Goredale Beck
- Thread starter braveduck
- Start date
AR
Well-known member
I ought to have paid a lot more attention to the geology when I lived in West Yorkshire and spent a lot of time round Malham and Grassington, but are there any thin shale beds or clay wayboards in the strata that die out to the east? I recall seeing shale to the east of Goredale but that memory could have been influenced by Old Peculier....
I suspect that the old adage 'water sinks underground when it flows onto limestone' is, at best, a half-truth. I think that the only way that caves can form (in limestone) is that there should be a pre-existing network of cracks and fissures for water to penetrate; I've no idea how big they'd have to be, but not mere hair-line cracks like bedding planes and joints in the walls, floors and roofs of caves often appear to be.
If there is no pre-existing network for water to seep or soak into, then you'd have a common-or-garden surface stream, with no cave. So maybe the limestone beds and joints at Gordale are tightly sealed, hair-line cracks, while those further west are more open?
If there is no pre-existing network for water to seep or soak into, then you'd have a common-or-garden surface stream, with no cave. So maybe the limestone beds and joints at Gordale are tightly sealed, hair-line cracks, while those further west are more open?
richardg
Active member
Interestingly a friend (Stoddy - latest UK Caving member) and I earlier today were discussing what cave would exist beneath Gordale Scar
There are sinks along the upper gorge, that would take the entire beck if it were not directed away from them.
There are some very big springs at the foot of the lower gorge
In the book "Caves of North West England" it recalls the year 1899 when the entire beck was engulfed by swallow holes in the upper gorge.
There must surely be a magnificent cave system awaiting discovery at Gordale Scar.
Richard
There are sinks along the upper gorge, that would take the entire beck if it were not directed away from them.
There are some very big springs at the foot of the lower gorge
In the book "Caves of North West England" it recalls the year 1899 when the entire beck was engulfed by swallow holes in the upper gorge.
There must surely be a magnificent cave system awaiting discovery at Gordale Scar.
Richard
Pie Muncher
Member
Caves & Karst of the Yorkshire Dales, pages 89-91 may help to answer your question. There's a little bit specifically about Malham and Gordale. Sinks being blocked appears to be the favoured reason, travertine possible playing a part in sealing holes.
Pitlamp
Well-known member
Hasn't Gordale been incised relatively quickly, from meltwater, as ice receded? If so then the exposed limestone in the present valley bottom won't have been subjected to cave development processes for very long (geologically speaking). In which case one might expect any cave system below it to be relatively immature. This is supported by the fact that only on rare occasions can all of the flow be accommodated by whatever passages do exist underground.
Pitlamp
Well-known member
I've spent many years looking at literature on the Malham area and I've never come across such a documented test. However, I have a vague memory of reading something somewhere about water chemistry work which was suggestive that the water at the sinks and the risings is the same. Rather than direct tracing, perhaps a detailed study of water chemistry (using modern techniques) would be of value?
Wouldn't it be grand if we could get permission to have a go at digging the springs? Mind you, I can't see that being possible - for a variety of reasons. Oh well . . . .
Wouldn't it be grand if we could get permission to have a go at digging the springs? Mind you, I can't see that being possible - for a variety of reasons. Oh well . . . .
richardg
Active member
Thank you Pitlamp.
I was out with a couple of caving buddies checking out some geological stuff above Malham when I took note of the large area of limestone tilting down towards Gordale Scar from the east
I was just contemplating a possibility that the Gore Beck sinks might drain to Malham Cove and that the Gordale Springs might be fed from caves draining the limestone to the east.
The chemical analysis study would be interesting...
I was out with a couple of caving buddies checking out some geological stuff above Malham when I took note of the large area of limestone tilting down towards Gordale Scar from the east
I was just contemplating a possibility that the Gore Beck sinks might drain to Malham Cove and that the Gordale Springs might be fed from caves draining the limestone to the east.
The chemical analysis study would be interesting...
Pitlamp
Well-known member
If you attend the BCRA Malham area hydrology study weekend, scheduled for mid May next year, I suspect there will be plenty of folk around who could answer your questions.
The Malham chapter for part 2 of the Waltham et al Dales Caves & Karst book will be going online soon (I did some proof reading last week); that may also be helpful.
The Malham chapter for part 2 of the Waltham et al Dales Caves & Karst book will be going online soon (I did some proof reading last week); that may also be helpful.
Andy Farrant
Active member
If the stream is depositing tufa, then that suggests the water is saturated with respect to calcium carbonate and thus won't be dissolving anything.
As I understand the geology the water exiting Malham Tarn is quite 'aggressive' in that it contains much dissolved co2 as it is not on limestone, and has co2 added from vegetation as well. Hence it sinks where it does, soon after crossing the limestone boundary. Joint weaknesses may also have been a factor. At Gordale the stream and any tributaries originate on, and cross, mainly limestone. The water absorbs some co2 from rainfall but the thin soils do not contribute a lot. Hence the water is less aggressive and quickly reaches saturation point. As the water falls over Gordale Scar the aeration releases co2, hence the tuff deposits. There was an article published a few years ago with co2 measurements for both becks.
braveduck
Active member
About four weeks ago I was up behind Kilnsy Crag.Looking down on the fishing lakes and was a bit surprised to
see that all the lakes were milky white.This suggests water saturated with dissolved limestone.
I know it is a long way away,but but is there any possibility the Gordale Beck sinks could rise there ! :-\
see that all the lakes were milky white.This suggests water saturated with dissolved limestone.
I know it is a long way away,but but is there any possibility the Gordale Beck sinks could rise there ! :-\
Pitlamp
Well-known member
I think the milky white colour sometimes seen at the Kilnsey water park is derived from run off from Cool Scar Quarry not far behind the rising. The quarry has not operated for some time but it still causes water to become cloudy in a deluge.
Most water containing "dissolved limestone" is clear - because the limestone is in solution. This is why many autogenic risings are that lovely clear blue colour, beloved of cave divers.
Most water containing "dissolved limestone" is clear - because the limestone is in solution. This is why many autogenic risings are that lovely clear blue colour, beloved of cave divers.
Pitlamp
Well-known member
What was the actual date Braveduck? Around 4 weeks ago we were getting localised downpours. It may be that one had hit the Cool Scar Quarry area just before you were there.
It was roughly around the same time last year when Great Whernside suffered a flood of biblical proportions yet the west side of Wharfedale was unaffected.
There is a man with a rain gauge not far down valley from Kilnsey who frequently makes valuable contributions to this forum. He's likely to see this discussion (assuming he's not currently on holiday) and, if you tell us the date of that observation, hopefully he may be able to give us some rainfall data (albeit from a few miles to the south).
It was roughly around the same time last year when Great Whernside suffered a flood of biblical proportions yet the west side of Wharfedale was unaffected.
There is a man with a rain gauge not far down valley from Kilnsey who frequently makes valuable contributions to this forum. He's likely to see this discussion (assuming he's not currently on holiday) and, if you tell us the date of that observation, hopefully he may be able to give us some rainfall data (albeit from a few miles to the south).
