【作者】 王兴涛；

【导师】 翟世奎；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2004， 博士

【摘要】 本文全面、系统地研究了全球各大洋内至今所发现的现代海底热液活动区的地质信息（如地理位置、水深、构造背景、活动性等），突出总结了各热液活动区的矿产资源特征及生物类型。 当前，海底热液活动研究已取得了丰硕的成果，但是许多深层次的问题仍未解决，突出表现在热液活动的成因机制、热液循环、物质演化和热液生物学等问题，而核心问题是热液循环。热液循环过程可以有机地分解为三个子过程：海底以下部分、海底与大洋交界处（热液喷口）及热液流体在大洋中的流动。根据三个子过程各自的流动特征及可获取的信息，运用质量守恒、动量守恒、能量守恒方程及流体力学知识，本文首次系统地建立了三个子过程处热液循环的数学模型，并分别确定了各个模型的初始条件、边界条件，讨论了方程求解方法。 本文重新编译了Hydrotherm软件，并应用此软件着重模拟了地质条件下热液流体的流场特征，在计算过程中首次考虑了岩石物性（渗透率、比热等）随温度的变化，而对参数并没有取常值。首次系统地分析了不同地层渗透率结构及不同边界条件下热液循环的特征。首先讨论了热液循环系统不同部位的压力、焓、温度、水流的密度、粘度及流动速度等参数的特征，其次分析了地层非均质性、裂缝带的存在对热液循环流场的影响，最后分别模拟了近临界状态及侵入体存在情况下的热液循环。 本文运用有限元软件ANSYS首次分析了烟囱体（黑烟囱和白烟囱）的结构特征、热场特征，并讨论了烟囱体内、外流场的对流系数（反映热液及海水的扰动程度）对烟囱体热分布的影响，探讨了带有细小分支的烟囱体的热场特征。水平裂缝在地质介质中较为常见，且在热液循环中起到非常重要的作用。本文应用ANSYS软件分析了不同形状、流速、粘度、雷诺数下裂缝的流场特征。 本文对现有的热液热通量估算方法进行了对比与讨论，提出了指数衰减模型来估算海底热液热通量。应用此方法计算的洋壳平均热通量为69mW／m²，计算的全球海洋热液活动总热通量为4.11×10¹²W。用烟囱体及羽状体估算的热通量分别为9.7359×10¹⁰W及8.4895×10¹⁰W。更多还原

【Abstract】 Geological information of all vent sites of modern seafloor hydrothermal activity found till now are researched systematically, such as geographical location, water depth, structural setting, activity, and so on. Deposit resource and biological features are summarized specially.Currently, plentiful and substantial achievements of seafloor hydrothermal activity research are gained. But, many deep-level questions still remain unsolved, mainly including: hydrothermal circulation, forming mechanism, mass evolution and hydrothermal biology, of them the first one is the key point. Process of hydrothermal circulation can be divided into 3 parts scientifically and reasonably, that is, (1) hydrothermal circulation under the seafloor, (2) hydrothermal circulation in the interface of seafloor and ocean (near vents), and (3) hydrothermal fluid entering the ocean (hydrothermal plume). According to flowing features and available data, applying conservation of mass, conservation of momentum, conservation of energy and hydrodynamics, mathematical model in every part is set up for the first time, and then initial conditions and boundary conditions of each model are determined, and numerical solution of equations are discussed respectively.Software Hydrotherm is recompiled and applied to model flow field of hydrothermal fluid in geological conditions. Some physical properties (for example, permeability, specific heat, etc.) do not keep constant in geological process, and changes of these parameters with temperature are considered for the first time. Systematically, hydrothermal circulations with different strata permeability structures and under different boundary conditions are analyzed for the first time. Firstly, pressure, enthalpy, temperature and velocity of pure water at different location of hydrothermal circulation system are described. Density and viscosity of fluid are calculated from temperature and pressure using properties of pure water. Secondly, influences of formational anisotropy and crack zone on hydrothermal circulation areanalyzed. Finally, hydrothermal circulation near critical state and with cooling pluton are modeled respectively.Finite Element software ANSYS are applied to analyze structure features and heat field of black smoker and white smoker for the first time. Effects of convective coefficients of inside and outside of smokers (reflecting disturbance of hydrothermal fluid and seafloor) on heat distribution of smoker are researched. Heat field of smoker with little lateral branch is analyzed. At the same time, flow fields with different shape, size, velocity and viscosity of fluid and Reynolds number in horizontal crack are discussed.On the base of contrasting and comparing current estimating method and estimated value of hydrothermal heat flux, exponential attenuation model are put forward to compute heat flux of hydrothermal activity. Using this method, calculated average heat flux of ocean crust is 69 mW/m2, and total heat flux of hydrothermal activity in global oceans is 4.11 X 1012 W. Whereas, values calculated from smokers and plumes are 9.7359 X 1010 W and 8.4895 X1010 W respectively.更多还原