内蒙古阿拉善呼口塞勒铜矿床Ⅱ号矿体原生叠加晕特征

研究了内蒙古阿拉善呼口塞勒铜矿床Ⅱ号矿体100线剖面原生叠加晕特征,结果表明,100线剖面+1 308~1 141m标高的轴向分带序列(由上到下)为W-Ni-As-Pb-Mo-Cu-Co-Au-Zn,有明显的相互叠置特征,地球化学参数在中段逐渐减小,可以确定矿体是多个成矿阶段叠加形成的。2个主成矿阶段形成的矿体部分叠加,矿体上部经过较强的剥蚀,但还有一定的延深。此次原生叠加晕的研究为下一步钻探施工提供了依据,明确了在该区继续进行原生晕研究的方向。     

Environmental dependence of dark matter halo growth – I. Halo merger rates

In an earlier paper, we quantified the mean merger rate of dark matter haloes as a function of redshift z , descendant halo mass M ₀, and progenitor halo mass ratio ξ using the Millennium simulation of the Λ cold dark matter cosmology. Here, we broaden that study and investigate the dependence of the merger rate of haloes on their surrounding environment. A number of local mass overdensity variables, both including and excluding the halo mass itself, are tested as measures of a halo's environment. The simple functional dependence on   z , M ₀  , and ξ of the merger rate found in our earlier work, is largely preserved in different environments, but we find that the overall amplitude of the merger rate has a strong positive correlation with the environmental densities. For galaxy-mass haloes, we find mergers to occur ∼2.5 times more frequently in the densest regions than in voids at both   z = 0  and higher redshifts. Higher mass haloes show similar trends. We present a fitting form for this environmental dependence that is a function of both mass and local density and valid out to   z = 2  . The amplitude of the progenitor (or conditional) mass function shows a similar correlation with local overdensity, suggesting that the extended Press–Schechter model for halo growth needs to be modified to incorporate environmental effects.     

The environment of formation as a second parameter for globular cluster classification

We perform an evolutionary multivariate analysis of a sample of 54 Galactic globular clusters with high-quality colour–magnitude diagrams and well-determined ages. The four parameters adopted for the analysis are: metallicity, age, maximum temperature on the horizontal branch and absolute V magnitude. Our cladistic analysis breaks the sample into three novel groups. An a posteriori kinematical analysis puts groups 1 and 2 in the halo, and group 3 in the thick disc. The halo and disc clusters separately follow a luminosity–metallicity relation of much weaker slope than galaxies. This property is used to propose a new criterion for distinguishing halo and disc clusters. A comparison of the distinct properties of the two halo groups with those of Galactic halo field stars indicates that the clusters of group 1 originated in the inner halo, while those of group 2 formed in the outer halo of the Galaxy. The inner halo clusters were presumably initially the most massive one, which allowed the formation of more strongly helium-enriched second generation stars, thus explaining the presence of Cepheids and of very hot horizontal-branch stars exclusively in this group. We thus conclude that the 'second parameter' is linked to the environment in which globular clusters form, the inner halo favouring the formation of the most massive clusters which subsequently become more strongly self-enriched than their counterparts of the galactic outer halo and disc.     

内蒙古包头市柳坝沟金矿区地球化学特征及深部预测

[摘要]柳坝沟金矿区位于华北地台北缘西段,产于太古代乌拉山群变质岩系中,矿床主要矿石 类型为钾长石-石英脉,钾长石化是最发育的近矿围岩蚀变,与金矿成矿作用关系密切。利用对钻孔地 球化学元素的分析研究,313 号脉具有多期多阶段叠加成矿成晕的特点,根据不同成矿阶段元素组合和 单阶段形成原生晕的垂直分带规律及不同成矿阶段形成矿体(晕) 在空间上的叠加特点,建立了矿床的 原生晕叠加晕模式,对主要矿脉进行了深部预测,最后利用钻探工作验证,取得了较好的地质效果,为该 区深部探矿起到指导作用。     

