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

Abstract

A 5.3 m lake core was drilled in Baahar Nuur Lake in the Ordos Plateau, and measurements of mean grain size, organic δ 13C (δ 13Corg), organic carbon content (TOC), C/N, carbonate content, carbonate δ 13C (δ 13Ccar) and δ 18O (δ 18Ocar) were conducted for retrieving the Holocene chronosequence of climatic changes based on 15 AMS 14C dates. The record documented four major stages of climate change in the Ordos Plateau: (IV) a cold and dry condition before ∼7.65 14C ka BP; (III) a warm and humid stage between ∼7.65 and ∼5.40 ka BP; (II) a generally drier and cooler climate since ∼5.40 ka BP with two humid events occurring from ∼4.70 to ∼4.60 ka BP and from ∼4.20 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 ∼7.65 to ∼6.70 ka BP, (IIIb) a warm and relatively dry episode from ∼6.70 to ∼6.20 ka BP, and (IIIc) the magthermal and maghumid episode of the Holocene from ∼6.20 to ∼5.40 ka BP.