Re: Erosional rates


Eigenvector wrote:
<rjtrembgeologist@xxxxxxxxx> wrote in message
news:1148581099.031510.182860@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Your question depends on many complex geologic variables. However, I
think its safe to say that over geologic time the denudation rate and
sedimentation rate is equal. When you think about it, there is no
other conclusion that would be valid. Matter can neither be created or
destroyed.

Sediments just get shifted around.

But what about if the earth was expan......Nope, not going to say it. Don't
want to give the EE'ers any more opportunities to fuel their arguments.

I guess on the suface that seems to make sense, I think some guy made a glib
remark to the same effect earlier in this thread only I think your statement
was much more descriptive and thoughtful.

Perhaps what I was referring to was the overall *roughness* of the surface
of the earth rather than anything, but erosion covers that too. You're
right, if it sinks under it has to pop back up somewhere, I guess I"m
envisioning a giant global shallow sea filled with sediment and a broad flat
archipeligo of islands in a few billion years.


Here is a good example of one, near where I live, which did exactly
that

http://www.cr.nps.gov/history/online_books/1292/sec1.htm
"These rocks are known as the Ohanapecosh Formation. Like the Puget
Group, the Ohanapecosh Formation is at least 10,000 feet thick. Yet,
nearly all of it accumulated in shallow water as western Washington
continued to sink slowly during the volcanic eruptions.

The long-continued sinking finally ended after the Ohanapecosh volcanic
activity ceased. Western Washington was then lifted several thousand
feet above sea level, and the Puget and Ohanapecosh rocks were slowly
compressed into a series of broad shallow folds."


http://vulcan.wr.usgs.gov/Volcanoes/Washington/ColumbiaRiver/geo_history_gorge.html
"40-20 million years ago ( Eocene to Miocene)

Thousands of volcanic eruptions piled layers of volcanic ash, lava, and
mudflows over the region, creating the Ohanapecosh Formation. These
rocks weathered into slippery red clay and greenish rocks visible near
Stevenson, Washington.

.