The Paleo－Environmental Significance of Sr and Ca Contained in Acid－Soluble Fraction of Plateau Loess Deposits in Xining Basin     

谭红兵  马海州  鹿化煜  张西营  魏海珍 《中国地球化学学报》2003,22(2):156-163

The Xining Basin,located on northeastern Qinghai-Xizang Plateau,is adjacent to the Qaidam Bsim and Gobi-desert.Therefore,thick,integrated deposits of loess or paleo-sol sequence were well developed.As is well known,there is much paleo-environmental information recorded in loess and plaeo-sol.So if we deal with paleo-environmental index from different an gles ,especially from loess geochemistry,some important and detailed paleo-environmental evolutional information will be acquired.Based on this,the authors determined the contents of Sr and Ca contained in acid-soluble fraction from the bottom to the top of the Panzishan section.This section was obtained through making a well about 17 m in depth,including S1 paleo-sol that was developed during the last interglacial period.According to the results,it is found that variations in contents of Sr and Ca are well correlated with conversion of loess and paleo-sol.In loess deposits,the contents of Sr and Ca are higher than those in paleo-sol deposits.It is known that loess was deposited under cold-dry climate conditions and paleo-sol was developed during warm-humid climate episodes.It is concluded that due to their mobile behaviors,under cold-dry climate conditions,Sr and Ca are stagnant during weak weathering,but under warm-humid climate conditions,Sr and Ca are easily leached and transported in aqueous solution.Therefore,they can be utilized as indicatiors of climate changes.Moreover,variations in contents of Sr and Ca are more sensitive than susceptibility.The mobile behaviors of Sr and Ca contained in acid-soluble fraction can serve as a new quantitative index to evaluate paleo-environmental changes on the plateau.  相似文献   

Engineering geology of loess and loess-like deposits: a commentary on the Russian literature     

I. F. Jefferson  D. Evstatiev  D. Karastanev  N. G. Mavlyanova  I. J. Smalley 《Engineering Geology》2003,68(3-4):333-351

Loess and loess-like deposits were much studied in the Soviet Union, and are currently under investigation in Russia and surrounding countries. There is a vast literature in Russian, which touches on all aspects of loess science and technology. In particular, the studies of the origin of collapsibility are almost totally in Russian, and of course studies on the various regions of Russia and the countries of the Former Soviet Union FSU appear in Russian. This review looks at the literature in Russian and attempts to pick out key contributors, major topics and works and to identify the critical regions and zones of investigation. Because so many regions of the FSU had people living on loess ground, there is a vast literature on engineering geology and ground engineering topics, and this tends to dominate all the literature on loess in Russian. Following Russian practice, the fine-grained deposits under consideration are divided into loess and loess-like deposits. Three main topics are recognised across the whole spectrum of loess research: formation and distribution of loess deposits; stratigraphy, cyclicity and palaeoclimatology; and engineering topics, in particular hydrocollapse and subsidence, and we concentrate on the engineering geology topics. An attempt is made, based on the map of Abelev and Abelev [Abelev, Yu.M., Abelev, M.Yu., 1968. Fundamentals of design and construction on collapsible macroporous soils, 2nd ed. Stroiizdat, Moscow, 431 pp. (in Russian)] of collapsing loess deposits, to define seven loess regions within the geographical limits of the old USSR. The seven regions are those where geotechnical problems might be expected.  相似文献   

饱水黄土隧道变形规律研究   总被引：7，自引：0，他引：7  

乔春生  管振祥  滕文彦 《岩土力学》2003,(Z2)

新松树湾隧道位于饱和的砂粘土中,土体的稳定性极差,施工难度较大。为此,在隧道施工期间,通过土工试验、隧道收敛和围岩内部位移的现场监测、隧道变形的三维有限元仿真计算等手段,对该隧道的变形规律进行了系统研究,获得了大量试验数据。研究成果对隧道的施工组织和支护参数的确定起到了重要作用,为此类隧道的施工积累了经验。  相似文献   

甘肃巴谢剖面黄土-古土壤的光释光测年研究   总被引：2，自引：0，他引：2  

陈杰  卢演俦  尹功明  刘爱国  孙瑛杰  胡碧茹 《地球学报》1997,18(Z1):239-241

光释光（OSL）测年是测定第四纪沉积物年龄的一种新技术。它通过单色光束激发使晶体中储存的电离辐射能释放出来。与热释光（TL）测年相比，OSL测年可以不考虑残留的OSL信号，而且测量具有简便、迅速且准确等优点。本文用细颗粒光释光技术对甘肃巴谢剖面的黄土-古土壤进行了测定，其测年结果与14C测年结果相吻合。这表明，光释光是一项极潜力的年代学技术。  相似文献   

我国特殊岩土研究   总被引：1，自引：0，他引：1  

顾宝和 《水文地质工程地质》1997,24(2):43-45

本文分析，总结了我国特殊岩土理论与应用研究方面的新进展，内容涉及湿陷性黄土，软土膨胀岩土，红土，软岩和特殊土的结构性，指出需要进一步研究的问题，最后对特殊土的研究方法做了阐述。  相似文献   

