ORIGIN OF THE DIAMOND 385
others
requiring more space, as heat transforms water into steam. These being
absent, the molten material would simply ooze into the funnels, and
rise with the settling pressure of the crust of the plateau.
Another
important factor would be introduced by the rending of the earth's
crust. Immense quantities of surface material, including probably great
volumes of water, would pour in, dislodging and carrying with it
fragments of the earth's strata, from the surface down, which had been
broken or loosened when the break occurred. At first this material
would be assimilated on reaching the interior heat, but gases would be
generated, steam evolved and a great cauldron of magma permeated with
superheated steam, established. Huge bubbles would lift this mass in
columns toward the surface; explosions would rend and dislodge
protrusions of the reef about the walls of the chimney, and break up
deep lying strata into fragments which would also be mixed and lifted
with the mass. Probably very deep connections with similar funnels in
the neighborhood would be established.
As
the upper mass cooled, the fragments of the surrounding strata carried
or falling into the cauldron would, in the inclusion, hold their
original form and be recognized later, as the inclusions of the
kimberlite are today.
Upon the character of this surface supply of material,
the presence of diamonds in the agglomerate probably
depends. There has been and is a general supposition
that diamonds are always associated with kimberlite, but
that the latter does not necessarily contain diamonds is
demonstrated by the fact that it occurs in various places, 25
