兴安地块南段晚泥盆世包格德岩体时代的厘定及地质意义

中亚造山带东端兴安地块南段的包格德岩体由石英二长岩、二长花岗岩和花岗斑岩3种岩性组成,岩体锆石LA-ICP-MS U-Pb定年结果分别为368±+1 Ma、364±1 Ma、355±1 Ma,为晚泥盆-早石炭世岩浆活动的产物;岩体的(Na2O+K2O)含量为7.62％～8.82％,K2O/Na2O值为0.93～4.21...     

川滇地块的震源力学机制、运动速率和活动方式

用 4 4 2次中强地震的震源机制解分析了川滇次级地块应力场的优势方向。使用 771次 3级左右地震的滑动角λ参数统计确定震源断层的错动方式 ,并用中强地震P波初动解的N轴仰角的统计分布结果得到的震源断层错动或滑动型式去佐证。拟合中强地震的矩张量速率式 ,计算了川滇次级地块各地震构造区的年均滑动速率 ,并进行比较。根据 1980— 2 0 0 1年川青地块、雅江地块和滇中地块边界断裂带跨断层短水准、短基线定期复测结果 ,分析了水平和垂向年均形变速率。川滇地块间的运动是不均匀的。川青地块的运动方向为SEE。雅江地块压应力场优势方向为SSE ,相对川青地块的运动速率更大。滇中地块承袭雅江地块的运动方向 ,略偏东。密支那滇西地块压应力场有 2组优势方向 ,存在向NE方向的推挤和SSE方向的逃逸 ,活动速率大     

Structure,Timing, and Mechanism of the Pliocene and Late Miocene Uplift Process of the Ailao Shan-Diancang Shan,SE Tibet,China

The uplift of the Ailao Shan-Diancang Shan(ASDS) along the Ailao Shan-Red River(ASRR) shear zone is an important geological event in the southeastern margin of Qinghai-Tibet Plateau tectonic domain in the Late Cenozoic,and it preserves important information on the structures,exhumational history and tectonic evolution of the ASRR shear zone.The uplift structural mode and uplift timing of the ASDS is currently an important scientific topic for understanding the ASDS formation and late stage movements and evolution of the ASRR shear zone.The formation of the ASDS has been widely considered to be the consequence of the strike-slip movements of the ASRR shear zone.However,the shaping of geomorphic units is generally direct results of the latest tectonic activities.In this study,we investigated the timing and uplift structural mechanism of the ASDS and provided the following lines of supportive evidence.Firstly,the primary tectonic foliation of the ASDS shows significant characteristic variations,with steeply dipping tectonic foliation developed on the east side of the ASDS and the relatively horizontal foliation on the west side.Secondly,from northeast to southwest direction,the deformation and metamorphism gradually weakened and this zone can be further divided into three different metamorphic degree belts.Thirdly,the contact relationship between the ASDS and the Chuxiong basin-Erhai lake is a normal fault contact which can be found on the east side of the ASDS.40Ar/39 Argeochronology suggests that the Diancang Shan had experienced a fast cooling event during 3–4 Ma.The apatite fission track testing method gives the age of 6.6–10.7 Ma in the Diancang Shan and 4.6–8.4 Ma in the Ailao Shan,respectively.Therefore the uplift of the ASDS can be explained by tilted block mode in which the east side was uplifted much higher than the west side,and it is not main reason of the shearing movements of the ASRR shear zone.The most recent uplift stages of the ASDS happened in the Pliocene(3–4 Ma) and Late Miocene(6–10 Ma).     

