Gold and Ca are probably brought to the surface biochemically, being cycled via vegetation, but the Au carbonate association in soil is probably largely physical in origin, arising from precipitation via evaporative processes.
(Gold and Ca; are probably brought; to the surface; T:biochemically) (the Au carbonate association in soil; is probably; largely physical in origin) (the Au carbonate association in soil; arising; from precipitation)
Gold and Ca the Au carbonate association in soil the Au carbonate association in soil
are probably brought is probably arising
to the surface T:biochemically
largely physical in origin
from precipitation