Plate tectonics and astronomy

On 30 Dec, 20:06, "mta" wrote:
The sun and moon DO affect tectonics where high pressure water is present in
subduction zones and deep under volcanic zones.


What I wouldn't give to discuss the Earth's spherical deviation under
the generalised rules for all viscous rotating bodies where,depending
on the viscosity of the internal composition,the correlation between
maximum equatorial speed and spherical deviation is bound together
with differential shear bands or what amounts to the same thing - a
rotating body in a viscous state cannot rotate as a single unit but
must display latitudinal variations in rotation rates.

The global feature of the Mid Atlantic Ridge and the symmetrical
generation of crust either side of the ridge is a magnificent
statement of a lag/advance mechanism which creates crust in one
direction due to a faster latitudinal speed compared to the slower
rotational speed of the shear band towards the poles while it creates
crust in the opposite direction due to the slower speed of the bands
towards the equator,the telltale S shape dividing the hemispheres and
the orientation of the fractures zones compliments the global
mechanism which binds planetary shape with crustal motion.

Appealing to external circumstances such as the moon or Sun to
account for plate tectonics is fine for those who can't work with the
latitudinal speeds of the Earth which represents 1669.8 km per 15
degrees/1 hour at the Equator but the real mechanism behind planetary
spherical deviation and crustal evolution/motion comes under the
generalised rules of fluid dynamics of the interior.







"Quadibloc" wrote in message

...
On Dec 25, 7:14 pm, oriel36 wrote:

You can even enjoy the inputs for the Earth's magnetic field based on
the idea that the material in contact with the surface crust does not
rotate as a single unit but in differential rotational sheer bands.

The molten rock in the Earth's mantle is still pretty viscous. That
means it's like molasses or butter - not like water or air. Yes,
Jupiter and the Sun have bands that rotate at different speeds, just
as Earth has trade winds in its atmosphere. But the kind of behavior
you are proposing for the Earth's interior is not reasonable, given
what the Earth is made of.

Analogy doesn't trump obvious physical facts like viscosity. I know,
that makes me one of those awful "empiricists".

John Savard