张菀漪^1,,
张静雅¹,
NusratNazir¹,
SafarovKhomid¹,
郑淇¹,
MischkeSteffen²,
张成君^1,,
1. 兰州大学地质科学与矿产资源学院, 甘肃省西部矿产资源重点实验室, 甘肃 兰州 730000
2. 冰岛大学地球科学学院, 雷克雅未克 101, 冰岛

基金项目: 国家自然科学基金面上项目（批准号：41571177）、国家自然科学基金青年项目（批准号：41601187）、甘肃省自然科学基金项目（批准号：18JR3RA276）和中央高校基本科研业务费专项基金项目（批准号：lzujbky-2018-it22）共同资助


详细信息

作者简介: 张菀漪, 女, 32岁, 讲师, 微体古生物与古环境重建研究, E-mail: zhangwanyi@lzu.edu.cn

通讯作者: 张成君, E-mail: cjzhang@lzu.edu.cn

中图分类号: P941.78, P534.63⁺.2, P532

收稿日期:2019-02-28
修回日期:2019-05-02
刊出日期:2019-07-30

The records of Donggi Cona lake-level fluctuations since the Holocene in the Northeastern Tibetan Plateau

Zhang Wanyi^1,,
Zhang Jingya¹,
Nusrat Nazir¹,
Safarov Khomid¹,
Zheng Qi¹,
Mischke Steffen²,
Zhang Chengjun^1,,
1. Key Laboratory of Mineral Resources in Western China (Gansu Province), School of Earth Sciences, Lanzhou University, Lanzhou 730000, Gansu
2. Faculty of Earth Sciences, University of Iceland, 101 Reykjavík, Iceland


More Information

Corresponding author: Zhang Chengjun,E-mail:cjzhang@lzu.edu.cn

MSC: P941.78, P534.63⁺.2, P532

--> Received Date: 28 February 2019
Revised Date: 02 May 2019
Publish Date: 30 July 2019


摘要
摘要:青藏高原处于东亚季风、印度季风和西风环流交互作用区。末次冰消期以来，太阳辐射对该地区的古气候环境产生了重要影响，湖泊随着季风系统的变化发生了明显的水位升降，对湖岸阶地的形成起到了直接作用。本项研究重建了青藏高原东北缘冬给错纳湖湖岸阶地记录的湖面波动历史，试图了解青藏高原季风系统演变过程。通过湖泊北岸265 cm厚湖岸阶地沉积物粒度、碳酸盐、矿物、元素和介形虫古环境指标，结合OSL年代模式，分析表明在约10.2 ka B. P.之前水体较浅；约10.2~9.0 ka B. P.湖面开始上升，气候凉湿；9.0~8.5 ka B. P.为印度季风强盛期，湖面明显上升，降雨量增高、温度上升；8.5~7.9 ka B. P.湖面降低与气候变冷有关；7.9~7.0 ka B. P.印度季风开始减弱，气温、降雨下降，但有效湿度较大，湖面降低；7.0~6.1 ka B. P.湖面上升可能与低蒸发作用有关，印度季风仍然影响该地区；6.1~5.2 ka B. P.，印度季风衰退，气候逐渐变冷、降雨量减小、水体变浅；5.2~4.6 ka B. P.气候冷干，有效湿度减小，湖面进一步下降；4.6 ka B. P.至今气候干冷，东亚季风衰退，湖面下降，期间也可能受西风环流影响而有短暂的降雨增加时期。
关键词: 青藏高原/
冬给错纳湖/
全新世/
气候变化/
湖面波动

Abstract:The Tibetan Plateau locates in the interaction area of the Eastern Asian monsoon, Indian monsoon and westerly circulation. Solar irradiation has an important impact on the paleoclimate since the last deglacial on the plateau. The lake water-level fluctuated obviously with the changing of this monsoon system. Lake terraces formed under the lake-level fluctuation directly. Therefore, the monsoon system changing procession in the Tibetan Plateau can be understood deeply based on the paleoenvironmental reconstruction from the terrace sediments. Lake Donggi Cona (35°18'N, 98°32'E), which is also named as Dongxi Co or Lake Tuosu Hu, is located within the Burhan Budai Mountain range on the northeastern Tibetan Plateau with an altitude of 4090 m above sea level (a.s.l.). The lake is supplied by the glacial snowmelt water from the Aemye Ma-chhen Range. The inflows are mainly from the eastern and northern parts of the lake. There is an underground hot water supply in the north of the lake. The region from the mountain ranges to the north of the lake is dominated by Permian granite, limestone and sandstone formations of Early to Middle Triassic age, and Neogene conglomerates. In the eastern, western, and southern part of the lake, limestone sand siliciclastic rocks of Permian age are the dominated bedrocks. The P14 section (35°20'05"N, 98°34'14"E; 4101.1 m a.s.l.) from the terrace 3 of Lake Donggi Cona was investigated to study the lake level fluctuations since the Holocene. The section is about 265 cm thickness with five units, i.e., 0~20 cm, loess layer; 20~55 cm, mud layer; 55~100 cm, silt and sand inter bed; 100~130 cm, mud layer; 130~180 cm, sand layer; 180~220 cm, mud-silt layer; 220~240 cm, mud layer; 240~265 cm, sand layer. Samples of 2 cm thickness were taken from the section. 179 samples in total were collected. Terrace sediment grain size, carbonate content, minerals and elements had been analyzed in this paper. Combining five OSL age-depth model, we had reconstructed the paleoenvironmental change since the Holocene in this area. Our results indicate that the lake experienced several oscillations throughout the Holocene:Donggi Cona lake was a shallow lake before ca. 10.2 ka B.P; the lake level started to rise, and the climate was cool and wet during ca. 10.2~9.0 ka B.P; the lake level increased obviously with the raised precipitation and temperature during 9.0~8.5 ka B. P., which is consistent with the Indian Monsoon strengthening event; the lake level dropped during 8.5~7.9 ka B. P., which may be responding to the global event; the lake level decreased further owning to the drop of precipitation and temperature but with the high effective humidity during 7.9~7.0 ka B. P; during 7.0~6.1 ka B. P., the lake level increased with the low evaporation, and meanwhile the Indian monsoon still had an impact on this area; from 6.1 ka B. P. to 5.2 ka B. P., the lake was shallow resulted by the cold climate and low precipitation with the Indian monsoon retreating; the lake level experienced a further decrease with cold and dry climate and low effective humidity during 5.2~4.6 ka B. P.; from 4.6 ka B. P. to present, the lake level decreased with southeastern summer monsoon retreating; and a short-time high precipitation may be influenced by the westerly in this interval.
Key words:Tibetan Plateau/
Donggi Cona/
Holocene/
climate change/
lake-level fluctuation



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