中国及邻区印支运动特征及其意义

通过概要论述印支运动在中国及邻区的表现特征,探讨了印支运动的主要成矿作用,指出印支运动首次使长期以来游离于全球主要大陆外的扬子、中朝、塔里木等小陆块拼合在一起,为新生代大型聚煤盆地的形成奠定了基础,也为燕山期和喜马拉雅山期二次大规模的对流地幔输入大陆事件奠定了重要基础,使之成为中国及邻区大陆上最重要的成矿时期。     

过去2000年气候变化对中国经济与社会发展影响研究综述

It is one of the important focuses of the Past Global Changes (PAGES) to investigate the long-term impacts of climate change on regional social and economic development over the past two millenniums. The past decades in China have witnessed great progresses in the study of past climatic influence on human society. In this paper, reviews have been made on the latest proceedings related with researches about the past 2000-year climatic impacts on Chinese history in terms of the following three aspects: economic fluctuations, social stability, and the rise and fall of dynasties in China. It is concluded that climate change and socio-economic fluctuation in historical China really temporarily demonstrated a good coincidence, which indicates a potential driving-response mechanism was likely embedded in the complicated relationship between climate change and human society. A warm climate provided relatively stable conditions of agricultural production and thus generally played a positive role in the healthy development of the economy and society. On the contrary, socio-economic adverseness triggered by a colder climate was preconditioned with social problems such as the intensification of the contradiction between people and land, as well as the gradual accumulation of social rigidity. These social problems accompanying with social development contributed higher vulnerability of society in the face of changing climate, which to some extent might amplify the effects of climatic deterioration. The authors emphasize that the future studies of the relationship between past climate change and human history in China should attach more attention to the following key problems: making deeper exploitation of the potential of Chinese historical documents, exploring the mechanism of climate-society interaction, and studying the differences of climatic effects on socio-economic development at the regional scale. This study from a historical perspective might enhance the understanding of human-environment relationship under a situation of global warming, and also provide the scientific basis for the sustainable social development in China.     

陆生植物氮同位素组成与气候环境变化研究进展

近年来,由于植物氮同位素组成(δ15N)记载了气候环境变化的信息,因而被广泛应用于全球变化研究中,成为古气候环境再造和了解现代气候环境变化信息的有力工具。然而,人们对气候环境引起的δ15N变化及其指示的气候环境意义并不完全清楚,这就有可能限制植物δ15N在古气候环境变化等领域研究中的应用。在概述植物氮同位素分馏和植物不同氮源的氮同位素分布的基础上,分析了温度、降水、大气CO2浓度和海拔高度等气候环境因子对陆生植物δ15N的影响以及它们的关系。指出了目前研究中存在的问题及其研究前景,认为在全球变化研究中利用植物氮同位素技术不仅可以重建古气候环境(如重建大气CO2浓度变化),揭示历史时期温度、降水的变化,而且还可以在一定的时间和空间上综合反映生态系统氮循环的特征。     

Tectonic Settings and Geological Implications of Neoproterozoic Liujiaping VMS Deposit,Northwestern Yangtze Block,China

Liujiaping VMS (volcanic massive sulfide) deposit contains mainly copper and zinc, which is located at the Longmenshan orogenic belt of the northwestern margin of Yangtze block. The deposit is hosted in Neoproterozoic Datan terrane (composed of Datan granitoids and Liujiaping group) and is a typical, and the biggest, VMS deposit in this area. The Datan granitoids and Liujiaping group are contemporary and both parental magmas have the same genesis. The tectonic evolution history of Northwestern Yangtze is complicated. Chronology, isotope and geochemistry of the Liujiaping VMS ores and wall rocks (especially the Datan granitoids) are analyzed to restrict the tectonic progress. High‐precision secondary ion mass spectrometry (SIMS) analysis of the Datan granitoids resulted in two concordant ages, 815.5 ± 3.2 Ma and 835.5 ± 2.6 Ma, which are contemporary with the Liujiaping Cu–Zn ore and volcanics. The wall rocks are characterized by enrichment in LREE and with a weak negative anomaly of Eu. The Pb isotope data of sulfide and volcanics from the Liujiaping deposit indicate that the material source is lower crust. Together with variable negative anomalies of high strength field elements HFSE (Th, Nb, Ta, Zr, Hf, P and Ti), positive ε_Nd (825 Ma) values (+1.8 to +3.1) and the Nd model age T_2DM = 1.2–1.3 Ga, it shows that the Liujiaping deposit and wall rocks were formed by partial melting of Mesoproterozoic lower crust. Geological and geochemical characteristics of Liujiaping deposit indicate that this deposit was formed during subduction of the oceanic crust. This study clarified that that the Liujiaping deposit and the northwestern margin of the Yangtze block were part of an arc setting at ~820 Ma rather than intra‐continental rift.     

