Percolation of core melts at lower mantle conditions
Percolation of core melts at lower mantle conditions
复制标题
较低地幔条件下岩心熔体的渗流
作者：
Shannon;Agee
在高压和高温下进行的实验确定了下地幔相中岩心熔体的二面角，结果显示钙钛矿为主的基质的二面角约为 71 度。该角度虽然大于完全有效渗滤所需的 60 度，但远小于实验中在上地幔压力-温度条件下在矿物基质中观察到的角度。换句话说，熔融铁合金在下地幔矿物中比在上地幔矿物中更容易流动。因此，虽然在上地幔中通过熔体渗流来分离核材料可能是不可行的，但在下地幔中通过渗流形成核是可能的。
Experiments at high pressure and temperature to determine the dihedral angle of core melts in lower mantle phases yielded a value of approximately 71 degrees for perovskite-dominated matrices. This angle, although greater than the 60 degrees required for completely efficient percolation, is considerably less than the angles observed in mineral matrices at upper mantle pressure-temperature conditions in experiments. In other words, molten iron alloy can flow much more easily in lower mantle mineralogies than in upper mantle mineralogies. Accordingly, although segregation of core material by melt percolation is probably not feasible in the upper mantle, core formation by percolation may be possible in the lower mantle.