[ExI] wyoming has lithium

[Eric Messick]

spike wrote:
>Is it not astonishing that this world's elements are not more uniformly
>distributed?  I never did see why it is that 200 km from here all that rich
>gold ore was discovered but my own backyard is just dirt.

Fascinating indeed!

I spent a good deal of time during a recent road trip through Utah
pondering similar thoughts.

In that case, the entire Colorado plateau consists basically of rusted
sedimentary rock.  All the cool colors of the rocks come from iron
oxides.  The question I kept asking myself was:  how did all that iron
come to be floating on the surface of the planet, rather than at the
core with the rest of the iron?

There are processes which concentrate and purify materials, and other
processes which dilute and distribute them.

In thinking about the geologic processes which concentrate materials,
I realized that most (if not all) of them have analogs in the
chemistry laboratory.  This isn't an accident, as these lab methods
were probably inspired by watching similar processes in nature.

It seems to me that most of the heavy elements accessible near the
surface must have arrived after the crust solidified, otherwise they
would have sunk to the core like most of the iron.  So the Colorado
plateau iron must have arrived as one or more meteorites at some point,
then was eroded, oxidized, and distributed by water, but confined to
an inland sea whose sediments eventually became the plateau.

The original iron meteors are largely solid chunks of metal.  We know
that the iron was created in stars, from which it would be widely
distributed by supernovae, yet it has since come to be concentrated
and pure.  I see two successive processes doing this, both stratifying
material by density.  First, the balance between the sun's gravity
pulling inward, and light pressure and solar wind pushing out, which
would tend to sort material by orbital distance (hence rocky inner
planets versus the outer gas giants).  Second, any bodies large enough
to be molten from the energy of their constituents falling together
during their formation would stratify materials within them before
cooling.

So, the universe has processes on various scales which concentrate and
distribute materials, and we live on an interesting planet where these
processes continue, with the balance shifting one way or the other for
various materials at various places and times.  A cool, chaotic place
to be!

-eric