The Naked Scientists

The Naked Scientists Forum

Author Topic: Geology Question of the Week  (Read 166797 times)

Offline Chemistry4me

  • Neilep Level Member
  • ******
  • Posts: 7709
    • View Profile
Geology Question of the Week
« Reply #150 on: 03/04/2009 06:15:43 »
Spelunkers? ???
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Geology Question of the Week
« Reply #151 on: 05/04/2009 00:30:22 »
Spelunkers? ???

Why yes, C4 It is always useful to have a dictionary around or on yuor computer. Here iss what mine says:

spe-lunk-er (spi lung'kuhr)  n.
                  1.  a person who explores caves, esp. as a
                       hobby.
             [1940-45; < L spelunc (a) cave (< < Gk spêlynx, s.
             spelyng-, akin to spélaion; cf. SPELAEAN) + - ER 1]
   Derived words
             --spe-lunk'ing, n.

frethac tried to explain it to me - the production of CO2 form plant material during winter inhibits the chemical process he posted and thus somehow causes solubility of the carbonate to be less. - heck I'll get him to post it when he gets home from work. As a lowly student - albeit an excellent one - he needs to have a part time job. I will call him and put us all out of our misery with a decent answer to the poser he posted.
 

Offline frethack

  • Sr. Member
  • ****
  • Posts: 394
    • View Profile
Geology Question of the Week
« Reply #152 on: 05/04/2009 16:13:53 »
Quote
Heres the stoichiometry...maybe that will help?

CaCO3 + 2H+ = Ca2+ + H2O + CO2(gas)

It would also help to post the correct stoichiometry...sorry guys!  ;D

Ca+2(aq) + 2HCO3-(aq) <---> CaCO3(s) + CO2(g) + H2O(l)

The above is the degredation of bicarbonate (a product of carbonic acid) into calcium carbonate.

Biological production during the spring/summer months generally increases soil CO2, which dissovles into groundwater, forms carbonic acid (and later bicarbonate), and seeps into the cave system.  As excess CO2 builds up from increasing soil production and limited ventilation of the cave atmosphere the reaction that forms the speleothems (stalactite/stalagmite/helectite etc.) is driven backward, which keeps the bicarbonate in solution and limits speleothem growth.
« Last Edit: 05/04/2009 16:17:08 by frethack »
 

Offline maruti.int

  • First timers
  • *
  • Posts: 2
    • View Profile
Geology Question of the Week
« Reply #153 on: 04/06/2009 04:12:29 »
Dear All
           How are you, I have a unique problem for you guys. I have a Sand stone(image is attached), This sand stone is having base colour of yellow. and there are Red and White Veins in between. These white veins are made of Milk Quartz. We want to change the colour of these white veins into red. Please tell us the way to do it.
regards
varun agarwal
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Geology Question of the Week
« Reply #154 on: 08/06/2009 00:16:27 »
History of this rock??



« Last Edit: 08/06/2009 00:19:39 by Bass »
 

Offline Solius

  • First timers
  • *
  • Posts: 8
    • View Profile
Geology Question of the Week
« Reply #155 on: 08/06/2009 07:12:10 »
A re-worked arenite peeble that has under gone tensional stresses associated with some orogeny???(quartz veins?) Too, some graded bedding indicative of the paleo flow regime in the original environment.???

hey, I'm, trying.
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Geology Question of the Week
« Reply #156 on: 08/06/2009 15:55:49 »
Picked this up in NW Montana yesterday whilst waiting for a horse show.  Looked like lots going on for such a small rock - just thought I'd throw it out for discussion.  Exposures in the area are upper Belt Supergroup (Missoula Group).
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Geology Question of the Week
« Reply #157 on: 16/06/2009 03:54:10 »
When I look at this rock, I see mud rip-ups, soft sediment deformation, cross-beds and a graded bedding mix of iron stained mudstone, siltstone and sandstone.  Suggests shallow water deposition with differing energies, slumping and channels.  The rock has been slightly metamorphosed to argillite/siltite/quartzite.  After millions of years of burial, this rock was uplifted and eroded, tumbling down some stream or river to give it a rounded shape.

 
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Geology Question of the Week
« Reply #158 on: 17/06/2009 15:58:50 »
WHAT A ROCK!! Find another like it - I want one!!!

And dang, Bass, you don't need to team up with a sedimentologist for your work.  Why did you do it?

There looks to be a bit of bio-turbation (see picture below) but it probably isn't, what with it being Mezoproterizoic. Of course you never know what was around 1.6 Billion Years Ago. Aliens? I'll bet it is just a strange looking rip-up clast

Lastly, what struck me about this specimen was is sub-hexagonal shape. That is easily produced by one set of stress, a shear and the two accommodation ax-es. (hyphen for pronunciation - it is the correct plural) The stress regime was perpendicular to the bedding planes. There are also small-scale load cast? visible. 



 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Geology Question of the Week
« Reply #159 on: 20/06/2009 06:11:36 »
Don't have another one...

would a nice breccia do?
 

