After the second
expansion there is a stable period followed by the beginning of
During the contraction stage,
the extensional plates of the Pacific, and the extensional fault
line of the Atlantic, continue to spread. Simultaneously, the reduction
in the size of the sphere causes this spreading to further increase
the pressure on plate-boundaries, and the deformation of the continental
plates and original shileds.
The pressure of the compressional
areas around the Ring of Fire cause new and more widespread volcanic
and seismic activity, and the resulting natural disasters, to begin
to obscure much of the original continents. Australia, Antarctica
and Asia, now collided and shredded, pile up to eventually become
Syrtis Major, just above the equator of Mars.
( This section still deals
only with the crustal features: the cause of the contraction with
be dealt with separately, along with the cause of second expansion.
See 'Full Sequence and Notes'