用质子磁力仪测定岩（矿）石标本几个问题

在前人研究的基础上,针对用质子磁力仪进行岩（矿）石标本磁性参数测定和计算过程中遇到的测定位置含糊不清、T0取值单位不正确、标本面的编号混乱以及出现负磁化率等问题,从最初对磁秤法测定磁参数高斯位置的定义和公式推导过程人手,从原理上分析了质子磁力仪与磁秤法测定磁参数的不同之处,对质子磁力仪标本测定时的高斯第一位置和高斯第二位置、标本面的编号、测定顺序、地磁场的取值单位等进行明确说明,同时对视磁化率出现负值的原因进行分析,并提出了相应的改进措施,对今后用质子磁力仪进行岩（矿）石标本磁性参数测定和计算有一定的帮助。     

新疆东昆仑托库孜达板—野狼沟一带地质背景及找矿方向

托库孜达板—野狼沟地区分布于祁曼塔格成矿域西段,是白干湖成矿带的一部分,区内岩性主要为石炭系喀拉米兰河群火山岩,浅成岩及花岗岩广泛分布,又位于在阿尔金断裂带及昆中断裂带的交汇部位,两断裂的次一级在区内特别发育。从以往1/50万化探成果及1/5万遥感解译成果看,矿致异常在区内大面积分布。近年发现的野狼沟铜多金属矿于石炭系次火山岩及北西向断裂构造关系密切。所有地物化遥等特征都预示了该区良好的找矿前景。     

云南金平勐拉峨眉山玄武岩型铜矿矿化规律

赋矿的峨眉山玄武岩系以爆发相角砾状玄武岩为底,沉积相凝灰岩为顶,可明显划分为三大火山喷发旋回和三岩性段,每一喷发旋回分别对应Ⅰ、Ⅱ、Ⅲ铜矿化层,喷发旋回与铜矿(化)体(层)间存在明显的对应关系,工业矿体由后期含矿构造热液叠加再富集而成。     

安徽淮北地区寒武系“崮山阶”—凤山阶新知

根据三叶虫Acanthometopus obesus、Trianguraspis nodus、Petalocephalus laevis、Taishaniasp.等的发现,将淮北地区捻山剖面原属凤山阶的地层划归长山阶,以Acanthometopus带作为该区长山阶最顶部的三叶虫带,淮北地区凤山阶与长山阶的界线应在Ptychaspis-Tsinania带与Acanthometopus带之间;通过与标准剖面及邻近地区的对比,淮北地区的崮山组应予解体,原崮山组上部与炒米店组岩性一致,应划入炒米店组,其下部岩性与张夏组一致,应划入张夏组,淮北地区无崮山组。淮北地区的炒米店组跨越了整个长山阶和凤山阶中下部,据岩性差异可分为上、下两段;炒米店组在华北地区具有明显的穿时性,其底界从长山阶底界跨至凤山阶顶界。     

Asteroid (21) Lutetia as a remnant of Earth’s precursor planetesimals

Isotopic and chemical compositions of meteorites, coupled with dynamical simulations, suggest that the main belt of asteroids between Mars and Jupiter contains objects formed in situ as well as a population of interlopers. These interlopers are predicted to include the building blocks of the terrestrial planets as well as objects that formed beyond Neptune ( [Bottke et al., 2006] , [Levison et al., 2009] and [Walsh et al., 2011] ). Here we report that the main belt asteroid (21) Lutetia – encountered by the Rosetta spacecraft in July 2010 – has spectral (from 0.3 to 25 μm) and physical (albedo, density) properties quantitatively similar to the class of meteorites known as enstatite chondrites. The chemical and isotopic compositions of these chondrites indicate that they were an important component of the formation of Earth and other terrestrial planets. This meteoritic association implies that Lutetia is a member of a small population of planetesimals that formed in the terrestrial planet region and that has been scattered in the main belt by emerging protoplanets (Bottke et al. 2006) and/or by the migration of Jupiter (Walsh et al. 2011) early in its history. Lutetia, along with a few other main-belt asteroids, may contains part of the long-sought precursor material (or closely related materials) from which the terrestrial planets accreted.     

