肥城邓家庄剖面寒武系微生物碳酸盐岩沉积序列

山东肥城邓家庄剖面寒武系出露连续,构成了7个三级层序。微生物碳酸盐岩主要发育在高位体系域和强迫型海退体系域单元中,以徐庄组凝块石、张夏组核形石、长山组叠层石、凤山组均一石为代表,是研究早古生代微生物碳酸盐岩复苏期的良好实例。多样化的微生物碳酸盐岩中可见大量保存精美的附枝菌（Epiphyton）、葛万菌（Girvanella）以及肾形菌（Renalcis）等钙化微生物残余物,指示了微生物碳酸盐岩形成与蓝细菌为主导的微生物新陈代谢活动密切相关。此外,微生物碳酸盐岩沉积特征反映了生长环境的分异性:均一石、凝块石分别生长在潮下带下部、上部;柱状叠层石主要发育在能量较高的潮间带环境;核形石指示了沉积环境浅且能量高的鲕粒滩相沉积环境。邓家庄寒武系剖面微生物碳酸盐岩为了解寒武纪地球微生物、古环境、古气候提供了重要的岩石记录。     

Hydrogeochemistry at mining districts

The Southern Urals exemplifies hydrogeochemical environments at mining districts. Information obtained by studying the geochemistry of nonferrous-metal industrial wastes (both mine and dump drainage) is important not only because these wastes are potential sources of base metals but also in the context of geoecological problems. The Southern Urals is one of Russia’s principal producers of Cu and Zn concentrates for metallurgical processing: the region produces 12–15% Cu and 49% Zn concentrates in the country and 35% Cu and 69% Zn concentrates in the Urals. The Yubileinoe, Podol’skoe, Sibai, Uchaly, Novy Uchaly, and Gai deposits are the largest in the Urals. The ores of these deposits contain certain components (Se, Te, Cd, Co, Ga, Ge, In, Be, etc.) that are environmental contaminants. The volume of mine and dump drainage in the Southern Urals amounts to 9 million m³/year, and its mineralization varies from 3.0 to 30–40 g/L, occasionally as high as 365 g/L, with a sulfate, chloride–sulfate calcic–magnesian, magnesian–sodic, and magnesian–calcic composition of the waters. The minor and trace elements of the regional waste waters whose concentrations exceed the regional background values are Cu, Zn (one to four orders of magnitude), As, Cd (one to three orders of magnitude), Li and Be (one to two orders of magnitude). All waste waters transfer various contaminants into environmental subsystems and most actively modify the composition of the groundwaters. At the same time, dump drainage is a potentially important secondary source of valuable mineral components.     

Prospects at Parys Mountain

Parys Mountain, a small hill in north-east Anglesey, North Wales, has a very long history of copper mining, although exploration from 1955 onwards failed to locate deposits that were economic in modern terms. However, more detailed studies since the early 1980s have revealed a much more promising prospect.     

Looking at computer cartography

Computer Cartography has gone through many changes during its short life. This article tries to document some of the results of the development. The major conclusions are:

- whereas the application of computer mappins is fluurishing, conceptual development is slow;

- as a result the applications are simpler than they could be, given the development of computer science, and brute force reigns over elegance.

To exemplify these points, the main types of Geographic Information Systems are discussed with respect to their recent achievements: Catastral mapping, Thematic mapping, Topographic mapping, Resource Information Systems, and Digital Terrain Models.     

达索普冰川海拔7100m处粒雪中空气的封闭

The air-bubble formation has been studied experimentally in the Dasuopu ice core from the northern slope of Mount Xixabangma. It was found that air-channel volume decreases gradually, but the firn remains permeable down to the depth above the transition of firn to ice, i. e., about the depth of the air-channels closing off to be isolated bubbles. Apparently, there exists an age difference between air trapped in bubbles and surrounding ice. Only when the air channels close off completely, the age of the air increases in the same rate as the surrounding ice. Air-bubbles formed in different depths at different sites depending on accumulation rate and mean annual temperature, but approximately at a mean density of 0.79～0.83 Mg·m -3 . The air-channels in the Dasuopu firn core closed rapidly in the depth between 40 and 47 m, and 50% of air-bubbles were formed in the depth of 45 m. It is calculated that the age difference between air and its surrounding ice is 59 a, and the bulk age distribution width of air trapped in ice bubbles is 11 a.     

Flood Forecasting and Warning at the River Basin and at the European Scale

Application of recent advances in numerical weather prediction (NWP) has the potential of allowing delivery of flood warning to extend well beyond the typical lead times of operational flood warning at the river basin scale. A prototype system, a European Flood Forecasting System (EFFS) developed to deliver such pre-warnings, aiming at providing a pre-warning at lead times of between 5 and 10 days is described. Considerable uncertainty in the weather forecast at these lead times, however, means that resulting forecasts must be treated probabilistically, and although probabilistic forecasts may be easy to disseminate, these are difficult to understand. This paper explores the structure of operational flood warning, and shows that integration in the flood warning process is required if the pre-warning is to fulfil its potential. A simple method of summarising the information in the pre-warning is presented, and the system in hindcast mode is shown to give clear indication of an upcoming major event in the Rhine basin up to 10 days before the actual event. Finally recommendations on the use of data assimilation to embed the EFFS system within an operational environment are given.     

