干旱区生态环境知识资源中心(Arid): 腾格里沙漠植物钙质根管Sr/Ca比值揭示的全新世千年尺度有效湿度变化

Arid

	腾格里沙漠植物钙质根管Sr/Ca比值揭示的全新世千年尺度有效湿度变化
其他题名	HOLOCENE MILLENNIAL-SCALE EFFECTIVE MOISTURE CHANGES REVEALED BY Sr/Ca RATIOS FROM CALCAREOUS ROOT TUBES IN THE TENGGER DESERT
	李若兰; 李卓仑; 宁凯; 王乃昂; 程弘毅; 高有红
来源期刊	第四纪研究
ISSN	1001-7410
出版年	2016
卷号	36 期号:2 页码:379-387
中文摘要	在阿拉善高原广泛分布不同地质历史时期的植物钙质根管,探索从这些植物钙质根管中提取可靠的环境信号并进行古环境重建,是一项具有一定指示意义的工作。本文共采集了腾格里沙漠14组全新世植物钙质根管样品,在~(14)C测年结果的基础上,通过X射线荧光光谱法对其进行元素测定,结果显示:8~5cal.ka B.P.阶段植物钙质根管中Sr/Ca比值较高;5~2cal.ka B.P.阶段时Sr/Ca比值较小。本文尝试用植物钙质根管中Sr/Ca比值的变化和植物钙质根管时间分布,重建该区域全新世千年尺度上的有效湿度变化:早全新世时期(8 cal.ka B.P.之前)气候干旱,中全新世时期(8-5cal.ka B.P.)气候湿润,晚全新世时期(5 ~ 2 cal.ka B.P.)气候由湿润转向干旱。上述重建结果与腾格里沙漠猪野泽地区以及毗邻的石羊河中游红水河地区的全新世千年尺度有效湿度变化重建结果基本一致,说明植物钙质根管中的Sr/Ca比值可以指示腾格里沙漠地区全新世千年尺度的有效湿度变化。因此,可以从植物钙质根管中提取可靠的古环境信号并将其应用于古环境重建研究中。
英文摘要	Calcareous root tubes,also called rhizoliths,are defined as secondary carbonate crusts produced by the root of terrestrial plants. Calcareous root tubes frequently occur in calcareous soils with a pronounced seasonal moisture regime. Paleo calcareous root tubes are widely distributed across the Alashan Plateau, Northwest China. Previous studies reveal that calcareous root tubes have potential to reconstruct the paleo-environment and paleo-vegetation. However, it remains unclear whether any environmental signals could be extract from the calcareous root tubes and used for reconstructing paleo-environmental conditions. The Tengger Desert, with area of approximately 42700km~2, is the fourth-largest desert in China. The annual average temperature of the Tengger Desert is 7.0 ?9.7°C,the regional annual average precipitation is 125 ?160mm and the annual average potential evaporation is 2400 ?3000mm. The effective moisture level affects the formation of calcareous root tubes, and different geochemical elements has different features of transport and enrichment in various controlling factors. Therefore, influenced by the soil water changes and the special nutrient-acquiring mechanism of terrestrial plants that live in calcareous soils with deficit nutrition, Sr and Ca was enriched in the calcareous root tubes and the Sr/Ca ratios will changes in different effective moisture level. In this study, based on previous conventional ~(14)C dating results of 14 Holocene calcareous root tube samples (37°54’59" ?38°55’31 "N,104°10’34" ?105°22’59"E) collected from the Tengger Desert (37°26’28" ~ 39°58’59"N, 102°48’25"?105°38’13"E),we used the X-ray fluorescence to analyzed the elemental composition of the calcareous root tubes samples. The results show that the highest value of Sr/Ca ratios (2332.02mumol/mol) was occurred in 8 ?5cal.ka B.P. with the mean value of 1215.26mumol/mol, and the Sr/Ca ratios of calcareous root tubes was decreased during 5 ?2cal.ka B.P. with mean value of 891.81 mumol/mol, but not in the Early Holocene. Based on the Sr/Ca ratios’ variation and temporal distributions of the calcareous root tubes in the Tengger Desert, we reconstructed the effective moisture level changes in this area during the Holocene. The results reveal that the climate was dry in Early-Holocene (ca. 8cal.ka B.P.), humidity in Mid-Holocene (8 ?5cal.ka B.P.),and from humidity to dry in Late-Holocene (5 ~ 2cal.ka B.P.). The reconstruction results were consistent with other previous reconstruction results from lake sediments of Zhuyeze terminal lake section and Hongshui River section,and consistent with the Holocene moisture pattern of the Asian monsoon margin of Northwestern China, which demonstrated that the Sr/Ca ratios of paleo calcareous root tubes can reflect millennial-scale effective moisture changes in this area. These studies reveal that the environmental signals can be extract from the calcareous root tubes and can be applied to paleo environment reconstruction.
中文关键词	腾格里沙漠 ; 全新世 ; 植物钙质根管 ; Sr/Ca比值 ; 有效湿度
英文关键词	Tengger Desert the Holocene calcareous root tubes Sr/Ca ratios effective moisture
语种	中文
国家	中国
收录类别	CSCD
WOS类目	GEOLOGY
WOS研究方向	Geology
CSCD记录号	CSCD:5661440
来源机构	兰州大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/234136
作者单位	兰州大学资源环境学院,干旱区水循环与气候变化研究中心, 兰州, 甘肃 730000, 中国
推荐引用方式 GB/T 7714	李若兰,李卓仑,宁凯,等. 腾格里沙漠植物钙质根管Sr/Ca比值揭示的全新世千年尺度有效湿度变化[J]. 兰州大学,2016,36(2):379-387.
APA	李若兰,李卓仑,宁凯,王乃昂,程弘毅,&高有红.(2016).腾格里沙漠植物钙质根管Sr/Ca比值揭示的全新世千年尺度有效湿度变化.第四纪研究,36(2),379-387.
MLA	李若兰,et al."腾格里沙漠植物钙质根管Sr/Ca比值揭示的全新世千年尺度有效湿度变化".第四纪研究 36.2(2016):379-387.