琼东南盆地华光凹陷天然气水合物稳定带厚度的影响因素     

刘杰  杨睿  邬黛黛  金光荣  张辉 《海洋学报》2019,41(8):13-25

为了探讨琼东南盆地华光凹陷海底天然气水合物稳定带的分布规律，定量研究了静水压力、底水温度、地温梯度和气源组分对水合物稳定带的影响程度。在此基础上，分析了华光凹陷现今甲烷水合物稳定带的厚度分布。最后，综合各因素的历史演化过程，初步探讨了华光凹陷1.05 Ma BP以来天然气水合物稳定带的演化。结果表明:(1)气源组分和海底温度的变化对研究区内水合物稳定带的影响较大；水合物稳定带厚度与海底温度呈良好的线性负相关性。(2)水深超过600 m的海域具备形成天然气水合物的温压条件；超过600 m水深的海域水合物稳定带厚度大部分超过 100 m，其中西北部稳定带的最大厚度超过300 m，是有利的水合物勘探区。(3)华光凹陷1.05 Ma BP以来天然气水合物稳定带厚度经历了快速增厚–窄幅变化–快速减薄和恢复的过程。麻坑群与水合物稳定变化敏感区在空间上具有较好的叠合关系。结合前人的研究成果，推测其形成与天然气水合物的分解释放有关。  相似文献   

南海神狐海域沉积物自生黄铁矿和石膏S同位素特征及对甲烷渗漏强度的示踪   总被引：1，自引：1，他引：0  

张美  陆红锋  管红香  刘丽华  邬黛黛  吴能友 《海洋学报(英文版)》2018,37(7):20-27

The northern slope of the South China Sea is a gas-hydrate-bearing region related to a high deposition rate of organic-rich sediments co-occurring with intense methanogenesis in subseafloor environments.Anaerobic oxidation of methane(AOM) coupled with bacterial sulfate reduction results in the precipitation of solid phase minerals in seepage sediment,including pyrite and gypsum.Abundant aggregates of pyrites and gypsums are observed between the depth of 667 and 850 cm below the seafloor(cmbsf) in the entire core sediment of HS328 from the northern South China Sea.Most pyrites are tubes consisting of framboidal cores and outer crusts.Gypsum aggregates occur as rosettes and spheroids consisting of plates.Some of them grow over pyrite,indicating that gypsum precipitation postdates pyrite formation.The sulfur isotopic values(δ~(34) S) of pyrite vary greatly(from –46.6‰ to –12.3‰ V-CDT) and increase with depth.Thus,the pyrite in the shallow sediments resulted from organoclastic sulfate reduction(OSR) and is influenced by AOM with depth.The relative high abundance and δ~(34) S values of pyrite in sediments at depths from 580 to 810 cmbsf indicate that this interval is the location of a paleo-sulfate methane transition zone(SMTZ).The sulfur isotopic composition of gypsum(from–25‰ to –20.7‰) is much lower than that of the seawater sulfate,indicating the existence of a 34 S-depletion source of sulfur species that most likely are products of the oxidation of pyrites formed in OSR.Pyrite oxidation is controlled by ambient electron acceptors such as MnO_2,iron(Ⅲ) and oxygen driven by the SMTZ location shift to great depths.The δ~(34) S values of gypsum at greater depth are lower than those of the associated pyrite,revealing downward diffusion of 34 S-depleted sulfate from the mixture of oxidation of pyrite derived by OSR and the seawater sulfate.These sulfates also lead to an increase of calcium ions from the dissolution of calcium carbonate mineral,which will be favor to the formation of gypsum.Overall,the mineralogy and sulfur isotopic composition of the pyrite and gypsum suggest variable redox conditions caused by reduced seepage intensities,and the pyrite and gypsum can be a recorder of the intensity evolution of methane seepage.  相似文献   

内陆水体溶解无机碳同位素研究进展及展望     

范美彤  葛璐  谭红兵  陈维 《地质论评》2020,66(6):1637-1648

碳是陆地生态系统中最重要的生命元素，能够在各个圈层之间相互转换和运移。碳循环作为地球各圈层相互连接的纽带，被认为是地表系统最重要的元素地球化学循环。碳在水体中主要以溶解性有机碳（dissolved organic carbon，简称DOC）和溶解性无机碳（dissolved inorganic carbon，简称DIC）形式存在。内陆水体（包括河水、地下水、湖水和水库等）尽管只占陆地表面1%，但它们在碳循环过程中发挥了重要作用。其DIC浓度(CDIC)和DIC同位素组成(δ13CDIC)可以为碳循环研究提供线索，因此成为近年来国际研究的热点之一。本文系统总结了全球内陆水体DIC同位素的研究进展。DIC同位素具有广泛的地质应用，不同碳源具有独特的同位素特征。因此，DIC同位素被用于定性和定量地示踪碳源，指示碳循环过程以及确定河水补给端元。  相似文献   