陕西洛川黄土-古土壤剖面中伊利石结晶度——黄土物质来源和古气候环境的指示   总被引：6，自引：0，他引：6  

季峻峰  陈骏  王洪涛 《地质论评》1997,43(2):181-185

伊利石是我国黄土和古土壤中最主要的粘土矿物。本文选择陕西洛川黄土-古土壤国际典型剖面为研究对象,通过测定伊利石的结晶度(Kubler指数)、Srodon峰强比值(Ir)和2M_1多型含量,发现黄土物质的起源与中高温(>280℃)地质环境有关;黄土样品中伊利石结晶度值为0.25°2θ(Cu Ka),古土壤样品中伊利石结晶度值大于0.27°2θ(Cu Ka);黄土和古土壤中伊利石结晶度值的差别,是由于古土壤中伊利石含少量的膨胀层,而黄土样品中的伊利石不含有膨胀层而引起的。古土壤中伊利石的膨胀层的成因,与伊利石  相似文献   

黄土高原黄土、红色粘土与古湖盆沉积物关系   总被引：7，自引：0，他引：7  

岳乐平 《沉积学报》1996,14(4):148-153

本文通过磁性地层学、古生物地层学、沉积学的对比研究，讨论了中国黄土高原地区黄土，红色粘土与该区重要古湖盆之一，古三门湖堆积物之间关系，并分析气候环境对它们的影响。主要结论如下：１）红色粘土与上覆黄土可以是连续沉积，并呈相渐变关系。２）中国黄土与三门组记录了布容正极性带与松山负极性带。Ｂ／Ｍ界限位于Ｌ８，Ｊ亚带位于标志层Ｌ９与Ｌ１５之间，大约Ｓ１０－Ｓ１３之间，Ｏ亚带位于Ｓ２２－Ｓ３３，或三门组之中。Ｍ／Ｇａ界限对应于黄土与红土界限。并基本对应于三门组与游河组界限。３）红色粘土（三趾马红粘土）并非仅仅是中新世保德期沉积物。它包括上新统与中新统，上新世静乐组记录了高斯正极性带，吉尔伯特负极性带，中新世蓝田组记录了Ｅｐｏｃｈ５。４）古三门湖堆积包括早更新世早期三门组（１．２０—２．５０Ｍａ，松山负极性带），上新世晚期游河组（２．５０—３．５０Ｍａ，高斯正极性带），更早期的三门湖沉积未出露。三门组与午域黄土为同期异相沉积，记录了松山负极性带，游河组则与该区上部红色粘土（静乐组上段）为同期异相沉积，记录了高斯正极性带  相似文献   

陕西洛川黄土沉积物中稀土元素及其它微量元素的化学淋滤研究   总被引：35，自引：0，他引：35  

陈骏  鹿化煜 《地质学报》1996,70(1):61-72

本文采用化学淋滤的方法对洛川黄土沉积物的酸溶和酸不溶相中稀土元素以及其它微量元素的分布分配特征进行了系统的分析。  相似文献   

Behaviours of REE and Other Trace Elements During Pedological Weathering-Evidence from Chemical Leaching of Loess and Palaeosol from the Luochuan Section in Central China     

Chen Jun  Wan Hongtao  Department of Earth Sciences  Nanjing University  Nanjing  Jiangsuand Lu HuayuKey Lab. of Loess  Quaternary Geology  Chinese Academy of Sciences  Xi an  Shaanxi Liu Xinzhu 《《地质学报》英文版》1996,70(3):290-302

The chemical leaching method is used for a systematic analysis of distribution characteristics of acid-soluble and acid-insoluble REE and other trace elements from the Luochuan loess deposits. The study shows that the acid-insoluble phase in loess and palaeosol is a stable component of old aeolian dusts and is characteristic of the provenance; the acid-soluble phase is the unstable component in the weathering pedogenic process and reflects rock-forming features after accumulation of aeolian dusts. The acid-insoluble REE and acid-soluble Sr and Pb can be used as geochemical indicators respectively to trace the provenance characteristics and the weathering pedogenic process.  相似文献   

夯扩桩半模夯扩试验及夯扩机理探讨   总被引：6，自引：0，他引：6  

陈荣  俞季民 《岩土力学》1996,17(2):16-22

设计了夯扩桩半模夯扩试验，采用读数显微镜直接测读上体质点位移，获得了不同密度的均匀砂土中砂粒的位移，由此确定土体的位移场和密度场。借鉴魏西克（Ｖｅｓｉｃ）球形孔穴膨胀理论和梅耶霍夫（Ｍｅｙｅｒｈｏｆ）塑性剪切理论，结合模型试验成果，对夯扩机理作了探讨，并定性地提出了夯扩机理模式。  相似文献