The closing of
the Pacific brings the planet surface to the point before the seabeds
spread. When all the continental shelves meet the sphere has an
approximate diameter of 6,800 km, an expansion which appears to
be caused by displacement from the 2,000 km wide object which entered
the planet's interior through the Indian plate.
The original shields are separated at this
stage only by the younger continental rock that lies between them.
This is at the point before the beginning of the second expansion.
NOTE: This section deals only with the
basic surface activity. The questions of interior and the cause
of the second expansion, from the continental shelves to the present
seabeds, will be dealt with separately. See: Full
Sequence And Notes