有机质在微细浸染型金矿化中的作用—以黔桂地区为例

黔桂地区微细浸染型金矿主要产于碳酸盐岩—碎屑岩混合沉积层序中,溶矿岩石以泥质岩、粉砂岩和碳酸盐岩为主,富含有机质。矿石中有沥青分布,含金石英中存在有机质裹体。碳质含金量较高,可达53.60×10~(-6),在黄铁矿型矿石中,碳质含量与金的富集具有同步消长的正相关关系,有机质与金矿化关系密切。有机质中对金的迁移和富集起主要作用的是Au(CN)_2~-,Au(CN)_1~-,Au(HS_2)~-等化合物,含金有机络合物在岩石的孔隙或裂隙中运移沉淀。     

国际参考电离层用于中国地区时的修正计算方法

在充分利用中国电离层台站长期观测资料的基础上，阐述了国际参考电离层用于中国地区时的一种修正计算方法．它采用“亚大地区Ｆ_２电离层预测方法”计算ｆ_０Ｆ_２和Ｍ（３０００）Ｆ_２，合理地描述Ｆ_１层的出现和提高Ｅ层的峰值高度．与实测的电离层数据的系统比较说明，该方法在中国地区使用时，其精度比国际参考电离层有明显提高．     

关于地球表层的讨论

根据天地生综合研究现状、任务和建立地球表层学的需要,综合考虑岩石圈、大气圈的整体性和水圈、生物圈或有机圈的扩散渗透性等,就“地球表层”的概念和范围作了综合讨论,认为现在广为沿用的地球表层概念存有局限性,应重新修定,拓展并充实其内涵,提出地球表层应该是包括整个岩石圈、水圈、大气圈和生物圈(或有机圈)及其相互关系和地表能量场在内的地球部分,它是地表各圈层相互渗透、交织、相互作用和调节的有机整体,是人类赖以生存与发展的地球环境。     

南桐矿区煤有机显微组分特征及与油气生成关系研究

根据有机岩石学方法研究了南桐矿区煤有机显微组分的特征。在显微镜下发现了大量与煤成烃有关的有机显微组分,如渗出体,变渗出体,各向异性微粒体,各向异性沥青质体,变木栓质体等。它们与该矿区煤层的高含烃性有着密切的成因关系,并且是高含烃性煤成烃的显微光学标志。     

有机相研究及其在盆地分析中的应用

有机相是具有一定丰度和特定成因类型的有机质的地层单元，决定有机相类型的最重要参数是干酪根的成因类型。为了反映沉积盆地中有机相的时空分布，我们提出了有机相组合和盆地有机充填序列等新概念。有机相及有机相层序、有机充填序列和有机相组合不仅是预测和在三维空间确定生油岩的分布、预测主力生油岩的排烃期和排出产物的组成的有效工具，而且可以弥补以骨架砂岩体为主要研究对象的沉积学分析的不足，在确定层序界线或不整合面的位且、研究盆地的构造沉降和沉积充填史等方面发挥重要作用。     

Effects of incorporating two organic materials at varying levels on splash detachment of some soils from Borno state,Nigeria

Splash detachment by raindrops was measured using a factorial experiment involving three soils (sandy loam, clay loam and clay) and two organic materials (cow dung and groundnut haulms) applied at five levels (0, 2, 4, 6 and 8 per cent by mass). A simulated rainfall intensity of 145 mm h^?1 for 10 min duration was used for the tests. Detachment was described in terms of the direct effects and the first and second order interactions of the variables mentioned above. Results indicated that mean splash detachment was reduced significantly (P < 0·01) from 1·97 kg m^?2 in the sandy loam to 0·67 kgm^?2 in the clay soil. For each soil type, detachment was reduced significantly (P < 0.01) with increasing levels of added organic matter. Groundnut haulms produced lower values of detachment than cow dung. There were also significant interaction effects between the study variables. These interactions were used to describe the effect of added organic materials on splash detachment. For each soil type and organic material, negative exponential relationships were established to relate splash detachment to levels of added organic matter.     

Cotton certification in Sub-Saharan Africa: Promotion of environmental sustainability or greenwashing?

