气候变化领域集成服务门户(CCPortal): Mechanism of variations in environmental magnetic proxies of lake sediments from Nam Co, Tibet during the Holocene

CCPortal

DOI	10.1007/s11434-012-5324-7
	Mechanism of variations in environmental magnetic proxies of lake sediments from Nam Co, Tibet during the Holocene
	Su YouLiang; Gao Xing; Liu QingSong; Hu PengXiang; Duan ZongQi; Jiang ZhaoXia; Wang JunBo; Zhu LiPing; Doberschuetz, Stefan; Maeusbacher, Roland; Daut, Gerhard; Haberzettl, Torsten
通讯作者	Gao, X (通讯作者)
发表日期	2013
ISSN	1001-6538
EISSN	1861-9541
起始页码	1568
结束页码	1578
卷号	58 期号:13
英文摘要	High-resolution environmental records from the Tibetan Plateau are essential to understand past global climatic and environmental changes. Magnetic minerals in lake sediments are important proxies to reconstruct environmental and climatic changes. Nam Co (lake) is a typical great lake in the transitional region of southwest monsoon in the Tibetan Plateau. Previous studies have extensively focused on geochemistry, microfossils, sedimentology and biochemistry analysis of Nam Co, which provides sound interpretation of paleoclimatic and paleoenvironmental changes. However, up to now, no systematic environmental magnetic studies have been carried out. Therefore, high-resolution and systematic magnetic studies combined with geochemical parameters were carried on lake sediments of core NC 08/01 from Nam Co for the Holocene period (11.3 cal ka BP) in order to explore how magnetic properties of the sediments respond to climatic changes. Based on variations of magnetic proxies, the sequence can be separated into 3 units. Unit 1 (236-199 cm, 11.3-7.8 cal ka BP) contains dominantly coarse-grained magnetite with homogeneous grain size. A positive correlation between magnetite and Ti strongly suggests that these coarse-grained detrital magnetites reflect detrital input signals due to insignificant effects of postdepositional dissolution processes on these coarse-grained magnetite particles. For Unit 2 (198-102 cm, 7.8-2.1 cal ka BP), magnetic grain size is finer and the corresponding concentration of magnetite is also reduced. This is mainly due to significant dissolution of these fine-grained detrital magnetite particles, which were transported under reduced water flow conditions during this period. For Unit 3 (101-0 cm, 2.1-0 cal ka BP), the bulk magnetic properties are dominated by a mixture of single domain biogenic magnetite and detrital magnetite. The concentration of magnetic minerals is not correlated with the Ti content. In conclusion, the preservation of magnetic minerals in the lake sediment and thus the corresponding magnetic properties are related to the initial grain size. Combination of magnetic properties (including variation of grain size and concentration) and other proxies of detrital inputs (e. g. Ti) can be used to infer the variation of redox conditions in Nam Co. These results provide a viable framework for reconstructing the paleoenvironmental changes of this lake.
关键词	ROCK PLATEAU MINERALS RECORD PLEISTOCENE REACTIVITY BASIN
英文关键词	lake sediment; rock magnetism; Nam Co; Tibetan Plateau; Holocene
语种	英语
WOS研究方向	Science & Technology - Other Topics
WOS类目	Multidisciplinary Sciences
WOS记录号	WOS:000318527200013
来源期刊	CHINESE SCIENCE BULLETIN
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258164
推荐引用方式 GB/T 7714	Su YouLiang,Gao Xing,Liu QingSong,et al. Mechanism of variations in environmental magnetic proxies of lake sediments from Nam Co, Tibet during the Holocene[J]. 中国科学院青藏高原研究所,2013,58(13).
APA	Su YouLiang.,Gao Xing.,Liu QingSong.,Hu PengXiang.,Duan ZongQi.,...&Haberzettl, Torsten.(2013).Mechanism of variations in environmental magnetic proxies of lake sediments from Nam Co, Tibet during the Holocene.CHINESE SCIENCE BULLETIN,58(13).
MLA	Su YouLiang,et al."Mechanism of variations in environmental magnetic proxies of lake sediments from Nam Co, Tibet during the Holocene".CHINESE SCIENCE BULLETIN 58.13(2013).