二轴晶临界干涉图的发现及其消光影特征

在偏光显微镜的锥光系统中,垂直二轴品光率体─—圆切面与光轴面交线的切面干涉图此处定义为临界干涉图。结合球面和平面解析法可以证明,这种干涉图消光影一般为双曲线形,但具体形状与晶体2V角及从0°位置（光轴面平行上或下偏光镜振动方向）旋转的角度有关。它与已知其它切面干涉图的最大区别是,当晶体从0°位置旋转45°时,消光影为一条与目镜横丝或纵丝夹45°角的直线,它到视域中心的距离随晶体2V角的减小而加大,因而在特定物镜数值孔径和晶体折射率的情况下,只有较大2V角晶体的这条消光影才会处在视域之内。在观察橄榄石和角闪石晶体临界干涉图时证实了它的上述特性。     

Vertical ground motion analysis for submerged pore-elastic media with random void ratios

Recently, very strong vertical ground motions have been recorded during several earthquakes. The vertical motions are the consequence of compressional stresses which are mainly transmitted by pore fluids. For linear elastic analysis of a submerged soil layer, the permeability has a very minor effect on shear-wave response for which pore fluids are not taken into account. But on compressional-wave response, the permeability dominates the damping effect and is thought as the principal influential factor from pore fluids. In this study, the effect of changing permeability on damping is explored. In practice it is harder to obtain the coefficient of permeability, κ, than to measure the void ratio, e. In order to evaluate the permeability and explore its influence on vertical shaking, the formula relating κ–e for the saturated soil is selected for a 1D submerged pore-elastic model subjected to vertical sine-wave loading. The random, linear, linear-plus-random, logarithmic, and log-plus-random depth functions of void ratio are taken into account in this study. The intrinsic error due to the use of the arithmetic mean of permeability for a certain area with a heterogeneous distribution of permeability has also been assessed. Numerical simulations show that the five depth distributions of void ratio all result in the extra viscous forces. The damping effect on vertical shaking is mainly controlled by the harmonic mean of permeability and spatial distribution of permeability rather than the arithmetic mean of permeability. The harmonic mean is more appropriate than the arithmetic mean to be the representative permeability, because the damping coefficient is inversely proportional to permeability.     

苏、皖石炭系石灰岩的胶结作用

分析了苏、皖石炭系石灰岩的胶结作用。查明了胶结物的晶形、碳、氧同位素成分、发光特征及包体均一化温度。指出胶结作用主要发生在大气淡水补给较充分的含水层内,这与本区属海退成岩序列有关。     

黑龙江省砂金指纹（化学成分）特征

对黑龙江省８４个砂金，７个岩金样品的化学成分进行了研究。通过Ｒ型聚类分析、探讨了不同元素之间相关性及其地质意义。通过Ｑ型聚类分析将所有样品进行分类，探讨了砂金样品与已知岩金样品之间的成因联系，并对砂金的可能原生金源的剥蚀程度进行了估计。     

上置晕与物质的“类气相”垂向迁移

阐明了上置晕的术语概念,指出文献中术语运用的失当之处,归纳出以上置晕为基础的各类隐伏矿化探方法。按传统的观念,上置晕主要是由不同形式的水迁移作用造成的。地气法、ＭＦＥ法和离子晕法的出现,揭示出在覆盖层中存在着一种新的元素迁移机制,即元素以非常细小的固相微粒随地气流迁移。一系列实验和实测结果表明,这种固相微粒可能是纳米粒径的物质,它们具有类气相的性状,故可将这种迁移机制称为物质的类气相垂向迁移。这一机制可以说明按传统机制难以解释的现象,对相应化探方法的研制、改善和应用有理论和实践上的指导意义。     

关联指数误差和样本容量

根据关联指数的定义，推导了ＧＰ法计算关联指数时的观测数据误差与关联指数误差的关系，导出了任意两个嵌入空间维上关联指数之差的表达式，并提出了一种确定样本容量限的方法。     

GPS地壳形变监测网应变解算方法与程序设计

分析了在平面直角坐标系和大地坐标系内解算应变的方法及其特点,并以Matlab为开发平台,研制出一套在平面直角坐标系和大地坐标系中解算应变的程序GPSstrain。利用GPS监测网测站位移(速率),该程序能够解算剪切应变(γ1、γ2)、面应变、块体旋转、主应变及其方向、最大剪切应变及其方向,同时也可解算出这些应变分量的误差。另外该程序还具有高斯投影解算功能,根据各测站坐标能够自动形成所有的Delaunay三角形,并以图形方式显示。最后以实际算例给出了该解算程序的部分结果,并进行了初步的分析和讨论。     

