Re: Plate techtonics and asteroid hits

On Jun 22, 2:00 pm, Timberwoof <timberwoof.s...@xxxxxxxxxxxxxxxxxxxxx>
wrote:
In article
<uranium-1182531916.604184.160...@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,



UC <uraniumcommitteechair...@xxxxxxxxx> wrote:
On Jun 22, 12:58 pm, Jim Willemin <jim***willemin@hot***mail.com>
wrote:
UC <uraniumcommitteechair...@xxxxxxxxx> wrote in news:uranium-
1182529843.792779.7...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

We have learned about the plates upon which the continents ride. Is
there any evidence or even speculation that these fractures in the
Earth's surface were not part of the original equipment of the planet
Earth? Is there any suggestion that they are residual damage from
asteroid impacts?

No. Initial plate boundaries are primarily determined by variations in
heat flow and inherited structural anisotropy. Indeed, insofar as there
have been several supercontinent cycles, during which plate boundaries are
both eliminated and reformed, it is difficult indeed to imagine how some
initial configuration may be still expressed.

Another consideration is that those major impact features we know about
(e.g. Chixulub, Manacouagan) don't have a plate boundary anywhere close to
them, or any indication that they had an effect on plate mechanics.

But in Earth's ancient history, what about really big ones?

This is one of those questions that requires some background knowledge
in order to be able to ask it well. Perhaps if you read up on the
current model of planetary formation and the formation of the Earth and
moon, you could phrase your question in a way that makes sense with that
context.

For instance, the moon was probably formed after the iron catastrophe
when a mars-sized planet glanced off the Proto-Earth. That would have
had an effect on the stratigraphy of the Earth, but Im not sure that's
what you mean.

--
Timberwoof <me at timberwoof dot com>http://www.timberwoof.com
When you post sewage, don't blame others for
emptying chamber pots in your direction. ?Chris L.


There is no evidence of plates on Luna, is there?


.

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