干旱区生态环境知识资源中心(Arid): 内蒙古准格尔旗红粘土序列的成因、年代及其古气候意义

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	内蒙古准格尔旗红粘土序列的成因、年代及其古气候意义
其他题名	ORIGIN AND AGE OF ’RED CLAY’ SEDIMENT AT JUNGAR BANNER, INNER MONGOLIA,AND ITS PALAEOCLIMATIC IMPLICATIONS
	冯少华; 唐自华; 王旭; 杨石岭
来源期刊	第四纪研究
ISSN	1001-7410
出版年	2010
卷号	30 期号:5 页码:911-918
中文摘要	文章对内蒙古准格尔旗红粘土沉积进行了粒度和磁性地层研究.粒度分析表明,该红粘土序列的粒度分布特征与灵台、泾川剖面的第四纪古土壤、新近纪红粘土十分类似,结合野外观察基本可以确认其风成成因.磁性地层和碳同位素地层研究表明,准格尔旗剖面古地磁极性序列可与标准极性柱C3n.lr-C3An.2n极性段相对应,根据沉积速率外推,其沉积时代为4.13-6.61Ma.该剖面是迄今为止有年龄报道的纬度最高的红粘土沉积,表明黄土高原主体地区红粘土的北界至少在现代毛乌素沙漠以北,其分布北界比黄土更靠北.空间粒度对比表明,红粘土的空间粒度分异远远小于第四纪黄土一古土壤序列,表明新近纪粉尘沉积区至源区的距离远大于第四纪时期
英文摘要	A 62-m-thick ’red clay’ sequence was discovered recently at Jungar Banner(39°55’N,11°057’E)in Inner Mongolia, Northern China. It consists of 45 paleosol units and 46 carbonate nodule layers. The’red clay’ sequence can be subdivided into two parts from the top to the bottom according to its pedogenic characteristics. The soils in the lower part(29m to 62m) are reddish brown and have abundant clay skins and Fe-Mn films, while the soils in the upper part(0 to 29m) are characterized by a relatively light color and weak, coarse subangular blocky structure. Grain size analysis shows that in most soils, the median grain size are centered at about 4-8 um with the sand fraction being negligible. Overall, the ’red clay’ shows grain-size distributions very similar to well-developed Pleistocene paleosols(e.g.Ss), all being broad and flat curves. Field characteristics and particle size distributions all suggest an eolian origin for the ’red clay’ sequence. We collected 263 0rientated samples at an interval of 20 ~ 25cm from the ’red clay’ sequence. The magnetic remanence was measured with a 2G-760 U-channel system in the Institute of Geology and Geophysics, Chinese Academy of Science. In addition,we measured the carbon isotopic composition of 46 carbonate nodules in order to constrain the paleomagnetic polarity, since a significant C4 plant expansion at 4Ma is well documented in the ’red clay’ sediment on the Loess Plateau. The 613C record indicates a major expansion of C4 plants at the depth of 3m. The combined results from magnetostratigraphy and isotope stratigraphy demonstrate that the polarity zones of the Jungar Banner section correlate with those between C3n. lr and C3An. 2n of the GPTS, yielding an age range of 4.13-6.61Ma and a relatively constant sedimentation rate of 2. 52cm/ka. The Jungar Banner section is the northernmost ’red clay’ sequence so far found in the main body of the Loess Plateau, implying the northern distributional limit of the Neogene 6red clay’ can be extended at least to the north of the present-day Mu Us desert. In other words, the northern distributional limit of the ’red clay’ is located further north than that of the Pleistocene loess. In contrast to a steep north-south gradient in grain size of Pleistocene loesssoil sequences, the ’red clay’ shows a slight spatial change in its particle size, indicating a greater dust transport distance in the Neogene than in the Quaternary
中文关键词	红粘土 ; 风成沉积 ; 粒度 ; 磁性地层
英文关键词	red clay eolian deposits grain size magnetostratigraphy
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:3985054
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/224886
作者单位	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
推荐引用方式 GB/T 7714	冯少华,唐自华,王旭,等. 内蒙古准格尔旗红粘土序列的成因、年代及其古气候意义[J],2010,30(5):911-918.
APA	冯少华,唐自华,王旭,&杨石岭.(2010).内蒙古准格尔旗红粘土序列的成因、年代及其古气候意义.第四纪研究,30(5),911-918.
MLA	冯少华,et al."内蒙古准格尔旗红粘土序列的成因、年代及其古气候意义".第四纪研究 30.5(2010):911-918.