The Naked Scientists
  • Login
  • Register
  • Podcasts
      • The Naked Scientists
      • eLife
      • Naked Genetics
      • Naked Astronomy
      • In short
      • Naked Neuroscience
      • Ask! The Naked Scientists
      • Question of the Week
      • Archive
      • Video
      • SUBSCRIBE to our Podcasts
  • Articles
      • Science News
      • Features
      • Interviews
      • Answers to Science Questions
  • Get Naked
      • Donate
      • Do an Experiment
      • Science Forum
      • Ask a Question
  • About
      • Meet the team
      • Our Sponsors
      • Site Map
      • Contact us

User menu

  • Login
  • Register
  • Home
  • Help
  • Search
  • Tags
  • Member Map
  • Recent Topics
  • Login
  • Register
  1. Naked Science Forum
  2. Non Life Sciences
  3. Geology, Palaeontology & Archaeology
  4. Rocks Rocks Rocks !!...But What is Rock ?
« previous next »
  • Print
Pages: 1 [2]   Go Down

Rocks Rocks Rocks !!...But What is Rock ?

  • 34 Replies
  • 29940 Views
  • 0 Tags

0 Members and 1 Guest are viewing this topic.

Offline Bass

  • Naked Science Forum King!
  • ******
  • 1385
  • Activity:
    0%
  • Thanked: 16 times
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #20 on: 20/11/2007 22:59:22 »
Quote from: JimBob on 18/11/2007 18:03:45

Sedimentary rocks - rocks that have been weathered from another rock - doesn't matter what type - and formed in water or transported by water. Alluvial fans conglomerates that have formed on a mountainside and cemented by subsequent deposition of a substance, such as calcite, are sedimentary rocks even if they were not formed under water.


JimBob, I'm surprised a soft rocker (folks who study sedimentary rocks) like yourself would include only clastic (made up of particles eroded from other rocks) rocks as sedimentary rock.  Other sedimentary rocks, like limestone and coal, are created from biogenic activity- animal and plant remains that accumulate and are lithified.  There are also chemical precipitates, such as evaporites, gypsum and certain iron formations.

Quote
NO, Ignimbrites (volcanic ash that falls hot in the air then solidified while still hot) are NOT sedimentary rocks. Whats wrong with you guys???

 
However, lahars are classified as sedimentary rocks.  A lahar is basically a volcanic mudflow, commonly occurring during the eruption of stratovolcanos.  Hot waters circulating in the volcano alter the rocks into clays; when mixed with water (snowmelt or surface waters), becomes a muddy mess that can quickly move down the slopes and runoff channels.  How would you classify hydrothermal sinter or travertine (I've seen it both as sedimentary and igneous)?

Quote
Igneous rocks - formed from molten material. They are the most dense and the least dense of all rocks. Puzzled, think pumice - it can float if enough air is trapped in it.

Probably right as far as the least dense rocks- however, I've also seen some chalk rocks (sedimentary) that will float.  Not sure about most dense- some mineral deposits classified as sedimentary are more dense than "formed from molten material" rocks.  Metamorphic rocks can also be very dense, especially silicated rocks.

Quote
Metamorphic rocks - rocks that have been partially melted/chemically altered and reformed. These can range form incipiently metamorphic rocks which can form at at low temp - pressure (6 km depth and 150° C). There are subtle changes in this  type of metamorphic rock, grains are slightly altered in shape, some changes in cementing, some changes in chemistry but basically still the same rock and differences only detectable under a microscope. Other metamorphic rocks can form from an almost complete remelting and recrystallization. The typical ones thought about are those that were the former consistency of toothpaste.
A better definition for metamorphic rocks- rocks that are changed by physical or chemical processes in response to heat and/or pressure- but not to the point of melting.  Once melting occurs, the rock is considered igneous.

This is nit-picking.  JimBob's definitions are more than adequate for the 3 types of rocks that occur on earth.
« Last Edit: 21/11/2007 01:44:14 by JimBob »
Logged
Old enough to have grandsons
Slow enough to study rocks
Thirsty enough to build a pub
 



Offline JimBob

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6543
  • Activity:
    0%
  • Thanked: 8 times
  • Moderator
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #21 on: 21/11/2007 01:44:56 »
R.H.I.P.
Logged
The mind is like a parachute. It works best when open.  -- A. Einstein
 

Offline Bass

  • Naked Science Forum King!
  • ******
  • 1385
  • Activity:
    0%
  • Thanked: 16 times
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #22 on: 21/11/2007 03:38:25 »
Relativistic Heavy Ion Physics?? [::)]