北黄海温盐分布季节变化特征分析

利用2006～2007年夏冬春秋4个季节北黄海的大面调查资料,分析了4个季节北黄海温度和盐度大面以及典型断面分布特征,得出以下结论:2007年冷水团势力范围强于2006年,北黄海冷水团的形成受地形影响.黄海暖流冬春季较强,冬季最强,夏季最弱,秋季开始形成.鲁北沿岸流冬季最强,春季减弱,夏秋季消失,但夏季鲁北沿岸存在冬季鲁北沿岸流水的残余体,即鲁北沿岸水.辽南沿岸水4个季节都以低盐为特征,除夏季低盐中心位于庄河口外,其它3个季节低盐中心均位于调查区域的东北角.渤海与北黄海之间的水交换4个季节都存在.春季,断面盐跃层形成滞后于温跃层;秋季,断面盐跃层消失滞后于温跃层.     

贵州西北部基性侵入岩锆石U-Pb年代学、岩石地球化学特征 及其与铅锌成矿关系初探

贵州西北部发育多处基性侵入岩,总体规模较小(约0.25 Km2),多沿深大断裂侵位,出露于铅锌矿点外围,本文对猫猫厂、凉山两处矿点附近的儿马冲和白岩庆两地小型基性侵入岩进行了重点研究。侵入岩主要岩性为细粒辉长岩,造岩矿物主要为拉长石、普通辉石。SiO2范围为49.60-51.09 wt%,MgO从3.88-4.27 wt %,TiO2为3.69-3.85 wt %。LA-ICP-MS锆石U-Pb定年结果为268.3±7.4 Ma,显示岩浆侵位于二叠纪。基性侵入岩的微量元素蛛网图呈OIB型特征,富集大离子亲石元素（LILE）、轻稀土元素（LREE）,亏损重稀土元素（HFEE）,相对亏损高场强元素（Nb,Ta）,有Sr、Y亏损,Pb富集。(87Sr/86Sr)i范围0.706749～0.707069,(143Nd/144Nd)i范围0.512313～0.512363,εNd(t)范围0.2～1.2;源区熔融深度处于石榴石橄榄岩相深度,可能经历了1-3 %的部分熔融,处于亏损石榴石二辉橄榄岩相向原始石榴石二辉橄榄岩相的过渡区。成岩过程中发生了单斜辉石、斜长石等矿物分离结晶,受到了有限的地壳混染作用,未经历明显的AFC过程。地壳物质在地幔源区中的加入可能是造成地幔富集的主要原因。侵入岩与成矿作用之间的关系,主要通过两方面所表现。一方面是二者间构造活动上的耦合性。另一方面是基性岩在成矿过程中可能发挥了重要的化学屏障层作用。     

Carboniferous ridge subduction in the Xingmeng Orogenic Belt: Constraints from geochronological,geochemical, and Sr-Nd-Hf isotopic analysis of strongly peraluminous granites and gabbro-diorites in the Xilinhot micro-continent

The Xingmeng Orogenic Belt evolved through a long-lived orogeny involving multiple episodes of subduction and accretion. However, there is a debate on its tectonic evolution during the Late Paleozoic. Here, we report geochemical, geochronological, and isotopic data from strongly peraluminous granites and gabbro-diorites from the Sunidzuoqi–Xilinhot region. Zircon U–Pb ages suggest that the intrusive rocks were emplaced during the Early Carboniferous (333–322 Ma). The granites exhibit geochemical characteristics similar to S-type granites, with high SiO₂ (72.34–76.53 wt.%), Al₂O₃ (12.45–14.65 wt.%), and A/CNK (1.07–1.16), but depleted Sr, Nb, and Ta contents. They exhibit positive ε_Nd(t) and ε_Hf(t) values (?0.3 to 2.8 and 2.7–5.7, respectively) and young Nd and Hf model ages (T_DM2(Nd)=853–1110 Ma and T_DM2(Hf)=975–1184 Ma), suggesting that they may be the partial melting products of heterogeneous sources with variable proportions of pelite, psammite, and metabasaltic rocks. The meta-gabbro-diorites from the Maihantaolegai pluton have low SiO₂ (47.06–53.49 wt.%) and K₂O (0.04–0.99 wt.%) contents, and demonstrate slight light rare earth element (REE) depletion in the chondrite-normalized REE diagrams. They have high zircon ε_Hf(t) values (14.41–17.34) and young Hf model ages (T_DM2(Hf)= 230–418 Ma), indicating a more depleted mantle source. The variations of the Sm/Yb and La/Sm ratios can thus be used to assess the melting degree of the mantle source from 5% to 20%, suggesting a quite shallow mantle melting zone. We propose that the petrogenesis and distribution of the strongly peraluminous granites and gabbro-diorites, as well as the tectonic architecture of the region, can be explained by a ridge subduction model. Based on these results, and previous studies, we suggest a southward ridge subduction model for the Sunidzuoqi–Xilinhot region.