Geology for dummies err climbers

[Dru]

But your "one chunk" won't be granite. It will be a mineral, either quartz or feldspar, or mica or hornblende or whatever. There is no thing as "one chunk of granite". The individual pieces that mnake it up are minerals, but there is no "granite mineral"

[iain]

A mixture is a good way to put it actually, as it forms in a mixed-up liquid state in the continental crust. Based on how it cools, and what it picks up as it does so, various minerals crystallize out at different temperatures. This is why there are a million kinds of "granite" out there, hence all the ridiculous sub-names. Doesn't really matter unless you work for Exxon or carry a rock hammer as a profession.

[Dru]

Put another way, there is no more a "granite mineral" than there is an "ethanol atom". If you break down ethanol into its component atoms, all you are left with is hydrogen, carbon and oxygen. Damn

[klenke]

I think I'm beginning to understand the difference between what my mind is saying and your minds are saying. That's why I didn't call a full bullshit.

 

You could go up to Dragontail, hack off a piece of the mountain (a piece of granodiorite), call it a chunk of granite, and you wouldn't be wrong. Just because it's no longer on the mountain it doesn't mean it's no longer granite (granodiorite).

 

Because the chunk would be a mixture of minerals within it, it would be hard to write out a chemical formula for the chunk as a whole, as if to say the quartz or feldspar or whatever is in it is immiscible with everything else, or the chunk as a whole. If you had a perfect separation device, you could separate out the individual constituents and lay them in different mineralogical piles on the table.

[iain]

You could go up to Dragontail, hack off a piece of the mountain (a piece of granodiorite), call it a chunk of granite, and you wouldn't be wrong.

 

You wouldn't be too wrong, since there is a chemical distinction, but you would avoid being labeled a total geek. I am not sure what Dragontail is, actually. I never read anything about it.

 

If you had a perfect separation device, you could separate out the individual constituents and lay them in different mineralogical piles on the table.

 

This is exactly what the iron ore extraction business is all about.

[iain]

Often it comes down to looking at a thin-section under the scope of diorite and granite to tell them apart, as they have very similar texture when you just look at them. Sometimes it's easier though. Maybe I just need more experience at it. Fun times!

[klenke]

I'm pretty sure Dragontail (and all of the Enchantments) are part of the granitic (granodioritic) Stuart Batholith, which was emplaced in the Cretaceous Period.

 

My geology book said it was once capped by volcanic strata that has long since eroded away. That is, it rose up through the volcanic bedding.

[Dru]

Also the constituents weather at different rates. Feldspar weathers much faster than quartz, and physically disintegrates too - both breaking apart and chemically changing from feldspar to clay minerals like chlorite as it hydrates and oxidizes. Eventually granite weathers down to a high-quartz content sand, like the soil at J Tree, or the granola you have to climb through on Yak Crack.

[MisterMo]

So granite in general is a mixture, I understand that. But once you get down to one chunk of granite with a definite chemical constituency, that chunk (if homogenous) is a mineral. That is, you can write out a chemical formula for it.

I should know better but I'll try anyhow. It is not homogeneous, rather discrete crystals of quartz (a mineral), feldspar (a mineral), often (always?) mica (a mineral),etc. all globbed together. You can't write out a chemical formula for granite, in pieces of any size. Only if you break it up down to the level of individual crystals would you get homogeneity but you would have one of the constituent minerals; you would then have, say, a crystal of feldspar; it wouldn't even be granite any more. I give up, probably made it all worse

[Dru]

I think I'm beginning to understand the difference between my ignorance and your knowledge. It looks like I, klenke, have been proven wrong AGAIN. I should go soak my head and acknowledge Dru and Iain 0wnz0red me.

[klenke]

Asshole.

[Dru]

double 0wnz0red

[Alpinfox]

 

Thanks guys. That was very informative.

 

[olyclimber]

Thanks for schoolin me on the the rocks and stuff.

 

Now, God Man wants you sing a little song with him:

 

 

Well alright, somethin's got you goin' tonight

Doin' all she can, it's alright

Come on can't you see

That when we all let go

We get high on rock 'n' roll

 

Journey to the stars, rock 'n' roll guitars, yeah

I like to rock, some like it hot, baby

I like it, you like it

I like to rock, I like to rock

 

I can sing, that's the kind of life for me

Want it loose and fancy free

Come on then let's go

And it'll be alright

We can rock 'n' roll all night

 

Journey to the stars, rock 'n' roll guitars, yeah

I like to rock, some like it hot, baby

I like it, you like it

I like to rock, I like to rock

 

Ooh, I like to rock

Some like it hot, baby

I like it, you like it

I like to rock, I like to rock

[Szyjakowski]

the proper catch-all term for many igneous plutons that we enjoy in this state is "granitic" not granite.

A mineral is any naturally occurring homogeneous solid with a definite chemical composition and highly ordered atomic arrangement. compositions are generally formed by inorganic processes although generally not fixed...that is they want to change and join with others...

which is why minerals are so valuable when large and unaltered.

if you want to learn the most about geology i suggest taking a field course...the easy classes like 101 are informative but they don't give you the hands on experience that is very much needed to actually appreciate the complexities and beauty that makes geology.

a good book to buy for our area is

Beckey's descriptions are good too.

[k.rose]

Hey Dru, sounds like you need to take a basic geology course, since when is shale a metamorphic rock?

[Dru]

Shale is a slightly metamorphosed mudstone. Mudstone---> shale---> slate---> schist.

[Szyjakowski]

shale----slate---phyllite----schist----gneiss----mylonite

[Dru]

Granite---->Szyjakowski's head----->Scar---->Beer

[Szyjakowski]

no no no. granite----szyjakowski's head---scar----bt---beer---climbing