(this is a science forum after all)
JB will probably come up with some rank acronym
Logged
Old enough to have grandsons
Slow enough to study rocks
Thirsty enough to build a pub
 

Offline Alandriel

  • Hero Member
  • *****
  • 520
  • Activity:
    0%
  • Thanked: 8 times
    • View Profile
    • Some of my photography
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #23 on: 21/11/2007 17:50:24 »
WOW - you've done a fly by of Titan? That must have been.... erm.... titanic

 [;D]


Ok ok..... can I now please take my foot out of my mouth

... thank you!  [;D] saunters off to NASA (not another silly acronym)
Logged
 

Offline JimBob

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6543
  • Activity:
    0%
  • Thanked: 8 times
  • Moderator
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #24 on: 23/11/2007 00:01:15 »
Yes, it was Titanic but when I left orbit I had a sinking feeling I would never get back there.

 [V]
Logged
The mind is like a parachute. It works best when open.  -- A. Einstein
 



Offline Sarah Elizabeth

  • Jr. Member
  • **
  • 13
  • Activity:
    0%
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #25 on: 17/12/2007 15:25:58 »
i really love rocks and geology is my favourtie subject next to geography !!some sedimentary rocks are basically the broken up and weathered remains of  igneous and metamorphic rocks. other sedimentary rocks have been formed simply from layers adding ontop of one another, and sedimentation occuring to make them rock-like haha . Igneous rocks are volcanic and made in very high pressure and high temperature environments where as Metamorphic rocks were once sedimentary ( and in rare cases igneous) and theyve been heated intensely and had alot of pressure put on them to recreate rocks of a metamorphic composition... my favourites, Gneiss and Schist... god you have to love them :P 
Logged
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • 31794
  • Activity:
    0%
  • Thanked: 25 times
  • "come fly with me"
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #26 on: 19/12/2007 22:38:25 »
OK here are some rocks what can you tell me about them.. I found them today on my walk..What kind are they?








 



« Last Edit: 19/12/2007 22:44:14 by Karen W. »
Logged

"Life is not measured by the number of Breaths we take, but by the moments that take our breath away."
 

Offline Bass

  • Naked Science Forum King!
  • ******
  • 1385
  • Activity:
    0%
  • Thanked: 16 times
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #27 on: 19/12/2007 23:45:35 »
Hi Karen
I particularly like the green rock.  Can you tell me any more about it?  Can you scratch it with a knife?  Does it feel smooth, or rough?  Can you see any crystals in it?
The larger piece has some obvious veins in it, I would guess quartz.  Also some iron staining.
The small dark red rock is probably jasper.
With the possible exception of green rock, they are probably all sedimentary- although they've probably all been altered (or changed) since deposition.  It appears that all these rocks may have been silicified (silica added), making the rocks harder.
Logged
Old enough to have grandsons
Slow enough to study rocks
Thirsty enough to build a pub
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • 31794
  • Activity:
    0%
  • Thanked: 25 times
  • "come fly with me"
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #28 on: 20/12/2007 00:55:58 »
Nope can't scratch it with a knife Smooth on one side and has some texture on the other side. It has some teeny tiny holes on the smoother side harly visible like you might have seen if it were to boil. needle size tiny needle.

No crystals that I can see but it is super hard and pretty green.. me favorite color!

The big rock the picture is deceiving.. It is not that color It is burgandy around the bottom with whit splashes On the top there is a large white section on the back..





Logged

"Life is not measured by the number of Breaths we take, but by the moments that take our breath away."
 



Offline Bass

  • Naked Science Forum King!
  • ******
  • 1385
  • Activity:
    0%
  • Thanked: 16 times
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #29 on: 20/12/2007 04:42:57 »
larger rock may be volcanic?  Hard to tell from the picture.
Logged
Old enough to have grandsons
Slow enough to study rocks
Thirsty enough to build a pub
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • 31794
  • Activity:
    0%
  • Thanked: 25 times
  • "come fly with me"
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #30 on: 20/12/2007 06:15:13 »
Oh dear that middle picture is so blurry..Sorry.. aai will try tomorrow to get a better one. Thanks bass.

What did you think the green one was?
Logged

"Life is not measured by the number of Breaths we take, but by the moments that take our breath away."
 

