceae forest-steppe between 129 ka and 117 ka, to Artemisia-Humulus-Ranunculaceae steppe from 117 ka to 96 ka. After 96 ka, the vegetation types changed to Pinus-Betula-Chenopodiaceae forest-steppe. Comparing these pollen records with other climatic proxies from the CLP and the oxygen isotope records from the Pacific Ocean suggests that vegetation and climate change features around the study site were synchronous with East Asian monsoon variations near 65° N. The regional tectonic uplift probably provided only a subordinate influence on vegetation and climate variation on the CLP during MIS 5.