发现天然产高压相矿物的微矿物学途径

迄今人们已经在陨石中发现了 11种高压相矿物 ,它们是地幔过渡带和下地幔的主要矿物相 ,其中有 8种是最近 5年来随着研究工作的深入和微矿物学技术的不断发展而连续发现的。1995年在寺巷口陨石中发现了属于地幔过渡带的林伍德石、瓦茨利石、镁铁榴石、镁方铁矿和磷酸盐A相 ,随后又参与了陨石中其它新高压同质多像矿物的发现和研究。在工作中使用了多种近代微矿物学技术 ,特别是激光拉曼探针和原位X射线显微分析技术在鉴定中起了关键作用。

河北平山阜平群夕线石钾长浅粒岩深熔作用的微区矿物学标志

河北省平山县阜平群是一套高角门岩相岩石。根据宏观现象,某些地段曾经历过深熔作用过程。深熔效应以小觉地区的夕线石钾长浅粒岩最为典型。通过电子显微镜观测确认,所研究的夕线石钾长浅粒岩经受了深熔作用的改造,具有丰富而显著的微区矿物学标志。主要表现为前存矿物,如钾长石、条纹长石、石英、钠长石、黑云母和磁铁矿等,不同程度地被熔蚀,主要组成元素发生迁移和重组,沿矿物的解理、裂隙及粒间形成夕线石、石英、云母、长石、金红石等再结晶相。在深熔过程中,元素的迁移有两种可能形式:①选择性地从前存矿物晶格中移出;②通过前存矿物的熔融。Fe、Ti等元素从黑云母中移出,形成再结晶磁铁矿和金红石;Si、Al等元素则从黑云母和长石中移出,形成夕线石和再结晶石英。

Technological mineralogy and environmental activity of zinc leaching residue from zinc hydrometallurgical process

Chemical, physical, structural and morphological properties of zinc leaching residue were examined by the combination of various detection means such as AAS, XRF, XRD, M？ssbauer spectrometry, SEM-EDS, TG-DSC, XPS and FTIR. The toxicity characteristic leaching procedure （TCLP） was used to investigate the environmental activity of zinc leaching residue for a short contact time. The phase composition analysis indicated that the zinc leaching residue mainly consists of super refined flocculent particles including zinc ferrite, sulfate and silicate. The physical structural analysis showed that it has a thermal instability and strong water absorption properties. The results of TCLP indicated that the amounts of Zn and Cd in the leaching solution exceed 40 and 90 times of limit, respectively, which demonstrate that this residue is unstable in weak acidic environment for a short contact time.

Micromineralogical Investigations on the Metasomatism in Mantle Xenoliths from Basalts in Southeastern China

IntroductionCenozoic alkali-rich lavas,which often contain mantle-derived xenoliths,arewidely distributed in the coastal area of eastern China.There are more than 30 con-firmed peridotite and eclogite localities in this area.They form a belt along the WestPacific coast and may thus be considered as an important part of the Circum-Pacificbelt.The inclusion-bearing host rocks include alkali basalt,subalkali basalt,basanite,

Comparative study on bioleaching of two different types of low-grade copper tailings by mixed moderate thermophiles

The bioleaching of two different types of low-grade copper tailings,acid-leaching tailings(ALT)and copper flotation tailings(CFT)by mixed moderate thermophiles,and the variation of mineralogical and microbiological characteristics during their dissolution processes were comparatively investigated.Results showed that bioleaching behaviors of the two types of tailings were significantly different.In ALT bioleaching,lower redox potential,higher[Fe3+]/[Fe2+]ratio and higher cell density in solution were obtained.These resulted in higher total copper,primary copper sulfide and secondary copper sulfide extractions,compared with CFT bioleaching.X-ray diffraction analysis suggested that gypsum and some metal organic complexes were detected in CFT bioleaching,which could cause the sluggish oxidation of sulphide minerals.The shifts of microbial community in the leachates and leaching residues varied greatly between ALT and CFT bioleaching.The percentage of iron-oxidizing bacteria in ALT bioleaching was higher than that of CFT,but the sulfur-oxidizing bacteria percentage was the opposite.The archaeon F.thermophilum L1 was detected in ALT but not in CFT.

