细粒浊积体研究现状与展望   总被引：8，自引：1，他引：8       下载免费PDF全文

姜涛  解习农 《地球学报》2003,24(3):289-292

本文简述了浊积体的研究历史，分析了细粒浊积体的特点、形成过程、相模式、石油地质意义及其识别技术等方面的研究现状和新进展。指出目前所存在的问题及将来的研究方向。  相似文献   

长坑-富湾金、银矿床铅同位素组成特征及其意义   总被引：3，自引：0，他引：3  

毛晓冬  黄思静 《华南地质与矿产》2003,(1):27-32

测定的金、银矿石矿物铅同位素组成表明，矿石铅同位素组成变化幅度较大，在单阶段增长曲线图上均呈线性分布，金矿石拟合直线与μ=8.64的普通铅单阶段地长曲线相切，说明金矿石铅为普通铅和放射成因铅两阶段混合而成的异常铅；单阶段演化方程计算结果显示，金矿石混合铅的正常端元在1048.1Ma前已从它的放射性母体中（源区）分离出来，铅来源的最大可能是云开地区老于1048.1Ma的中元古代地层；按两阶段异常铅演化方程，给定假设的含异常铅矿物结晶时间的可能范围t2=227-23.3Ma，计算得到对应的t1=1225.9-1357.1Ma，也表明异常铅来源于中元古界，属两阶段演化的产物。银矿石铅同位素组成部分落在金矿石的铅异常直线上，说明银矿石异常铅是富^207Pb的端元铅与金矿石的两阶段异常铅的不同比例混合铅。为三阶段演化的异常铅。负同位素构造模式图反映金矿石铅的壳源性质，而银矿石铅则有壳幔混合源的特点。  相似文献   

起算数据误差影响下的方差分量估计     

黄加纳 《武汉大学学报(信息科学版)》1998,(3)

探讨了起算数据误差影响下的方差分量估计方法,给出了顾及起算数据误差影响时求解方差分量估值的方程组及单位权中误差估值的计算公式,并通过实例说明了当起算数据误差较大时,它们对方差分量估计的影响是不应忽略的。  相似文献   

热泉热液金矿化中嗜热微生物——有机质的地球化学作用   总被引：3，自引：0，他引：3  

潘海祥  陆元法 《矿物岩石》1998,18(3):45-50

本文主要通过对热泉热液金成矿过程中的热泉水化学成分和组分的分析,得出泉水中金与氮磷硫、氟硅碳两组组分有很好的相关性。嗜热硫酸盐还原菌能使［Ａｕ（ＨＳ）２］－和［Ａｕ（Ｓ２Ｏ３）２］３－都氧化还原成硫化物,从而使金由热水溶液中沉淀。热泉沉积软泥的有机质中的含硫氨基酸、含硫芳烃也起到了一定的聚金作用。  相似文献   

合成孔径雷达遥感新技术--InSAR介绍   总被引：5，自引：1，他引：5  

刘国祥 《四川测绘》2004,27(2):92-95

InSAR是正在发展中的极具潜力的微波遥感新技术。为使广大测绘工作者对它有一个全面了解，本系列讲座将分六部分对InSAR作较为详细的介绍与讨论。作为第一部分，本文将对InSAR的发展历史、技术背景、系统构成与应用情况等方面作总体介绍。  相似文献   

Response to orthogonal components of ground motion and assessment of percentage combination rules     

Ernesto Heredia‐Zavoni  Raquel Machicao‐Barrionuevo 《地震工程与结构动力学》2004,33(2):271-284

The effects of horizontal components of ground motion on the linear response of torsionally stiff and torsionally flexible systems, on soft and firm soil conditions, are examined. A one‐story, two‐way asymmetric structural system is used, subjected to uncorrelated ground motion components along their principal directions. Spectral densities for ground accelerations in firm and soft soils are modeled based on recorded data from large intensity Mexican earthquakes. It is shown that for firm soils, in general, these effects are important in the case of torsionally flexible systems that are stiff under translation, or for torsionally stiff systems that are flexible in translation. The percentage combination rules usually specified in seismic design codes are assessed against the dynamic response. Such combination rules can result in overly conservative design forces or underestimated design forces, particularly for torsionally flexible structures. Given the relative magnitude of the response to each ground motion component, it was found that using different percentage values in the combination rules has no significant effect on improving the estimation of the total response. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Distribution of hydrous components in jadeite of the Dabie Mountains   总被引：1，自引：0，他引：1  

Wen Su  Zhiping Ji  Zhendong You  Jie Yu 《Earth and Planetary Science Letters》2004,222(1):85-100

