Lots of science is intuitively known but has never really been exhaustively studied. I hqvent read the paper but Id bet that this is the result of some geophysical model (rather than direct geochemical evidence) .
In the last few years, reflection seismology has been advanced so much that the "relative bulk chem" of various deep mantle fluids can be ascertained from using seismic tools.
Either that or weve developed new drilling techniques that allow us to get to the core.(I sorta doubt that)
As far as hot dogs and mustard, you understand that was a foody metaphor . You seem to immediately bristle at just about anything tht draws comparisons in food .
Youll not find me being expressively insulting at your country"s cuisine, no sir, not me. Even though UK "bacon" is comparable only to salted wooden pallets, and your entire country has never learned how to make a proper breakfast EGG!.
Dont even get me going on English "toast"
Nope, youll never see me making cheap shots at what passes for food in the UK. Qs long as the people arent starving, you can eat whatever you wish and make believe its delicious.