Process mineralogy of copper-nickel sulphide flotation by a cyclonic-static micro-bubble flotation column

In our study we investigated a refractory copper-nickel sulfide ore separation by using a cyclonic-static micro-bubble flotation column (FCSMC). The process mineralogy of the main products was studied. Using a scanning electron microscope-energy dispersive system (SEM-EDS) and an X-ray spectrometer the mineral category and content of samples were analyzed. By using a mineral liberation analyzer (MLA) the mineral liberation characteristics were revealed. It is shown that in roughing feed the monomers liberation degree of nickel pyrite and chalcopyrite take up 84.11% and 88.82%, respectively. In tailings, the lost nickel pyrite and chalcopyrite are mainly monomers. Therefore, strengthening the micro-fine particle recovery capacity is the key to increase recovery.

Towards Understanding Paleosols in Southern Levantine Eolianites:Integration of Micromorphology,Environmental Magnetism and Mineralogy

The paper addresses the controversial question of the role of clay-sized dust in the formation of paleosols in coastal eolianites, Israel. At the Habonim type section, the pedocomplex dated by archaeology and luminescence to 45-135 ka ago shows at least three paleosols, not separated by non-soil sediments. The oldest reddish paleosol （apparently related to MIS 5） is magnetically enhanced, leached from carbonates, with signs of bioturbation and strongly aged clay coatings. The reddening is due to very fine, -20 nm, poorly crystallized, superparamagnetic （SP） hematite, as determined by Mossbauer studies. In subsoil, lithorelics of eolianite are found. Over time, the soil surface aggraded due to accelerated fine dust accumulation alongside local slope wash. On younger materials formed magnetically depleted vertisols, dominated by smectite-type expandable paramagnetic clays. In thin sections, vertisols exhibit strong stipple-speckled and striated b-fabric due to shrink-swell processes, impregnative calcite nodules and Fe-Mn redistribution. The uppermost hydric vertisol shows the strongest expression of juxtaposed features of recurrent calcite and Fe precipitation. This paleosol developed on colluvial soil materials, as evidenced by mixing of clay coated and uncoated grains of quartz and calcite allochems. M6ssbauer spectra show high amounts of Fe（III） incorporated in the clay structure, low amounts of SP goethite and absence of SP hematite. Whilst magnetic susceptibility drops in vertisols to minimal values, increase. The latter along ferrimagnetie grain sizes with differences in the hierarchy of microfabric features is taken as indication for lithologic discontinuities which may have resulted from continuous, albeit variable and low-intensity, input of eolian clay from both remote Saharan and local sources, roughly dated to the earlier to middle part of the Last Glacial.

Microstructure and Mineralogic Evidences of Fractional Differentiation： The Yesilova Ophiolite Example

The Yesilova ophiolite located in the Alpine zone. This work deals with differentiation mechanism of ultramafic cumulate in ophiolite. Generally, the sequence consists of gabbro and plagiogranite. The petrographic and petrolgichal properties of it show that the layering in gabbros are products of a differentiation by fractional crystallization insitu. Because it has ferrous compounds （magnetite, hematite） by means of volatiles （H2O, CO2） that evidence magma at high temperatures （〉700 ℃）. Ferrous liquids are compatible with fractional crystallization through olivine, plagioclase, clinopyroxene removal; whereas the evolved gabbros represent clinopyroxene, plagioclase cumulates from ferrous liquids with little amounts of trapped melt. Furthermore, cathodo luminesans image of zircons shows chemichal characteristic of oceanic plagiogranit （such as Fe2O3/MgO, Rb, Sr, Zr, TiO2） that these characters can be explained by fractional crystallization processes in the late stage of magma generation. Furthermore, all plagiogranites have small positive Eu anomalies indicating the significant role of plagioclase in the fractional crystallization. So, the Yesilova ophiolite ultramafic cumulates are the most probably related to crystal-liquid fractionation process of the oceanic crust of the Alpine belt. The plagiogranite is differentiation products of crystal-liquid insitu ofa mafic magma in the magma chamber.

