Relationship between Mesozoic Magmatism and Subduction in the Da Hinggan-Yanshan Area

High-resolution tomographic images of the belt crossing the Japan Trench-Changbai Mountains-Dong Ujimqin Qi are represented in this paper, revealing the shape of a subducted slab in the western Pacific region and characteristics of the lithospheric structures under the Changbai Mountains and the Da Hinggan Mountains. Studies of the spatial distribution, subduction time and the time-lag between the subduction and magmatism, combined with petrology and isotope geochemistry of the Late Mesozoic volcano-plutonic rocks from the Da Hinggan Mountains-Yanshan Mountains have further proved the independence of magmatic activities from the subduction of the Pacific plate. The Mesozoic tectono-thermal evolutionary history and structural characteristics of the lithosphere in the Da Hinggan Mountains and North China suggest that the formation and evolution of magma have probably a close relationship with the delamination and thinning of the continental lithosphere and the underplating resulting from the consequent up     

Numerical Modelling of Ore-forming Dynamics of Fractal Dispersive Fluid Systems

Based on an analysis of the fractal structures and mass transport mechanism of typical shear-fluid-ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic study of the ore formation system. The model of point-source diffusive illuviation of the shear-fluid-ore formation system was constructed, and the numerical simulation of dynamics of the ore formation system was finished. The result shows that: (1) The metallogenic system have nested fractal structure. Different fractal dimension values in different systems show unbalance and inhomogeneity of ore-forming processes in the geohistory. It is an important parameter to symbolize the process of remobilization and accumulation of ore-forming materials. Also it can indicate the dynamics of the metallogenic system quantitatively to some extent. (2) In essence, the fractal dispersive ore-forming dynamics is a combination of multi-processes dominated by fluid dynamics and supplemented by molecule dispersion in fluids and     

峡东地区震旦系层型剖面的界定与层序划分

通过震旦系研究历史的回顾,在前人研究的基础上,结合近年来综合地层研究的成果,试图建立可供全球对比的中国末元古系层型剖面。我国震旦系研究历史悠久,典型剖面经历南北之争,数十年来存在多种界定意见。通过近十年的研究,笔者依然认为峡东地区震旦系剖面沉积最为连续,出露完整,具有生物演化特征明显和形态多样的特点,可与世界各地的末元古纪地层进行广泛对比。目前,其上界定位于峡东地区灯影组天柱山段小壳化石带之下(即相当云南晋宁梅树村剖面震旦—寒武系界线小壳化石带B点,年龄为539±34Ma),而底界的厘定在国内一直存在多种意见。本文通过对峡东地区震旦系剖面的综合地层研究,结合生物地层学、年代地层学、层序地层学、C/O同位素研究以及沉积相等方面的综合分析,认为震旦系底界应划定在南沱冰期之后的陡山沱期沉积的下界,重申应选定峡东地区剖面为震旦系的层型剖面。     

润扬长江公路大桥三维地质分析

该文从三维地质建模的概念出发,探讨了其一般过程,包括地质变量预测、地质特征解译、空间分析等,并介绍了三维地质建模的体视化方法,最后以润扬长江公路大桥工程为例,运用切片级重建方法,建立地质模型,并进行了三维地质分析.实践表明,三维地质建模技术是认识复杂地质体的空间关系和特征的强有力的工具,具有广阔的应用前景.     

Devonian Frasnian-Famennian Transitional Milankovitch Cycles and High-Resolution Stratigraphic Correlation

Four hierarchical cyclothems, superbundlesets, bundlesets, bundles and laminae, have been identified from the Devonian Frasnian-Famennian carbonate strata in Guangxi, South China. Their hierarchical structures, ratio relationships and sequence in conodont zones are continuous and stable and can be traced across different facies zones and sedimentary basins. Our data show that hierarchically organized superbundlesets, bundlesets, bundles and laminae correspond to the long eccentricity, eccentricity, obliquity or precession and sub-Milankovitch cycles respectively. Their periods were 400,000, 100,000, 33,333, 16,667 and 8,000-17,000 a, respectively. The ratios of long eccentricity to eccentricity, eccentricity to obliquity, and eccentricity to precession in the Devonian are 1:4, 1:3 and 1:6 respectively. Using these hierarchical Milankovitch cyclothems, chronostratigraphical division and correlation can be realized at a resolution of 100 ka or 10 ka at the Frasnian-Famennian transition. The time intervals     

