Dear list members,
Sorry for making this post after I said that this thread can be closed.
I'd like to repost here the content of my two blog posts, the latest is below:
The post to my blog was made yesterday 02-May, 2011.
Continental Formation And Evolution.
If the concept of magma propagation in crust along temperature
gradient caused by crust deformation is correct, then interesting
perspective on Continental Formation is opening. Let's assume border
forces are the main forces that drive continents. Then the next basic
rules could be derived:
- The main source of the force to move continents are ocean floor
- The main source of the force to break a continent apart are the
divergent boundaries within the continent. These divergent boundaries
later can start ocean floor spreading.
- The force a sub-ducting ocean floor is acting on the continent with,
is much less than the force of non-sub-ducting floor. Therefore, the
sum of vectors of forces acting on a continent would point the
continent in the direction of its borders under which ocean floor
Let's go further:
- If between two convergent boundaries one has to sub-duct, the more
dense one would go down.
- The crust is made of the material that a) is lighter than underlying
magma and b) have higher melting temperature than the temperature of
the underlying magma.
- The sub-ducting crust may not necessarily melt under the continent,
as current temperature of magma can be lower than the temperature of
magma the old crust was formed at.
The above rules lead us to a non-that-obvious mechanism of ocean floor
/ continent transformations:
1. Initial sequence:
- Very thin chunks of crust start to pop up all over the surface.
- The chunks are drifted towards Earth poles by the Moon induced tidal waves.
- All the surface is filled up with the chunks. Polar layers are thicker.
- The chunks are merged into crust. Moon induced waves are braking
the crust into big plates. The plates are getting thick enough to
resist moon induced waves to overlap them. The underlying heat is
blocked. Atmosphere and ocean are developing. Polar crust regions are
first continents as they are thicker and are made of lighter crust.
2. The ocean plates with the help of Moon develop divergent
boundaries. The divergent boundaries stress the crust globally, the
most stressed direction is East-West on Equator. The beginning of
sub-ducting process is inevitable.
3. The weakest point breaks (probably with the help of some asteroid).
If not with the help of the asteroid, it would probably break on
Equator, as Equator crust at this time is newest, thinnest, and most
4. The sub-ducted crust around the fault line creates a continent. The
crust sub-ducting under the continent borders expands the continent.
The distant divergent boundaries push the crust to the continent. The
crust is getting jammed on its way toward the continent. The structure
of the resulting islands I'd expect to be heavily twisted. The island
are bumped into the continent's plate adding to the plate's area.
5. The two old Polar continents are moving toward the new continent,
but not too fast as the diverging in North-South direction is slower
than in East-West direction on Equator. Soon they enter the
continent's Ring Of Fire of sub-ducting process and bump into the
continent's plate, having traveled not too far. The remnants of those
Polar continent's, I'd like to think, can be found in Australia and
North of Canada and Greenland.
6. The line of Ring Of Fire of sub-ducting process expands to embrace
the hemisphere the continent belongs to. Then The Ring Of Fire shrinks
and disappears within the other hemisphere. Now again Earth's crust
has no place to easily sub-duct the extra area added by newly
developed crust. The divergent boundaries stress the crust. The
beginning of new sub-ducting process is inevitable. Loop to paragraph
7. A number of cycles of the process had passed, I'd like to think,
before Earth's crust reached its current state.