南丹铁陨石微量元素的微区分布特征

本文用同步辐射X荧光微区扫描法(SRXRFMS)研究了南丹铁陨石中微量元素的微区分布特征。讨论了南丹铁陨石的分类、起源及演化等基本问题。指出南丹铁陨石似分为IAB群较合理,它可能是由具有球粒陨石组成的母源物质受冲击、经局部熔融而形成。     

我国九个球粒陨石化学组成的研究

在球粒陨石化学组成的研究中,经过试验我们建立了测定各化学元素的分析流程,测定了九个球粒陨石样品中各元素的含量,根据测定结果论证了它们各自所属的化学群、氧化还原趋势以及某些共同特征。     

几种主要陨石类型的Hugoniot参数

根据各类陨石的模式化学组成或矿物组成,采用比容叠加法计算了铁陨石,ＥＨ和ＥＬ群顽辉石球粒陨石,Ｈ,Ｌ和ＬＬ群普通球粒陨石这几种主要陨石类型的Ｈｕｇｏｎｉｏｔ参数,计算结果与已表的同灰型陨石的冲击波压缩数据一致。     

亳县陨石中球粒的主量和微量元素的丰度特征及其启示

用仪器中子活化法分析了毫县(LL3-4)陨石中14个球粒的Al,Mg,Mn,Na,V,La,Sm,Au,Sc,Cr,Fe,Co,Ni,Eu,Ir等元素的含量。该陨石的球粒平均成分对Mg和Cl球粒陨石标准化值与其它不平衡普通球粒陨石一致。通过模糊聚类分析和因子分析讨论了元素间的相关关系。这些球粒的原始物质组分至少包括亲铁元素,难熔和中等难熔亲石元素以及中等挥发性元素等,这也与其它不平衡普通球粒陨石大体一致。因此,普通球粒陨石各化学群的差别主要是由基质造成的。      

亳县球粒陨石化学组成的研究

本文报道了安徽毫县球粒陨石的化学全分析结果及主要的化学参数,并对陨石中金属铁和陨硫铁的不同测定方法进行了研究及结果比较。根据球粒陨石的分类原则,毫县陨石属LL化学群。      

吉林陨石（H5）的冲击压缩线及其意义

在二级轻气炮动高压装置上运用电探针技术测量了具有H群球粒陨石典型代表性的吉林陨石冲击压缩线。当冲击压力>～70GPa时,吉林陨石发生相变,其高压相零压密度为4.425g/cm~3,硅酸盐部分高压相零压密度为4.068g/cm~3。吉林陨石冲击压缩性质的研究结果与地球形成的星子堆积模型(IAB铁陨石+H群球粒陨石)一致。此外,根据陨石或其类似物的冲击压缩线,用阻抗匹配原理计算了主要类型陨石中重要冲击特征形成的最小碰撞速度,揭示了陨石冲击效应形成的动力学条件与空间环境。     

未分群铁陨石及其硅酸盐包体的研究

本文对Guin陨石进行了化学、矿物学和岩石学方面的研究,表明Guin是一块含有45μg/gGa和186μg/g Ge的难于分类的铁陨石,它是具有异常高镍含量(92.5mg/g)的粗八面体陨铁。它还包含有6±3vol.％硅酸盐包体。包体的组成类似于球粒陨石冲击而成的融体玻璃。因此,我们认为Guin是球粒陨石母体冲击熔融而形成的集合体。      

安徽亳县陨石的热释光研究

毫县陨石于1977年10月20日下午2时30分左右降落于安徽亳县张沃公社吝子门大队.陨石表面灰黑色,有0.5mm厚的烧蚀层,具有明显的球粒结构.已查明[1]该陨石的透明矿物有镁橄榄石、贵橄榄石、透铁橄榄石、古铜辉石、顽火辉石、斜顽辉石、顽火透辉石、易变辉石、斜长石、正长石、白磷钙矿、石英、黑云母、白云母、方解石、刚玉等;不透明矿物有陨硫铁、铁纹石、镍纹石、铬铁矿、镁铁尖晶石、钛铁矿、镍黄铁矿、石墨、磁铁矿、方铁矿、自然铜和张衡矿等.经研究[1]该陨石的化学-岩石类型为LL₄,属于平衡球粒陨石.      

