Holocene climatic and environmental changes recorded in Baahar Nuur Lake core in the Ordos Plateau, Inner Mongolia of China

A 5.3 m lake core was drilled in Baahar Nuur Lake in the Ordos Plateau, and measurements of mean grain size, organic delta C-13 (delta C-13(org)), organic carbon content (TOC), C/N, carbonate content, carbonate delta C-13 (delta C-13(car)) and delta O-18 (delta O-18(car)) were conducted for retrieving the Holocene chronosequence of climatic changes based on 15 AMS C-14 dates. The record documented four major stages of climate change in the Ordos Plateau: (IV) a cold and dry condition before similar to 7.65 C-14 ka BP; (III) a warm and humid stage between similar to 7.65 and similar to 5.40 ka BP; (II) a generally drier and cooler climate since similar to 5.40 ka BP with two humid events occurring from similar to 4.70 to similar to 4.60 ka BP and from similar to 4.20 to similar to 3.70 ka BP, and (I) a dry climate characterized by complete desiccation of the lake after 3.70 ka BP. Stage III can be further divided into three sub-stages: (IIIa) a warm and humid episode from similar to 7.65 to similar to 6.70 ka BP, (IIIb) a warm and relatively dry episode from similar to 6.70 to similar to 6.20 ka BP, and (IIIc) the magthermal and maghumid episode of the Holocene from similar to 6.20 to similar to 5.40 ka BP.