漠河盆地西部二十二站组碎屑锆石U-Pb年龄、地球化学特征及其物源意义

大兴安岭北部漠河盆地内广泛发育二十二站组,其形成时代及物质来源一直以来备受争议.本文在野外地质调查及岩相学的基础上,利用碎屑锆石LA-ICP-MS U-Pb法测年,并结合岩石地球化学等方法,探讨了二十二站组形成时代、物源区大地构造环境及沉积物来源.测年结果显示132个测点年龄主要分布在4个群落,分别为508.3～492.3 Ma;486.9～435.5 Ma;278.3～254.2 Ma;209.5～178.1 Ma.本次获得二十二站组最小碎屑锆石年龄为178.1 Ma,并结合漠河盆地东西部碎屑锆石的年龄,综合认为二十二站组形成时代应为中晚侏罗世.地球化学分析结果显示,二十二站组砂岩的稀土元素与活动大陆边缘的稀土元素曲线吻合较好,且相对亏损高场强元素(Nb和Ta)和大离子亲石元素(Ba和Sr),相对富集高场强元素(La、Th、Zr、Hf),地球化学特征与活动大陆边缘相似.综合古流向、源区母岩分析、碎屑锆石测年分析、微量元素特征等诸多因素,本次研究认为本区二十二站组砂岩的母岩主要来源于盆地南缘广泛分布的前中生代沉积-变质基底(兴华渡口岩群、佳疙瘩组、额尔古纳河组等)及各期中酸性火成岩.     

煤炭地质勘查产业转型发展的思考与探讨

煤炭地质勘查工作关系国家能源安全,在国民经济发展中具有重要的战略地位。伴随煤炭行业绿色转型和新能源革命新形势,及时调整产业结构,向大地质、大资源、大生态方向拓展服务领域,为国家生态文明建设和煤炭产业绿色安全高效发展提供坚实的地质技术保障,成为煤炭地质勘查产业转型发展必然趋势和未来发展方向。结合煤田地质勘查工作发展历程及现状、发展趋势,对煤炭地质勘查产业转型发展方向进行深入剖析和探讨。     

Numerical analysis of the effect of natural microcracks on the supercritical CO2 fracturing crack network of shale rock based on bonded particle models

The problem of predicting the geometric structure of induced fractures is highly complex and significant in the fracturing stimulation of rock reservoirs. In the traditional continuous fracturing models, the mechanical properties of reservoir rock are input as macroscopic quantities. These models neglect the microcracks and discontinuous characteristics of rock, which are important factors influencing the geometric structure of the induced fractures. In this paper, we simulate supercritical CO₂ fracturing based on the bonded particle model to investigate the effect of original natural microcracks on the induced‐fracture network distribution. The microcracks are simulated explicitly as broken bonds that form and coalesce into macroscopic fractures in the supercritical CO₂ fracturing process. A calculation method for the distribution uniformity index (DUI) is proposed. The influence of the total number and DUI of initial microcracks on the mechanical properties of the rock sample is studied. The DUI of the induced fractures of supercritical CO₂ fracturing and hydraulic fracturing for different DUIs of initial microcracks are compared, holding other conditions constant. The sensitivity of the DUI of the induced fractures to that of initial natural microcracks under different horizontal stress ratios is also probed. The numerical results indicate that the distribution of induced fractures of supercritical CO₂ fracturing is more uniform than that of common hydraulic fracturing when the horizontal stress ratio is small.     

辉钼矿铼－锇同位素年代学研究简介

辉钼矿铼－锇同位素年代学测定依据该矿物中含有由１８７Ｒｅ通过β－衰变而形成的放射性成因１８７Ｏｓ。这一同位素年代学方法由于８０年代以来微量铼、锇同位素质谱技术的成熟而逐渐应用于研究中，获得了具有地质意义的年龄值。对辉钼矿年龄测定的成功与否，选择适当的样品至关重要。一般而言，红外透光性（ｉｎｆｒａｒｅｄｔｒａｎｓｐａｒｅｎｃｙ）大于３．５的辉钼矿样品适合于铼－锇同位素年代学研究，其辉钼矿的铼－锇同位素年龄值十分接近于围岩的钾－氩或其它常规同位素方法的年龄值。     

