Holocene dust deposition in the Ili Basin and its implications for climate variations in Westerlies-dominated Central Asia

Understanding Holocene paleoclimate in arid Central Asia (ACA) is helpful for predicting future climate. However, Holocene climate patterns and their forcing mechanisms across ACA are vigorously debated in the context of global climate change. Here, we present a Holocene loess profile (SGX) from the...

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Bibliographic Details
Published in:Palaeogeography, Palaeoclimatology, Palaeoecology
Main Authors: Sun, Huanyu, Song, Yougui, Chen, Xiuling, Cheng, Liangqing, Liu, Huifang
Format: Report
Language:English
Published: ELSEVIER 2020
Subjects:
OSL ages
Grain size
Color index
Loess
Tianshan Mountains
ARID CENTRAL-ASIA
LOESS-PALEOSOL SEQUENCE
GRAIN-SIZE DISTRIBUTION
LAST GLACIAL PERIOD
CHINESE LOESS
MOISTURE EVOLUTION
LATE QUATERNARY
SUMMER MONSOON
NORTH-ATLANTIC
MAGNETIC-SUSCEPTIBILITY
Physical Geography
Geology
Paleontology
Geography
Physical
Geosciences
Multidisciplinary
North Atlantic
Online Access:http://ir.ieecas.cn/handle/361006/14812
http://ir.ieecas.cn/handle/361006/14813
https://doi.org/10.1016/j.palaeo.2020.109731
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Summary:Understanding Holocene paleoclimate in arid Central Asia (ACA) is helpful for predicting future climate. However, Holocene climate patterns and their forcing mechanisms across ACA are vigorously debated in the context of global climate change. Here, we present a Holocene loess profile (SGX) from the Ili Basin in the Westerlies-dominated Central Asia. Based on high-resolution, medium-grained (38-63 mu m) quartz optically stimulated luminescence (OSL) dating, and grain size and color measurements, we reconstruct the Holocene paleoclimate. OSL geochronology indicate that this SGX loess profile covers the last 11.5 ka, and grain size analyses reveal that the sediments are sandy loess, and the environmentally sensitive fractions are < 35.6 mu m and 35.6-252 mu m which represent suspensions after dust storms and proximal deposit components transported mainly during dust storms, respectively. And the redness and yellowness in the loess profile are closely related to the concentrations of hematite (Hm) and goethite (Gt); the ratio Hm/Gt also can be used to reflect the evolution of dry/humid conditions in Central Asian loess. The Holocene Westerlies-dominated climate in ACA is characterized by a dry early Holocene, persistently wet conditions in the middle and late Holocene, and a climatic optimum in the late Holocene. The winter solar insolation at 60 degrees N is considered the major forcing of Holocene climate evolution in ACA.

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