Erosion Controls Cascade Uplift?

[catbirdseat]

I saw this article in Science Daily. The first thing I thought was "Duh, of course rainfall controls erosion". But after reading the article, what they seem to be saying is that removal of rock mass causes uplift at an accelerated rate.

 

"People have thought the scale and pattern of rock uplift is mostly controlled by deep, plate-tectonic forces," he said. "Based on our findings, the pattern of bedrock uplift is closely tied to climate through erosion."

 

Rainfall Controls Cascade Mountains' Erosion And Bedrock Uplift Patterns

[Dan_Harris]

Hmmmm . . .So, with global warming there should be an increase in warm weather phenomena, rain, increasing the erosion rate, reducing the mass of the mountains, thus incresing the upward push on the plates and increase the likelyhood of eruptions in the Cascades.

Actually thanks for the arcticle. Some interesting stuff. The other links were interesting too. I would be curious to see if they felt there was a link to the bulging near the Sisters and in Yellowstone, or are these part of a regular cycle.

[Dru]

There was an article about this in Scientific American like 4 years ago you geek-wannabes!

[catbirdseat]

Dru, you da man.

[Dru]

You're still stumped over how Venus can have active vulcanism but no magnetic field aren't ya

[catbirdseat]

A molten core is necessary but not sufficient for there to be a magnetic field. So tell us, then. You want to.

[Dru]

Explain what you mean by "necessary but not sufficient" you lost me there

 

Oh well anyway it's cause the core of Venus might be iron sulfate like a giant pyrite crystal, and hence non-magnetic

[catbirdseat]

A planet's core must be molten AND it must be electrically conductive.

[Dru]

nonmagnetic material can still be electrically conductive eg: pyrite

[catbirdseat]

It turns out that Venus volcanism is very ancient. The huge volcanoes exist because there is no water to erode them. While Vensus' core is thought to be iron/nickel like Earth's, it is believed that Venus' core has largely solidified. There may be some volcanism still going on, but in any case there isn't enough flow in the core to support a dynamo.

[iain]

if venus was made out of pyrite first it would be cube-shaped and after that it would then fall out of the sky because it is so heavy

 

 

[chelle]

Since we don't have a "geek spray" section, it 's getting shipped to the regular one. Not much relevant to climbing here...

[crazyjizzy]

My points:

1) This does not belong in spray goddamn it! This is fricking science!

 

2) Warren Hamilton attributed late Mesozoic metamorphism and ductile deformation to erosionally caused isotasy in the Sonoran Detachment terrane in a 1981 paper. So I would say that this idea even pre-dates Dru's refered source.

[Mos_Chillin]

ehmmic said:

Since we don't have a "geek spray" section, it 's getting shipped to the regular one. Not much relevant to climbing here...

 

The "Ehmminator" strikes!

[Fairweather]

catbirdseat said:

I saw this article in Science Daily. The first thing I thought was "Duh, of course rainfall controls erosion". But after reading the article, what they seem to be saying is that removal of rock mass causes uplift at an accelerated rate.

 

"People have thought the scale and pattern of rock uplift is mostly controlled by deep, plate-tectonic forces," he said. "Based on our findings, the pattern of bedrock uplift is closely tied to climate through erosion."

 

Rainfall Controls Cascade Mountains' Erosion And Bedrock Uplift Patterns

 

Almost like "glacial rebound" on a grand scale?

[chelle]

CJZ - I left it in the climbers board until it degenerated into a "who knows more" match between Dru and CBS. Don't blame me...

 

If you want a geology/planetary science forum start lobbying Jon and Timm@y. Peter Puget got his forum after a very concerted lobbying effort.

[Dru]

catbirdseat said:

It turns out that Venus volcanism is very ancient. The huge volcanoes exist because there is no water to erode them. While Vensus' core is thought to be iron/nickel like Earth's, it is believed that Venus' core has largely solidified. There may be some volcanism still going on, but in any case there isn't enough flow in the core to support a dynamo.

 

Venus has completely resurfaced from vulcanism within the last 600 million yrs or so. There are huge pillow lavas everywhere. Your source quoted above is 40 yrs out of date.

 

However: there is no plate tectonics on Venus because the planet lost all its water quite some time ago and it turns out you need water to keep the plates ductile. So the crust locked up and it's just "episodic crustal evolution" ever since.

[arlen]

What about Vulcan Venusism?

 

[E-rock]

catbirdseat said:

I saw this article in Science Daily. The first thing I thought was "Duh, of course rainfall controls erosion". But after reading the article, what they seem to be saying is that removal of rock mass causes uplift at an accelerated rate.

 

"People have thought the scale and pattern of rock uplift is mostly controlled by deep, plate-tectonic forces," he said. "Based on our findings, the pattern of bedrock uplift is closely tied to climate through erosion."

 

Rainfall Controls Cascade Mountains' Erosion And Bedrock Uplift Patterns

 

Almost like "glacial rebound" on a grand scale?

 

Yeah, it's exactly the same thing. This is a hot field of research in geology right now, how climate controls tectonics. The idea is not that erosion rates are making the Cascades "uplift" (there are actually two types of uplift: surface uplift and bedrock uplift) but that the high erosion rates are helping maintain the rugged topography. As material is removed from the valleys, isostatic rebound elevates the ridges and peaks, allowing the process to continue. This is why the North Cascades are much more rugged than the southern cascades.

[Fairweather]

I was in Dyea, at the start of The Chilkoot Trail a few years ago, and noticed the decayed pilings that once held up the warf at the turn of the century now stand in a meadow/marsh. Glacial rebound of almost 6 inches/year has lifted the seabed and turned what was once a gold rush era port into a grassy field! It is stunning to see this type of change in the geologic blink-of-an-eye.