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rope up this 8=D


gapertimmy

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Muffy, tuff is a rock type that generally refers to ash-fall deposits. How hard a tuff is depends on how hot the ash was.

 

The volcanos in the Cascades are violent belching monsters that spew hot ash more often than flowing lava. The event that formed the smiffy tuff was probably very large by modern volcanic standards (keep in mind that the ash deposited by Mt. St helens was only several inches thick close to the source) The rock in smith was probably created by one eruptive event and deposited close to the source. As ash accumulates quickly it insulates itself and retains it's heat. If it accumulates quickly enough the temperature will be high enough for it to "weld", which is why Smith Rock is hard and sharp rather than ashy and soft. The main constituent of the rock is volcanic glass (silica rich rock that cooled too quickly to form ordered mineralogy), which is fairly stable at earth's surface so it is resistent to chemical weathering in Arid environs However, in more humid environments like the west slope of the Cascades, tuff will weather and erode much more quickly. The reason you don't have good rock to climb near Eugene is probably because there are no strong, thick units (yuck that was not an intended pun) of welded tuff.

 

[ 10-19-2002, 07:35 PM: Message edited by: E-rock ]

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Okay, I saw the little pictures at Smiff and read the thingy [Wink] but at other more remote yet closer to eugene climbeing areas no pictures [Razz] so say I find out the type of rock... is it the reasonable to asume that a particulre type of rock is always formed in the same way... so if you have tuff in eastern oregon it was formed in the same way (generaly) that the tuff in say New Mexico (have no idea if the have tuff there) was formed. Yes I know thease are stupid questions, but my last geology class wa in in the 8th grade and I am OLD, and can't remember shit [Wink]

 

I supose I could buy a book [laf][laf]

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Yes that's reasonable. Tuff will always be formed by an ash flow or ash fall, regardless of it's location. However, if you don't KNOW it's a tuff, it's up to you to find clues in the rock that lead you to the conclusion that it is.

 

Whether two tuffs, say one in New Mexico and one in Oregon, formed from exactly the same type of volcano in the same type of tectonic setting is unlikely, and a far more difficult question to answer.

 

[ 10-19-2002, 07:03 PM: Message edited by: E-rock ]

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I seem to remember that you can get a plant idetification feild guid type thing.... do they have the same deal for rock identification???? so that one as uneducated as myself might beable to figure out what kind of rock I am looking at????? [Wink][big Grin]

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I'm only kidding, sorry, it's my fault I'm here anyway.

 

Yes there are rock and mineral field guides very similar to the plant and insect field guides. Many people buy them when taking petrology and mineralogy courses to supplement the text. In your case, since you're not taking a class they would be far more useful than a petrology or mineralogy text.

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thanks, I will check one out and see if I can use it. The plant field guide that I had for a class a million years ago was more of a pain in the ass than it was helpful, I burned the stupid thing [big Grin]

 

Now get back to WORK [Wink] I have to feed my kids some dinner [big Grin]

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google is my copilot [smile]

 

I think the NOAA websites are some of the coolest geek sites on the web. You can find all kinds of neat pictures and datasets. You want a picture of a tropical storm or hurricane with your name? I bet they have one. You want monthly precipitation for some obscure corner of the world for the last 50 years? got it. US taxpayers money well spent in my opinion [big Grin]

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quote:

Originally posted by gapertimmy:

ohhh we are all so lame, we are having a discussion about geology whilst we all wish we we're drunk and spraying and moonlight cragging, c'mon folks, how bout we just feel sorry for ouselves.
[Razz]

I feel sorry for you. [smile]

Oh wait, that's not right. I mean, I feel sorry for us. So, ya wanna go smiffytuffing tomorrow? I'll bet beckers still wants to get to the pumkin patch and watch for the Great Pumpkin...

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quote:

Originally posted by Muffy The Wanker Sprayer:

thanks, I will check one out and see if I can use it. The plant field guide that I had for a class a million years ago was more of a pain in the ass than it was helpful, I burned the stupid thing
[big Grin]

 

Now get back to WORK
[Wink]
I have to feed my kids some dinner
[big Grin]

I burned a book once, it was call "The social construction of reality". God it was fucking dry and boring, and in many cases not very clever either. We used it for the first half of a class called Communication and Social behavior. I burned it in the Weber as a Halloween seance.

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Hey Muffy, here's another interesting fact about Smith. I figured this out when I was there. The basalt exposed in the gorge is younger than the Tuff. The basaltic lava flowed across a plain or Valley occupied by an ancient Crooked river and formed a hard pavement. Any river (like the crooked) that flowed over the top of the young basalt flow would migrate back and forth across the valley it occupied (like the Mississippi does today). When this migrating river intersected the contact between the outcropping Tuff and the younger basalt (think of a flat plain of basalt that surrounds an older, resistant mountain of Tuff), it would begin to erode downward through the basalt to re-establish the original base-level of the river, creating a gorge with basalt on one side and Tuff on the other.

 

[ 10-19-2002, 07:48 PM: Message edited by: E-rock ]

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ohh you guys are krazy... this is really sad. we should all be sitting around the campfire right now tossing back a cold one showing each other are days war wounds...

 

this sucks.

 

muff hows it goin? are you going to get out there and climb a little snow with us this winter...?

 

wow - just jump in and lookie me i'm on top page [Wazzup]

 

[ 10-19-2002, 08:05 PM: Message edited by: krazy 1 ]

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