北京北部上侏罗统辫状河体系沉积特征   总被引：1，自引：0，他引：1  

郭佳  邓宏文  季春辉  秦雁群 《现代地质》2011,25(4):642-649

根据野外露头的沉积构造和沉积层序特征,对北京北部延庆硅化木国家地质公园上侏罗统后城组进行沉积相研究,认为该地区以辫状河沉积为主,构成辫状河体系的4种沉积微相类型包括河道、心滩、河间湖泊和溢岸沉积,其中的溢岸沉积相当于曲流河中发育的决口河道与决口扇沉积。运用基准面旋回变化原理,识别出了2个中期旋回和构成中期旋回的多个短期旋回。总结了基准面旋回特征,阐明了地层叠加样式随A/S(可容纳空间/沉积物供给)比值的变化规律,认为低A/S比值时,河道砂体的连通性较好,而高A/S比值时,河道较孤立,连通性较差;且溢岸沉积的地层厚度随着A/S比值的增加不断增大,溢岸沉积的厚度可以作为判断可容纳空间大小的一个依据。  相似文献   

Characteristics of severe Atlantic hurricanes in the United States: 1949–2006     

Stanley A. Changnon 《Natural Hazards》2009,48(3):329-337

Property insurance data available for 1949–2006 were assessed to get definitive measures of hurricane losses in the U.S. Catastrophes, events causing >$1 million in losses, were most frequent in the Southeast and South climate regions. Losses in these two regions totaled $127 billion, 85% of the nation’s total losses. During the period 1949–2006 there were 79 hurricane catastrophes, causing $150.6 billion in losses and averaging $2.6 billion per year. All aspects of these hurricanes showed increases in post-1990 years. Sizes of loss areas averaged one state in 1949–1967, but grew to 3 states during 1990–2006. Seven of the ten most damaging hurricanes came in 2004 (4) and 2005 (3). The number of hurricanes also peaked during 1984–2006, increasing from an annual average of 1.2 during 1949–1983 to 2.1 per year. Losses were $49.3 billion in 1991–2006, 32% of the 58-year total. Various reasons have been offered for such recent increases in hurricane losses including more hurricanes, more intense tropical storms, increased societal vulnerability in storm-prone areas, and a change in climate due to global warming, although this is debatable.  相似文献   

磁化率各向异性椭球三维图形显示的VB .net实现     

赵庆乐  张世红  韩以贵  李海燕  董进  张元厚 《吉林大学学报(地球科学版)》2009,39(6)

磁组构在地球科学研究中具有广泛的应用.磁化率各向异性椭球形状可以反映丰富的地质信息.目前磁化率各向异性测量仪器所用软件不能以图形的方式直观地反映样品的磁化率椭球形状,其数据以二进制及文本方式存储,以纯文本方式显示,需借助其它数据处理与绘图程序来判别椭球形状.使用Visual Basic.net编程语言计算岩石样品的主磁化率及主方向,再调用Mathematica数学系统软件核心显示磁化率各向异性椭球的三维图形,调用Grapher绘图程序核心显示主方向,测量数据可直接存储到Excel文件中.首次实现了显示磁化率各向异性椭球的三维图形的功能,同时可以显示主方向的二维图形,可以进行从样品坐标系到地理坐标系的转换及手动输入15个方向磁化率数据进行主磁化率与主方向的计算.  相似文献   

浅析含硫化氢地质环境对钻井作业的影响   总被引：1，自引：0，他引：1  

吴何 《四川地质学报》2009,29(3):320-323

在高含硫地质环境钻井作业中,硫化氢溢流给安全钻井带来极大的挑战。本文介绍了硫化氢的成因以及含硫地质环境的特点,并重点对含硫化氢地质环境对钻井作业的影响进行了分析和研究。  相似文献   

昆仑山口西8.1级地震前后地壳垂直运动的负位错模型   总被引：9，自引：2，他引：7  

张希  张四新  王双绪 《地震研究》2004,27(2):153-158

利用昆仑山口西8．1级地震震区外围格尔木一五道梁300km长水准测线在1979,1991和2002年3期垂直形变资料,借助研究改进的负位错模型获取发震构造及其相关断裂的运动、变形特征及应力应变积累部位和强度,对与此次大震有关的区域构造形变背景及可能的震后影响进行了研究。结果表明：1991～2002年相对1979～1991年垂直差异运动及应变积累加速增强的特征与昆仑山口西8．1级地震孕育有关;且这样的一个地壳垂直运动加速过程可能还未因地震发生而结束,发震构造相关的断裂构造部位仍有发生较强地震的可能。  相似文献   

