大岭子金矿地质特征及选矿浸出率

大岭子金矿V1矿体赋存于中元古界高黎贡山群变质岩中,受韧性剪切带控制,矿石类型以氧化矿石为主。提出选矿依据。     

云南绿春咪霞金矿成矿地质条件

咪霞金矿赋存在多元素高背景值下志留统薄层状蚀变板岩中,受北西向F6-1断裂及正长岩、煌斑岩控制,与多元素异常、黄铁矿化等多种围岩蚀变对应,具较好的成矿地质条件。     

Time-dependent stress change during failure of rocks

The energy balance of a solid subject to fracture has been explored using heat and mass transfer equations with regard to the volumetric and superficial components. In the suggested model, brittle fracture of a cracked solid considered as a heterogeneous two-phase medium is described by an equation analogous to the Griffith’s criterion for propagation of a single crack. The derived equation is used, together with estimates of relative change in specific interface area, to study the respective change of free strain energy and pressure in rocks associated with failure.     

节理岩体卸荷强度特性的试验研究

卸荷状态工程岩体的强度特性与传统的加载岩体有本质的区别。目前对于岩石卸荷强度特性的研究比较多见,但对于含节理的岩体在卸荷应力状态下的强度特性,尤其是节理面对其强度的影响研究实属少见。本文通过岩体三轴模拟试验研究了卸荷应力状态下节理岩体的破坏特征,突出考虑了节理面性质对卸荷强度的影响,在此基础上提出了节理岩体卸荷强度准则的一般表达式并进行了对比验证。     

Zircon M257 ‐ a Homogeneous Natural Reference Material for the Ion Microprobe U‐Pb Analysis of Zircon

We introduce and propose zircon M257 as a future reference material for the determination of zircon U‐Pb ages by means of secondary ion mass spectrometry. This light brownish, flawless, cut gemstone specimen from Sri Lanka weighed 5.14 g (25.7 carats). Zircon M257 has TIMS‐determined, mean isotopic ratios (2s uncertainties) of 0.09100 ± 0.00003 for ²⁰⁶pb/²³⁸U and 0.7392 ± 0.0003 for ²⁰⁷pb/²³⁵U. Its ²⁰⁶pb/²³⁸U age is 561.3 ± 0.3 Ma (unweighted mean, uncertainty quoted at the 95% confidence level); the U‐Pb system is concordant within uncertainty of decay constants. Zircon M257 contains ～ 840 μg g^?1 U (Th/U ～ 0.27). The material exhibits remarkably low heterogeneity, with a virtual absence of any internal textures even in cathodoluminescence images. The uniform, moderate degree of radiation damage (estimated from the expansion of unit‐cell parameters, broadening of Raman spectral parameters and density) corresponds well, within the “Sri Lankan trends”, with actinide concentrations, U‐Pb age, and the calculated alpha fluence of 1.66 × 10¹⁸ g^?1. This, and a (U+Th)/He age of 419 ± 9 Ma (2s), enables us to exclude any unusual thermal history or heat treatment, which could potentially have affected the retention of radiogenic Pb. The oxygen isotope ratio of this zircon is 13.9%o VSMOW suggesting a metamorphic genesis in a marble or calc‐silicate skarn.     

Composition-Induced Variations in SIMS Instrumental Mass Fractionation during Boron Isotope Ratio Measurements of Silicate Glasses

An analytical artefact is reported here related to differences in instrumental mass fractionation between NIST SRM glasses and natural geological glasses during SIMS boron isotope determinations. The data presented demonstrated an average 3.4‰ difference between the NIST glasses and natural basaltic to rhyolitic glasses mainly in terms of their sputtering-induced fractionation of boron isotopes. As no matrix effect was found among basaltic to rhyolitic glasses, instrumental mass fractionation of most natural glass samples can be corrected by using appropriate glass reference materials. In order to confirm the existence of the compositionally induced variations in boron SIMS instrumental mass bias, the observed offset in SIMS instrumental mass bias has been independently reproduced in two laboratories and the phenomenon has been found to be stable over a period of more than one year. This study highlights the need for a close match between the chemical composition of the reference material and the samples being investigated.     

