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	东秦岭黄土物源的常量元素和微量元素地球化学证据
其他题名	GEOCHEMICL EVIDENCE FOR THE PROVENANCE OF LOESS DEPOSITS IN THE EASTERN QINLING MOUNTAINS,CENTRAL CHINA
	李楠 1; 郝青振 2; 张绪教 1; 高新勃 2; 韩龙 2; 张伟 3; 彭淑贞 3; 旺罗 2; 许冰 2; 乔彦松 4; 顾兆炎 2
来源期刊	第四纪研究
ISSN	1001-7410
出版年	2016
卷号	36 期号:2 页码:332-346
中文摘要	物源是黄土研究的基础工作之一,东秦岭地区西北毗邻黄土高原,处于西北粉尘向东南传输的路径之上。东秦岭黄土物源存在较大争议,对东秦岭黄土物源的研究,不仅能够揭示物源区古环境信息,为探究东亚冬季风古粉尘搬运和扩散提供关键证据,还可能为长江中下游地区下蜀黄土物源研究提供新线索。本文选取东秦岭南坡洛南盆地和商丹盆地4个黄土剖面,对其代表性样品进行全岩样品粒度和<20mum组分的常量、微量元素组成研究,并与黄土高原黄土进行对比。结果发现,东秦岭黄土全岩样品的粒度组成与黄土高原西峰驿马关黄土相似,具有典型风成黄土特征;<20mum组分的常量元素比值(TiO_2/Al_2O_3)、稀土元素特征参数比值(La_n/Sm_n、Gd_n/Yb_n, La_n/Yb_n、Eu/Eu ~*)、微量元素比值(Zr/Nb、Hf/Nb、Y/Nb、La/Nb、Th/Nb、Ta/Zr、Zr/Hf、Y/Ho)、常量和微量元素间比值(Al/Nb、Ti/Nb、 Zr/Ti、Zr/Al)等与黄土高原西峰黄土有显著差异。根据风尘动力学研究,<20mum组分可以在中等风暴条件下远距离搬运,东秦岭黄土<20mum组分有可能与黄土高原黄土一样都来自西北荒漠区,但是上述地球化学证据排除了东秦岭黄土物质主要来自西北荒漠区的可能,这进一步印证了前人的结论。我们推测东秦岭原地风化物质和河流的冲积物等近源物质可能为东秦岭黄土的主要物源。
英文摘要	Provenance of aeolian dusts has long been regarded as one of the major interests in the loess research. The widespread loess deposits in the Eastern Qinling Mountains, which are located in the climate boundary between temperate zone and subtropical zone, yield valuable paleoclimatic records. However, the provenance of these loess deposits remains controversial. The Eastern Qinling Mountains are proximal to the Chinese Loess Plateau in the northwest, and are on the transportation pathway of the East Asian winter monsoon carrying dust from the northwest to the southeast. Distinguishing the provenance can not only reveal the paleoenvironmental informations of the source regions and provide the key evidences for the dust transportation and deposition of the East Asian winter monsoon, but also possibly provide new clues to determine the loess source of the middle and lower reaches of the Yangtze River region. In this study, four sections from the two major basins in the Eastern Qinling Mountains were investigated. Among these sections, Liuwan (LW, 34.143°N,110.137°E) and Shipo (SP,34.183°N,110.250°E) sections are located in Luonan basin, and Shangluo (SL, 33.885°N, 109.914°E) and Dabuzi (DBZ, 33.719°N, 110.237°E) sections, in Shangdan basin. The grain-size distribution of 39 bulk samples, and the major element as well as trace element of the <20mum fraction of 23 samples mainly from the first loess layer of the four sections were analyzed and compared with the Xifeng loess which is the typical loess deposits from the Chinese Loess Plateau. The geochemical compositions for 5 samples of Pleistocene age from Xifeng section are used to characterize the average geochemical composition of the deserts in Northern China and grain-size data for 11 samples from Xifeng Yimaguan section to characterize the grain-size distribution of typical loess deposits. The results show that the grain-size distribution of the bulk samples from the Eastern Qinling Mountains is similar to that of the Xifeng loess, indicating the four studied loess sections are of typical eolian origin. The immobile element ratios of the <20mum fraction (e.g. TiO_2/Al_2O_3, La_n/Sm_n, Gd_n/Yb_n, La_n/Yb_n, Eu/Eu~*, Zr/Nb, Hf/Nb, Y/Nb, La/Nb, Th/Nb, Ta/Zr, Zr/Hf, Y/Ho, Al/Nb, Ti/Nb, Zr/Ti, and Zr/Al) in the loess deposits from the Eastern Qinling Mountains are different from those of loess from the Chinese Loess Plateau. According to the aerodynamic property of aeolian dust, only dust particles finer than 20mum can transport a few tens to a few hundred kilometers under typical windstorm conditions. The clear distinction in immobile element ratios of <20mum fraction between samples from the two regions indicates that the loess deposits in the two regions have different provenances. We suggest that the adjacent alluvial deposits and clastic sediments from the weathered bedrocks are the dominant dust sources of the loess deposits from the Eastern Qinling Mountains.
中文关键词	黄土物源 ; 东秦岭黄土 ; 常量元素 ; 微量元素 ; 地球化学示踪 ; 古环境
英文关键词	loess provenance loess from the Eastern Qinling Mountains major element trace element geochemical provenance tracing paleoclimate
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:5661436
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/234135
作者单位	1.(北京)中国地质大学地球科学与资源学院, 北京 100083, 中国; 2.中国科学院地质与地球物理研究所, 中国科学院新生代地质与环境重点实验室, 北京 100029, 中国; 3.泰山学院旅游学院, 泰安, 山东 271021, 中国; 4.中国地质科学院地质力学研究所, 国土资源部新构造运动与地质灾害重点实验室, 北京 100081, 中国
推荐引用方式 GB/T 7714	李楠,郝青振,张绪教,等. 东秦岭黄土物源的常量元素和微量元素地球化学证据[J],2016,36(2):332-346.
APA	李楠.,郝青振.,张绪教.,高新勃.,韩龙.,...&顾兆炎.(2016).东秦岭黄土物源的常量元素和微量元素地球化学证据.第四纪研究,36(2),332-346.
MLA	李楠,et al."东秦岭黄土物源的常量元素和微量元素地球化学证据".第四纪研究 36.2(2016):332-346.