大别超高压榴辉岩高温高压下电导率实验研究

为研究大陆中下地壳高导层成因及与物质组成之间的关系，用模拟实验的方法在不同的温度、压力条件下分别测定了干的和1mol/LNaCl溶液饱和的榴辉岩的电导率.结果表明，干榴辉岩平行线理方向的电导率比垂直于线理方向的高，但两个方向上的活化能相近.在中下地壳条件下，干榴辉岩的电导率比中下地壳高导层电导率值低几个数量级.常温下1mol/LNaCl溶液饱和的榴辉岩两个方向上的电导率对压力具有不同的依赖性；在中下地壳条件下，1mol/LNaCl溶液饱和的榴辉岩的电导率可达到一般高导层的电导率值.无论干的还是饱和的榴辉岩都不能解释大别山20-50km深处的高导层成因，因此，在该深度范围内榴辉岩不可能是主要的岩石组成.     

海河流域平原浅层地下水消耗与可持续利用

通过对海河流域平原区地下水储量消耗过程、空间分布及机理研究,揭示了区内地下水系统与相邻层圈之间水分通量因人为活动影响而发生剧变的规律,并在现状开采与补给条件下警告性预测了地下水资源可持续利用前景.     

华北地台晚古生代海侵模式雏议

本对华北地台的山西太原西山上石炭统太原组的7、8和11号煤层及其顶板灰岩的地球化学特征、煤核和生物化石进行了系统分析，发现煤层形成过程中有海水的影响，煤层上覆石灰岩形成过程中亦有淡水参与，说明煤层及其顶板灰岩在相序上是连续的，其海侵模式并不是突发型海便。而为渐进型海侵。本还应用层序地层学原理论述了海平面变化与聚煤作用的关系。     

塔里木盆地志留系层序地层特征

通过对塔里木盆地西缘露头、盆内钻井、测井和地震资料以及大量室内分析化验资料的层序地层综合分析，可将志留系划分成五个三级层序，志留系沉积层序厚度40--155m。层序界面多为分布范围较广的区域性或局部不整合。层序叠置样式可用具陆棚坡折的I型层序地层样式来描述。每个沉积层序可由完整的低位、海侵和高位体系域组成或由其中的一个、两个体系域组成。体系域边界主要依据滨岸上超点位置、岩性组合及准层序叠置样式变化来确定。低位体系域由向上粒度变细、砂岩厚度向上减薄的准层序组成；海侵体系域表现为向上泥岩厚度加大、砂岩厚度减薄的叠置特点；高位体系域表现为加积--进积沉积特征。志留纪，研究区接受了滨外陆棚及滨岸、海湾潮坪沉积，发育典型的海相沉积构造，表现出明显的旋回特征。     

准噶尔盆地西北缘车排子地区侏罗系物源及古水流分析

通过岩石岩屑组分分析、重矿物组分分析、倾角测井、地层厚度分析等方法，对准噶尔盆地西北缘车排子地区侏罗系进行物源及古水流方向分析。岩屑组分分析指示着大致的物源前进方向，重矿物分析明确了物源泄入的主要通道，倾角测井在单井点处对古流向有相当高的表现精度，但这三种方法均存在数据平面覆盖率较低和分布密度差异大的缺陷，而运用地震层位解释所得的地层等厚度图则可以在较大尺度上的二维平面内推测沉积时期的古地形，进而可以推测古流向，但它仅是一种间接预测方法，存在局部古流向预测精度较低的不足。文中综合各种方法，将直接预测方法的高精度和间接方法的高覆盖能力结合起来，对古流向作出较高精度的预测。在古流向研究的基础上建立了冲积扇－辫状河－河泛平原沉积体系的沉积相模式。该模式认为对于水流能量保持能力差的冲积扇，其古流向应该沿短轴陡坡降方向，即大致为SEE方向，而对于水流能量保持能力较强的辫状河来说，其古流向应该沿长轴缓坡降方向，即为SE甚至SSE方向。该模式的提出对于提高地震相－沉积相的转相精度具有一定的指导意义。