热液柱的形态研究

A STUDY ON SHAPE OF HYDROTHERMAL PLUME

热液柱是海底热液系统将其自身的能量输人海水的一种重要形式，是进行热液活动环境效应研究的主要物理对象。给出了描述热液柱形成与演化的运动方程、连续性方程和能量方程，并给出了问题的近似解。通过解的分析指出，热液流体从海底喷口喷出以后，由于初速度和浮力的存在将沿一个通道上升，随离海底距离的增大上升的速度迅速降低，同时，热液流体的上升通道在侧向上将随之扩展，到达中性浮力面后不再上升，而仅在一个层面上扩展。在不考虑底层流的情况下，热液柱由热液颈和热液透镜组成。热液颈上粗下细，下部与热液喷口连接，上部与热液透镜连接；热液透镜呈宽扁的透镜状。

By hydrothermal plume, the most part of the energy contained in hydrothermalsystem is transferred to ocean water. Hydrothermal plume is one of the important ob-jects chosen to study the environmental effect of hydrothermal activity. This paper givesthe mass, momentum and energy equations used to describe hydrothermal plume, aswell as the simplified solution. Based on the so1ution, the paper points out that the hy-drothermal fluid will rise along a channel after venting out from the sea floor due to ini-tia1 velocity and buoyancy. Its vertical velocity will decrease and the channel diameterwill expand as it continues rising. Finally it reaches the neutral buoyancy level. Ignoringthe benthal current, the shape of the hydrothermal plume consists of two parts, thelower part in a shape of column named hydrothermal neck and the upper part in a shapeof lens named hydrothermal lens. The hydrothermal neck joins the vent in the seafloorwith small diameter and joins the hydrothermal 1ens in the upper with larger diameter.The hydrotherma1 lens is usually thin, with diameter more than several kilometers.