The Petrology and Mineralogy Analysis of Noble Metal Alloys in the Inclusions of a Chondrite: An Implication on the Evolution of the Solar Nebula

The calcium-aluminium-rich inclusions (CAIs) in chondrites are believed to be the most early solids formed in the solar system, and retain the original information of the early solar nebula. However, in-depth researches revealed that most inclusions had experienced a complex history of evolution, including partial melting and secondary alteration. Focused on the refractory and chemically stable noble metal particles in the CAI of a CV meteorite (NWA 2140), a study of astrochemistry is made in this paper. The petrology and mineralogy analysis as well as the composition determination have been made on the noble metal particles. Based on the result of composition analysis, the thermodynamic process experienced by the CAI is inferred, and two kinds of noble metal alloys are identified, which correspond to the early-stage condensation products and the secondary alteration products of primordial metals, respectively.     

The effect of a dense atmosphere on the tidally induced potential of Titan

The effect of the dense atmosphere of Titan on the tidal variations of the external gravitational potential of degree two is quantified. The atmospheric tides perturb the external gravitational potential of Titan in two ways. First, the atmosphere itself contributes directly to the external gravitational potential with a period of 15.945 days. Second, the variable loading of the atmosphere induces mass redistribution within Titan, which also changes the external gravitational potential. It is shown that the relative atmospheric contributions to the tides are most likely less than 2% and vanish almost completely for the most plausible models with a subsurface ocean. This suggest that atmospheric tidal perturbations will contribute only negligibly to Cassini measurements of Titan's gravitational field so that the tidal Love numbers derived from these observations can be directly interpreted in terms of the satellite's interior.     

Comment on the paper “Fast tidal cycling and the origin of life” by Richard Lathe

We show that the fast tidal cycling postulated by Lathe [Lathe, R., 2004. Icarus 168, 18-22] is not a plausible mechanism to explain the origin of life on Earth about 3.9 Ga ago. The value of LOD at this remote epoch was probably comprised between 15 to 17 h, and the Earth-Moon distance was only about 20% smaller than nowadays, implying that the tidal frequencies and amplitudes were not so dramatically different from the present ones as stated in Lathe's paper.     

Dehydration melting of solid amphibolite at 2.0 GPa: Effects of time and temperature

The dehydration melting of the natural rock at high pressure is important to investigating the magma formation in the earth’s interior. Since the 1970s, a lot of geological scientists have paid more atten- tion to the dehydration melting of the natural rock[1―5]. Previous experiments of dehydration melting and observations of fieldwork argued that the dehy- dration melting of the rock was probably the most important fashion for the melting of the lower crust rock[6―12]. The genesis of most …     

The influence of obliquity on europan cycloid formation

Tectonic patterns on Europa are influenced by tidal stress. An important well-recognized component is associated with the orbital eccentricity, which produces a diurnally varying stress as Jupiter's apparent position in Europa's sky oscillates in longitude. Cycloidal lineaments seem to have formed as cracks propagated in this diurnally varying stress field. Maps of theoretical cycloid patterns capture many of the characteristics of the observed distribution on Europa. However, a few details of the observed cycloid distribution have not been reproduced by previous models. Recently, it has been shown that Europa has a finite forced obliquity, so Jupiter's apparent position in Europa's sky will also oscillate in latitude. We explore this new type of diurnal effect on cycloid formation. We find that stress from obliquity may be the key to explaining several characteristics of observed cycloids such as the shape of equator-crossing cycloids and the shift in the crack patterns in the Argadnel Regio region. All of these improvements of the fit between observation and theory seem to require Jupiter crossing Europa's equatorial plane 45° to 180° after perijove passage, suggestive of complex orbital dynamics that locks the direction of Europa's pericenter with the direction of the ascending node at the time these cycloids were formed.     

