黄土热释光测年问题     

李秉成 《地球科学与环境学报》1998,20(4):41

回顾了热释光测年的简史,展示了我国黄土热释光测年的现状,表明尚达不到建立可靠而精确的地质年代标尺的要求,其原因在于问题的复杂性,而主要是样品的残余热释光信号问题。目前,红外光释光法的初步成功显示了良好的前景。  相似文献   

Magnetostratigraphy and palaeoclimatic significance of Late Tertiary aeolian sequences in the Chinese Loess Plateau   总被引：11，自引：0，他引：11  

Sun Donghuai  An Zhisheng  J. Shaw  J. Bloemendal  & Sun Youbin 《Geophysical Journal International》1998,134(1):207-212

The aeolian Red Clay sequence in the central part of the Chinese Loess Plateau was investigated in an attempt to obtain magnetostratigraphic and palaeoclimatic records. From the results, we deduce that aeolian dust accumulation and the related East Asia palaeomonsoon system began at least 7.6  Myr ago, and that the Tibetan Plateau had reached a significant elevation by that time. The Late Tertiary palaeoclimatic history of the Red Clay as reflected by magnetic susceptibility is reconstructed for the time period 7.6–2.5  Ma. Increases in aeolian dust accumulation for the last 7.6  Myr appear to have a close relation with the uplift processes of the Tibetan Plateau. The remarkable increase of aeolian dust accumulation beginning at 3.2  Ma appears to reflect the influence of an increasing global ice volume on the East Asian monsoon and aeolian dust accumulation.  相似文献   

陕西段家坡黄土剖面中布容／松山古地磁界线附近铱异常的发现及其启示   总被引：3，自引：0，他引：3  

马配学  侯泉林 《地质学报》1998,72(2):173-177

利用高灵敏度放射化学中子活化分析方法,对我国陕西段家坡黄土剖面早－中更新统（约０．７３Ｍａ）沉积界线附近铱和其它元素的丰度进行了测定。结果表明,在布容／松山（Ｂ／Ｍ）古地磁界线附近铱的含量明显增大,最大值为４６．３ｐｇ／ｇ。相对于整个剖面的平均背景值（约１５ｐｇ／ｇ）大约富集了３倍。用地壳元素钪进行标准化之后,铱异常十分明显,而其它元素在界线附近则没有变化。黄土剖面上铱异常的赋存层位与西南太平洋钻  相似文献   

Metallogenic focus-area and superlarge mineral deposits in the bordering zones between China,Russia and Mongolia     

Shaokang Hu  Hongquan Yan  Mao Ye  Weidong Xiang 《中国科学D辑(英文版)》1998,41(1):28-34

Two deep-sea cores in the northwest Pacific have been analysed for sedimentology, mineralogy and environmental magnetism. The results show that after eliminating the interference from volcanism, several proxies such as quartz content, mass susceptibility and anhysteretic magnetic remanence can be used to indicate the eolian deposit from East Asia, and provide information on paleo-atmospheric circulation. A comparison of eolian record in Cure RC10-175 with its oxygen isotopic curve has revealed that the peaks of eolian accumulation occurred at the climatic “optimum” of the Holocene and the last interglaciation, showing the fairly complex nonlinear relationship between continental/pelagic eolian records and the global glacial cycles as well as within the climatic and environmental system. Project supported by the National Natural Science Foundation of China (Grant No. 9291104)  相似文献   

The Loess in the Qinling Mountains and Its Records of Palaeoenvironmental Changes     

LEI Xiangyi  YUE LepingLoess Research Section  Department of Geology  Northwest University  Xi'' an  Shaanxi 《《地质学报》英文版》1998,72(4):420-431

The Fengzhou loess section is very typical in the Qinling Mountains. The section, which is about 82 m thick and underlain by Neogene red clays, consists of 33 layers of loess and 33 layers of palaeosol. It covers the Brunhes normal polarity zone and Matuyama reversed polarity zone, and the B/ M boundary is located in the middle part of loess layer 8 (L8). The loess of the Matuyama reversed polarity zone records the Jaramillo, Olduvai and Reunion normal polarity subchrons. The boundary between the Matuyama reversed polarity zone and Gauss normal polarity zone (M / Ga) appears on the lithological boundary between loess and Neogene red clays. Loess accumulation in the Fengzhou section started before 2.48 Ma B.P. Based on the stratigraphical structure, the material composition and magnetic susceptibility curve of the Fengzhou loess section, the palaeoclimatic changes during the last 2.48 Ma in the Qinling Mountains are subdivided into 66 cold-dry and warm-humid stages, equivalent to 33 climatic cycles. The  相似文献   