Two kinds of jadeite occur in the jadeite-quartzite from the Dabie Mountains, Eastern China: associated either with weak or strong deformation. The former shows a uniform composition while the latter shows both uniform and zoning composition. These jadeites were examined with infrared (IR) spectroscopy. All jadeite displays hydroxyl (OH) stretching bands, implying that hydrous components commonly exist in jadeite. The concentration of the hydrous components in the jadeite with weak deformation is homogenous, whereas the concentration of the hydrous components in strongly deformed samples is variable. The correlation between the intensity of OH-band absorbance and compositional zoning of jadeite with strong deformation indicates that Na-rich jadeite can accommodate more OH than Na-poor jadeite. Its interpretation is that there is more Na associated with greater OH availability in the initial crystallization environment. Our data of the comparatively high OH concentrations recorded in the core of the jadeite which contains relative high vacancies in M2 site imply that both OH content and the vacancies in M2 site could decrease during exhumation of the jadeite-quartzite. The decrease of OH solubility in jadeite would result in the formation of H₂O fluid during the early exhumation of UHP metamorphic rocks. The H₂O fluid transformed from OH during exhumation could trigger and enhance the early retrograde metamorphism of the host rocks and facilitate plastic deformation of jadeite grain by dislocation creep and diffusion creep.  相似文献   

Meteorological fields variability over the Indian seas in pre and summer monsoon months during extreme monsoon seasons   总被引：1，自引：0，他引：1  

U. C. Mohanty  R. Bhatla  P. V. S. Raju  O. P. Madan  A. Sarkar 《Journal of Earth System Science》2002,111(3):365-378

In this study, the possible linkage between summer monsoon rainfall over India and surface meteorological fields (basic fields and heat budget components) over monsoon region (30‡E-120‡E, 30‡S30‡N) during the pre-monsoon month of May and summer monsoon season (June to September) are examined. For this purpose, monthly surface meteorological fields anomaly are analyzed for 42 years (1958-1999) using reanalysis data of NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research). The statistical significance of the anomaly (difference) between the surplus and deficient monsoon years in the surface meteorological fields are also examined by Student’s t-test at 95% confidence level. Significant negative anomalies of mean sea level pressure are observed over India, Arabian Sea and Arabian Peninsular in the pre-monsoon month of May and monsoon season. Significant positive anomalies in the zonal and meridional wind (at 2 m) in the month of May are observed in the west Arabian Sea off Somali coast and for monsoon season it is in the central Arabian Sea that extends up to Somalia. Significant positive anomalies of the surface temperature and air temperature (at 2 m) in the month of May are observed over north India and adjoining Pakistan and Afghanistan region. During monsoon season this region is replaced by significant negative anomalies. In the month of May, significant positive anomalies of cloud amount are observed over Somali coast, north Bay of Bengal and adjoining West Bengal and Bangladesh. During monsoon season, cloud amount shows positive anomalies over NW India and north Arabian Sea. There is overall reduction in the incoming shortwave radiation flux during surplus monsoon years. A higher magnitude of latent heat flux is also found in surplus monsoon years for the month of May as well as the monsoon season. The significant positive anomaly of latent heat flux in May, observed over southwest Arabian Sea, may be considered as an advance indicator of the possible behavior of the subsequent monsoon season. The distribution of net heat flux is predominantly negative over eastern Arabian Sea, Bay of Bengal and Indian Ocean. Anomaly between the two extreme monsoon years in post 1980 (i.e., 1988 and 1987) shows that shortwave flux, latent heat flux and net heat flux indicate reversal in sign, particularly in south Indian Ocean. Variations of the heat budget components over four smaller sectors of Indian seas, namely Arabian Sea, Bay of Bengal and west Indian Ocean and east Indian Ocean show that a small sector of Arabian Sea is most dominant during May and other sectors showing reversal in sign of latent heat flux during monsoon season.  相似文献   

方差分量估计简化公式新探   总被引：1，自引：0，他引：1  

王仲锋 《测绘工程》2002,11(1):26-27,41

给出方差分量估计的一个新的简化公式-多余观测分量平均匹配公式，讨论其统计性质，并通过实例验证其实用性。  相似文献   

Kosa (yellow sand) components in precipitation collected at central Japan     

Chohji Tetsuji  Kitamura Moritsugu  Tabata Masahiro 《中国科学D辑(英文版)》2002,45(Z1)

In east Asia, acidic gases derived from fossil fuel combustion have increased in the pastdecades. On the other hand, the Asian dust, also called Kosa (yellow sand) is transported follow-ing windstorms from arid lands in the Asian continent. Many researchers have been interested inthe reaction between acidic aerosols and Kosa aerosols as well as the long-range transport ofthese emissions. To investigate the characteristics of chemical components in precipitation on along-term basis over Japan, precipitation was sequentially collected from April 1984 to March 1997at Kanazawa located near the coast of the Sea of Japan. Precipitation samples were collected at 1mm intervals for the first 5 mm rainfall and all volume of rainwater after 6 mm for all precipitationevents with an automatic wet only precipitation collector. According to the analyses of precipitationincluding Kosa aerosols during Kosa periods, the reaction in the air between Kosa and acidiccomponents during the long-range transport was discussed.  相似文献