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311.
<正>本文系六五期间地质矿产部承担的国家重点科技攻关项目:“南方海相碳酸盐岩攻关课题”成果之一。 一、前言 世界上目前有50%以上的油、气藏分布在碳酸盐岩地层中,特别是一些高产油气井,有许多与岩溶作用所形成的储集空间有关。有利于生成油气的有机质,往往与碳酸盐一起沉积于开阔的陆棚区,碳酸盐失水成岩迅速,易于保存早期生成的烃类;又由于岩溶作用常常和   相似文献   
312.
茹锦文 《中国岩溶》1985,4(4):324-324
<正>川西北,岷山山区海拔标高均在3000~4000米以上,主峰雪宝顶,海拔5588米,在当地的雪线以上。地质上位于川西地槽带,南坪复式向斜的南翼。早古生代以来至三叠系,发育了一套巨厚的浅海相及火山碎屑岩沉积,厚达40000米泥盆、石炭系的碳酸盐岩广泛发育。为高山岩溶的发育提供了一个物质前提。   相似文献   
313.
不同盐度下蓝非鲫鳃泌氯细胞的结构变化   总被引:2,自引:1,他引:1  
实验研究生活于不同水环境中蓝非鲫[Oreochromisaureus(Steindachner)]鳃泌氯细胞显微和超微结构的变化。泌氯细胞分布于鳃小叶基部,淡水环境中,泌氯细胞胞体较小,无分泌腔,核大,中位;海水环境中,泌氯细胞体积增大,有明显分泌腔,核小,基位;淡水过渡到海水的过程中,粗面内质网减少,核缩小,核内染色质凝聚程度增加;胞质中形成发达的微细小管系统;线粒体大量增多,以分泌腔为中心放射状分布。研究结果表明,微细小管系统由多分支膜质小管组成,是Na+、K+、Cl-等离子代谢吸收和运输的主要细胞器;微细小管系统的增多与粗面内质网的减少是同步发生的,膜质小管可能源于内质网,随渗透压改变,二者相互转化;线粒体在渗透压变化过程中提供细胞代谢所需的能量。  相似文献   
314.
彭茹  张小群 《气象科技》2008,36(4):385-388
复经验正交分析在气象学和海洋学研究领域有着广泛的应用,其核心部分就是求解复Hermite矩阵的特征值、复特征向量和复主成分.但是,在以往的研究中,并没有讨论复Hermite矩阵解的统计和物理意义.研究证明,复Hermite矩阵的特征值反映了方差贡献、异常能量,复特征向量本身并没有明确的物理意义,而有明确的统计意义.但是复主成分有清晰的物理意义.并且其实部和虚部不是独立的.因此,在研究二维矢量场变化的优势模态时,只能使用一维线性回归分析方法.  相似文献   
315.
杨光忠  石睿 《贵州地质》2019,36(4):307-315
黔东南地区石英脉型金矿找矿勘查难获突破,甚至关于成矿作用过程的研究也有待深入,本文根据《中国区域地质矿产志·贵州卷·金矿》编撰过程中所掌握的各类资料文献,结合近些年关于金的成矿作用思考和地质观察,尤其是天柱金井金矿"纯净"石英脉明金似层状成矿、黎平三什江金矿(含金)石英脉白云石"层状"条带构造特征现象,以及天柱扒草金矿顺层(含金)石英脉稀土元素及微量元素对称性分布的地球化学分析等表明,黔东南地区石英脉型金矿并非传统认识的沉淀沉积成矿,而应为载体石英脉挂壁结晶生长、自然金粘附成矿的结果,其过程首先进行的是含矿热液混浊期成矿,形成主要产于暗色杂质条带的细粒明金成矿及其富矿金包和"狗头金"等,然后才是含矿热液干净期成矿,形成比较厚大的纯净石英脉及其中似层状明金成矿。  相似文献   
316.
