Recently I was reading 'How to build a habitable planet' by Langmuir and Broecker and in chapter 15 they speak about how Life has led to a difference in oxidation potential in the atmosphere, essentially leading to the earth becoming a fuel cell. They also spoke about how this led to certain ions being oxidized - ie uraninite to uranyl oxide, iron to hematite.
I was wondering if this could mean that as atmospheric composition would affect the sea floor, when this subducted it would affect the melt of the mantle - as far as I'm aware, it is the dehydration of the subducting slab which allows for the hydration, and therefore melt, of the mantle in regions such as Japan. If the subducting slab's composition is affected by the atmosphere, could this have any effect on the composition of the igneous rocks formed? Would this be detectable?