DAMAGE EVALUATION BASED ON POINT-AREA INTEGRATED INFORMATION IN FLOOD DIVERSION BASIN

1 INTRODUCTION In recent years, the increased human activities in river basins have resulted in severe soil erosion and subsequent river sedimentation. Higher water levels for the same flow discharge imply that the flood risk has increased, as has the possibility of using flood diversion basins (FDB抯). To reduce the potential flood damage, rapid flood risk prediction and efficient flood damage evaluation are needed. The flood risk prediction is closely related to hydraulic information s…     

库尔勒-吉木萨尔剖面Q值结构及其动力学意义

介绍了二维横向非均匀介质Q值结构反演方法, 利用横跨天山造山带的库尔勒-吉木萨尔剖面人工地震宽角反射/折射资料实现了二维Q值结构反演, 获得了库尔 勒-吉木萨尔剖面岩石圈二维Q值结构. 结果表明, 库尔勒-吉木萨尔剖面的岩石圈二维Q值结构具纵向分层、横向分区的特点. 纵向上可分为上、中、下地壳, Q值分布有规律地递增; 横向上, 剖面大体可分为塔里木盆地北缘、天山造山带和准噶尔盆地南缘. 在塔里木盆地北缘, Q值由南向北逐渐增加, 意味着塔里木盆地在向天山造山带的深部俯冲; 天山造山带内部Q值在库米什附近发生跳跃, 形成台阶状系统差异; 准噶尔盆地南缘的Q值分布给出了准噶尔盆地向博格达山下俯冲的图像. 库尔勒-吉木萨尔剖面所揭示的塔里木盆地与准噶尔盆地向天山造山带的对冲与沙雅-布尔津剖面所揭示的塔里木盆地向天山造山带“层间插入与俯冲消减”、准噶尔盆地与天山造山带主要以走滑接触形成明显的差异, 为东西天山的分段提供了岩石圈尺度的动力学依据.     

Fluid Inclusion Studies of Ore and Gangue Minerals from the Piaotang Tungsten Deposit, Southern Jiangxi Province, China

The Piaotang deposit is one of the largest vein-type W-polymetallic deposits in southern Jiangxi Province, South China. The coexistence of wolframite and cassiterite is an important feature of the deposit. Based on detailed petrographic observations, microthermometry of fluid inclusions in wolframite, cassiterite and intergrown quartz was undertaken. The inclusions in wolframite were observed by infrared microscope, while those in cassiterite and quartz were observed in visible light. The fluid inclusions in wolframite can be divided into two types: aqueous inclusions with a large vapor-phase proportion and aqueous inclusions with a small vapor-phase ratio. The homogenization temperature (Th) of inclusions in wolframite with large vapor-phase ratios ranged from 280°C to 390°C, with salinity ranging from 3.1 to 7.2 wt% NaCl eq. In contrast, the Th values of inclusions with small vapor-phase ratios ranged from 216°C to 264°C, with salinity values ranging from 3.5 to 9.3 wt% NaCl eq. Th values of primary inclusions in cassiterite ranged from 316°C to 380°C, with salinity ranging from 5.4 to 9.3 wt% NaCl eq. Th values for primary fluid inclusions in quartz ranged from 162°C to 309°C, with salinity values ranging from 1.2 to 6.7 wt% NaCl eq. The results show that the formation conditions of wolframite, cassiterite and intergrown quartz are not uniform. The evolutionary processes of fluids related to these three kinds of minerals are also significantly different. Intergrown quartz cannot provide the depositional conditions of wolframite and cassiterite. The fluids related to tungsten mineralization for the NaCl-H2O system had a medium-to-high temperature and low salinity, while the fluids related to tin mineralization for the NaCl-H2O system had a high temperature and medium-to-low salinity. The results of this study suggest that fluid cooling is the main mechanism for the precipitation of tungsten and tin.     

Accumulation Pattern of Jurassic Tight Oil in Sichuan Basin and Its Exploration & Development Prospect

<正>Jurassic tight oil in Sichuan Basin is chiefly distributed over the central basin with an area of about 4.2×104 km2.Since the first drilling in 1953,it has experienced four stages,including the Central Sichuan Basin Brought under Exploration and Development,Progressive Exploration and Development,Setting A Goal of 30×104 t/a,and Adjusting and Keeping A Stable Production.More than sixty-year exploration and development history     

The Clam Cyclina sinensis (Gmelin) Phylogeography Study with 28S rRNA Gene and Potential of Nuclear rRNA Genes in Genetic Assessments of Molluscs

Intraspecific diversity of molluscan species is usually studied based on maternally inherited mitochondrial DNA,from which only part of the evolutionary history can be reflected.Some nuclear ribosomal RNA genes such as 28S rRNA represent poten-tial candidates that can be easily applied in phylogeography because of lacking intraindividual variation.However,considering their low polymorphism,genetic appraisals on whether and how they can be used in population studies are necessary.Here,we applied a short 28S rRNA to assess genetic patterns of the clam Cyclina sinensis along the coast of China and compared the results with a for-mer study based on COI and ITS-1 analyses.The results revealed the 28S rRNA data set was characterized by an extremely low level of variation,with only seven haplotypes defined for 93 individuals.Haplotype and nucleotide diversity for each population was al-most the lowest when compared with the other two markers.However,the distribution of two dominant haplotypes showed clear geo-graphic patterns,and significant population differentiation was revealed between the East China Sea and the South China Sea.These patterns were highly concordant with findings of the former study that populations of C.sinensis were historically separated by land bridges among sea basins.Our study suggested that although the nuclear rRNAs have shortcomings such as low variation,they have advantages including lack of intraindividual variation and high amplification rates.Applying rRNA genes can enrich the toolbox of nuclear markers in molluscan phylogeographic studies.     