The interior structure of Mercury and its core sulfur content

Depth-dependent interior structure models of Mercury are calculated for several plausible chemical compositions of the core and of the mantle. For those models, we compute the associated libration amplitude, obliquity, tidal deformation, and tidal changes in the external potential. In particular we study the relation between the interior structure parameters for five different mantle mineralogies and two different temperature profiles together with two extreme crust density values. We investigate the influence of the core light element concentration, temperature, and melting law on core state and inner and outer core size. We show that a sulfur concentration above 10 wt% is unlikely if the temperature at the core-mantle boundary is above 1850 K and the silicate shell at least 240 km thick. The interior models can only have an inner core if the sulfur weight fraction is below 5 wt% for core-mantle boundary temperature in the 1850-2200 K range. Within our modeling hypotheses, we show that with the expected precision on the moment of inertia the core size can be estimated to a precision of about 50 km and the core sulfur concentration with an error of about 2 wt%. This uncertainty can only be reduced when more information on the mantle mineralogy of Mercury becomes available. However, we show that the uncertainty on the core size estimation can be greatly reduced, to about 25 km, if tidal surface displacements and tidal variations in the external potential are considered.     

超声提取-固相萃取小柱净化-气相色谱法测定土壤中14种有机氯农药

对土壤中14种有机氯农药的超声提取技术和磺化、固相萃取小柱两种净化方法进行系统研究。结果表明,超声提取节省提取时间,提高分析效率;磺化法和固相萃取小柱法都有净化作用,但磺化法使样品中的艾氏剂、狄氏剂和异狄氏剂全部损失;固相萃取小柱净化当丙酮-正己烷淋洗液体积比为1∶9、淋洗液收集8 mL时回收率>90%,干扰最小。方法检出限为0.63~2.59μg/kg,精密度(RSD,n=7)为1.17%~14.66%,基体加标平均回收率为82.78%~106.94%。方法用于生态地球化学调查评价批量土壤样品的实际分析,检测结果满足评价工作需要。     

云南剑川金河岩体中地幔流体交代特征及其成矿意义

云南剑川金河岩体中的硅化霓辉正长斑岩含有较多的镁铁-超镁铁质深源岩石包体.岩相学研究表明,伴随交代蚀变,其主岩和各类包体岩石中普遍发育沿矿物粒间和矿物晶体裂隙或解离纹贯入或穿插的呈网状和细脉浸染状分布的黑色不透明物质.对该物质进行了电子探针及扫描电镜和能谱分析,发现其组成以微晶硅酸盐矿物为主,含少量微晶石英,尤其是含有微晶地幔标型矿物--含钛磁铁矿(或镜铁矿)和含铬自然铁;后两者与硅酸盐矿物构成超显微熔离结构交生.研究认为,这种物质组成和特征,是具超临界和熔浆性质的地幔流体的微观表现,其活动所引发的交代蚀变表现为硅化、钠化及深源包体中的暗色矿物由辉石→角闪石→黑云母的退变序列.这一地幔流体作用微观踪迹的揭示,对于分析和论证滇西地区新生代多金属成矿的深部地质作用规律具有重要的理论和现实意义.     

沥青包裹体的拉曼光谱特征

对石油中的沥青质组分进行了拉曼光谱分析,发现有两种不同的拉曼光谱特征的沥青质:一是具碳质拉曼特征峰的沥青质,二是无碳质拉曼特征峰的沥青质,将前者称为碳质沥青质.对储集砂岩中的深色沥青质包裹体拉曼分析并据其拉曼光谱图特征将这类包裹体分为三种类型:含碳质沥青包裹体、碳质沥青包裹体和沥青包裹体.如果烃包裹体形成后经历了地质构造应力而破裂和地热作用而发生轻组分移出,就形成了沥青包裹体;若再经地质高温变质作用而发生了碳化,就形成碳质沥青包裹体;若只经历地质高温变质作用而发生碳化,组分热解但未移出,可能会形成含碳质沥青包裹体.