第六届全国陨石学和空间化学学术讨论会

由中国空间科学学会空间化学与地质专业委员会和中国矿物岩石地球化学学会陨石学与天体化学专业委员会举办的第六届全国陨石学和空间化学学术讨论会于１９９９年９月２６－１０月３日在广西北海举行，参加会议的代表共４０余人，提交会议论文２０多篇．到会代表就陨石学、天体化学和空间化学等诸多领域的研究成果和科学问题进行了充分的讨论，展示了我国在陨石学、表面化学和空间化学等领域自１９９５年以来的最新研究成果，并对该领域今后可能的研究热点和方向进行了热烈的讨论和展望．第六届全国陨石学和空间化学学术讨论会     

H型球粒陨石TL灵敏度与冲击相和钾含量的研究

测定了坠落在我国武安、枣阳、信阳等地的10个H型球粒陨石的热释光(TL)灵敏度、自然热释光峰温和峰半高宽温度,同时对它们的K含量进行了测定.将测得的H型球粒陨石的TL灵敏度与它们的钾含量和所属冲击相进行比较.结果表明,H型球粒陨石的TL灵敏度与其钾含量和冲击相之间存在着规律性的关系.      

吉林陨石冲击波压缩和幔岩模型

应用冲击波试验技术研究吉林陨石在冲击压缩期间所出现的相转变。试验雨贡纽点采用最小二乘方去拟合伯奇-默纳汉或默纳汉状态方程分析。文中提出了估计吉林陨石高压态的零压参数方法;试验结果得出,在高压吉林陨石中大部分矿物形成高压相矿物聚合体。它的零压密度为4.395g/cm3,可能含有零压密度6.32g/cm3的钙钛矿结构矿物。计算得出,吉林陨石硅酸盐相零压密度是4.10g/cm3。显然,它与地球模式的下地幔矿物聚合体的零压密度(4.15g/cm3)极一致。由此得出,原始下地幔可能是普通球粒陨石;原始地核是铁陨石小行星。这样,陨石和铁镁硅酸盐中的铁化物岐变,随着地球增长源源不断的提供外核的铁来源。      

Meteorites in Antarctica — Statistics on falls, concentration, recovery and alteration on ice-sheet

The Antarctic meteorites are distributed on the blue-ice area surfaces in the ablation zone of the Antarctic ice-sheet, to where meteorites have been transported by the ice-flow within the ice-sheet from the wider accumulation zone. Among the Antarctic meteorite collection H- and L-chondrites are most abundant; this is also true in the non-Antarctic meteorite collection. Meteorite showers also are involved in the collection. Several new types of stony meteorites have been discovered from the Antarctic meteorite collection. The mass and shape of Antarctic meteorites are in agreement with those of resultant fragments of high-speed impact basaltic rocks. In Antarctica, small fragments of meteorite smaller than 1 kg in weight can easily be found and collected. The solidification and the gas retention ages of Antarctic meteorites also are concentrated around 4.5×10⁹ years, but some of them are considerably younger. Their cosmic-ray exposure ages are extended up to 9×10⁶ years and their terrestrial ages are 9×10⁴-7×10⁵ years.     

Early solar system magnetic fields as recorded in meteorites

A number of meteorites have now been analyzed on a particle by particle basis to assess whether the magnetizations are random or are uniform in direction. The most detailed studies have been on the Allende meteorite and on the Abee meteorite. The chondrules (clasts) have randomly oriented magnetizations which strongly suggest that they record fields that predate the accretion of the meteorites. These fields are large in intensity and range from 1–20 oersteds. Although we do not know the origin of these fields we infer that they infer pre-meteorite fields in the solar system. Several other meteorites have been studied in a similar way and in some cases they show similar results, while in others there is clear evidence of accretion or post-accretion fields.     