Ore-forming Fluid and Metallogenic Mechanism of Wolframite–Quartz Vein-type Tungsten Deposits in South China

South China is endowed with copious wolframite–quartz vein-type W deposits that provide a significant contribution to the world’s tungsten production. Mineralization is spatially associated with highly evolved granites, which have been interpreted as products of ancient crustal anatexis. Ore veins are mainly hosted in low-grade metamorphosed quartz sandstone, slate and granitic rocks. The ore minerals mainly comprise wolframite, cassiterite, scheelite and pyrite, with minor molybdenite, arsenopyrite and chalcopyrite. Typical steeply dipping veins can be divided into five zones from top to the bottom, namely: (I) thread, (II) veinlet, (III) moderate vein, (IV) thick vein, and (V) thin out zones. In general, three types of fluid inclusions at room temperature are commonly recognized in wolframite and/or quartz from these veins: two-phase liquid-rich (type L), two-phase CO2-bearing (type CB), and CO2-rich (type C). Comparative microthermometry performed on fluid inclusions hosted in wolframite and associated quartz indicates that most wolframite was not co-precipitated with the coexisting quartz. Detailed petrographic observation and cathodoluminescence (CL) imaging on coexisting wolframite and quartz of the Yaogangxian deposit, show repeated precipitation of quartz, wolframite, and muscovite, suggesting a more complex fluid process forming these veins. Previous studies of H-O isotopes and fluid inclusions suggested that the main ore-forming fluids forming the wolframite–quartz vein-type deposits had a magmatic source, whereas an unresolved debate is centered on whether mantle material supplemented the ore-forming fluids. The variable CO2 contents in the ore-forming fluids also implies that CO2 might have had a positive effect on ore formation. Fluid inclusion studies indicate that wolframite was most likely deposited during cooling from an initial H2O + NaCl ± CO2 magmatic fluid. In addition, fluid-phase separation and/or mixing with sedimentary fluid might also have played an important role in promoting wolframite deposition. We speculate that these processes determine the precipitation of W to varying degrees whereas the leading mechanistic cause remains an open question. Comprehensive studies on spatial variation of fluid inclusions show that both the steeply and gently dipping veins are consistent with the “five floors” model that may have broader applications to exploration of wolframite–quartz vein-type deposits. Recent quantitative analysis of wolframite- and quartz-hosted fluid inclusions by laser ablation inductively-coupled plasma mass spectrometry shows enhanced advantages in revealing fluid evolution, tracing the fluid source and dissecting the ore precipitation process. Further studies on wolframite–quartz vein-type W deposits to bring a deeper understanding on ore-forming fluids and the metallogenic mechanism involved.     

华北东北部裂陷盆地与燕山隆起地壳结构

天津—北京—赤城深地震测深剖面采用密集炮点和接收点距设计构成了较为完整的观测系统,利用该剖面地震测深资料研究华北东部裂陷盆地与燕山隆起地壳结构及构造耦合.结合该区域已有研究成果,进一步分析了张渤地震带东段的地震构造环境.结果显示,华北克拉通东部裂陷盆地结晶基底构造形态和界面结构性质与新生代以来的地壳构造运动密切相关,北侧燕山隆起区高速稳定和南侧裂陷盆地低速松散截然不同的地壳结构,使宝坻－桐柏、宁河－昌黎断裂构造分区线和燕山隆起之间的中间过渡带为张渤地震带东部平原区地震的孕发提供了良好的构造环境.     

利用接收函数研究青藏高原东南缘的地壳上地幔结构

本文使用位于青藏高原东南缘的25个地震台站的远震数据,采用P波和S波接收函数的方法研究了台站下方的Moho深度、泊松比以及地幔过渡带的厚度.计算结果表明：① 青藏高原东南缘的地壳厚度由松潘—甘孜地体和羌塘地体的约60 km,向邻区的印支地体以及扬子板块分别减薄为约38 km和约42 km; ② 羌塘地体的泊松比主要集中范围为0.25～0.28,地壳物质组分主要为中基性岩石,推测与下地壳镁铁质成分的增加有关.松潘—甘孜块体、印支块体和扬子板块的泊松比为0.25～0.26,主要为中酸性岩石组分.缺乏高的泊松比(≥0.30)分布表明青藏高原东南缘的地壳不存在广泛的部分熔融,但是不排除局部部分熔融的存在;③ 青藏高原东南缘的羌塘地体内存在一个比较明显的、异常变化范围为10～26 km的地幔过渡带增厚区域,其对应着地幔过渡带内100℃～260℃的温度降低,可以推断与此异常区域的地幔过渡带内存在俯冲的板块有关.     

Utilization of recycled solid waste as ecological reclamation materials based on plant growth experiments and soil quality analysis

During the highway construction, a large number of spoil areas will be generated while a large amount of waste slag and soil could not be rationally utilized. Besides, the vegetation recovery is slow in the spoil areas due to the soil depletion. Aiming at recycling the solid waste, the sieved engineering waste slag with local red clay and corn straw biochar was supplied to solve the problem of insufficient nutrients in engineering waste slag and soil. In addition, planting experiments of alfalfa...