Collaborative Research: Numerical Modeling of the Main Endeavour Vent Field, Juan de Fuca Ridge

智力优势：将为位于胡安德富卡山脊的“奋进号”主要油田开发相分离和热液循环的二维和三维数值模型。这些模型将整合现有的喷口流体温度、盐度和热流数据，以及所有其他相关约束条件，如岩浆透镜的几何形状和深度、挤出层厚度和喷口区域面积。一个特别的目标是了解西南到东北的温度和盐度梯度在MEF的原因。除了建立一个准稳态环流模型来代表MEF在1988 - 1995年间的行为外，现有的数据还将用于模拟该系统对1999年岩浆事件的响应，以及自那时以来热液热输出的下降。初步模拟表明，热流口温度、盐度和热输出主要受地壳渗透率分布和底边界条件的控制，而底边界条件控制着深部两相带的温度和面积范围。该研究项目包括三个相互关联的任务：(1)开发二维单通道模式，以匹配整个MEF西南至东北的温度和盐度梯度；(2)发展涉及堤防就位的二维模型，以了解1999年事件的响应和随后的系统衰退；(3)在现有热流数据约束下，建立了考虑2A层诱导环流影响的三维单道单相和两相热液环流模型。这将是第一个海洋中脊热液系统相分离的二维和三维数值模型，也是第一个受喷口温度、热液输出和盐度等时间序列数据约束的特定喷口场的数值模型。这也将是岩脉附近NaCl-H2O流体相分离和热液循环的第一个完整的数值模型。最后，研究结果将提供重要的见解，了解一个主要的热液系统如何随时间衰减。因此，该模型的结果将为海底热液系统的相分离过程提供重要的见解，并提供对脊轴渗透性结构的约束。研究结果将有助于确定热液热输出衰减是由岩浆结晶和深部冷却控制还是由地壳渗透率演化控制。更广泛的影响：虽然这些模型将具体针对MEF，但结果将增加对大洋中脊相分离和热液循环的理解，这是一个广泛的跨学科研究领域。三维两相程序fish的开发将成为热液模拟的重要社区工具。二维和三维版本的鱼类，以及用户手册，将放在私人网站上，当它们可供一般使用时。这项研究将在一个重要的跨学科研究领域培养一名新的女研究生，并训练该学生使用数字代码。这项研究还将促进一位年轻女性研究员的科学发展。这项研究的结果将纳入大学一级关于流体过程的课程。

Intellectual Merit: Two- and three-dimensional numerical models of phase separation and hydrothermal circulation will be developed for the Main Endeavour Field (MEF) on the Juan de Fuca Ridge. The models will integrate available vent fluid temperature, salinity, and heat flow data, along with all other relevant constraints, such as magma lens geometry and depth, extrusive layer thickness, and vent field area. A particular goal is to understand the reason for the southwest to northeast gradients in temperature and salinity across the MEF. In addition to developing a quasi-steady state circulation model that represents the behavior of the MEF between 1988 and 1995, the available data will be used to model the response of the system to the magmatic event of 1999, and what appears to be the decline in hydrothermal heat output since that time. Preliminary modeling shows that vent temperature, salinity and heat output are controlled primarily by crustal permeability distribution and the bottom boundary conditions, which control the temperature and areal extent of the two-phase zone at depth. The research program involves three inter-related tasks: (1) the development of 2-D single-pass models in order to match southwest to northeast temperature and salinity gradients across the MEF; (2) the development of 2-D models involving dike emplacement to understand the response to the 1999 event and the subsequent system decline; (3) the development of 3-D single pass single phase and two-phase models of hydrothermal circulation that includes the effect of induced circulation in layer 2A, constrained by all available heat flow data. These will be the first 2- and 3-D numerical models of phase separation for a mid-ocean ridge hydrothermal system and the first numerical models for a particular vent field that are constrained by time series data of vent temperature, hydrothermal heat output, and vent salinity. These will also be the first fully numerical models of phase separation and hydrothermal circulation of a NaCl-H2O fluid near a dike. Finally, the results will provide important insights into how a major hydrothermal system decays in time. The results of this modeling will thus provide important insights into the process of phase separation in seafloor hydrothermal systems and provide constraints on the permeability structure of the ridge axis. The results will help determine whether the decay of hydrothermal heat output is controlled by magmatic crystallization and cooling at depth or by the evolution of crustal permeability.Broader Impacts: Although these models will be specific to the MEF, the results will lead to increased understanding of phase separation and hydrothermal circulation at mid-ocean ridges, which is a broad field of interdisciplinary study. The development of the 3D two-phase code FISHES will become an important community tool for hydrothermal modeling. The 2-D and 3-D versions of FISHES, and a user's manual, will be placed on the PIs' personal websites when they are available for general use. This research will train a new graduate female student in an important area of interdisciplinary research and train the student in the use of numerical codes. The research will also advance the scientific development of a young female researcher. The results of this research will be incorporated into courses on fluid processes taught at the university level.