华北克拉通-扬子克拉通与秦岭造山带古地幔组成及状态的对比

经研究，华北克拉通古地幔以含石榴石的二辉橄榄岩、方辉橄榄岩及纯橄榄岩为主．地幔交代作用强烈，岩石富集不相容元素，明显高于南非及西澳克拉通者．扬子克拉通古地幔主元素亏损程度差，交代作用较弱，岩石为石榴石／尖晶石二辉橄榄岩．秦岭造山带壳、幔交界带的岩石类型复杂，包括蛇纹石化尖晶石二辉橄榄岩（蛇纹岩）、石榴石辉石岩、榴闪岩、变辉长岩及变玄武岩等．蛇纹岩遭受强的塑性流变，剪切变形结构发育．与克拉通相比，地幔交代作用很弱．３个地幔域的古地温状态有差异，秦岭造山带最高，扬子克拉通居中，华北克拉通最低．上述结果表明，两克拉通的古地幔特征相差显著，暗示经历了不同的演化过程．交代作用可能发生在１７００Ｍａ以前和１１００～５００Ｍａ，后者强于前者．造山带地幔的剪切变形明显强于克拉通地幔     

第四纪地质定年与地质年表

时、空、质(物质)、能(动力)是研究地质过程、环境演变的基本要素，其中时间是关键．任何一个自然事件、任何一个地质过程，都与时间相关联，时间的重要性需要通过年龄的精确测量来体现。本文综述了第四纪定年的基本方法和特点以及近年来年代地层学所获得的进展，提出了中国第四纪的划分简表。     

甘肃桦树沟(铁)铜矿床的成因机制

矿床地质地球化学特征研究结果表明，随着古陆边缘弧－槽－盆体系的发生与发展，元古代基底火山（沉积）岩系经深循环水（海水）－热系统的作用，成矿物质被浸出和搬运，并经海底喷溢作用沉淀于海盆洼地中形成桦树沟矿床含铜建造，后期变质作用使成矿物质活化、转移和富集。桦树沟矿床为喷气（流）沉积－变质改造型（铁）铜矿床。     

若尔盖高原及其周围山地的冻土和环境

若尔盖高原内部年平均气温０．６～３．３℃，气温年较差１９．１～２１．２℃，已不具备多年冻土形成和保存的气候条件。据１９９２年７月间试坑和钻孔测温，在１．０～２．２ｍ深处地温为５～８．４℃，浅层地下水温６．０～７．８℃，由此判断不存在多年冻土，季节冻结深度为１．０～２．０ｍ。据冻土现象和试坑资料判断，周围山地海拔４１５０～４２００ｍ以上发育山地岛状多年冻土。区内沼泽演化表明，部分沼泽已疏干或向疏干趋势发展，草场退化和草原沙化已成为本区生态环境的重要问题，并已影响畜牧业发展     

地下工程中圆截面巷道应力的光粘弹性研究

利用光粘弹性实验方法模拟了地下工程中圆截面巷道围岩及冻结壁的蠕变过程，给出了巷道围岩和冻结壁的应力分布规律及随时间的变化规律，为地下工程的设计及预报提供了一种有效的实验手段。     

冀西北东坪金矿床含金石英脉石英流体包裹体Rb-Sr等时线及其地质意义

用石英流体包裹体Ｒｂ－Ｓｒ等时线法测得产于碱性岩体中具有超大型潜力的东坪金矿床含金石英脉的年龄为（１０３±８）Ｍａ，远晚于赋矿岩体的就位时间（元古宙），显示了成岩与成矿是两期不同构造运动的产物，两者之间没有直接的成因联系。８７Ｓｒ／８６Ｓｒ示踪结果显示成矿物质主要来源于赋矿碱性岩体。研究结果认为，东坪金矿是后期与大气降水热液有关的改造成矿作用的产物。     

Early Estimation of Strong Aftershock Duration Time

In order to solve the problem of early estimation of moderately strong aftershock duration time in an earthquake sequence,this study has been conducted.First,the definition of the strong aftershock has been given.It is pointed out that there is a difference in the strong aftershock duration time between the main shock type sequence and the strong earthquake swarm sequence.After dividing the three cases,i.e.,a strong aftershock duration time larger than 1 day,smaller than 1 day,and no strong aftershock occurred in a main shock type sequence by using the pattern recognition method,we gave the rough correlation relation between strong aftershock duration time and first large shock magnitude for two types of sequences.Finally,the judgment index and method of estimating strong aftershock duration times for different sequence types have been given.     

Optimal weighting in the finite difference solution of the convection-dispersion equation

Oscillation and numerical dispersion limit the reliability of numerical solutions of the convection-dispersion equation when finite difference methods are used. To eliminate oscillation and reduce the numerical dispersion, an optimal upstream weighting with finite differences is proposed. The optimal values of upstream weighting coefficients numerically obtained are a function of the mesh Peclet number used. The accuracy of the proposed numerical method is tested against two classical problems for which analytical solutions exist. The comparison of the numerical results obtained with different numerical schemes and those obtained by the analytical solutions demonstrates the possibility of a real gain in precision using the proposed optimal weighting method. This gain in precision is verified by interpreting a tracer experiment performed in a laboratory column.     

Chemical composition of upper crust in eastern China

In an area of 3.3×10⁶ km² within eastern China, 28 253 rock samples were collected systematically and combined into 2718 composite samples which were analyzed by 15 reliable methods using national preliminary certified reference materials (CRMs) for data quality monitoring. The average chemical compositions of the exposed crust, the sedimentary cover and the exposed basement as well as the upper crust for 76 chemical elements in eastern China are given. A key basic geology projcct supported by Ministry of Geology and Mineral Resources of China.