* *因为核心和地球表面是非常不同的条件。* *因为早期的地球是一个减少环境等构成的行星形成铁核心从未有机会与氧、硅吸收了。即使它在下沉的过程中核心的所有氧气会被迫出去。氧化铁只稳定的表面上。地球上最铁的氧化后只有氧化光合作用演化,淹没了大气中氧气(从分裂水),核心是令人难以置信的隔绝氧气。不,它也不会起太大作用,即使你使用所有的氧气在大气中它甚至不会氧化1%的核心。正如Ginelist指出没有那么多地球上氧气决不能硅酸盐。(硅具有更高的亲和力氧)。氧气与铁相比是那么的轻,它不能到达核心和任何可能出现在地球形成以来一直被迫由压力和亲和力氧化物不会沉到核心。在形成密度的稀土材料分离出来。 oxygen and oxides are just too light compared to heavier metals. Any oxides present at the very beginning would have quickly given up the oxygen to other materials with higher affinity once it was heated as the earth built up enough mass and energy to become molten. Today it is hard to find unoxidized iron on the surface, but life had to lock up many of the other oxidizable materials before iron started to oxidize in large amounts.