黄土基底构筑物边坡稳定的研究方法   总被引：1，自引：0，他引：1  

祖国林  洪宇 《地质灾害与环境保护》1998,9(4):16-20

我国适合露天开采的煤田,主要分布在西部及西北部的黄土高原地区。黄土基底构筑物在加载过程中,曾出现过某些惨痛的工程教训。基于黄土基底排土场形成后黄土底工程性质演化规律及失稳机制分析,提出其边坡稳定的研究方法,对黄土高原地区煤炭资源开发建设具有重要的理论与实际意义。  相似文献   

关于黄土碳酸盐与气候环境关系探讨   总被引：1，自引：0，他引：1  

陈忠  马海州  曹广超  周笃珺  张西营  姚远 《云南地理环境研究》2007,19(3):7-10,14

黄土中碳酸盐与气候环境密切相关。从碳酸盐的成因看，干冷的气候利于原生碳酸盐的保存，而温湿的气候使大量的次生碳酸盐产生。碳酸盐的存在形式与降水量多少有关，降水量大可形成结核层和钙板等，而降水量小则形成各种胶膜。胶膜中各种不同形态的方解石胶膜又可反映不同的气候条件。黄土一古土壤中形成的碳酸盐实际上在古土壤期形成的碳酸盐要高于黄土期形成的，只是由于古土壤期强烈的风化淋溶作用，大量的碳酸盐从古土壤中淀积到下伏的黄土层中。黄土中CaCO3的淀积可分为连续淀积和不连续淀积两类。依据淀积深度和降水量的关系，可建立二者定量的关系。从黄土碳酸盐的不同方面，得到其与气候环境关系较为全面的认识。  相似文献   

Using archaeological data and sediment parameters to review the formation of the Gravettian layers at Krems-Wachtberg     

Marc Händel  Roswitha Thomas  Tobias Sprafke  Philipp Schulte  Michael Brandl  Ulrich Simon  Thomas Einwögerer 《第四纪科学杂志》2021,36(8):1397-1413

  相似文献   

模糊评判法在公路黄土洞穴发育程度分区中的应用   总被引：1，自引：1，他引：0  

孙萍  彭建兵  陈立伟 《地球科学与环境学报》2007,29(4):393-399

阐述了影响黄土洞穴形成的黄土湿陷性、崩解性、地质构造、节理裂隙、微地形地貌和水文及气候条件等工程地质特性和地质因素;在公路沿线地区,公路工程质量及人类活动也是黄土洞穴形成的影响因素。洞穴发育程度分区预测和评价极具复杂性、随机性和模糊性,为此,在对各影响因素分析的基础上,借助模糊综合评判法,对黄土区公路沿线洞穴发育程度分区进行了研究。与实际情况对比分析表明,预测评价结果合理可靠,可作为黄土区已建公路洞穴灾害的防治依据。  相似文献   

黄土填方区地表沉降时序InSAR监测分析     

王建业  梁小龙  金喜  白泽朝  齐二恒 《测绘通报》2021,(8):158-161

“削山填沟造地”等岩土工程在湿陷性黄土沟壑地区屡见不鲜,掌握填方区沉降情况具有重要意义。本文收集了2017年11月—2020年12月获取的56景TerraSAR-X StripMap模式影像,利用时序InSAR技术监测了陕北某湿陷性黄土填方地基工程的沉降信息,并与2017年11月—2020年12月期间监测区3个水准点的沉降测量结果比对。结果表明,在填方区地表以沉降为主,在挖方区地表以抬升为主,研究区存在有1处较为明显的地表沉降情况,位于填挖边界线附近填方区内,形变速率范围为-40~-20 mm/a,最大形变速率达-49.9 mm/a,累计量为-151.6 mm,时序InSAR形变结果和实地水准结果吻合性较好,垂直方向形变速率中误差为1.8 mm/a,表明时序InSAR技术在湿陷性黄土填挖方区变形监测中具有较好的应用价值。  相似文献