川西裂缝性致密碎屑岩气藏高渗区成因机理及预测

川西深层上三叠统须家河组二段致密碎屑岩气藏非均质性极强,裂缝网络与相对优质储层叠加形成的高渗区分布预测是钻井获得高产稳产的技术关键。通过地表露头调查、钻井资料统计分析及地震地质综合研究,剖析了高渗区地质成因机理,认为在砂岩及岩性相变带、相对薄层及地层厚度突变带、优质储层发育区、强构造褶皱变形区、断裂附近等易于形成裂缝及高渗区。通过高渗区储层测井及波阻抗特征、地震响应特征对比分析、模型正演等方法,建立了“杂乱弱反射”地震暗点识别模式,利用吸收处理、像素成像、三维可视化等地震技术手段,预测了高渗区分布,解释了各高渗区地质成因,钻井验证了预测结果。     

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基于证据权法的伊尔岗地块金矿成矿预测

在分析澳大利亚伊尔岗地块金矿床成矿特征的基础上,建立了区域金矿找矿模型,提取各类找矿信息,在GIS中构成了与成矿有关的容矿岩石、构造、岩浆岩、物探、化探异常等6个证据图层。用证据权法统计综合证据图层生成研究区成矿后验概率图。按照后验概率的相对大小划分出3级成矿远景区,共圈定3个I级成矿远景区,为澳大利亚的金矿预测提供了有效方法。     

黑龙江省佳木斯地块北缘金矿资源潜力超低密度的地球化学预测

在黑龙江省森林沼泽景观区大面积开展超低密度地球化学调查尚属首次,针对森林沼泽景观区有机质及硅胶含量高的特点,此次工作采样介质采用泛滥平原沉积物表层--A层土,采样密度为1样／100km²,溶矿剂采用四酸(HCl+HNO₃+HF+HClO₄)溶矿法。四酸溶矿法可咀将有机质及硅皎所吸附、包裹的金属释放出来,从而能够有效地发现异常。在较短的时间内快速掌握了全区70000km²范围内的Au、As、Sb、Hg、Ag、Pb、Zn、Bi、Cu、Co、Cr、Ni、U、Mo、W等15种元素的含量分布特征,并研究了该区超低密度地球化学异常特征．所圈定的地球化学块体及区域异常与已知的成矿区(带)吻合较好,同时又发现了几处新的地球化学块体和区域异常。运用超低密度地球化学调查方法,对佳木斯地块北缘乌拉嘎金地球化学块体的金矿资源潜力进行了预测。     

阿中地块北缘库木达坂岩体群特征及锆石U-Pb测年

分布于阿中地块北缘中浅变质岩隆起带之上的库木达坂岩体(群),为一规模较大的复式岩体,不同岩石类型之间接触关系清楚,由早到晚其侵位顺序为细粒黑云二长花岗岩→中粒含斑黑云二长花岗岩。岩石地球化学资料研究证明,该岩体群与大陆岛弧型花岗岩(CAG)相似,显示壳源花岗岩特点,岩体群中获得(449.7±5.8)Ma的单颗粒锆石U-Pb年龄值,确定该岩体群侵位时代为晚奥陶世,岩体形成可能与红柳构—拉配泉早古生代洋壳向南俯冲相关。     

Modelling the effects of motion on primary production in the mixed layer of lakes

A model of the time dependent relationship between productivity and light intensity following changes in light intensity is briefly described. The model incorporates two response timescales simulating initial response and photoinhibition, although additional timescales could easily be incorporated. The model is calibrated against one set of time dependent data, and applied to two simple models of motion in the upper mixed layer of a lake. The two models are: organised motion simulating Langmuir cells, and disorganised motion simulating the turbulent velocity field associated with surface wind stirring. The depth and therefore light histories for a number of photosynthesising particles are calculated by these models, and used by the productivity model to calculate mean productivities. The results show that the influence of the time dependent nature of the productivity relationship depends on the ratio of the mixed layer depth to the euphotic depth, and to a less extent, on the rate at which the particles circulate in the mixed layer.     

岩体边坡楔形体动力学分析

本文对岩质边坡中楔形块体作了动力分析,推导了一组相应的动力平衡公式,并编制了计算程序。算例计算表明,这是评价楔形体滑动位移的一种可行的方法。