Thermal conductivity measurements of porous dust aggregates: I. Technique, model and first results

We present a non-invasive technique for measuring the thermal conductivity of fragile and sensitive materials. In the context of planet-formation research, the investigation of the thermal conductivity of porous dust aggregates provide important knowledge about the influence of heating processes, like internal heating by radioactive decay of short-lived nuclei, e.g. ²⁶Al, on the evolution and growth of planetesimals. The determination of the thermal conductivity was performed by a combination of laboratory experiments and numerical simulations. An IR camera measured the temperature distribution of the sample surface heated by a well-characterized laser beam. The thermal conductivity as free parameter in the model calculations, exactly emulating the experiment, was varied until the experimental and numerical temperature distributions showed best agreement. Thus, we determined for three types of porous dust samples, consisting of spherical, 1.5 μm-sized SiO₂ particles, with volume filling factors in the range of 15-54%, the thermal conductivity to be 0.002-0.02 W m⁻¹ K⁻¹, respectively. From our results, we can conclude that the thermal conductivity mainly depends on the volume filling factor. Further investigations, which are planned for different materials and varied contact area sizes (produced by sintering), will prove the appropriate dependencies in more detail.     

天文常数研究的进展——IAU 2009天文常数系统

回顾了1900年以来LAU采用天文常数系统的简况,以及一些天文常数之间的数学关系,并描述了以前每次改变天文常数系统的主要因为.介绍了1991年以来IAU在天文常数方面的工作:包括IAU天文常数工作组和天文常数最佳估计值的情况.叙述了IAU 2009年天文常数系统替代IAU 1976天文常数系统的因为:随着人类对太阳系的探测,获得新的天文常数测定值;1991年以来在相对论框架下BCRS和GCRS的使用;P03岁差模型和MHB2000章动模型的采用.比较了IAU2009和1976天文常数系统的差异.最后介绍中国在天文常数方面工作的情况和今后工作的建议.     

The spatial and temporal distribution of grain‐size breaks in turbidites

Grain‐size breaks are surfaces where abrupt changes in grain size occur vertically within deposits. Grain‐size breaks are common features in turbidites around the world, including ancient and modern systems. Despite their widespread occurrence, grain‐size breaks have been regarded as exceptional, and not included within idealized models of turbidity current deposition. This study uses ca 100 shallow sediment cores, from the Moroccan Turbidite System, to map out five turbidite beds for distances in excess of 2000 km. The vertical and spatial distributions of grain‐size breaks within these beds are examined. Five different types of grain‐size break are found: Type I – in proximal areas between coarse sand and finer grained structureless sand; Type II – in proximal areas between inversely graded sand overlain by finer sand; Type III – in proximal areas between sand overlain by ripple cross‐laminated finer sand; Type IV – throughout the system between clean sand and mud; and Type V – in distal areas between mud‐rich (debrite) sand and mud. This article interprets Types I and V as being generated by sharp vertical concentration boundaries, controlled by sediment and clay concentrations within the flows, whilst Types II and III are interpreted as products of spatial/temporal fluctuations in flow capacity. Type IV are interpreted as the product of fluid mud layers, which hinder the settling of non‐cohesive grains and bypasses them down slope. Decelerating suspensions with sufficient clay will always form cohesive layers near to bed, promoting the generation of Type IV grain‐size breaks. This may explain why Type IV grain‐size breaks are widespread in all five turbidites examined and are commonplace within turbidite sequences studied elsewhere. Therefore, Type IV grain‐size breaks should be understood as the norm, not the exception, and regarded as a typical feature within turbidite beds.     

PPP-B2b服务的实时精密单点定位精度分析

基于北斗官方发布的承载精密单点定位(PPP)服务的PPP-B2b信号与南方测绘最新研发高精度定位终端,本文采用全国6个城市连续一周的观测数据和实时定位结果,分析了基于PPP-B2b服务的PPP精度。其中重点分析了实时静态PPP与实时动态PPP定位的精度。试验结果如下:基于PPP-B2b服务的静态PPP定位精度水平方向优于7 cm,高程方向优于10 cm;基于PPP-B2b服务的动态PPP定位精度水平方向优于10 cm,高程方向优于15 cm。试验结果表明,基于该服务的实时PPP能达到静态厘米级、动态分米级的定位精度。