若干陨石微量元素的仪器中子活化分析

中子活化分析特别是仪器中子活化分析具有灵敏度高、使用样品量少、可同时测定多种元素、容易避免样品污染等优点,因而广泛地应用于地学和空间化学的研究中,本工作采用热中子仪器活化分析对安龙、东台、阳江、吉兰太、吉林、清镇等六个石陨石的微量元素进行了测定。分析中采用相对比较法,以美国地质调查所标准岩石样品G-1作为直接多元素标准,为了检验分析方法的准确性,还用G-1标准岩石对部分单元素液体标准做了对比验证分析,结果表明在误差范围内符合得较好,证明本方法是可靠的。     

Presolar grains in micro-inclusions of iron meteorites

In residues of several iron meteorites, obtained by dissolution of the metal in dilute H₂SO₄, the isotopic ratio of ¹⁹⁰Os/¹⁸⁴Os has been measured by radiochemical neutron activation analysis and is found to be anomalous in several cases. The largest deviation so far seen is a 40% enrichment of ¹⁸⁴Os in a mineral of Sikhote Alin. A lack of homogenization of the two isotopes that are produced in different nucleosynthetic processes suggests that iron meteorites are more primitive than any other matter available to us so far. Isotopic composition of Xe is found to be planetary in general. However the two light isotopes ¹²⁴Xe and ¹²⁶Xe are strongly depleted in some non-magnetic residues. Correlation diagrams of isotopic ratio pairs indicate that a two component mixture model is not adequate. EPR studies of the non-magnetic fractions of the residues show a large concentration of stabilized free radicals which could be ascribed to an irradiation of micro-inclusions prior to compaction into the metal matrix.     

吉林陨石的熔融实验研究及其在地球化学中的应用

组成地球的初始物质很可能是IAB铁陨石及H群球粒陨石,非均匀吸积形成地球以后,除由岩浆分异作用使幔中金属-硫化物下沉到原始地核外,在还原条件下还有部分Fe是由橄榄石中的FeO还原为Fe0而提供的并加入于地核内.对于大的陨石母体,由于内部加热或其表面受冲击加热而发生熔融和岩浆分异,导致形成某些铁陨石及无球粒陨石或7型岩石类型的球粒岩石.实验产物中的Fe-Ni-S相可作为判别宇宙球粒的标志之一.      

Mid 19th century minimum of galactic cosmic ray flux inferred from Ti in Allegan meteorite

Measurements of ⁴⁴Ti activity in meteorites show that the galactic cosmic ray (GCR) intensity has been declining in the interplanetary space during the past three centuries and has a component of cyclic variation, with periodicity of about 87 years [Taricco, C., Bhandari, N., Cane, D., et al. Galactic cosmic ray flux decline and periodicities in the interplanetary space during the last 3 centuries revealed by ⁴⁴Ti in meteorites. J. Geophys. Res. 111, A08102, 2006.]. In order to verify these results, we have measured ⁴⁴Ti activity in Allegan meteorite which fell in 1899 and in some other meteorites with better precision. The measurements confirm low cosmic ray flux and consequently high solar activity near the middle of 19th century.     

Comparison study of ductile iron produced with Martian regolith harvested iron from ionic liquids and Bosch byproduct carbon for in-situ resource utilization versus commercially available 65-45-12 ductile iron

As researchers continue to study methods to facilitate long-term missions beyond low-Earth orbit, the ability to manufacture high-quality mechanical and structural components on the Lunar and Martian surfaces remains a crucial piece to the puzzle for a sustained presence. Due to the immense cost of sending supplies to extraterrestrial bodies, in-situ resource utilization (ISRU) methods are critical for the success and feasibility of these habitation missions. Ionic liquids (ILs) are currently being studied at NASA’s Marshall Space Flight Center (MSFC) to harvest elemental metals from meteorites and regolith minerals. Additionally, the Bosch process is being explored as a life support system at MSFC for oxygen (O₂) regeneration, rendering a byproduct of elemental carbon (C). In this investigation, the viability of casting ductile iron (DI) using IL-sourced iron (IL-Fe) and Bosch C was studied given the range of applications and performance of DI as an as-cast alloy. Ingots were produced using commercial elements to simulate the use of IL-Fe with C sourced from the byproduct C of the Bosch process. Samples were cast and compared to commercially available 65–45-12 DI with phase transformation diagrams, microstructures, and hardness. Results showed that IL-sourced elements are a viable source of elemental alloying materials for a range of DI alloys, with some limitations.