铼－锇同位素体系在基性—超基性岩中应用现状的综述

综述了该同位素体系晚侏罗世以来，尤其是现代地幔岩石的研究成表明，地幔在晚侏罗世以来在１８７Ｏｓ／１８６Ｏｓ比值方面显示出非均一性，其比值从０．９０～１．２６，但此类岩石的１８７Ｏｓ／１８６Ｏｓ比值分别与各个不同研究者所确定的地幔演化线相一致；来自较古老正常地幔或贫化地幔的岩石，在锇同位素方面体现为１８７Ｏｓ／１８６Ｏｓ初始比值接近或低于Ｒｅ－Ｏｓ同位素体系地幔演化线值。在此类岩石中，Ｒｅ－Ｏｓ同位素体系与Ｓｍ－Ｎｄ同位素体系之间存在着三种可能的关系：①正相关关系；②负相关关系；③无相关关系。据认为，第一种关系是由羽状地幔端元和富集亲石元素而且贫铼之次大陆型岩石圈地幔端元混合而成；第二种关系则是由羽状地幔端元与地壳物质混合而成；第三种关系则是锇同位素成分相同但钕同位素成分明显不同的两端元物质混合而成。在第三方面，有古老俯冲大洋壳物质参与之基性－超基性岩石具有高于地幔演化线的初始１８７Ｏｓ／１８６Ｏｓ比值。具有此种锇同位素成分特征的岩石包括大洋岛弧玄武岩（ＯＩＢ）、洋中脊玄武岩（ＭＯＲＢ）以及榴辉岩。①     

校正大地电磁测深中静态效应的首枝重合法

着重论述如何用首枝重合法校正静态效应。提出用等权正交多项式拟合视电阻率曲线真实位置；指出了选择参考频率的原则；以及如何自动识别是否有静态效应的影响，产生了何种形式的静位移。分析静校正处理后的资料可知，静态效应影响几乎无所不在，但在盆地沉积中心有可能无静位移情形；静位移的形式是多样的，但主体形式是ρ＿（ＴＥ）曲线向上，ρ＿（ＴＭ）曲线向下位移，且ρ＿（ＴＥ）曲线在ρ＿（ＴＭ）曲线之上；ρ＿（ＴＥ）曲线与ρ＿（ＴＭ）曲线基本上一样容易产生静位移。     

单柱离子色谱测定二氧化锰产品中无机阴离子杂质

采用了单柱离子色谱法测ＭｎＯ２产品中无机离子杂质；提出了消除干扰的可行途径，将Ｌａ（ＯＨ）３加入后能同时消除进样峰的干扰和溶剂峰的出现。选用１．７５ｍｍｏｌ／Ｌ邻苯二甲酸１．７５ｍｍｏｌ／Ｌ三羟甲基氨基甲烷为混合淋洗剂测定Ｆ＾－，Ｃｌ＾－，ＮＯ３＾和ＳＯ＾２－４，其标准加入回收率为９５％－１０５％；ＲＳＤ（ｎ＝７）为２．４７％－８．０８％。     

对Nakai拟合法的改进及实际应用

本文对Nakai拟合法作了改进并应用于计算井水固体潮和气压系数。利用该方法还可以计算井水位对固体潮和气压响应的滞后时间。以鲁06井为例,用本文的方法计算出其井水位的固体潮和气压系数分别为16.9mm/10~(-3)和5.58mm/hPa,滞后时间分别为18.8和22.4分钟。校正后的中误差由8.5mm下降到6.1mm。     

Evaluation of factors influencing the inelastic seismic performance of torsionally asymmetric buildings

This paper addresses some fundamentally contradictory conclusions drawn by Tso and Ying¹ and the authors² regarding the additional seismic ductility demand in asymmetric building structures and the adequacy of certain code torsional provisions. It also clarifies a number of issues arising from the different approaches employed in the two studies. The Mexico 76 and 87 code torsional provisions are taken as examples. Results show that the structural element at the stiff edge is the more critical and that the Mexico 76 code torsional provisions (among others) are inadequate, substantially underestimating the strength demand of this element. On the other hand, the Mexico 87 code torsional provisions are found to be over-conservative. Recommendations are also given for improving the form and effectiveness of these code torsional provisions.