Re: Angles and Erosion Rates - For John Harshman


OvC wrote:
On 19 Jun 2006 07:44:50 -0700, Richard Forrest posted in article
<1150728290.904358.84050@xxxxxxxxxxxxxxxxxxxxxxxxxxx> ...
Seanpit wrote:

Have you seen any rocks on the surface being warped recently?
Have you tried putting a piece of rock in a vice and bending it?

LOL - As I told OvC, this notion that surface layers of rock will
fracture before they warp only helps my position all the more, not
yours. Fracturing surface layers increases their surface area and
speeds up the rate of their removal by weathering and erosion. It
doesn't slow it down in the least.

What on earth has this to do with the fact that rocks on the surface
don't warp?

Rocks on the surface either warp or crack. Either way they will be
disrupted and angled by the forces that caused the WWW-type warping
below.

Nothing. Nothing at all. Although it is a nice, if not unexpected,
diversion. Alas, he's still under the impression that a fault has to
have a surface expression,

I never suggested this. You are the one who suggested that the surface
layers would fracture before they warped - even though this sort of
thing works against your position in that it would speed up the erosion
of these surface layers.

and that folds are primary topographic features,

When the rocks are first starting to warp, topography is indeed changed
in this region as well. If you argue that the surface rocks would crack
before they actually bend at such sharp angles, that would only
increase their rate of erosion - it wouldn't decrease it as you
suggest.

and that folding doesn't thicken a sedimentary sequence.

If the folding is non-overlapping, it doesn't *perpendicularly* thicken
a sedimentary sequence at all. After erosion has flattened the uneven
topography of the warped region of the *** of layers, this region
will actually be *vertically* thinner than the non-warped region.

It is encouraging, though, to see Sean discover for himself what
geologists have known for a long time: weathering exploits weaknesses
in rocks exposed at the earth's surface. Looks like he's now up to
speed with mid-18th-century geologists. Or was that concept in _De
Res Metallica_?

Notice that this concept works in my favor - resulting in an increased
rate of erosion?

I wonder when he'll discover that we're already aware of increased
local weathering and erosion rates along joints and fractures, and
that such local rates are merely one contribution to a region's
overall erosion rate.

Exactly - - - These local increases in suface erosion only increase the
overall rate of surface erosion of surface layers. They do not decrease
this rate by any means.

OvC

Sean Pitman
www.DetectingDesign.com

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