Andy Sparrow
Active member
I have recently noticed that the entrance passages of Rod's Pot, once devoid of moonmilk, are now displaying areas of dramatically rapid moonmilk deposition. This has led me to reflect on this strange formation and consider its origins. I have found various articles online, some suggesting a mico-biological component but no simple consensus explanation.
I would like to suggest a very simple explanation for the formation of moonmilk. This chalky calcium carbonate deposit is clearly not formed by the dripping or trickling water that forms stals or flowstone. Cave walls are often naturally damp and it seems to me that moonmilk precipitates from this film of moisture. This being the case it raises a question - what mechanism fills the cave air with this fine aerosol of water containing dissolved calcium carbonate? Picture the classic back-lit photograph of the drip landing on the stalagmite and we may have the answer. The drip fragments explosively and a small portion of the water, water containing dissolved calcium carbonate, becomes part of the aerosol suspended in the cave atmosphere. The aerosol is transported by draughts to cave walls where evaporation and/or gassing off of CO2 occurs and calcium carbonate is deposited. There seems to be a 'clumpiness' in the deposition, as if the precipitate deposits preferentially upon itsself.
So why the the new and rapid growth in Rods Pot - what has changed? One obvious answer is the draught. Since the Bath Swallet connection was opened nearly 2 years ago the cave seems to consistently draught out from the Rod's entrance. This seems to be strong evidence to support a correlation between draughts and moonmilk.
Anyway that is ther theory and I welcome other views and comments (even from Graham, (as if I had a choice)).
I would like to suggest a very simple explanation for the formation of moonmilk. This chalky calcium carbonate deposit is clearly not formed by the dripping or trickling water that forms stals or flowstone. Cave walls are often naturally damp and it seems to me that moonmilk precipitates from this film of moisture. This being the case it raises a question - what mechanism fills the cave air with this fine aerosol of water containing dissolved calcium carbonate? Picture the classic back-lit photograph of the drip landing on the stalagmite and we may have the answer. The drip fragments explosively and a small portion of the water, water containing dissolved calcium carbonate, becomes part of the aerosol suspended in the cave atmosphere. The aerosol is transported by draughts to cave walls where evaporation and/or gassing off of CO2 occurs and calcium carbonate is deposited. There seems to be a 'clumpiness' in the deposition, as if the precipitate deposits preferentially upon itsself.
So why the the new and rapid growth in Rods Pot - what has changed? One obvious answer is the draught. Since the Bath Swallet connection was opened nearly 2 years ago the cave seems to consistently draught out from the Rod's entrance. This seems to be strong evidence to support a correlation between draughts and moonmilk.
Anyway that is ther theory and I welcome other views and comments (even from Graham, (as if I had a choice)).