黄、东海海域水团发育对底质沉积物分布的影响   总被引：6，自引：0，他引：6  

郭志刚  杨作升  王兆祥 《中国海洋大学学报(自然科学版)》1995,(1)

通过对黄、东海海域底质沉积物中的细粒级粘土矿物组合特征和全粒级碳酸盐含量分析、对比上覆水团和悬浮体资料，探讨研究区水团发育消长对底质沉积物分布的影响作用。结果表明研究区可以划分为长江冲淡水影响的长江型物质沉积区；黄海水影响的黄河型物质沉积区和黑潮水以及东海次表层水影响的残留型物质沉积区。而水团发育消长可直接影响下伏底质的分布特征。黄河型物质沉积区与残留型物质沉积区的分界相应于黄海冷水向东南扩展与黑潮次中层混合水向陆架爬升互为消长的长期综合平衡位置，而黄海冷水向东南的扩展范围代表着黄河物质在陆架向东南扩展沉积的最大范围．  相似文献   

Freshening of the Intermediate Waters in the Northern South China Sea over the PastSix Decades     

陈栩洋  王东晓  舒业强  成里京  范双双 《热带气象学报(英文版)》2024,30(1):42-50

The properties of salinity in the South China Sea (SCS), a significant marginal sea connecting the Pacific andIndian Oceans, are greatly influenced by the transport of fresh water flux between the two oceans. However, the long-termchanges in the intermediate water in the SCS have not been thoroughly studied due to limited data, particularly in relationto its thermodynamic variations. This study utilized reanalysis data products to identify a 60-year trend of freshening in theintermediate waters of the northern South China Sea (NSCS), accompanied by an expansion of low-salinity water. Thestudy also constructed salinity budget terms, including advection and entrainment processes, and conducted an analysis ofthe salinity budget to understand the impacts of external and internal dynamic processes on the freshening trend of theintermediate water in the NSCS. The analysis revealed that the freshening in the northwest Pacific Ocean and theintensification of intrusion through the Luzon Strait at intermediate levels are the primary drivers of the salinity changes inthe NSCS. Additionally, a weakened trend in the intensity of vertical entrainment also contributes to the freshening in theNSCS. This study offers new insights into the understanding of regional deep sea changes in response to variations in boththermodynamics and oceanic dynamic processes.  相似文献   

滇西地区地壳上地幔电性结构与地壳构造活动的关系   总被引：46，自引：3，他引：43       下载免费PDF全文

孙洁  徐常芳 《地震地质》1989,11(1):35-45

本文根据滇西地区18个大地电磁测深点资料的数据处理和分析结果,对测区深部导电率在纵、横向上的变化特征进行了研究。结果表明:滇西地区深部电性为多层结构,大致可分四至五个电性结构层;深部电性结构横向变化大,明显受区域构造控制;该区上部地壳内普遍存在低阻层;上地幔高导层明显存在两个隆起区,一个以剑川—鹤庆为中心呈北北西向展布的隆起区,另一个以腾冲—潞西为轴呈南北向展布的隆起区。 本文还讨论了地壳上地幔电性结构与大地构造的关系,滇西北裂陷区盆地的形成,以及该区地震活动与深部构造的关系  相似文献   

西藏崩错8级地震地表破裂的变形特征及其破裂机制   总被引：7，自引：2，他引：5       下载免费PDF全文

吴章明  邓起东 《地震地质》1989,11(1):15-25

1951年11月18日,西藏那曲崩错附近发生了一次8级地震,地表产生了长达约91公里的破裂带。本文总结了该破裂的几何、位移分布特征,讨论了破裂的形成机制和崩错地震的发震构造条件  相似文献   

从《徐霞客游记》看明末南方的社会经济生活——纪念徐霞客逝世350周年     

杨载田  熊绍华 《地理研究》1992,11(1):48-55

本文以《徐霞客游记》为依据,对明末南方的社会经济生活状况进行了初步归纳和分析,以揭示徐霞客对我国人文地理学的突出贡献。  相似文献   

山西能源重化工基地建设研究     

李乃华  胡积善 《云南地理环境研究》1992,4(2):56-64

山西能源重化工基地建设关系到全国四个现代化的实现,被列为国家重点建设工程,制定了《山西能源重化工基地综合规划》。本文分析了80年代山西省经济建设的成就与问题。提出了“整体创新,综合开发”,把山西能源重化工基地建设成内陆经济开放区的战略大思路,为此,90年代应完成11项大型经济战略工程,同时展望了经济发展改革前景。  相似文献   

