[Elderberry]

Way before approaching the depths where the core is molten, iron would be above it’s curie temperature and would no longer be magnetic.

[tet68]

Good point, Iron is unusual stuff, just looking at a T3 chart it’s all about the carbon content vs the molecular
structure. Once the carbon is no longer trapped in the lattice it’s no longer magnetic.

And to think our whole society is built of the stuff...

[bt_dooftlook]

True, and I miscalculated the ratio of iron to water (which is 5% of the crust, not of the whole volume). However, the magnetic effects of the iron in the crust would seem to dwarf the effect of seawater, wouldn't it?

According to link from other post in this thread, the earth's crust is 20 mi thick on average under the continents and 3 mi thick on average under the oceans. Using the 71% ocean ratio, we get the average thickness of the crust is 7.93 miles; applying our formula for volumes, the volume of the crust would be:

Volume crust = 4/3 * pi * (r1^3 - r2^3)

= 4/3 * pi * (3963^3 - 3955.07^3)

= 4/3 * pi * (62240377347 - 61867493758)

= 4/3 * pi * 372883589

= 1,561,931,148 cu miles

From earlier post, volume of ocean = 378,080,439 cu miles

Ratio of solid crust to ocean = roughly 4/1 (earth's crust is approximately 80% solid and 20% water)

If 5% of crust = Fe, then there is 4% iron in crust compared to 20% water (5:1 ratio); ignoring the negligible amount of iron dissolved in seawater (< 10^-9 moles/kg), I still think the magnetic properties of the iron would have far greater effect on earth's magnetic field than the electrolytic/conductive properties of sea water - what are your thoughts?