Incised valleys that develop due to relative sea‐level change are common features of continental shelves and coastal plains. Assessment of the factors that control the geometry of incised‐valley fills has hitherto largely relied on conceptual, experimental or numerical models, else has been grounded on case studies of individual depositional systems. Here, a database‐driven statistical analysis of 151 late‐Quaternary incised‐valley fills has been performed, the aim being to investigate the geological controls on their geometry. Results of this analysis have been interpreted with consideration of the role of different processes in determining the geometry of incised‐valley fills through their effect on the degree and rate of river incision, and on river size and mobility. The studied incised‐valley fills developed along active margins are thicker and wider, on average, than those along passive margins, suggesting that tectonic setting exerts a control on the geometry of incised‐valley fills, probably through effects on relative sea‐level change and river behaviour, and in relation to distinct characteristics of basin physiography, water discharge and modes of sediment delivery. Valley‐fill geometry is positively correlated with the associated drainage‐basin size, confirming the dominant role of water discharge. Climate is also inferred to exert a potential control on valley‐fill dimensions, possibly through modulations of temperature, peak precipitation, vegetation and permafrost, which would in turn affect water discharge, rates of sediment supply and valley‐margin stability. Shelves with slope breaks that are currently deeper than 120 m contain incised‐valley fills that are thicker and wider, on average, than those hosted on shelves with breaks shallower than 120 m. No correlation exists between valley‐fill thickness and present‐day coastal‐prism convexity, which is measured as the difference in gradient between lower coastal plains and inner shelves. These findings challenge some concepts embedded in sequence stratigraphic thinking, and have significant implications for analysis and improved understanding of ‘source to sink’ sediment route‐ways, and for attempting predictions of the occurrence and characteristics of hydrocarbon reservoirs.  相似文献   
317.
吕拉昌  何爱  黄茹 《地理研究》2014,33(10):1817-1824
随着知识经济的发展,城市创新职能成为研究热点。基于知识产出,参考城市职能的研究方法进行城市创新职能研究,利用城市职能创新指数及城市职能专门化指数,在与中国城市创新能力位居前列的上海、深圳、广州、天津等城市比较的基础上,对北京城市创新职能结构和强度进行分析。研究表明:以论文发表量和专利授权量分别测度的城市创新职能指数和专门化指数表现出一定的差别,但总体上,北京交通信息业、科教文卫业的创新职能指数均较高。北京各行业部门的创新专门化指数均大于平均值,除少数部门外,基本优于上述四城市,但北京的创新强度并不占绝对优势。  相似文献   
318.
Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern.  相似文献   
319.
Satellite observations of atmospheric CO2 are able to truly capture the variation of global and regional CO2 concentration.The model simulations based on atmospheric transport models can also assess variations of atmospheric CO2 concentrations in a continuous space and time,which is one of approaches for qualitatively and quantitatively studying the atmospheric transport mechanism and spatio-temporal variation of atmospheric CO2 in a global scale.Satellite observations and model simulations of CO2 offer us two different approaches to understand the atmospheric CO2.However,the difference between them has not been comprehensively compared and assessed for revealing the global and regional features of atmospheric CO2.In this study,we compared and assessed the spatio-temporal variation of atmospheric CO2 using two datasets of the column-averaged dry air mole fractions of atmospheric CO2(XCO2)in a year from June 2009 to May 2010,respectively from GOSAT retrievals(V02.xx)and from Goddard Earth Observing System-Chemistry(GEOS-Chem),which is a global 3-D chemistry transport model.In addition to the global comparison,we further compared and analyzed the difference of CO2 between the China land region and the United States(US)land region from two datasets,and demonstrated the reasonability and uncertainty of satellite observations and model simulations.The results show that the XCO2 retrieved from GOSAT is globally lower than GEOS-Chem model simulation by 2 ppm on average,which is close to the validation conclusion for GOSAT by ground measures.This difference of XCO2 between the two datasets,however,changes with the different regions.In China land region,the difference is large,from 0.6 to 5.6 ppm,whereas it is 1.6 to 3.7 ppm in the global land region and 1.4 to 2.7 ppm in the US land region.The goodness of fit test between the two datasets is 0.81 in the US land region,which is higher than that in the global land region(0.67)and China land region(0.68).The analysis results further indicate that the inconsistency of CO2concentration between satellite observations and model simulations in China is larger than that in the US and the globe.This inconsistency is related to the GOSAT retrieval error of CO2 caused by the interference among input parameters of satellite retrieval algorithm,and the uncertainty of driving parameters in GEOS-Chem model.  相似文献   
320.
The paper presents some results of seismic experiments carried out on the territory of northern Moravia and Silesia, roughly delimited by the coordinates 16°E–19°E and 49°N–51°N. The experiments were aimed at compiling a velocity model of the uppermost Earth’s crust using the database of arrival times of Pg and Sg waves recorded at a fairly large number of seismic stations, which enabled us to produce a simple 1D-layered velocity model of the region. The velocity model was computed using the traditional tomographic iterative process composed of consecutive solutions of linear equations. Based on the analysis of velocity distribution, it was found that the velocities of Pg and Sg waves increase from about 5.9 and 3.3 km/s at the surface, to about 6.1 and 3.5 km/s at a depth of 11 km, respectively.  相似文献   
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