干旱区生态环境知识资源中心(Arid): 毛乌素沙漠东南缘湖沼相沉积物粒度特征记录的12.2 cal. ka B.P·以来的区域环境变化

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	毛乌素沙漠东南缘湖沼相沉积物粒度特征记录的12.2 cal. ka B.P·以来的区域环境变化
其他题名	ENVIRONMENTAL CHANGES RECORDED FROM GRAIN-SIZE CHARACTERISTICS OF THE LACUSTRIN-PEAT SEDIMENTS FROM SOUTHEASTERN MARGIN OF MU US DESERT SINCE 12.2 CAL. ka B.P
	贾飞飞 1; 鲁瑞洁 2; 高尚玉 2
来源期刊	第四纪研究
ISSN	1001-7410
出版年	2018
卷号	38 期号:5 页码:1211-1220
中文摘要	选取毛乌素沙漠东南缘典型湖沼相沉积炭窑沟剖面,通过分析沉积序列粒度组成与粒度分布特征,结合AMS 14C年代数据,恢复了本区12.2 cal. ka B.P.以来的环境变化过程。结果显示:12.2 cal. ka B.P.之前沉积物较粗,以极细砂和细砂为主,粒度分布曲线与现代风成砂一致,为典型风成砂堆积,说明这一时期气候干旱,炭窑沟地区为沙漠环境;12.2~6.2cal.ka B.P.堆积湖相沉积,粉砂和粘土含量增加,指示气候变湿,变为湖滨或浅湖环境;6.2~3.0cal. ka B.P.发育泥炭,沉积物以粉砂为主,在细颗粒及300~500 mum处各有一个弱峰,说明这一时期气候持续好转,植被生长茂密,湖滨或浅湖变为湿地或沼泽;3.0 cal. ka B.P.之后沉积物平均粒径变粗,各组分随深度变化频繁,但粒度分布曲线主要表现为两种模式,一种为典型风成砂模式,一种为细颗粒显著增加的湖相沉积模式,指示这个时期气候总体变干,但期间经历了多次干湿变化。12.2cal.ka B.P.以来毛乌素沙漠东南缘环境演化过程与季风边缘区气候变化有很好地一致性,与东亚季风变化也具有同步的变化规律,说明本区环境演化进程主要受到东亚季风的控制。
英文摘要	The Mu Us Desert, located in the desert/loess transition zone and in the margin of the East Asian summer monsoon, is an ideal region for studying past environmental changes due to its sensitive climatic response. Fluvial-lacustrine sediments, peat and aeolian deposits have been used to explore past climate changes in this area. Compared to aeolian deposits, fluvial-lacustrine sediments and peat provide high resolution climatic or environmental information because of the relatively uniform accumulation rate in an aquatic or wetland environment. In this paper, we obtained a 1050 cm-long lacustrine-peat sediment sequence(TYG section: 37°43’10.73"N,109°0’4.2"E) from the southeastern margin of Mu Us Desert. This section located on the first terrace of the Xuanhe River, a third-order tributary of the Yellow River. Subsamples were taken generally at an interval of 2 cm or 5 cm, and a total of 218 samples were collected for grain-size analysis using Malvern Mastersizer 2000.11 samples were collected from the TYG section for Accelerator Mass Spectrometry (AMS) 14C dating at the Beta Analytic Radiocarbon Dating Laboratory. The dating results indicated the aeolian sand at 1050 ~834 cm accumulated before 12.2 cal. ka B.P., lacustrine sediments at 834~593 cm deposited from 12.2 cal. ka B.P. to 6.2 cal. ka B.P., peat at 593 ~317 cm developed from 6.2 cal. ka B.P. to 3.0 cal. ka B.P., and silt-sand at 317 ~11 cm accumulated after 3.0 cal. ka B.P. We reconstructed regional environment changes since 12.2 cal. ka B.P. based on the grain-size characteristic of a high-resolution Holocene sequence of lacustrine-peat sediments. Our results indicate that before 12.2 cal. ka B.P.,sediments sizes of TYG section were coarser than other periods, and main fractions of grain size were fine sand and sand,with the content of fine sand was 40.7%,distribution curve of grain size was bimodal. These results indicated climate was dry and this region was in a desert environment before 12.2 cal. ka B.P. From 12.2 cal. ka B.P. to 6.2 cal. ka B.P., lacustrine sediments occurred in the TYG section, accompanying with decreased sand fraction and increased fine grain-size fraction. The content of silt increased from 14.6% to 31.1% , and the content of clay changed from 1.7% to 4.5% .These evidences indicated that climate was wet and desert environment turned to shallow lake. Peat replaced lacustrine sediments in TYG section between 6.2 cal. ka B.P. and 3.0 cal. ka B.P. Clay and silt fraction content increased to 49.4%. The distribution curve of grain size was multimodal and there was a weak peak at 300 ~ 500 mum because coarse grains were more easily captured by the plants. These suggested that climate was optimum and shallow lake changed to swamp during this period in this region. Silt-sand accumulated and grain-size of sediments has two different distribution patterns since 3.0 cal. ka B.P. One was similar with that of aeolian sand, and the other was similar with that of lacustrine sediments. These evidences implied that climate turned to dry but it fluctuated frequently with several wet fluctuations since 3.0 cal. ka B.P. Comparison with other lacustrine sediments from surrounding areas shown that the environmental evolution in the southeastern margin of Mu Us Desert since 12.2 cal. ka B.P. was consistent with the climate changes in the margin of the East Asian summer monsoon,and was also synchronous with the changes of East Asian monsoon, indicating that the environmental evolution in the southeastern margin of Mu Us Desert was controlled by East Asian monsoon.
中文关键词	毛乌素沙漠 ; 湖相沉积 ; 泥炭 ; 粒度 ; 环境变化
英文关键词	Mu Us Desert lacustrine peat grain-size environmental changes
语种	中文
国家	中国
收录类别	CSCD
WOS类目	GEOSCIENCES MULTIDISCIPLINARY
WOS研究方向	Geology
CSCD记录号	CSCD:6340392
来源机构	北京师范大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/237496
作者单位	1.辽宁师范大学,城市与环境学院, 大连, 辽宁 116029, 中国; 2.北京师范大学地理科学学部;;北京师范大学地理科学学部;;北京师范大学地理科学学部, 地表过程与资源生态国家重点实验室;;防沙治沙教育部工程研究中心;;环境演变与自然灾害教育部重点实验室, ;;;;, 北京;;北京;;北京 100875;;100875;;100875, 中国
推荐引用方式 GB/T 7714	贾飞飞,鲁瑞洁,高尚玉. 毛乌素沙漠东南缘湖沼相沉积物粒度特征记录的12.2 cal. ka B.P·以来的区域环境变化[J]. 北京师范大学,2018,38(5):1211-1220.
APA	贾飞飞,鲁瑞洁,&高尚玉.(2018).毛乌素沙漠东南缘湖沼相沉积物粒度特征记录的12.2 cal. ka B.P·以来的区域环境变化.第四纪研究,38(5),1211-1220.
MLA	贾飞飞,et al."毛乌素沙漠东南缘湖沼相沉积物粒度特征记录的12.2 cal. ka B.P·以来的区域环境变化".第四纪研究 38.5(2018):1211-1220.