Is the Earth's Core Leaking?

12 February 2005

Guest Scientist: Dave Walker

Is the Earth's Core Leaking? One would have thought that the core would be a perfect waste repository. The gravitational and chemical stability of the system which put the core in place should be quite difficult to upset. The core formation process should not run backwards. And yet there is some evidence that the core is leaking a little bit. How this might happen is explored. One mechanism that reconciles some previously enigmatic observations involves the subduction of oxidized material from the Earth's surface to the core-mantle boundary. A process like titration precipitates oxides from the core's iron-rich substance as the result of the oxidizing subducted material reaching the liquid outer core. Oxides produced from the core are lighter than the core and join the mantle. It is interesting to speculate that there is a feedback between oxygen-generating biological processes and deep-earth core-mantle chemical interactions.