Diagenetic Sequences Analysis of Fuyu Reservoir in Qijia-Gulong Depression,Northern Songliao Basin

Five paragenetic associations are recognized in Fuyu reservoir of Qijia - gulong depression of Daqing oil field: 1) detrital illite permeation, glauconite and pyrite precipitation; 2) feldspar dissolution, kaolinite precipitation and the incipient quartz overgrowths; 3) early calcite cements; 4) postdate quartz overgrowths and pore - filling quartz, authigenetic illite and chlorite formation, feldspar overgrowths, petroleum injections, K - feldspar and calcite cement dissolution; 5) pore - filling calcite and calcite replacement.     

综合旱涝季度预报方法及对1991~ 1995年夏季季度与超季度预测试验

本文简要地介绍我们在对旱涝规律与成因研究的基础上所提出的综合旱涝预报方法及其改进,方法是由一个ＩＡＰ二层大气环流数值模式加滤波方案、物理相关分析、环流型、时间序列与回归分析等的综合。经过多年的预报实践,证明它是提高旱涝季度与超季度预报准确率的一种可行方法。利用改进的综合旱涝季度预报方法对１９９１～１９９５年夏季汛期全国旱涝分布进行了预报试验,这５年预报试验结果与实况基本相符,并且对于像１９９１年和１９９４年夏季大范围的严重旱涝基本上没有漏报,表明此方法对于中国汛期旱涝分布有较高的预报能力,受到有关部门的重视     

Model test and stress distribution law of unsymmetrical loading tunnel in bedding rock mass

The exit section of Duck River Tunnel owns characteristics of bedding geology and unsymmetrical loading terrain. A centrifugal model test concerning the destruction process of Duck River Tunnel is conducted. Test results are concluded as follows: The surrounding rock at the bottom of the right sidewall is the first to be destroyed; the fracture planes in surrounding rock on both left and right side lead to the ground surface; the rupture angles are different from homogenous rock mass. Results of numerical model are consistent with the test results. For doing some comparative study, numerical models of homogeneous and bedding rock mass are respectively established. Conclusions are summarized from numerical analysis as follows: The stress distribution law of bedding surrounding rock is basically similar with that of homogeneous surrounding rock, while the stress value of bedding surrounding rock is larger than that of homogeneous rock. Meanwhile, the surrounding rock stress of the structural plane increases or decreases by leaps and bounds, and the stress intensity at the bottom of right sidewall is the highest as well as the surrounding rock, there is also the most easily destructible, which is the same as the test result. The research results have significant reference value to similar projects.     

Exploring variations in upper ocean structure for the last 2 Ma of the Nansha area by means of calcareous nannofossils

A great number of calcareous nannofossils have been found in the deep-sea sediments of 2.32 Ma at ODP Site 1143 located in the Nansha area, the southern South China Sea. The number of coccoliths varies from about 0.5×10⁶ up to almost 53×10⁶ coccoliths/g sediment, with an average of 16×10⁶ coccoliths/g sediment. The accumulation rate of total coccoliths varies from 1×10⁶ to 278×10⁶ coccoliths/cm² ka. The nannofossil assemblages are usually dominated by a lower-photic species-Florisphaera profunda, of which the average percentage is about 70% in all samples. The absolute abundance and the accumulation rate of nannofossils as well as the percentage ofF. profunda display significant oscillations on two different time scales. One is the fluctuation coincident with the glacial-interglacial cycle, and the other is the long-term changes on a time scale longer than 100 ka. Six evolutionary stages of calcareous nannofossils could be divided for the last 2.32 Ma, from which we can reconstruct the changes in the depth of nutricline of the Nansha area. In this paper, the possible mechanism resulting in these variations is also discussed.     