The activities of comets related to their aging and origin     

Fred L. Whipple 《Celestial Mechanics and Dynamical Astronomy》1992,54(1-3):1-11

Two indices have been developed for the purpose of comparing the natures of various classes of comets. The first is the Activity Index (AI), measuring the inherent magnitude increase in brightness from great solar distances to maximum near perihelion. The second, or Volatility Index (VI), measures the variation in magnitude near perihelion. Tentative determinations of these two indices are derived from observations by Max Beyer over more than 30 years for long-period (L-P) and short-period (S-P) comets near perihelion and from other homogeneous sources. AI determinations are made for 32 long-period (L-P) comets and for 14 short-period (S-P). The range of values of AI is of the order of 3 to 10 magnitudes with a median about 6. An expected strong correlation with perihelion distance q, is found to vary as q ^–2.3. Residuals from a least-square solution (AI) are used for comparing comets of different orbital classes, the standard deviation of a single value of AI is only ±1^m.1 for L-P comets and ±1^m.2 for S-P comets.Among the L-P comets, 19 of period P larger than 10⁴ years yield AI = 0^m.27 ± 0^m.25 compared to 0^m.39 ± 0^m.26 for 13 of period between 10² years and 10⁴ years. This denies any fading with aging among the L-P comets. Also no systematic change with period occurs for the VI index, leading to the same conclusions. Weak correlations are found with the Gas/Dust ratio of comets. No correlations are found between the two indices, nor of either index with near-perihelion magnitudes or orbital inclination.The various data are consistent with a uniform origin for all types of comets, the nuclei being homogeneous on the large scale but quite diverse on a small scale (the order of a fraction of kilometer in extent). Small comets thus may sublimate away entirely, leaving no solid core, while huge comets may develop a less volatile core by radioactive heating and possibly become inactive like asteroids after many S-P revolutions about the Sun. When relatively new, huge comets may be quite active at great solar distances because of volatiles from the core that have refrozen in the outer layers.  相似文献   

Review of resource analysis and related studies: Working group,Mathematical Geology,freie Universität Berlin     

M. Shulman  H. Burger  C. Kliem  W. Skala 《Natural Resources Research》1992,1(1):97-106

The working group Mathematical Geology of the Freie Universität Berlin was formed in 1971. We review quantitative methods used by the working group since 1983 to treat mineral exploration problems. The methods applied vary from elementary statistical analysis of multivariate exploration data to optimal strategies for selecting favorable targets, and from multiobjective decision-making for additional drill hole locations to expert systems in exploration.The methods applied are directly related to the level of information at each stage of the exploration process. Special emphasis was placed on the relationship between and evaluation of subjective and objective data. Case studies illustrating the various methods are presented for different kinds of mineral deposits and exploration environments.  相似文献   

思林水电站通航建筑物高边坡稳定分析和评价     

徐力群  沈振中  俞凯加  吕军 《岩土力学》2008,29(Z1):42-46

应用ANSYS结构分析软件,模拟了思林水电站通航建筑物高边坡的地形、地质条件以及开挖的过程,建立边坡开挖的有限元计算分析模型,分析边坡在自然状态、分级开挖以及锚杆支护加固等工况下的应力、变形及其整体稳定性.定义单元的局部安全系数,得到了边坡开挖加固后稳定安全系数的分布.根据计算成果,指出现设计加固措施可以保证边坡稳定,无需增加其他工程措施.  相似文献   

外生铀矿成矿系统研究与古水动力分析     

马亮  王萍 《国外铀金地质》2008,(1):19-23

分析了砂岩型铀矿的国内外研究现状和发展趋势,尝试从成矿系统演化论的角度提出新的研究思路：即,以系统观为指导,以物质迁移的动力学为主线,从区域地质背景演化,特别是构造动力演化、岩相古地理等方面入手,恢复矿前期、成矿期、矿后期的区域古地形格局。运用融入了地下水流动系统理论的古水文地质分析方法,重建区域演化进程中各地质时期的古流场。着重从区域尺度上研究矿质的源-迁移-汇（成矿）-保存的动力学过程。  相似文献