Environmental sustainability is a major challenge for cotton production in Sub-Saharan Africa (SSA). The creation of voluntary certification programs is an effort aimed at finding new ways to influence corporate conduct along supply chains. This article contributes novelty and insight on cotton certification in SSA by exploring the most relevant programs in detail with regard to the demands of international non-governmental organizations (NGOs). We selected the five most central NGOs dedicated to environmental sustainability in agriculture: Friends of the Earth (FoE), Greenpeace, Oxfam, Pesticide Action Network (PAN), and World Wildlife Fund (WWF). After identifying these NGOs’ demands regarding pesticides, fertilizers and genetically modified (GM) cotton, we analyzed the requirements of the four most dominant programs certifying SSA cotton cultivation: the Better Cotton Initiative (BCI), Cotton made in Africa (CmiA), the EU Organic Regulation and Fairtrade Labelling Organization (FLO). The results of our document analysis are bolstered by semi-structured interviews with stakeholders on NGOs’ stances and roles in standard setting and implementation. We find that the EU Organic Regulation scores best in terms of environmental sustainability. Those programs in which NGOs actively participate are less ambitious compared to the public standard. Therefore, we conclude that, if NGOs maintain their commitment to multi-stakeholder initiatives, they risk contributing to ‘greenwashing’ corporate conduct by mobilizing consumer support for labelling programs that actually fall behind existing public regulation on organic certification.     

DEM investigation of the effect of intermediate principle stress on particle breakage of granular materials

This study investigates the influence of the intermediate principle stress on the particle breakage of granular materials. The crushable agglomerate method is applied to model soil particles and numerical true triaxial tests were carried out. The results show that particle breakage increases with increasing b value, the relationship of which follows an exponential function and agrees well with previous experimental results. More importantly, the study found that the relationship between particle breakage and total energy input is independent of the intermediate principle stress, which provides a good basis for the constitutive modeling of granular materials.     

铜陵矿集区层状硫化物矿床成因

新桥硫铁矿床是铜陵矿集区重要的硫（铁、铜、金）多金属矿床,长期以来对其成矿作用存在争议。采用光学显微镜、粉晶X射线衍射（XRD）、场发射扫描电镜（FE SEM）和高分辨透射电镜（HR TEM）等矿物学研究手段,对新桥硫铁矿床层状矿体中胶状黄铁矿—菱铁矿型矿石矿物学进行了研究,结果表明该矿石主要由黄铁矿和菱铁矿组成（含量分别为743%和244%）,含少量石英和伊利石;黄铁矿主要呈现纳米—亚微米粒径的自形、半自形立方体形态,菱铁矿以20~50μm的半自形菱面体产出,石英和伊利石呈现碎屑颗粒形态;偏光显微镜下胶状黄铁矿和菱铁矿呈现共生关系,FE SEM下观察到微米粗粒菱铁矿与纳米—亚微米黄铁矿之间呈现镶嵌关系,可观察到菱铁矿表面存在黄铁矿的印模。FE SEM和HR TEM观察和能谱分析确证胶状黄铁矿—菱铁矿型矿石中仍然保存有少量的微生物残体和有机质。这些综合信息反映新桥胶状黄铁矿非岩浆热液成因,而是生物化学沉积成因。该层状铁硫化物—碳酸盐建造由于具有较高的地球化学活性,对燕山期岩浆活动驱动热液形成层状矿体发挥了重要的控制作用。     

Uranium mineralization in the Alum Shale Formation (Sweden): Evolution of a U-rich marine black shale from sedimentation to metamorphism

The Alum Shale Formation is a metal-rich black shale, deposited on the Baltoscandian platform between Middle Cambrian and Early Ordovician. These black shales may be of particular economic interest for their relatively high uranium content (100–300 ppm) and their wide distribution from Norway to Estonia. Scandinavian Alum Shale may thus constitute a great potential resource of uranium, as a low grade ore. The Alum Shale Formation is particularly interesting to study the mineralogical expression and content of uranium in series submitted to progressive burial and metamorphism. For this purpose, the behavior of U, P, Ti and organic matter was studied on a series of representative samples from most Alum Shale prospection zones. In southern Sweden, where Alum Shale underwent fairly shallow burial, uranium concentrations have no mineralogical expression except a rather high U content of biogenic phosphates. Calcite concretions (beefs) and fractures recorded the migration of hot overpressured hydrocarbons and brines from thermally mature areas to immature Alum Shale. However, thermal maturation and fluid migration did not allow remobilization of uranium and metals. At the opposite, in northern Sweden, where the series were folded, duplicated and submitted to low grade Greenschist metamorphism during Caledonian orogeny, phospho-silicates U-Si-Ca-P (±Ti ±Zr ±Y) and minor amounts of uraninite are identified and indicate that U, P, and Ti were mobile and precipitated as new phases. The effect of metamorphism is therefore important to consider as the leachability of U, especially during (bio)-hydrometallurgical processes, which will be by far different between the two considered areas.