Forcing mechanism of the Pleistocene east Asian monsoon variations in a phase perspective

The variations of the Earth’s geometry (ETP) pre-dominate climate changes such as monsoon on the Earth[1], serving as its external forcing. The loess/ paleosol sequence in Central China provides a good record of terrestrial deposition to study the evolution of the east Asian monsoon[2―4]. However, the deep sea deposition, due to its high resolution dating and abun-dant climate proxies, should be able to provide more climatic information in the geological time, such as the forcing mechanis…     

基于层次包围盒的纹理体绘制加速算法

提出了一种层次包围盒(BVH)方法,以加速基于GPU的3D纹理体绘制。该方法首先利用GPU的片元着色程序实现了后分类3D纹理体绘制;然后设定高度逐层对体数据进行分解,为每个生成的子体数据建立相应的包围盒,并用对应层次包围盒树的结点保存相关信息;最后遍历层次包围盒树,读取层次包围盒树的结点信息以判断对应子体数据是否被绘制或跳过,从而实现空间跳跃,加速3D纹理体绘制。实验结果表明,本文方法与基于GPU的3D纹理体绘制算法相结合,能取得良好的加速效果。     

水进砂研究进展

水进砂在水进过程中被侵蚀、淘洗、搬运,其沉积特征明显有别于背景砂体,表现出明显的穿时性。水进砂的发现完善了层序地层学理论,同时它在油气储存运移、原油物性预测以及油气勘探开发方面也有重要价值。本文从砂体的性质、来源、所处背景砂体的环境以及发育的构造条件4个方面对水进砂进行了分类,并总结了具代表性的形成机制：地层响应模型、水进型三角洲模型、海侵—海退模型、水动力模型、下切谷模型和潮汐改造的沙脊模型。近年来,相关学者在传统沉积学的基础上,又运用水动力学、遗迹学和不整合面识别等比较独特的方法对水进砂进行了研究。未来水进砂的研究工作将不再局限于海相砂体中,同时将运用更精细的方法对水进砂进行更深入的研究。     

上地幔不相容元素的显交代作用

通过矿物微区成分和图象分析，研究了在金伯利岩中发现的多种氧化物矿物的成分、结构特点及其相互关系．指出富含硅酸盐不相容元素的地幔流体交代、熔融先期形成的矿物以及充填作用，形成了近年来我国和南非金伯利岩中发现的多种新矿物相，包括沂蒙矿系列、蒙山矿系列、Ｋ－Ｃｒ柱红石、阿玛科矿、Ｚｒ－Ｔｉ氧化物（锆钛矿）、ＲＥＥ－Ｔｉ氧化物（铈钛矿）等．这些新矿物高度富集了Ｋ，Ｂａ，Ｃａ，Ｓｒ，Ｔｉ，Ｚｒ，ＲＥＥ等不相容元素．研究表明不相容元素的显交代作用可分早、中、晚３个阶段，各阶段不相容元素的富集程度、温压条件及流体的动力学特征等既有明显的差异性，又有一定的继承性     

基于弹性系数法的径流对气候变化与人类活动响应研究

基于永定河流域内1957~2010年降雨、蒸发和径流数据,采用Mann-Kendall趋势检验法结合距平序列变化情况分析蒸发能力、降雨和径流的变化趋势;运用Mann-Kendall突变检验法、Hurst系数法分析流域径流序列的突变年及对应的突变程度;在此基础上以径流突变年为界划分基准期和变化期,采用弹性系数法定量分析气候变化和人类活动对径流的影响,并简要分析其原因。结果表明:流域蒸发能力呈现上升趋势,降雨和径流呈现递减趋势;径流序列突变点发生在1984年,突变程度属中度变异;永定河流域由气候变化引起的径流变化率为28%,而由于人类活动引起的径流变化率为72%,可见人类活动是影响永定河流域径流变化的主要驱动因素。     

Mathematical Model of the Geothermal Water Resources in the South Hot Spring System in Chongqing

INTRODUCTION Southhotspring,smallhotspringandQiaokou barepresent,betweenthem,thegeothermalwaters ofthesouthhotspringsysteminthesouthhotspring anticlineinChongqing.Thesouthhotspringanti clineisageothermalwaterstoragesystem.Itex tendsfromnorthtosouthinthecentralpartof Chongqing.Itis45kmlongfromsouthtonorthand2kmwide.Thesouthhotspringandsmallhot spring,inthemiddleoftheanticline,arewell known touristattractionsfortheirgeothermalwaters.Ex cessiveexploitationledtoagradualdeclineinthewa terlev…