The astrometric observations of planetary satellites, close approaches and occultations of stars by asteroids and mutual events in the systems of planetary satellites with the 26-in. refractor of Pulkovo observatory in 1995-2006     

T.P. Kiseleva  I.S. Izmailov  A.A. Kiselev  E.V. Khrutskaya  M.Yu. Khovritchev 《Planetary and Space Science》2008,56(14):1908-1912

Astrometric and photometric observations of major planets, their satellites and asteroids have been made with the 26-in. refractor of the Pulkovo observatory during the period from 1995 to 2006. The CCD (ST6) and photographic observations were carried out. Accurate relative position of satellites of Jupiter and Saturn have been derived. The positions of Saturn have been calculated using the theoretically predicted coordinates of satellites relative to the planet without measurements of the photographic images of the planet. Also the observations of Hale-Bopp comet and Mercury transit have been made. The 26-in. refractor has been included into the international campaign PHEMU-2003: photometric CCD observations of mutual occultations and eclipses of Galilean satellites. The light curves of the events have been obtained and parameters of the events have been determined.  相似文献   

天津蓟县长城系串岭沟组混层粘土矿物     

陈涛  王河锦 《地球科学》2008,33(5):716-722

为了解天津蓟县长城系串岭沟组地层中混层粘土矿物的组成和结构特征, 利用X射线粉晶衍射(XRD) 和高分辨透射电镜(HRTEM) 对其进行了深入研究.通过对比该区粘土矿物的自然干燥片、Ca离子饱和片、Ca饱和的乙二醇膨胀片、加热到375℃和550℃的乙二醇膨胀片获取的XRD衍射峰, 确定该区混层粘土矿物为伊利石/蒙脱石(I/S) 不规则混层矿物和绿泥石/蒙脱石(Chl/S) 不规则混层矿物.从高分辨透射电镜观察到I/S规则及不规则混层的晶格条纹像以及Chl/S不规则混层的晶格条纹像, 揭示了该区I/S混层和Chl/S混层的层间堆跺结构特征.该研究为蓟县中元古界典型剖面提供了重要的混层粘土矿物的结构信息.   相似文献   

Accumulation of Phosphorus and Heavy Metals in the Peel-Harvey Estuary in Western Australia: Results of a Preliminary Study     

R.G. Gerritse  P.J. Wallbrink  A.S. Murray 《Estuarine, Coastal and Shelf Science》1998,47(6):679-693

Concentrations of P and of heavy metals (Zn, Cd, Pb, Cu) were determined in sediment cores from the Peel-Harvey Estuary in Western Australia. Two cores were extracted, each representing one of the two basins of the estuary. Sediments were dated by surplus²¹⁰Pb, by¹³⁷Cs and by changes in the Fe/S ratio. Increasing exports of P from the mainly agricultural catchments have resulted in more than a doubling of both total P and acid extractable inorganic P in sediments of the estuary. Accumulation of P in the estuary is less than expected for complete retention of inputs of P from the major tributaries. Historical data show that since 1950 average concentrations of dissolved inorganic P have approximately doubled in the Peel Inlet and increased by times seven in the Harvey Estuary. Increases in concentrations in surface sediments of acid extractable Zn, Cd, Pb and Cu are noticeable in the Peel Inlet, and of Zn and Cd in the Harvey Estuary. The greatest increase, relative to background, is shown by Zn. Concentrations of extractable Zn and Cd in surface sediments are similar to those estimated from average concentrations in the water column for equilibrium adsorption to organic matter in sediments. Extractable Pb is greater than estimated for equilibrium adsorption to sediments. Extractable Cu is of the order of what can be expected for equilibrium adsorption to sediments in the Peel Inlet, but is less than expected in the Harvey Estuary.  相似文献   

浅谈数字化专题地图的设计与制作     

赵永军  魏翠英  程培嵩 《测绘与空间地理信息》1999,22(1):23-24

本文结合生产实践介绍了数字化专题地图设计与制作的方法、数据获取途径及相关的理论知识。并提出个人见解以供探讨。  相似文献   

建立海洋平台管节点PSN曲线的贝叶斯方法     

王自力  张家新  朱安庆 《海洋工程》1999,17(3)

针对管节点疲劳试验的小样本特点,探讨了建立ＰＳＮ 曲线的贝叶斯方法。在贝叶斯方法中,ＰＳＮ曲线的统计参数作为随机变量处理,首先根据贝叶斯定理求出参数向量的后验概率密度,然后建立ＰＳＮ曲线的贝叶斯方程,最后再编程计算。算例表明,与传统的ＰＳＮ 曲线相比,贝叶斯ＰＳＮ 曲线更加安全可靠  相似文献