碳酸盐岩地区电磁波场的特性分析     

刘海滨  佟文琪 《世界地质》1996,15(1):82-87

形成岩溶的高阻碳酸盐岩对电磁波的吸收较弱，而且成层沉积的特定环境使碳酸盐岩地区岩石的各向异性现象较明显，由于地空界面的存在及岩溶洞壁两侧介质电性差异明显，界面清晰，又使电磁波出现强烈的反射及散射现象，从理论上对碳酸盐岩地区电磁波传播的特有现象进行了研究和分析，并给出结论。  相似文献   

中国大陆岩石圈的化学元素丰度   总被引：32，自引：3，他引：32  

黎彤  倪守斌 《地质与勘探》1997,33(1):31-37

中国大陆岩石圈模型的面积９６０万ｋｍ＾２，平均厚度１１０ｋｍ，体积１０．６亿ｋｍ＾３，岩石平均密度３．０６４ｇ／ｃｍ＾３、总质量３．２４５×１０＾１８ｔ。在中国大陆地壳元素丰度的基础上，作者首次求出中国大陆岩石圈的元素丰度值。其质量丰度，厚子丰度和相对丰度列于表１。此外还按１０类（７８种）元素分别讨论中国大陆岩石圈的主要化学特征。  相似文献   

Sequence Stratigraphy of the Permian--Triassia Boundary Section of Changxing, Zhejiang, Southern China   总被引：1，自引：0，他引：1  

Zhang Kexin  Tong Jinnan  Yin Hongfu  Wu Shunbao China University of Geosciences  Wuhan  Hubei 《《地质学报》英文版》1997,71(1):90-103

Three third-order sequences and about one hundred high-frequency cycles or Milankovitchcycles within the Late Permian Changxingian to Early Triassic Griesbachian are identified in theMeishan Section of Changxing, Zhejiang Province, southern China, the candidate stratotype sec-tion of the global Permo-Triassic boundary, based on a detailed study of the biological,ecological and high-resolution allochthonous cyclic events, microfacies and depositional systems.Furthermore, the stacking pattern of the depositional systems across various Changxingian andGriesbachian sedimentary facies of the Lower Yangtze and the sequence stratigraphic frameworkare outlined with the Meishan section as the principal section. In this paper the habitat types offossil biota are applied to semiquantitative palaeobathymetry and the study of relative sea levelchanges.  相似文献   

地史转折期的生态系   总被引：7，自引：2，他引：7  

殷鸿福  童金南 《地学前缘》1997,(Z2)

生态系的演变是地球各圈层系统耦合关系变化的直接标志。地史转折期的生态系具有复杂的生物内涵，在绝灭—残存—复苏过程中，各生物类别的演替遵循着一定的生存型式。大绝灭后生态系复苏的原动力是绝灭后迁入避难所的复活类型和大绝灭末期高压环境中产生的祖先类型的新生和辐射发展。全面了解绝灭后生态系的组成和结构，对于正确认识地史转折期，即圈层耦合结点处的地质作用型式和过程具有重要作用。  相似文献   

Study of charge structure and radiation characteristic of intracloud discharge in thunderstorms of Qinghai-Tibet Plateau     

ZHAGN Yijun  DONG Wansheng  ZHAO Yang  ZHANG Guangshu  Zhang Hongfa  CHEN Chengpin  ZHANG Tong 《中国科学D辑(英文版)》2004,47(Z1)

The comprehensive observations on lightning discharges were conducted in Naqu area of Qinghai-Tibet Plateau in summer of 2002. The electric structures of thunderstorms and the characteristics of lightning discharges at initial stage were analyzed by using the observation data. The results show that most of intracloud (IC) lightning flashes were polarities inverted in thunderstorms with tripole electric charge structure and occurred between negative charge region located in the middle of the thunderstorm and positive charge region located at the bottom of the thunderstorm. The radiation characteristics of discharge processes in cloud with longer lasting time involved in Cloud-to-Ground (CG) lightning flashes were similar to that of IC discharges.A lot of radiation pulses were produced in these discharge processes. Because the IC discharges took place at the bottom of thundercloud and were near the ground, they may produce more serious damage to equipment on the ground therefore should not be neglected in lightning protection.  相似文献   

Study of charge structure and radiation characteristic of intracloud discharge in thunderstorms of Qinghai-Tibet Plateau     

Yijun Zhagn  Wansheng Dong  Yang Zhao  Guangshu Zhang  Hongfa Zhang  Chengpin Chen  Tong Zhang 《中国科学D辑(英文版)》2004,47(1):108-114

