What is Moonmilk?

[Dep]

...
It could be aragonite.
...

Probably is, it has the exact same 'cauliflower' appearance.

 

[Peter Burgess]

Write up now slightly amended.

http://www.wcms.org.uk/pages/barons_efflorescence_jan2007.shtml

... and more investigations in hand. White growth appears to have an interesting distribution, not controlled by geological features of the sandstone. Geophys of the lawn above the cave would be very useful!

 

[Limestone_Cowboy]

I agree it could be aragonite, however aragonite is not technically a stable phase at the surface of the earth. It can grow at the earths surface however if the partial pressure of CO2 is increased or through the action of sea creatures who grow it in their shells although that is not much help in this case.

 

[Dep]

What about in water with a high CO2 content?

 

[Peter Burgess]

Perhaps I'd better stop thinking so much. OK if it isn't aragonite, is it calcite? Are the needle-like crystals in the photo typical of calcite? What mineral are those anthodite (is that the right word?) crystals in that Quantock cave which I've forgotten the name of? Aren't they a form of CaCO3?

Time to lie down after so much thinking.

 

[Limestone_Cowboy]

I fear I may have to go pick the brains of one of the carbonate geologists here in Liverpool as I am but a lowly hard rock geologist (metamorphic and igneous) and only have some knowledge of sedimentary rocks. I'll get back to you guys on this one, it may turn out to be aragonite after all.
Peter I've never heard of anthodite but then again there are hundreds of weird minerals out there I don't know the name of.

 

[Peter Burgess]

It so happens I have my Mendip 'pamphlet' with me. The cave with anthodite in it is Holwell Cavern. The 'pamphlet' says that the cave is one of only three caves where anthodites (clusters of aragonite flowers) can be found.

 

[Dep]

I thought aragonite was also associated with evaporites?
Such as the flowers within (not on top) of this water trough
http://www.wcms.org.uk/cgi-bin/wcmsgallery.pl?galid=list;ilist=791,792;slide=1

On a related note I've often wondered if aragonite might also not have something to do with helictites.
But I admit I am pushing the boundaries of what I actually know for sure here!

 

[Dep]

...
But I am very sure this occurs elesewhere in Reigate, Peter told me he did not find it in another nearby site where I had said I was sure I had seen it, I shall have another look as I am sure it's there but cannot remember exactly where.
...

Was in TRE a few days ago. Had a good wander around with PWS looking for this. Found it in a few places. In the long E-W gallery to the extreme south. It is halfway down along the north wall by the big concrete step.
A few lesser bits elsewhere.
All have brickwork close by.
PWS agrees insignificant CaCO3 in rock to produce it so must be 'foreign'.
Didn't have time for good check of TRE but MT thinks might be in far east side near display of old kit.

Also intrigued as to what black deposit is. In some places too localised and strangely distributed to be lamp/candle soot alone.

PWS showed me on a plan where known archaeological evidence suggests buildings were. Very good correlation to your composite photo of the roof.

 

[Peter Burgess]

I am putting together an overlay of the photo composite of the roof and the cave plan and the plan of the castle grounds, and should have it written up soon - other stuff permitting.

 

[Dep]

Cool - I look forwards to it. Newsletter content?

 

[ditzy 24//7]

is moonmilk poisonus?

 

[graham]

is moonmilk poisonus?

Doubt it, it's probably not even poisonous.

 

[ditzy 24//7]

ok am i right in thinking moonmilk is the white stuff you get on the rocks in caves?

 

[Dep]

is moonmilk poisonus?

It wasn't when I tried it - but I only had a little bit just in case.

If you wish we can send you a bagful to try out - you can have as much as you can eat.
I gather you have relatives in this forum so if the worst happens they can let us know you gave your life to science.


If CaCO3 is poisonous then it has some serious implications for caving 
Make sure you wash your hands afterwards!

 

[graham]

ok am i right in thinking moonmilk is the white stuff you get on the rocks in caves?

One of them, yes.

 

[Peter Burgess]

It's the stuff that millions of years ago turned into the cheese that constitutes 95 percent of the moon hence the name.

 

[Les W]

Moonmilk is the soft white deposits (white mud) that is found in some caves. It is thought to be caused by a bacteriological process, eg. bacteria are causing the deposition of "soft" calcite based formations. nobody is absolutely sure of the causes and it may be that there is more than one cause and even more than one type of moonmilk.

I see from the preliminary program from this years BCRA cave science symposium that there is a paper being presented on this very topic:-

Moonmilk: a biogenic precipitate? (Alison Blyth and Silvia Frisia)

 

[Dep]

ok am i right in thinking moonmilk is the white stuff you get on the rocks in caves?

One of them, yes.

...and moonmilk is probably one of the few types 'white stuff on rocks' that _isn't_ poisonous or at least inedible.

 

[Dep]

Instead of moonmilk do you get suncream in caves near the seaside?