Convection in a mantle with variable physical properties
Convection in a mantle with variable physical properties
复制标题
具有可变物理特性的地幔中的对流
DOI：
10.1029/jb074i006p01458
复制
发表时间：
1969
影响因子：
--
通讯作者：
E. R. Oxburgh
中科院分区：
文献类型：
--
作者：
D. Turcotte;E. R. Oxburgh
首先考虑不需要知道粘性的地幔对流方面。利用由磁异常数据获得的扩展速率，确定了邻近洋底的热边界层中的温度分布。将表面热流量值与实测值进行了比较。通过将边界层廓线与符合有限振幅对流边界层理论的绝热廓线进行匹配，得到了上地幔的温度分布。讨论了类流体地幔的形成机制。假定存在扩散蠕变，给出了粘性随温度和压力变化的半经验表达式。发现粘性在100公里深度附近有一个很强的最小值。研究了强温变粘性对洋脊附近上升、发散流动的影响。洋脊的地形是水平流动所需的静水压头造成的。与上升流有关的超高温度约为50°K。
The aspects of mantle convection that do not require a knowledge of the viscosity are considered first. Using spreading rates obtained from magnetic anomaly data, the temperature distribution in the thermal boundary layers adjacent to the ocean floors is determined. The values of the surface heat flux are compared with measurements. A temperature distribution in the upper mantle is obtained by matching the boundary-layer profiles to adiabatic profiles consistent with the boundary-layer theory for finite amplitude convection. Mechanisms for a fluid-like mantle are considered. Assuming that diffusion creep is occurring, a semi-empirical expression for the temperature and pressure dependence of the viscosity is given. The viscosity is found to have a strong minimum near a 100-km depth. The effect of a strong temperature-dependent viscosity on the ascending, diverging flow near ocean ridges is studied. The topography of ocean ridges is attributed to the hydrostatic head required for the horizontal flow. The excess temperature associated with the ascending flow is found to be of the order of 50°K.
影响因子：
64.8
作者：
A. Holmes
通讯作者：
A. Holmes