基于LEAP模型的城市交通低碳发展路径研究——以广州市为例     

黄莹  郭洪旭  廖翠萍  赵黛青 《气候变化研究进展》2019,15(6):670-683

以广州市为例,应用长期能源替代规划系统（LEAP）模型,通过设置政策情景、低碳情景和绿色低碳情景,模拟不同发展情景下广州交通领域未来的能源消费需求和CO₂排放趋势,分析城市低碳发展的方向和路径。结果显示,随着城镇化进程的加快和生产生活运输需求的增加,广州交通领域碳排放总量将持续增长,但增长速度有所放缓。政策情景下,广州交通领域的CO₂排放将于2035年左右达到峰值,严重滞后于广州市提出的碳排放总量达峰目标;低碳和绿色低碳情景下,通过加大低碳政策措施的力度,达峰时间有望分别提前到2025年和2023年。要实现城市交通的低碳发展,促进交通碳排放提前达峰,需要大力发展铁路和水路运输,全面落实公交优先发展战略,有效控制小汽车数量和出行频率,不断提高交通工具的清洁化和能效水平,逐步形成各种运输方式协调发展的综合交通运输体系,推动城市交通低碳发展。  相似文献   

Contamination and distribution of heavy metals in urban and suburban soils in Zhangzhou City,Fujian, China   总被引：2，自引：0，他引：2  

Zhen-ang Cui  Sheng-ying Qiao  Zheng-yu Bao  Neng-you Wu 《Environmental Earth Sciences》2011,64(6):1607-1615

The urban environment is of growing concern as its continued population increase in China. Due to the urbanization and industrialization, heavy metals have been continuously discharged into the soil recently, and creating the anthropogenic contamination. This study investigated heavy metals contamination in urban and suburban soils in Zhangzhou City, Fujian, China. Multivariate analysis and geographical information system technology were employed in source identification and contamination assessment of heavy metals in the city soils. The survey results indicated that the urban soils were contaminated by heavy metals, especially by Hg, Cd and Pb. The multivariate analysis demonstrated that the distribution of Cu, Zn, Cr and Ni was controlled by pedogenesis, Cd and Pb had been disturbed by industrialization in some urban locations, and Hg was mainly influenced by the hot-spring in some urban park sites. The distribution of heavy metals and soil pollution index suggested the soils of Zhangzhou City have been affected by human activities.  相似文献   

Using iron speciation in authigenic carbonates from hydrocarbon seeps to trace variable redox conditions     

《Marine and Petroleum Geology》2015

Seepage of hydrocarbon-rich fluids out of the marine sedimentary column is characterized by temporal changes of flow intensity and resultant spatially variable redox conditions. Authigenic carbonates at marine hydrocarbon seeps provide excellent geological and geochemical archives that serve to explore seepage dynamics over time. In this study, we investigated the potential of Mössbuaer spectroscopy and Fe contents of seep-related authigenic carbonates from the Congo Fan, the Gulf of Mexico, and the Black Sea for reconstructing past redox conditions and fluid seepage activity at cold seeps. The Fe speciation observed by Mössbauer spectroscopy and Fe contents suggest that (1) the Congo Fan carbonates precipitated in a sulfidic environment, (2) the formation conditions of seep carbonates were variable at the Gulf of Mexico seep site, ranging from oxic to suboxic and anoxic and even spanning into the methanogenic zone, and (3) the stratified water column of the Black Sea or suboxic condition resulted in low Fe contents of Black Sea carbonates. The study reveals that Fe speciation can provide constraints on the wide range of redox conditions that imprinted seep carbonates during the life span of seepage. Similarly, Mössbauer spectroscopy – particularly when used in combination with the analysis of redox-sensitive elements – is a promising tool to trace variable redox conditions in marine paleoenvironments other than seeps.  相似文献   