The Wenchuan Earthquake (May 12, 2008), Sichuan Province,China, and resulting geohazards

On Monday, May 12, 2008, a devastating mega-earthquake of magnitude 8.0 struck the Wenchuan area, northwestern Sichuan Province, China. The focal mechanism of the earthquake was successive massive rock fracturing 15 km in depth at Yingxiu. Seismic analysis confirms that the major shock occurred on the Beichuan–Yingxiu Fault and that aftershocks rapidly extended in a straight northeast–southeast direction along the Longmenshan Fault zone. Fatalities approaching a total of 15,000 occurred, with a significant number resulting from four types of seismically triggered geohazards—rock avalanches and landslides, landslide-dammed lakes (“earthquake lakes”), and debris flows. China Geological Survey has identified 4,970 potentially risky sites, 1,701 landslides, 1,844 rock avalanches, 515 debris flows, and 1,093 unstable slopes. Rock avalanches and landslides caused many fatalities directly and disrupted the transportation system, extensively disrupting rescue efforts and thereby causing additional fatalities. Landslide-dammed lakes not only flooded human habitats in upstream areas but also posed threats to potentially inundated downstream areas with large populations. Debris flows become the most remarkable geohazards featured by increasing number, high frequency, and low triggering rainfall. Earthquake-triggered geohazards sequentially induced and transformed to additional hazards. For example, debris flows occurred on rock avalanches and landslides, followed by landslide-dammed lakes, and then by additional debris flows and breakouts of the landslide-dammed lakes and downstream flooding. Earthquake-induced geohazards occurred mainly along the fault zone and decreased sharply with distance from the fault. It can be anticipated that post-earthquake geohazards, particularly for debris flows, will continue for 5–10 years and even for as long as 20 years. An integrated strategy of continuing emergency response and economic reconstruction is required. The lesson from Wenchuan Earthquake is that the resulted geohazards may appear in large number in active fault regions. A plan for geohazard prevention in the earthquake-active mountainous areas is needed in advance.     

铜镍硫化物矿床的成冈——以诺里尔斯克（俄罗斯）和金川（中国）为例

与超基性岩浆作用有关的铜镍硫化物矿床主要有两种成矿建造,一种为含铬建造,另一种为含铂建造。尖晶石类矿物成分的变化清楚地反映了这两类建造的成矿属性,含铬建造的尖晶石属于铬铁矿－尖晶石系列,含铂建造中则为尖晶石－磁铁矿系列。从含铬建造向含铂建造转变的原因,可以解释为超基性岩艇中硫的作用增加,从而引起反应：４ＦｅＯ＋Ｓ＝ＦｅＳ＋Ｆｅ３Ｏ４（磁铁矿）,同时分散性铂族元素的专属性特征也发生相应变化（Ｒｕ＋Ｏｓ＋Ｉｒ）→（Ｐｔ＋Ｐｄ）。因此,含铬建造中主要富含Ｒｕ、Ｏｓ和Ｉｒ,而含铂建造中则富含Ｐｔ和Ｐｄ。超基性岩浆作用中硫的化学活动性增加与基碱度增加直接有关。因此,含铂的超基性岩大多数情况下与富碱的玄武岩形成共生组合,当富铁熔浆发生硫化作用时,将会导致硫化物与硅酸岩熔浆的不混融,从而形成矿浆,据此,金川含铂铜镍矿石不是矿     

Advance in Matrix Effect Study of LA‐MC‐ICPMS U‐Pb Dating on U‐Bearing Oxide Minerals

正Objective With the development of analytic technologies,in-situ dating on U-bearing oxide minerals(e.g.,cassiterite,rutile and baddeleyite)has been widely used in geological chronological researches and has attracted remarkable attention to explore evolution of the earth and obtain age information of various geological processes.Matrix effect     

Sealing efficiency analysis for shallow-layer caprocks in CO<Subscript>2</Subscript> geological storage

The CO₂ migrated from deeper to shallower layers may change its phase state from supercritical state to gaseous state (called phase transition). This phase transition makes both viscosity and density of CO₂ experience a sharp variation, which may induce the CO₂ further penetration into shallow layers. This is a critical and dangerous situation for the security of CO₂ geological storage. However, the assessment of caprock sealing efficiency with a fully coupled multi-physical model is still missing on this phase transition effect. This study extends our previous fully coupled multi-physical model to include this phase transition effect. The dramatic changes of CO₂ viscosity and density are incorporated into the model. The impacts of temperature and pressure on caprock sealing efficiency (expressed by CO₂ penetration depth) are then numerically investigated for a caprock layer at the depth of 800 m. The changes of CO₂ physical properties with gas partial pressure and formation temperature in the phase transition zone are explored. It is observed that phase transition revises the linear relationship of CO₂ penetration depth and time square root as well as penetration depth. The real physical properties of CO₂ in the phase transition zone are critical to the safety of CO₂ sequestration. Pressure and temperature have different impact mechanisms on the security of CO₂ geological storage.     

Computational homogenization of uncoupled consolidation in micro‐heterogeneous porous media

Variationally consistent homogenization is exploited for the analysis of transient uncoupled consolidation in micro‐heterogeneous porous solids, whereby the classical approach of first‐order homogenization for stationary problems is extended to transient problems. Homogenization is then carried out in the spatial domain on representative volume elements (RVE), which are introduced in quadrature points in standard fashion. Along with the classical averages, a higher‐order conservation quantity is obtained. An iterative FE²‐algorithm is devised for the case of nonlinear permeability and storage coefficients, and it is applied to pore pressure changes in asphalt‐concrete (particle composite). Various parametric studies are carried out, in particular, with respect to the influence of the ‘substructure length scale’ that is represented by the size of the RVE's. Copyright © 2009 John Wiley & Sons, Ltd.     

南梁煤矿多煤层开采地下水系统演化规律

煤层开采对所在矿区地下水系统有着重要影响.以往研究单煤层开采对地下水系统的影响较多,而对多煤层的影响研究甚少,特别对于我国西部缺水矿区.以南梁煤矿为例,运用地下水系统演化理论和岩石力学模拟等,对该矿井水文地质结构、矿井涌水变化规律、矿井地下水流场演变、矿井地下水化学成分变化等方面进行了综合分析研究,重构了多煤层开采条件...