[dkv (OP)]

There was research that rocks show periodic "breathing" pattern.
Is it true?

[rosy]

No idea... do you have a reference (link to the research, or to a news story about the research)?

[JimBob]

I need more info before I can even begin to answer this question. What exactly do you mean by "breathing"? Respiration does not happen in geology, so it must refer to some other process.

I'll be glad to help if I understand what you mean.

By the way, I don't think I have welcomed you to the forum yet. WELCOME!

[dkv (OP)]

Thanks .
I read an scientific article by a French Geologists.
He claimed that rocks breath... they inhale and exhale air at a very very slow rate ...
It takes weeks to follow the process.

[Ophiolite]

Interesting. do you recall the name of the geologist, or the jounral it appeared in, or any further information?

[frethack]

Hmmmm...could it be something to do with thermal expansion and contraction moving air in and out of the void spaces in rocks???

I brought a nice chunk of arkose with a WHOLE lot of hematite spherules from the dry environment in Austin to the wet (understatement) environment in Houston, and lo and behold, the hematite oxidized further and fell off of the outer surface.  I could still break the arkose to get a fresh surface, but the spherules would again weather off.  Seems that if this particular rock were to breathe, that the hematite throughout the interior of the stone would begin to oxidize further as well, instead of waiting to be exposed.

Then again...arkose is pretty poorly sorted, and may not have much void space.

Hmmmmmm

[frethack]

BTW...the facies that I found this sample in was faulted (normal fault...at least 10 meters of throw) One side of the fault (hanging wall) had almost no hematite, and the other side was chock full of it.  If I remember correctly, the formation was once an alluvial fan.  Would the mismatched presence of hematite be caused by the precipitation of iron from the feldspar at the top of the fan to the base of the fan before the formation was faulted?

[dkv (OP)]

I think you are close.
the pores act as ventilators somehow the inner oxidation takes time(periodic) in weeks to form oxidised substances inside the rock which on futher exposure releases different gas(or gases)..

[Bass]

BTW...the facies that I found this sample in was faulted (normal fault...at least 10 meters of throw) One side of the fault (hanging wall) had almost no hematite, and the other side was chock full of it.  If I remember correctly, the formation was once an alluvial fan.  Would the mismatched presence of hematite be caused by the precipitation of iron from the feldspar at the top of the fan to the base of the fan before the formation was faulted?

Hematite most likely from weathering of iron-bearing minerals (not feldspar).  Is the hematite restricted to the fault zone, or is it found throughout the footwall?

[JimBob]

Arkose often contains iron oxide as a cementing agent - thus it usually red color although the high feldspar percentages can sometimes cause it. I would think that the cementing agent for the fan changed during its diagenisis from a silicate or calcitic agent to a hematitic agent might be one explination.

However the telling thing to me is the fact that the hematite was in spherules. This type of hematite is most often found in fluvial systems. If it was washed into the fan from a source high in fluvial sediments, then it would have been concentrated further.

Hmmmm... .... from the dry environment in Austin to the wet (understatement) environment in Houston, and lo and behold, the hematite oxidized further and fell off of the outer surface.

THIS IS THE ANSWER ! You left Paradise for Hell. You now live in the Devil's sauna. WHY WHY WHY Oh, you poor lost soul!

(I suspect it is because that is where the job was. It is the reason I moved there. But after 12 years of Houston in the 70's & 80's I cam back to Austin. I am now much happier. and still able to survive as a geologer.

[frethack]

Hematite most likely from weathering of iron-bearing minerals (not feldspar).  Is the hematite restricted to the fault zone, or is it found throughout the footwall?

The spherules are pretty uniform throughout the footwall...well what I could see of it anyway.  The whole outcrop stretches for a hundred yards or so in both directions from the fault zone(Its a roadcut).  Also, the formation dates back to the Grenville Orogeny (~1,000 Ma) and sits on top of a massive granite batholith with a pretty high iron content...called "Texas Pink"...Enchanted Rock is part of this.

(I suspect it is because that is where the job was. It is the reason I moved there. But after 12 years of Houston in the 70's & 80's I cam back to Austin. I am now much happier. and still able to survive as a geologer.

Nope...thats where home, and school are (sad I know...I might be the only geo student in the world who has never seen a mountain up and personal...oh well...shoreline processes for me *sigh*). 

THIS IS THE ANSWER ! You left Paradise for Hell. You now live in the Devil's sauna. WHY WHY WHY Oh, you poor lost soul!

Houston is actually pretty mild this year, but there has been a WHOLE lot of rain.  I think we have seen one 100 degree day all year long, and most of the summer has been in the mid to high 80s, including August and September.  Strange that this weather change comes at the same time as solar minimum, and that the last time we had conditions this wet (to be read "not in a drought"), it was solar minimum also.  Hmmmmmm

[dkv (OP)]

What happens to a rock if it kept in
a) near vacuum.
b)Kept in inert atmosphere.
In both cases I assume that rock will undergo a change in shape , size and/or color. I imagine it will break  but there are asteroids ....which withstand space.
What is your opinion?

[amonceaux]

I know that I have come into this discussion late - but I read a similar article and am trying to locate it.  Does anyone have information on the article referred to herein?