Transmission electron microscopic study of the fine-grained vein matrix in the Suizhou L6 meteorite

The mineralogy of shock vein matrix in the Suizhou meteorite has been investigated by optical and transmission electron microscopy. It was revealed that the vein matrix is composed of majorite-pyrope garnet, mag- aesiowtistite, and ringwoodite, with FeNi-FeS inter- growths. The observation and character of ring-like selected electron diffraction （SAED） patterns indicate that Lhe idiomorphic garnet crystals in the vein matrix have different orientations. The polycrystalline nature of magnesiowtistite is also confirmed by a ring-like SAED pattern. Both garnet and magnesiowtistite crystals showed sharp Jiffraction spots, signifying the good crystallinity of these ：wo minerals. The SAED pattern of cryptocrystalline 5ngwoodite shows only diffuse concentric diffraction tings. FeNi metal and troilite （FeS）, which were molten during the shock event, occur in the matrix as fine eutectic FeNi-FeS intergrowths filling the interstices between garaet and magnesiowiistite grains. Based on the phase dia- gram of the Allende chondrite and the results of this TEM study, it is inferred that majorite-pyrope garnet first crystallized from the Suizhou chondritic melt at 22-26 GPa, Followed by crystallization of magnesiowtistite at 20-24 GPa, and then ringwoodite at 18-20 GPa. The eutectic intergrowths of FeNi-metal and troilite are proposed to have crystallized during meteorite cooling and solidified at the last stage of vein formation.

Mineralogical Features and Properties of Serpentine as Indicator of the Deep Earth Subduction Processes

The article presents the results of study of composition, structure and properties of three genetic types of serpentinite, developed by chromite-bearing ultrabasic rocks, by metamorphic zones of carbonate rocks and within the zone of weathering of ultrabasic rocks. The samples were selected from deposits, located along the Main Ural Fault-the Paleozoic subduction zone （named GUR）. Peculiarities of microstructure, chemical composition and properties of serpentinites formed in different geological conditions were investigated and their comparative study was held. They were devided three groups of serpentinites with oriented and non-oriented structure which formed by different protholites： mantle, lithosphere and crust.

Mineralogical and micromorphological characteristics of Si-Fe-Mn oxyhydroxides from the PACMANUS hydrothermal field, Eastern Manus Basin

The mineralogical and micromorphological characteristics of Si-Fe-Mn oxyhydroxides from the dacite-hosted PACMANUS hydrothermal field were analyzed.The samples are poorly crystallized Si-Fe-Mn oxyhydroxides with minor birnessite, todorokite, nontronite, goethite, and opal-A.There are some microtextures which are rather like fossil microbes such as the filamentous silica and the hollow pipes.Flakes of nontronite crystals are found either forming a honeycomb texture or distrib- uted on the surface of the hollow pipes.Nontronite is the product precipitated from low-temperature hydrothermal fluids, and microbes may play a role in its formation.Si-Fe-Mn oxyhydroxides have two kinds of nuclei: Si-Mn nuclei and Si nuclei, both enveloped by the similar Si-Fe outer layer, existing in the rod-shaped oxyhydroxide and spheroidal oxyhydroxide, respectively.In the Si-Mn nuclei, the concentration of SiO2 is between 39.32 wt% and 86.31 wt%, and MnO concentration is between 4.97 wt% and 27.01 wt%, but Fe2O3 concentration is very low (0.54 wt%-3.43 wt%).In the Si nucleus the concentration of SiO2 is 90.17 wt%, but concentration of MnO and Fe2O3 are low, with 0.06 wt% and 3.47 wt%, respectively.The formation of the Si-Mn nucleus is closely related to microbes, whereas the Si nucleus is of inorganic origin.