The comprehensive observations on lightning discharges were conducted in Naqu area of Qinghai-Tibet Plateau in summer of 2002. The electric structures of thunderstorms and the characteristics of lightning discharges at initial stage were analyzed by using the observation data. The results show that most of intracloud (IC) lightning flashes were polarities inverted in thunderstorms with tripole electric charge structure and occurred between negative charge region located in the middle of the thunderstorm and positive charge region located at the bottom of the thunderstorm. The radiation characteristics of discharge processes in cloud with longer lasting time involved in Cloud-to-Ground (CG) lightning flashes were similar to that of IC discharges. A lot of radiation pulses were produced in these discharge processes. Because the IC discharges took place at the bottom of thundercloud and were near the ground, they may produce more serious damage to equipment on the ground therefore should not be neglected in lightning protection.  相似文献   

Real-time retrieval of precipitable water vapor from GPS and BeiDou observations   总被引：3，自引：2，他引：1  

Cuixian Lu  Xingxing Li  Tobias Nilsson  Tong Ning  Robert Heinkelmann  Maorong Ge  Susanne Glaser  Harald Schuh 《Journal of Geodesy》2015,89(9):843-856

  相似文献   

Modeling the early warning of grassland fire risk based on fuzzy logic in Xilingol,Inner Mongolia     

Xing-peng Liu  Ji-quan Zhang  Zhi-jun Tong 《Natural Hazards》2015,75(3):2331-2342

  相似文献   

内蒙古自治区重要矿种成矿规律综述   总被引：4，自引：1，他引：3  

许立权  张彤  张明  张玉清  张永清  康小龙  许展  韩宗庆 《矿床地质》2016,35(5):966-980

2007~2013年开展的内蒙古矿产资源潜力评价项目,对铁、铜、铅锌、金、银、钨、钼、铬、镍等重要矿种进行了区域成矿规律总结,为矿产资源潜力评价提供了基础资料。文章即是对该项工作部分成果的概括总结。主要进展包括:在全国Ⅲ级成矿区带划分的基础上,首次进行了覆盖全自治区的Ⅳ级成矿亚带的划分,共划分出34个Ⅳ级成矿亚带;对内蒙古铁、铜等11个重要矿种的主要矿床类型及成矿特征进行了概述,对其时空分布规律做了归纳,认为全区70%以上的矿床数量和资源储量均集中在Ⅲ_5、Ⅲ_6、Ⅲ_8、Ⅲ_10和Ⅲ_11五个成矿区带。此外,不同矿种甚至同一矿种,由于成矿地质背景的差异,在不同的三级区带中的分布也不一样。主要成矿期为元古宙和中生代,次为太古宙和晚古生代,不同矿种的重要成矿期也不完全相同。从区域演化的角度探讨了构造与成矿的关系,认为不同的构造演化阶段形成不同的矿床类型和不同矿种的矿床,其中,古大陆边缘裂谷带以白云鄂博式铁_稀土元素矿床为代表,而大兴安岭岩浆岩带则以产出与燕山期中酸性火山侵入杂岩有关的多金属矿产为特点。  相似文献   

膏盐岩脆塑性变形特征及封闭能力定量评价   总被引：1，自引：0，他引：1  

吴桐  付晓飞  王海学  丁宇佳 《地质论评》2016,62(1):127-137

膏盐岩盖层作为全球许多含油气盆地最重要的盖层之一,本身物性封闭能力毋庸置疑,野外观察和三轴试验证实随埋深的增加膏盐岩存在脆塑性转化的过程。为了明确其在不同脆塑性域的变形特征和封闭能力定量评价方法,本文以野外露头观测、三轴压缩试验和镜下观察为基础,从变形机制、破裂模式、力学行为和声发射等方面系统总结了不同脆塑性阶段膏盐岩的变形特征。应用莫尔—库伦准则、拜尔利摩擦定律和应力降规律厘定了膏盐岩脆塑性转化的围压和深度。研究结果表明:1针对脆性膏盐岩盖层,首先应用保持力定量评价水力破裂风险性,保持力越小,盖层发生水力破裂的风险就越大。同时利用断接厚度定量表征脆性盖层内断层垂向封闭性;2应用SSF定量评价脆—塑性膏盐岩盖层中涂抹型断裂的垂向封闭性,野外断层解剖确定出膏岩涂抹连续的临界SSF值为3.5~4;3塑性膏盐岩盖层具有流动特征,伴随断层逆冲滑动,膏盐岩沿断面流动,此阶段断层垂向是封闭的,但在差异压实作用下,盐岩流动形成缺失区——"盐窗"可以为油气沿断层向上运移提供通道。因此,膏盐岩盖层封闭性分析要综合考虑盖层脆塑性、不同脆塑性盖层内断裂变形机制及断裂带内部结构,从而完善盖层垂向封闭性评价体系。  相似文献