构造原生晕法在地质找矿上的应用

在桦甸市三道沟金矿床300m中段两个受构造控制的、原岩为花岗闪长岩的蚀变带上取原生晕,经过与未蚀变的花岗闪长岩、金矿石及辉绿岩之间微量元素的对比分析,判断出该蚀变带为矿化蚀变带,进而在其延长方向上找到了矿体;在白山市石人金矿床控矿构造北东延长方向上,沿断裂构造走向采取原生晕,在Au、Hg元素较高的样品地段,揭露到了矿体。在尚没有完全掌握矿床原生晕分带性的勘查初期阶段,利用构造原生晕找矿是一种简捷经济的方法,但需要结合其它控矿条件,综合考虑其成晕原因,以达到最佳找矿效果。     

油气化探多元信息提取及含油气性灰色识别

以新疆塔北雅克拉测区为例,利用地表化探组合指标和因子得分为特征信息,由已知油气圈闭的特征指标构成灰色子波模型,对研究区的相应特征标志（比较数列）按一定的网度进行灰色滑动关联滤波分析,从中提取与灰色子波相关联的综合关联度异常,然后依据异常所处的地质背景,特征和幅值进行预测的区的含油气性识别评价,使复杂多样的化探异常转化为与油气直接相关的顶部信息,提高了油气晕圈闭评价的精度和识别的准确度。     

Extended source effects in astrometric gravitational microlensing

Extended source size effects have been detected in photometric monitoring of gravitational microlensing events. We study similar effects in the centroid motion of an extended source lensed by a point mass. We show that the centroid motion of a source with uniform surface brightness can be obtained analytically. For a source with a circularly symmetric limb-darkening profile, the centroid motion can be expressed as a one-dimensional integral, which can be evaluated numerically. We find that when the impact parameter is comparable to the source radius, the centroid motion is significantly modified by the finite source size. In particular, when the impact parameter is smaller than the source radius, the trajectories become clover-leaf like. Such astrometric motions can be detected using space interferometers such as the Space Interferometry Mission . Such measurements offer exciting possibilities for determining stellar parameters, such as stellar radius, to excellent accuracy.     

小南山铜镍矿区及外围地质地球物理特征及其找矿方法试验研究

小南山铜镍矿区的地面磁法（△Ｔ）、可控源音频大地电磁法（ＣＳＡＭＴ）、瞬变电磁法（ＴＥＭ）、激发极化法（ＩＰ）和原生晕方法的试验研究，表明航磁及地面磁法对基性、超基性岩体的中弱磁性有较好的反映，能圈定其形态、产状；ＣＳＡＭＴ法对基性、超基性岩体的低阻和矿化体及矿体的特低阻能进行电性分层，同时也能反映断裂构造带、蚀变矿化带的异常特征；ＴＥＭ法对硫化物铜镍矿化体有敏感的导电反映；ＩＰ法能有效地圈定矿化蚀变带或矿化体形态；Ｃｕ、Ｎｉ、Ｃｏ、Ａｓ、Ａｇ元素原生晕异常有直接指示找矿的良好效果。该区应用这些方法相互配合，综合找矿是行之有效的找矿手段。     

油气化探中△C与烃类异常的相互配置关系

通过对△Ｃ（即后生碳酸盐）成因机理的分析，结合典型实例，对△Ｃ异常与烃类异常的相互配置关系及其与地下深处油气藏联系的研究，大量事实证明，△Ｃ异常并不总是与烃类异常一致的，只有当△Ｃ异常与烃类异常较一致时，△Ｃ异常才具有找油气藏的意义。     

汞在460、534地区的分布特征及其找铀矿的意义

本文在介绍一种新的土壤汞量测量找矿方法的同时,着重用大量的实测数据阐明汞在460铀矿床上的分布特征。汞在该矿床上部“黑矿”中的平均含量高达11430ppb,最高达193800ppb,而一般岩石中的汞含量只有数十至数百个ppb。通过对铀矿石及其主岩中的汞的热释谱分析,发现释汞主峰温度在350℃以上的中温、高温相态汞与铀矿化关系密切。铀矿床上部土壤汞晕规模大(550×350m~2),平均含量可达563ppb,最高达6080ppb,平均衬度16,最高达174。汞含量随着采样深度的加深而升高。在矿床外围测出了相似的汞晕,并进行了成矿预测。上述成果已用于生产。