基于高导热材料填充漏失构造的深井换热器性能分析   总被引：1，自引：0，他引：1  

卜宪标  蒋坤卿  李华山  王令宝 《地质学报》2020,94(7):2139-2146

地热供暖可有效缓解北方雾霾天气。干热岩虽然储量丰富，但增强型地热技术由于开发费用较高，裂隙控制以及避免诱发地震的技术尚不成熟，现阶段还不能商业化应用。水热型地热开发技术虽较成熟，但受资源条件的限制，开发规模较小。对于大多地区，受地质构造和资源禀赋的控制，单井产水量较低或者回灌难，开发经济效益较差。深井换热器（DBHE）技术是开采地热水低产区或回灌难地区热能的有效方式，但受制于岩石导热系数低，单井输出功率小，投资回收期长。为提高DBHE的输出功率，本文提出了增强型深井换热器（EDBHE），通过主动将高导热性能的复合填充剂流进漏失构造的方式提高岩石的导热性能，通过调节回压、密度和黏度来控制漏失量。研究结果表明，单井EDBHE十个采暖季的平均取热功率为1002. 34 kW，是DBHE(424. 45 kW)的2. 36倍。而双井EDBHE十个采暖季的平均取热功率更是达到了27501. 61 kW，且热输出稳定，每年的衰减率0. 95%。EDBHE技术有效利用了出水量低或回灌难的水热型热储，大幅提高了其出力，扩大了地热供暖的应用范围。  相似文献   

Analytical method of radiation by a wave energy device with dual rectangular floating bodies     

WANG Wensheng  YOU Yage  ZHANG Yunqiu  WU Bijun  YE Yin 《海洋学报(英文版)》2010,29(3):106-115

The system with one floating rectangular body on the free surface and one submerged rectangular body has been applied to a wave energy conversion device in water of finite depth. The radiation problem by this device on a plane incident wave is solved by the use of an eigenfunction expansion method, and a new analytical expression for the radiation velocity potential is obtained. The wave excitation force is calculated via the known incident wave potential and the radiation potential with a theorem of Haskind employed. To verify the correctness of this method, an example is computed respectively through the bound element method and analytical method. Results show that two numerical methods. are in good agreement, which shows that the present method is applicable. In addition, the trends of hydrodynamic coefficients and wave force are analyzed under different conditions by use of the present analytical method.  相似文献   

On the radiation and diffraction of linear water waves by an infinitely long rectangular structure submerged in oblique seas   总被引：1，自引：0，他引：1  

Y.H. Zheng  P.F. Liu  Y.M. Shen  B.J. Wu  S.W. Sheng 《Ocean Engineering》2007,34(3-4):436-450

The radiation and diffraction of linear water waves by an infinitely long rectangular structure submerged in oblique seas of finite depth is investigated. The analytical expressions for the radiated and diffracted potentials are derived as infinite series by use of the method of separation of variables. The unknown coefficients in the series are determined by the eigenfunction expansion matching method. The expressions for wave forces, hydrodynamic coefficients and reflection and transmission coefficients are given and verified by the boundary element method. Using the present analytical solution, the hydrodynamic influences of the angle of incidence, the submergence, the width and the thickness of the structure on the wave forces, hydrodynamic coefficients, and reflection and transmission coefficients are discussed in detail.  相似文献   

Wave Loads and Protective Techniques of An On-Shore Wave Power Device     

You Yage YuZhi Associated Professor  Guangzhou Institute of Energy Conversion  Chinese Academy of Sciences  Guangzhou . Professor  Guangzhou Institute of Energy Conversion  Chinese Academy of Sciences  Guangzhou 《中国海洋工程》1995,(4)

In this paper, the extreme wave loads on an on-shore wave power device are investigated. First, boundary element method is applied to solve the three dimensional potential problem based on the small amplitude wave assumption. Then the motion of the Oscillating Water Column (OWC) inside the device and its laods on the device are calculated in time domain. Several protective techniques often applied are simulated by changing the constraint of the upper end of the chamber of the device. Numerical results are used to judge the effectiveness of these techniques. The investigation shows that damping can not effectively restrain the motion of OWC when the period of incident wave is long, which may cause dangerous loads on the structure. The shut chamber can effectively restrain the motion of OWC, but alternatively cause high pressure in the chamber. A Contracting opening with a Taper (CT) can exhaust a great amount of kinetic energy of OWC, and significantly decrease the loads. It is a promising protective tec  相似文献