I am interested in finding out more about "ascending" dissolution/erosion shafts/chimneys. To be as clear as I can, I mean those chimneys that are made by vortexes in the ceiling of a gallery by water under pressure (in the phreatic phase formation).

We're exploring a limestone cave that has many such shafts, especially in the ceiling of a main collector gallery, some as high as 40 m - a pleasure to climb artificially just to hit the ceiling closing those leads. Would like to learn more about genesis and morphological distinctive features of such chimneys.

Can you point me to research papers / books / literature about this subject?  I have searched over the internet and found some results but not too many relevant ones so I guess I am not using the correct terminology. I think I have grasped the basic and general genesis mechanism so I am interested in more advanced studies/theories and detailed explanation. As you figured out, I have no geoscience studies so I would like to know the dedicated terminology used in English as well to be able to search better. Thanks in advance.


I am not interested in the particular case of cave genesis by thermal water dissolution - I know that there are theories that say that many cavities were formed by geothermal processes but I guess that is a different thing.

I don't think vortices / physical abbrasion is the main causal factor in most cases. The only example I can remember seeing described in a scientific paper relates to the celebrated Torricellian Chamber in Peak Cavern's Buxton Water Sump. However, this provides a hypothesis about how a vortex (in flood) might drag air in or out, altering the water level in the airbell at the top from flood to flood (i.e. it doesn't use the vortex idea to explain the existence of the roof dome). Without looking it up I think the title of the paper was along the lines of "Water at a depth of -5 ft in Buxton Water Sump, Peak Cavern". (The "-5 ft" refers to the water level being 5 ft [about 1.5 metres] above that at either end of the sump. The author was R E Davies and it was published in Nature magazine in the early 1950s.

The answer to the riddle may be more related to the fact that water in sumps often becomes layered, with more aggressive water being trapped in roof domes by denser, less aggressive water beneath. As a result there is more rapid dissolution upwards in the domes than in the main part of the active phreatic conduit, so they extend upwards forming blind shafts. Once the phreatic passage is drained and we cavers explore them, these joint guided shafts look like juicy leads but are usually blind. There is a short paper about the role of hydrostratification in the "Scientific Notes" in the back if an issue of BCRA Cave Science from about 1991 (again, from memory).

Hope that helps.

Geothermal water may also have an impact, as presumably the warmer water would rise to the top & it can dissolve more limestone / faster than cold water.

My greatest knowledge of caves (particularly underwater ones) is in the Dales. Here we have very few where geothermal effects are likely to have been involved. (The Northern Dales area may be a different matter but let's not go there, to keep things simple.)

I've done a small amount of work on this hydrostratification in our Dales sumps on and off over the years, although I've not taken this very far yet. One thing I can confirm however is that in a fair number of examples the upper layer is cooler than the lower layer, which suggests the water layering is not due to temperature differences. It's far more likely to be related to the lower layer being denser due to what's dissolved in it.

I always wanted to collect water samples from different layers for chemical analysis to test this idea but never had the offer of laboratory help. If any hydrologists / chemists would be interested in doing a few water analyses, I'll happily get samples from our local underwater caves.

These water layers are often spectacular in Dales sumps because the upper layer is generally peat stained (orange or brown), over a lower (clearer) layer of water with a much higher autogenic content ("percolation water") which may sometimes be crystal clear and blue.

One thing we found was an initially puzzling relationship between overall depth and temperature. We tested this in Hurtle Pot, where a depth of almost 30 m is easily attainable close to the entrance. I can't remember the numbers offhand but I think we got readings of over 1 degree C higher at that depth than just below the surface. We'd been using a liquid in glass thermometer and the increased pressure (4 x atmospheric at -30 m) was probably causing the bulb of the thermometer to deform slightly at depth, pushing the mercury up. I mention this because if anyone else is measuring the temperature of water layers in a big passage (i.e. with a depth difference of several metres between roof and floor) it's worth being aware that temperature readings may not be perfectly comparable if using a liquid in glass thermometer.

Anywhere you get mineral / metal mining has generally had its share of geothermal activity in the past - North Pennines Peak District, Mendip etc

Pitlamp said:

One thing we found was an initially puzzling relationship between overall depth and temperature. We tested this in Hurtle Pot, where a depth of almost 30 m is easily attainable close to the entrance. I can't remember the numbers offhand but I think we got readings of over 1 degree C higher at that depth than just below the surface. We'd been using a liquid in glass thermometer and the increased pressure (4 x atmospheric at -30 m) was probably causing the bulb of the thermometer to deform slightly at depth, pushing the mercury up. I mention this because if anyone else is measuring the temperature of water layers in a big passage (i.e. with a depth difference of several metres between roof and floor) it's worth being aware that temperature readings may not be perfectly comparable if using a liquid in glass thermometer.

Click to expand...

Without knowing the exact conditions, it's worth noting that a strange quirk of water is that it's most dense at approx 4 degrees. I'm not a hydrologic, but based off a quick google search that said that the average temperature of water in caves is around that level, this could be another potential answer?

Hello DaveK - the typical water temperature in Dales sumps is almost always higher than that (thank goodness, for sump floppers like me!). It's only in conditions of winter meltwater that it may get down to 4 degrees C (or occasionally even fractionally lower). In summer after a warm weather flood it might creep up into double figures.

However, if the autogenic proportion of the flowing stream in a sump is fairly high, this tends to smooth out temperature fluctuations caused by what's going on in the atmosphere upstairs. In the Dales, sumps are most often somewhere around 8 degrees C.

Note, we are talking about sumps that are big enough to dive in, so hold a "reservoir" of water. The streamways may well be 4'C in winter (or colder - moving water can be below zero).

Aye - but the issue of depth related thermometer errors in deep sumps doesn't apply to vadose streamways.

The geothermal gradient in the UK is just over 2.5degC/100m. You get some variations, particularly very shallow, but it settles down.

Obviously things like caves with air circulating and taking surface water will have some impact very locally. But the Earth has a monstrous amount of heat in it and wins in the end.

When you are operating at 4000-5000m it really gets quite toasty.

I always assumed this was a dissolution dome. It?s about 140m high in the middle. The interesting bits are no doubt under the floor with no clues as to where. A strange place. If you drop out of the small crack right at the crest it?s really weird having the roof go out horizontally in all directions.