Offline Bass

  • Naked Science Forum King!
  • ******
  • 1385
  • Activity:
    0%
  • Thanked: 16 times
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #31 on: 20/12/2007 17:57:18 »
The color is close to fosterite (ultramafic mineral), but my guess would be diopside/augite (mafic minerals).  Minerals can be divided into two end spectrums- mafic and silicic.  Mafic minerals tend to be iron, magnesium and calcium rich.  In general, ultramafic and mafic minerals come from the mantle, silicic minerals from the continental crust.  Fosterite, diopside and augite would form as metamorphic minerals from mafic igneous rocks, which is reasonable for your location.
Logged
Old enough to have grandsons
Slow enough to study rocks
Thirsty enough to build a pub
 

Offline neilep (OP)

  • Withdrawnmist
  • Global Moderator
  • Naked Science Forum GOD!
  • ********
  • 20783
  • Activity:
    0%
  • Thanked: 51 times
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #32 on: 20/12/2007 19:01:35 »
I know all about Rocks !

Here is is my expert evaluation of Karens Rocks.


 [ Invalid Attachment ]


Glad I could help.

* Rocksfrommywalkdowntheroad011.jpg (48.67 kB, 597x349 - viewed 916 times.)
Logged
Men are the same as women, just inside out !
 



Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • 31794
  • Activity:
    0%
  • Thanked: 25 times
  • "come fly with me"
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #33 on: 20/12/2007 21:10:32 »
WOW.. YOU are amazing...What Knowledge lies in that Brain of yours!!! HEE HEE HEE! LOL..Thanks for the Info!
Logged

"Life is not measured by the number of Breaths we take, but by the moments that take our breath away."
 

Offline Karen W.

  • Moderator
  • Naked Science Forum GOD!
  • *****
  • 31794
  • Activity:
    0%
  • Thanked: 25 times
  • "come fly with me"
    • View Profile
Rocks Rocks Rocks !!...But What is Rock ?
« Reply #34 on: 20/12/2007 21:16:49 »
Quote from: Bass on 20/12/2007 17:57:18
The color is close to fosterite (ultramafic mineral), but my guess would be diopside/augite (mafic minerals).  Minerals can be divided into two end spectrums- mafic and silicic.  Mafic minerals tend to be iron, magnesium and calcium rich.  In general, ultramafic and mafic minerals come from the mantle, silicic minerals from the continental crust.  Fosterite, diopside and augite would form as metamorphic minerals from mafic igneous rocks, which is reasonable for your location.

The green one is very beautiful. Do you think it could be cut into a heart shape And polished?? I could not even scratch it with a knife.. I love the color and would also like to make a necklace out of it!

What about the red one? Do you think it could be made into a single stud earring?
It really is not orangy red? Sorry Neily it is quite brite red...! My camera does not seem to be doing a good job with closeups or the color.. LOL! Really, it is the photograper! LOL..!! Me is not good with a camera! LOL~!
Logged

"Life is not measured by the number of Breaths we take, but by the moments that take our breath away."
 



  • Print
Pages: 1 [2]   Go Up
« previous next »
Tags:
 

Similar topics (5)

What is the "rock cycle"?

Started by gurpalBoard Geology, Palaeontology & Archaeology

Replies: 2
Views: 11463
Last post 30/08/2009 02:35:40
by JimBob
need help identifying this "rock"

Started by dragan986Board Geology, Palaeontology & Archaeology

Replies: 3
Views: 6213
Last post 15/04/2015 16:24:51
by dragan986
Can someone help identify the orgin of this cross "+" in this strange rock?

Started by MgretchenBoard Geology, Palaeontology & Archaeology

Replies: 10
Views: 11037
Last post 08/01/2011 11:25:32
by Foolosophy
Have I found gold? It's a black and white layered rock with gold chunky flakes

Started by eschindler7714@gmail.comBoard Geology, Palaeontology & Archaeology

Replies: 2
Views: 3520
Last post 05/10/2018 19:52:27
by gwynhefar
I found a rock that looks like green onyx or similar with a pale blue area?

Started by chloeBoard Geology, Palaeontology & Archaeology

Replies: 3
Views: 4257
Last post 04/05/2010 12:26:57
by PhysBang
There was an error while thanking
Thanking...
  • SMF 2.0.15 | SMF © 2017, Simple Machines
    Privacy Policy
    SMFAds for Free Forums
  • Naked Science Forum ©

Page created in 0.136 seconds with 69 queries.

  • Podcasts
  • Articles
  • Get Naked
  • About
  • Contact us
  • Advertise
  • Privacy Policy
  • Subscribe to newsletter
  • We love feedback

Follow us

cambridge_logo_footer.png

©The Naked Scientists® 2000–2017 | The Naked Scientists® and Naked Science® are registered trademarks created by Dr Chris Smith. Information presented on this website is the opinion of the individual contributors and does not reflect the general views of the administrators, editors, moderators, sponsors, Cambridge University or the public at large.