Offline Chemistry4me

  • Neilep Level Member
  • ******
  • Posts: 7709
    • View Profile
Geology Question of the Week
« Reply #160 on: 20/06/2009 06:35:54 »
Why can a magmatic nickel deposit could not exist in a felsic host rock?
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Geology Question of the Week
« Reply #161 on: 20/06/2009 19:34:19 »
Nickel (along with chrome and pge) has an affinity for ultramafic rocks.  They form as immiscible minerals that accumulate due to their density in bands in the crystallizing magma (that is they rain down as discrete particles).
 

Offline Chemistry4me

  • Neilep Level Member
  • ******
  • Posts: 7709
    • View Profile
Geology Question of the Week
« Reply #162 on: 21/06/2009 00:38:29 »
The thing is, I don't really have an answer.... ::)
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Geology Question of the Week
« Reply #163 on: 21/06/2009 15:56:13 »
Hey dude - we are geologist - not chemist or even geochemist. Those guys are weird - really weird!
 

Offline Chemistry4me

  • Neilep Level Member
  • ******
  • Posts: 7709
    • View Profile
Geology Question of the Week
« Reply #164 on: 22/06/2009 03:50:14 »
Okay dudes, how about: What occurs when a smectite mineral swells?
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Geology Question of the Week
« Reply #165 on: 23/06/2009 00:45:25 »
It gets a smec tighter ::)
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1340
  • Thanked: 5 times
    • View Profile
Geology Question of the Week
« Reply #166 on: 23/06/2009 15:12:55 »
Smectites are phyllosilicate clays (montmorrillonite, nontronite) composed of an octohedral sheet sandwiched between two tetragonal sheets.  (just thought I'd throw a little jargon out there- helps to keep the rifraff in the profession)

What that mouthful means is that, when water is added, the clay can absorb the water and trap it between the sheets, which causes swelling.  Water is lost between the sheets as conditions turn dry, allowing shrinkage.
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Geology Question of the Week
« Reply #167 on: 23/06/2009 15:22:47 »
It becomes FURTHER hydrated. Water in the interstitial spaces of this phyllosilicate make it slick as greased owl sh1t.

Just what are you looking for C4 - some chemical reaction? Or do you wear cosmetics made of this stuff and are having problems when your face gets wet?

I can't help with that.

Will call later today, Bass
 

Offline Chemistry4me

  • Neilep Level Member
  • ******
  • Posts: 7709
    • View Profile
Geology Question of the Week
« Reply #168 on: 24/06/2009 04:42:49 »
It was simply a geology question of the week (supposedly).
 

Offline CreativeEnergy

  • Jr. Member
  • **
  • Posts: 28
    • View Profile
    • Eric's Journal
Geology Question of the Week
« Reply #169 on: 15/08/2010 18:43:49 »
Since I'm new here, I'm not sure whether or not the question has been answered. But in the event that it hasn't I offer this.

It is correct that the red color in sandstone is due to iron oxide. As for the patches of green, the primary minerals that make up sandstone are quartz and feldspar. Therefore, I would imagine that the green color is due to the alkali feldspar, microcline (KaAlSi3O8). But, I'm just guessing here.
« Last Edit: 15/08/2010 20:13:25 by CreativeEnergy »
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Geology Question of the Week
« Reply #170 on: 04/01/2011 04:52:29 »
iron on the red and iron on the green, just different valences for the Fe.  Copper is a very small, remote possibility for the green. It is a very unusual possibility.
 

Offline katesisco

  • Jr. Member
  • **
  • Posts: 42
    • View Profile
Geology Question of the Week
« Reply #171 on: 16/05/2011 17:53:11 »
I like Dr Ward's reference to this massive deposit of red soil in his African hunt for animals from the K/T die off.  He looks around and it is red everywhere.  And he is not high in elevation; it is oxidized iron.  The seas had receded although he doesn't state how far, I propose as low as only a couple miles of water from the sea bed up.  If one was to seriously consider that our E is circled N and S of the Equator by plasma as NASA proposes, then it is not inconceivable that the seas experienced massive beyond thinking electrical charges ala Birkeland current and that this charge separated the contaminants from the water.  The result of course, would be pure water but incomplete from the point of view from all living creatures which need minerals to survive.  It may have begun farming and cattle raising for the protein and the never-ending war for possession of surface water ala Jericho and its ever-flowing spring sufficient to wash the accumulation of salts away.  A prize fought over ever since. 
 

Offline JimBob

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 6564
  • Thanked: 7 times
  • Moderator
    • View Profile
Re: Geology Question of the Week
« Reply #172 on: 23/07/2015 22:51:07 »
How do you tell the hardness of a rock? What is a streak. And why are these two things important in identifying rocks?  How do you figure out these two properties?
 

The Naked Scientists Forum

Re: Geology Question of the Week
« Reply #172 on: 23/07/2015 22:51:07 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums