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Author Topic: What process created this?  (Read 16956 times)

Offline Bass

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What process created this?
« Reply #25 on: 04/02/2009 18:16:37 »
So #6 rock is a gneiss.
And the red intrusions?
low-grade garnet?  or?  [?]

Possibly garnet, but more likely iron staining (iron oxides)
 

Offline JimBob

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What process created this?
« Reply #26 on: 04/02/2009 20:04:03 »
Beem, you guessed right!! [:0]

Quote
Oh, Oh, someone get Bass into his chains.! This is his favorite rock - a breccia. He will surely give the lecture on this specimen.

And since JimBob asked so nicely...

Tectonic breccia- no doubt.  Note that the clasts are all the same material, and that there is little rotation with matching boundaries.

Solution collapse breccias typically contain a mix of clast types (but not always), and the clasts are obviously displaced- rotated, no matching clast boundaries, may be rounded, and are commonly coated with calcite rims or drusy calcite and/or quartz.

There are two obvious fault structures cutting the rock, one from the upper right to the lower left, and another from the upper left to the middle where it gets cut off by the first fault.

Bass, you are a Lord among men.

_____________________________

Hey, all the rest of you rabble, it is time to storm the castle and dispose of the despot!
 

Offline Bass

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What process created this?
« Reply #27 on: 04/02/2009 20:19:11 »
Chatter chatter shiver
clank clank

slowly drags his chains through the cold, dark dungeon in a solution cavity... :P
 

Offline JimBob

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What process created this?
« Reply #28 on: 05/02/2009 01:46:16 »
It is called an oubliette.
 

Offline beem

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What process created this?
« Reply #29 on: 05/02/2009 18:25:42 »
Oubliette-residents come out and see the light of day, just like this fossilized leaf:



Obviously a sedimentary deposit, is it a birch leaf?  beech? alder?  elm?
Leaf is 4.6 mm long. 

 

Offline Evie

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What process created this?
« Reply #30 on: 25/02/2009 20:06:23 »
Some educated guesses based on leaf shape are black cherry, beech, white birch, or ash; I would lean towards the last two.

This site told me it could be a common pear: http://www.ag.auburn.edu/hort/landscape/leafid/index.php/

Give it a try!
 

Offline dentstudent

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What process created this?
« Reply #31 on: 25/02/2009 20:39:50 »
Sorry - Did you say 4.6 mm long? That is very small!
 

Offline JimBob

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What process created this?
« Reply #32 on: 26/02/2009 01:02:21 »
Some educated guesses based on leaf shape are black cherry, beech, white birch, or ash; I would lean towards the last two.

This site told me it could be a common pear: http://www.ag.auburn.edu/hort/landscape/leafid/index.php/

Give it a try!

Hi Evie,

Good to see you again!

Post a question and liven up this coffin!
 

Offline beem

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What process created this?
« Reply #33 on: 28/02/2009 22:47:36 »
sorry that leaf length is 46 mm.

Thanks for the leaf link...common birch seems most likely.

Rock #7, sorry for poor quality.


Thanks!

 

Offline DoctorBeaver

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What process created this?
« Reply #34 on: 01/03/2009 18:32:15 »
Welcome to the inaugural meeting of the RHSAS (Rock Huggers Self-Appreciation Society)  ;D
 

Offline frethack

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What process created this?
« Reply #35 on: 01/03/2009 20:08:29 »
Looks like you have a very nice gneiss on your hands.
 

Offline JimBob

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What process created this?
« Reply #36 on: 03/03/2009 03:11:47 »
Welcome to the inaugural meeting of the RHSAS (Rock Huggers Self-Appreciation Society)  ;D

Hello, I would like to thank the president of the society for starting this farce - er, group. We will hold meetings ever day, all day and throw the rock we are hugging at other members. Thank you for drooping by - and we do mean droop.

 

Offline Bass

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What process created this?
« Reply #37 on: 04/03/2009 16:56:35 »
Rock #7, sorry for poor quality.


Thanks!

Quote from: frethack
Looks like you have a very nice gneiss on your hands.

Not so sure that this rock is a gneiss.  Beem, how hard are the white and dark layers in this specimen, can you scratch them with a knife?

Looks more like a sedimentary rock (shale? carbonate?) with solution/replacement veins (quartz? calcite?)  Can you try dripping a bit of hydrochloric acid on the rock?

Your photo is upside-down, I instinctively try to duck out of the way so it won't hit me when it falls off the computer screen
 

Offline beem

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What process created this?
« Reply #38 on: 04/03/2009 18:14:05 »
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how hard are the white and dark layers in this specimen, can you scratch them with a knife?
That'll have to wait a while...it's presently still under a foot of snow.  :(

So much for my orienting the image...
Hanging rock...so not to trip over it  :D
Thanks.
 

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What process created this?
« Reply #38 on: 04/03/2009 18:14:05 »

 

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