Methanol radio emission at millimeter wavelengths: New masers at 1.3 and 2.8 millimeters

The results of a search for maser emission in the methanol lines 8_?1-7₀ E at 229.8 GHz, 3_?2-4_?1 E at 230.0 GHz, 0₀-1_?1 E at 108.9 GHz, and in the J ₁-J ₀ E series near 165 GHz in star-forming regions are reported. At least two masers and two candidates have been detected at 229.8 GHz. Thus, methanol masers have been detected in the 1-mm band for the first time. At 108.9 GHz, masers have been detected toward G345.01+1.79 and possibly toward M8E as well. Thermal emission was found toward 28 objects. The 229.8-GHz sources are class I masers, whereas the 108.9-GHz sources are class II masers. An analysis using a large velocity-gradient method shows that the 229.8-GHz masers can appear at densities of about 3×10⁴ cm^?3. The ratios of the flux densities in different class I lines toward DR 21(OH) and DR 21 West can be approximated in models with gas kinetic temperatures of about 50 K. Detection of the 108.9 GHz masers toward G345.01+1.79 and M8E may provide information about the geometry of these objects.     

Staurolite at anomalously high grade

In the Huntly — Portsoy area, north-east Scotland, staurolite occurs in muscovite-free migmatized semipelites. This occurrence in the Sillimanite-potash feldspar Zone is petrographically distinct from lower-grade staurolite found nearby. Petrographic and chemical data indicate that the staurolite formed stably during the migmatization episode. It was stabilized by high zinc-content. Its formation was probably an early retrograde effect.     

在全国工程咨询设计行业发展高峰论坛闭幕式上的讲话

各位代表:全国工程咨询设计行业发展高峰论坛,在与会各方的通力合作和密切配合下,围绕着"咨询发展,设计未来"的主题,完成了两天的议程,通过了《北京宣言》,达到了预期效果,论坛与时     

Russian cities at a crossroads

The research project `Changes in the Russian urban system after the dissolution of the Soviet Union' supported by the German Science and Research Society aims to reveal the impact of change in (1) the national and regional urban network, (2) the type and condition of Russian cities, and (3) the factors and actors affecting urban development. In this contribution the focus is made on the first task. The authors argue that visible stabilisation of the Russian urbanisation under crisis and/or under a new stage involves a good deal of restructuring and qualitative change. The hierarchy of the nation-wide functional centres is in flux. Within regions `alternative' foci attract industries, capital and people, and compete with regional capitals. This revised version was published online in July 2006 with corrections to the Cover Date.     

Silicate--Carbonate Immiscibility at Oldoinyo Lengai

For approximately the last 50 years eruptions at Oldoinyo Lengaihave produced passive natrocarbonatite lavas interspersed withmixed silicate-natrocarbonatite events approximately every 15–25years. In 1993 an unusual blocky lava erupted and preserveddetailed mixed silicate-natrocarbonatite textures clearly indicatingan immiscible origin. The 1993 blocky flow consists of natrocarbonatitewith small silicate crystal aggregates which constitute 2–5%of the rock. These inclusions are composed of nepheline, melanite,clinopyroxene and wollastonite occurring both as isolated crystalsand ijolite micro-xenoliths. Most significantly, these ijoliticinclusions are surrounded by ‘globules’ of a fine-grainedintergrowth of nepheline, wollastonite and gregoryite, interpretedas quenched melt. Petrographic textures are characteristic ofliquid immiscibility between coexisting natrocarbonatite andsilicate melts. The presence of gregoryite within the silicatemelt globules is particularly important as it represents thecommon liquidus phase between the silicate and natrocarbonatitemelts theoretically required to demonstrate immiscibility betweentwo conjugate liquids. This is the first time that liquid immiscibilityhas been so clearly demonstrated in natural rock samples fromOldoinyo Lengai and agrees very closely with recent experimentalwork. Our detailed model for the petrogenesis of the natrocarbonatitesat Oldoinyo Lengai involves extensive fractionation of a carbonate-richalkaline silicate magma followed by immiscible separation ofnatrocarbonatite at low pressures. KEY WORDS: Oldoinyo Lengai; natrocarbonatite; silicate-carbonate immiscibility; East Africa ^*Corresponding author. Present address: Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW_{7 5}BD, UK     

Water structure at hematite-water interfaces

The atomic-level structure of water at mineral surfaces is an important controlling factor in interfacial reactions such as foreign ion incorporation, crystal growth and dissolution, and redox reactions. Molecular dynamics simulations with four different models based on interatomic potentials have been carried out to determine the atomic-level structure of three hematite-water interfaces. In addition, for each of the three surfaces, different terminations or protonation schemes were considered. The availability of surface X-ray scattering data for the surfaces considered here allowed for an extensive comparison with experimental data. Qualitatively, with the exception of one termination with one model, all models predict the correct arrangement of water molecules at the interface. Quantitatively, the agreement with experimental positions, distances, and layer occupancies is good to excellent, especially given the range of values reported in published experimental studies. Therefore, this study provides further evidence that interatomic potential models can be used to reliably predict the structure of mineral-water interfaces. In addition, molecular simulations are a valuable source of information to complement surface X-ray scattering experiments owing to their ability to directly determine the position of hydrogen atoms and to yield three-dimensional predicted structures at no added cost, as demonstrated in this work. Indeed, the molecular dynamics trajectories were analyzed to determine the surface structural controls on the interfacial water structure. Each of the three surface functional groups present at the surfaces considered in this work, namely, triply-coordinated oxo, doubly-coordinated hydroxo, and singly-coordinated aquo groups, was found to form similar hydrogen bond configurations with adsorbed water molecules at all surfaces. Oxo groups accept long-lasting and linear hydrogen bonds from adsorbed water molecules; hydroxo groups can form hydrogen bonds with other surface functional groups as well as with adsorbed water molecules; and aquo groups normally only donate hydrogen bonds to other surface groups or adsorbed water molecules. Additionally, the majority of adsorbed water molecules were found to adopt multiple configurations and orientations. This information was used to evaluate three-dimensional structural models of the interfaces, which were previously derived experimentally from one-dimensional electron density profiles and steric considerations.