Does Earth's mantle hold the key to keeping our planet hospitable for life?

[wolram]

http://news.yahoo.com/s/livescience/20071002/sc_livescience/hugestockpileofoxygenfounddeepinsideearth;_ylt=AlP5Y3bcO_CrB7jCXyUGvUkPLBIF

A mineral that acts like a sponge beneath Earth's surface stores more oxygen than expected, keeping our planet from becoming dry and inhospitable like Mars.



The key to the abundant oxygen storage is the mineral majorite, which exists deep below Earth's surface in the mantle. Without the oxygen stockpile, Earth would probably be a barren planet hostile to life, authors of a study suggest in the Sept. 27 issue of the journal Nature.

 

[billiards]

Yes, oxygen is abundant in the mantle, take the upper mantle, composed of 60% olivine (Mg, Fe)₂SiO₄, 18% orthopyroxene (Mg, Fe) SiO₃, 12% garnet (e.g. majorite) (Ca, Mg, Fe)₃Al₂Si₃O₁₂, with about 10% clinopyroxene Ca(Mg, Fe)Si₂O₆. There is a lot of oxygen there. Interesting that they pick out majorite, which I believe (from memory) forms under transition zone conditions - it's probably the most dominant type of garnet along with akimotoite - I'd like to know more about the significance of that. With regards to the water forming hypothesis, I was under the impression that hydrous volatiles were present in the transition zone, perhaps so much so that the rocks there were oversaturated, leading to partial melt (e.g. Bercovici and Kerato). So I would hesitate to accept that the "decomposition" of majorite was releasing oxygen which went on to join with hydrogen to form water. There already seems to be a lot of water in the upper mantle much of which can be accounted for by subducting slabs bringing it down with them. Majorite cannot exist in the lower mantle, it undergoes a phase transition into perovskite under the increased pressure and temperature. So if anything, majorite is just a weird stop gap in the geological water cycle in a very abstract way.

 

[ravenprp]

This discovery suggests that the Earth's mantle plays a crucial role in maintaining the hospitable conditions necessary for life to thrive on our planet. The presence of majorite and its ability to store large amounts of oxygen serves as a natural defense against the loss of oxygen from Earth's atmosphere. This is significant, as oxygen is essential for the survival of most living organisms.

Furthermore, this finding sheds light on the complex and interconnected systems that work together to sustain life on Earth. The mantle, which is largely composed of silicate minerals, is not typically thought of as a source of oxygen. However, this study shows that it is a crucial component in maintaining the delicate balance of gases in our atmosphere.

It is also important to note that this discovery may have implications for the search for life on other planets. The presence of majorite in Earth's mantle suggests that other rocky planets or moons may also have similar oxygen storage mechanisms, making them potentially habitable for life.

In conclusion, the discovery of a vast oxygen stockpile in Earth's mantle highlights the importance of this layer in maintaining the habitability of our planet. It serves as a reminder of the intricate and delicate systems that work together to make Earth a hospitable place for life to thrive. Further research in this area will undoubtedly continue to enhance our understanding of the Earth and its role in supporting life.