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Holocene lake shrinkage on the northwestern Tibetan Plateau revealed by K-feldspar single-grain pIRIR dating of paleo-shorelines
被引:0
作者:
Zhang, Shuai
[1
]
Zhao, Hui
[2
]
Wang, Leibin
[3
]
Chen, Fahu
[1
]
机构:
[1] Chinese Acad Sci, Inst Tibetan Plateau Res, State Key Lab Tibetan Plateau Earth Syst Sci LATPE, Grp Alpine Paleoecol & Human Adaptat ALPHA, Beijing 100101, Peoples R China
[2] Chinese Acad Sci, Key Lab Desert & Desertificat, Northwest Inst Ecoenvironm & Resources, Lanzhou 730000, Peoples R China
[3] Guangzhou Univ, Ctr Climate & Environm Changes, Sch Geog Sci, Guangzhou 510006, Peoples R China
基金:
中国国家自然科学基金;
关键词:
pIRIR;
K-feldspar;
Single grain;
Paleo-shoreline;
Lake level;
Indian summer monsoon;
Northwestern Tibetan plateau;
BASIN WESTERN TIBET;
ARID CENTRAL-ASIA;
SUMXI CO BASIN;
ENVIRONMENTAL-CHANGES;
SUBTROPICAL JET;
CLIMATE-CHANGE;
TANGRA YUMCO;
DOSE-RATE;
MONSOON;
QUARTZ;
D O I:
10.1016/j.quageo.2024.101583
中图分类号:
P9 [自然地理学];
学科分类号:
0705 ;
070501 ;
摘要:
As a vital component of the "Asian water tower", lakes on the Tibetan Plateau (TP) significantly influence the regional ecosystems and economies and they are also an effective sentinel of climate change. However, the temporal and spatial patterns of lakes and the related hydroclimatic evolution on the northwestern TP (NWTP) remain unclear. We reconstructed the lake level variations of a non-glacier-fed lake, Longjue Co, on the NWTP, using optical dating of paleo-shorelines. The optically stimulated luminescence signals of quartz grains were unsuitable for dating due to high contributions of the medium component, and thus the post-infrared infrared stimulated luminescence signals (pIR 50 IR 170 , pIR 50 IR 225 ) of K-feldspar single grains were used. Internal checks including dose recovery tests, residual dose tests, and anomalous fading tests showed that the pIR 50 IR 170 signal was suitable for paleo-shoreline dating in Longjue Co. However, some of the samples were affected by the incomplete bleaching of pIRIR signals before deposition, and in this case the Minimum Age Model was used to constrain the ages. We also examined the dependence of the K-feldspar equivalent dose (D e ) on grain brightness and explored the possible mechanisms, and the brightest grains were then used for D e calculations. The results show that Longjue Co reached its maximum Holocene level ( +34 m) during the early Holocene (10.06 +/- 1.39 ka), and then after -5 ka it commenced a shrinking trend, punctuated by two rapid lake level decreases. Reference to independent paleoclimate records suggests that the Holocene lake level variations of Longjue Co and the regional hydroclimate were mainly controlled by the Indian summer monsoon.
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