Rapid and cyclic dust accumulation during MIS 2 in Central Asia inferred from loess OSL dating and grain-size analysis.

Li Han,Zhisheng An,Yougui Song,Zhongping Lai,Yun Li

doi:10.1038/srep32365

Abstract

Due to lack of reliable proxies from the Westerlies-dominant region, the strength change of Northern Hemisphere Westerlies remains poorly understood. The aim of this study is to provide a reliable paleoclimatic proxy about the Northern Hemisphere Westerlies change. Here we report a 30.7 m thick loess section from the Ili basin directly controlled by the Westerlies. Based on optically stimulated luminescence (OSL) and high resolution grain-size records, we reconstruct the change history of the Westerlies strength during the last glacial period (mainly Marine Isotope Stages 2, MIS2), being similar with the Westerlies index recorded in the Qinghai Lake sediments. Within error limits, all ages are in stratigraphic order. We further compare the climatic records among the Ili loess, Qinghai Lake and the NGRIP, their similarity shows a good climatic coupling relationship among the Central Asia, East Asia and the North Atlantic, and the Westerlies plays a critical influence in transporting the North Atlantic signal to Central and East Asia.

Highlights

Sample No XEBLK-0 XEBLK-2 XEBLK-4 XEBLK-6 XEBLK-8 XEBLK-10 XEBLK-12 XEBLK-14 XEBLK-16 XEBLK-18 XEBLK-20 XEBLK-22 XEBLK-24 XEBLK-26 XEBLK-28 XEBLK-30
We report 15 optically stimulated luminescence (OSL) ages for a loess section in the Ili basin on the eastern Central Asia, and use high resolution grain size record of loess to calculate the Westerlies intensity change during MIS 2. It shows a striking match among temperature variations over Greenland, the grain-size change of the Ili loess and the Westerlies index (WI) from Lake Qinghai (QHH) sediments, their similarity showed the northern Westerlies passed the climatic change from the North Atlantic through Central Asia to East Asia during MIS 2
Independent OSL age models can be generated by linear interpolation of OSL ages after excluding the two abnormal OSL age

Summary

Introduction

Sample No XEBLK-0 XEBLK-2 XEBLK-4 XEBLK-6 XEBLK-8 XEBLK-10 XEBLK-12 XEBLK-14 XEBLK-16 XEBLK-18 XEBLK-20 XEBLK-22 XEBLK-24 XEBLK-26 XEBLK-28 XEBLK-30. We report 15 optically stimulated luminescence (OSL) ages for a loess section in the Ili basin on the eastern Central Asia, and use high resolution grain size record of loess to calculate the Westerlies intensity change during MIS 2. It shows a striking match among temperature variations over Greenland, the grain-size change of the Ili loess and the Westerlies index (WI) from Lake Qinghai (QHH) sediments, their similarity showed the northern Westerlies passed the climatic change from the North Atlantic through Central Asia to East Asia during MIS 2

Objectives

Methods

Results

Conclusion