Recommended Values of 239Pu, 240Pu and 239+240Pu Concentrations in Reference Material IAEA-315 (Marine Sediment) Estimated by Thermal Ionisation Mass Spectrometry, Inductively Coupled Plasma-Mass Spectrometry and Alpha Spectrometry

The recommended concentrations of ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu in reference material IAEA‐315 (marine sediment) were estimated by three analytical methods: isotope dilution thermal ionisation mass spectrometry (TIMS), isotope dilution inductively coupled plasma‐mass spectrometry (ICP‐MS) and alpha spectrometry. The determination of ²³⁹Pu and ²⁴⁰Pu (^239+240Pu by alpha spectrometry) was carried out with samples from randomly selected bottles using each method. Plutonium‐238 was also measured by alpha spectrometry. A plutonium‐242 reference material was used as a spike for the quantitative analysis. The influence of ²⁴²Pu in the samples was therefore calculated; however, this contribution was less than the range of uncertainty and did not influence the final results. The obtained data were statistically analysed using variance component analysis and paired comparison. The combined standard uncertainties from “method/measurement”, “bottle” and “sub‐sample” were in the order of 3 to 6%. The main contributions to the uncertainty were from the material heterogeneity and from systematic differences between methods. Based on this study with twenty‐seven analyses using 10–14 g sample mass, concentrations of (38 ± 3) Bq kg^?1, (28 ± 3) Bq kg^?1 and (66 ± 4) Bq kg^?1 are proposed as recommended values for ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu, respectively, and (9.5 ± 0.4) Bq kg^?1 for ²³⁸Pu as an information value in reference material IAEA‐315. In mass concentration units, these amount to (16.4 ± 1.2) ng kg^?1, (3.3 ± 0.4) ng kg^?1 and (0.015 ± 0.003) ng kg^?1 for ²³⁹Pu, ²⁴⁰Pu and ²³⁸Pu, respectively. The certified reference materials NIST 4350B and NIST 4354 were also analysed by TIMS for quality assurance of the method used in this study.     

An implementation of rock engineering system for ranking the instability potential of natural slopes in Greek territory. An application in Karditsa County

This paper presents an application of rock engineering system (RES) in an attempt to reveal and assess the inherent instability potential of 388 sites where equivalent landslides have been manifested and recorded in the region of Karditsa County, Greece. The main objective has been defining the principal causative and triggering factors responsible for the manifestation of landslide phenomena, quantify their interactions, obtain their weighted coefficients, and calculate the instability index, which refers to the inherent potential instability of each natural slope of the examined region. From the statistical interpretation of the data reported in a well-documented database and concerning the examined failure sites, a clear correlation between the instability index and the area affected by a single landslide event has been revealed. Almost the entire failure sites, 98% of the examined slope sites, exhibit an instability index value over 55, a value which is thought to be a critical threshold for landslide manifestation concerning natural slopes in Karditsa County. It is argued that the presented RES methodology, engaging the selected set of parameters, could be considered as an effective expert's tool for ranking, in an objectively optimal and simple way, the instability potential of natural slopes in Karditsa County, and thus providing a tool for sound zoning landslide hazard.     

Effect of volatiles erupted from Mesozoic and Cenozoic volcanic activities on paleo-environmental changes in China

Based on the determination of composition of volcanic volatiles and petrologic estimation of the total mass of volatiles erupted, we showed important advances in the study of the impact of Mesozoic and Cenozoic volcanic activities on paleo-environmental changes in China. The volcanic activities include western Liaoning and Zhangjiakou Mesozoic intermediate-acidic explosive eruptions, southern Tibet and Shanwang Cenozoic volcanism, and Mt. Changbai volcanic eruption around one thousand years ago. The paper predominantly discusses the earth’s surface temperature changes, ozone depletion, acidic rain formation and mass mortalities of vertebrate induced by the Mesozoic and Cenozoic volcanism in China. __________ Translated from Bulletin of Mineralogy, Petrology and Geochemistry, 2007, 26(4): 319–322 [译自: 矿物岩石地球化学通报]     

A quantitative analysis of the prototype [WCL] star CPD-56° 8032

We present a detailed, quantitative study of the standard [WC10] Wolf-Rayet central star CPD-56^o 8032 based on new high resolution AAT UCLES observations and the Hillier (1990) WR standard model. Our analysis of CPD-56^o 8032 gives the wind properties (T _*=34500K, lg (L/L )=3.8, lg (M/M a^–1)=–5.4,v =225 km s^–1) and chemistry (C/He=0.5, O/He=0.1, by number), the latter suggesting an intimate relationship with the Ovi PN central stars and the PG 1159-035 objects. A comparison between the wind properties of CPD-56^o 8032 and Sk-66^o 40 (WN 10) indicates that low excitation, low wind velocity WR winds are common to both low mass PN central stars (WC sequence) and high mass post-LBV's (WN sequence).