The announcement of an opportunity for
geologists to visit faults in a South
African gold mine, pressed upon by 4 km
Earth, listed no petrologist researching
the faults.
Some petrologists ignore foliations &
lineations, because they have yet no
theory relating chemical properties
having direction to one another.
Proposing that shear stress affected a
mineral's (3D) stability, championed by
Harker, did not survive. This was
probably not because of some natural
contradictions, but because the new tool
of thermodynamics declared only scalar
pressure necessary & sufficient.
Though the pressure along an inactive
fault does not differ from other rocks
at the same depth, (and, dissolved in a
calorimeter, the enthalpy of the gouge
may not differ) hydrothermal solutions
and replacement veins choose to move
along compressed fault surfaces rather
than elsewhere. Something is different,
something invisible to petrologists who
view rocks through spectacles of
classical, three dimensional
thermodynamics.
My question is, what control has
faulting upon volcanism or plutonism,
and why?
Bruce Bathurst
PS. Excuse my cross-posting this
in [log in to unmask]
Also, I'm aware the Rand Mines
are placer.
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