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[Peak][Millersdale Viaduct Crag][7a-7c+] (Read 7197 times)

mark20

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[Peak][Millersdale Viaduct Crag][7a-7c+]
August 16, 2015, 10:34:30 am
Spent the last couple of weeks sorting out some stuff at this often eyed but rarely visited crag. 2 new routes and a Paul Mitchell esoteric masterpiece with a couple of new bolts and direct start. Thanks to Mitch for his sensible approach to the replacement of the old rusty pegs  :thumbsup:

Park on the small bridge in Millers Dale (or Chee Dale car park if it's busy). Walk back along the road and wade the river under the Viaduct. Access seems fine.

The crag is short and steep with some impressive flowstone formations. Unfortunately the flowstone is soft and delicate. Hence the central section of the wall is unclimbed and probably best left that way. Please be delicate on the lower parts of the climbs that use the flowstone. The upper roof is compact limestone with nice and some surprising holds, giving some powerful and gymnastic cruxs.

The old route 'A Clip in Time' is currently filthy and missing the peg. "you could probably put one bolt in that", but not really worth the effort.

crag topo by 2010mark20, on Flickr

Under The Bridge 7a Climb up to the block then move rightwards and reach round the roof to a hidden jug. Finish direct

Trollhammaren 7b From the break under the roof, step right to the black flake and make a big move to small holds round the lip. A powerful sequence gains jugs above

Mister Blister 7c+ From the ladder (to protect the soft flowstone footholds) climb up on pinches to better rock and a poor rest at the roof. A series of hard moves on small holds gains the hanging crack and easier finish. Originally E6 6c on pegs, traversing in from the right.

Under The Bridge by 2010mark20, on Flickr

misterblister01 by 2010mark20, on Flickr

Ru

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I was wondering about this crag after browsing the old bmc wye valley guide. Good effort cleaning it up and rebolting.
« Last Edit: August 16, 2015, 08:45:30 pm by Ru »

deacon

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Nice one Mark for getting it finished. Did the 7a, and it's really nice. About as steep as Rubicon. Potentially permadry too.
Also, if you're into geology at all, the flowstone stalagmites/ stalagtites are the most impressive I've seen in the peak.

Ru

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Also, if you're into geology at all, the flowstone stalagmites/ stalagtites are the most impressive I've seen in the peak.

I'm not sure about that flowstone. It's probably just calcium carbonate deposits (like limescale in a kettle) and not limestone, which would explain why it's so fragile.

If you look elsewhere under the viaduct there's quite a lot of it. There's also none on any rock that's not under the viaduct. Which makes me guess that it's not limestone flowstone but probably "flowstone" that's formed from water draining over any concrete or lime based mortar in the bridge then falling onto the rock and draining through, like this:

« Last Edit: August 17, 2015, 08:06:13 am by Ru »

mark20

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That makes sense as there is some like that in the tunnels on the way to Cheedale too

Johnny Brown

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I'm not sure about that flowstone. It's probably just calcium carbonate deposits (like limescale in a kettle) and not limestone, which would explain why it's so fragile.

Limestone is largely calcium carbonate. There's no chemical or physical difference between natural stalactites and those under bridges. Natural stalactites of that size in caves are typically very fragile. Your theory is probably right though, as there would not appear to be enough rock above the crag to cause percolating water to become saturated with CaC03.

Ru

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You're right that both are calcium carbonate, but the reaction for forming limestone stalactites is different to the concrete reaction, both precipitating CaCO3 on contact with air. I don't know why this makes for a more fragile deposit, but it seems to. Possibly because the limestone mechanism takes a lot longer. Needs someone that's not just remembering bits of geology and chemistry from 15 years ago.

Edit: done some googling. None the wiser.

andy_e

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No, it's the same process, it just occurs far quicker with concrete as the limestone content of the concrete is in much smaller granules, therefore has a higher surface area to allow it to dissolve more readily. As concrete also has a far higher permeability than limestone, there's far more potential to dissolve calcite quicker and reprecipitate it elsewhere quickly.

Johnny Brown

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What Andi said. I remember being fascinated to learn on my degree that some concrete bridges have been found to have quartz veins in them, which again is generally eon-slow in nature.

andy_e

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Wow, it's not so much the time of quartz but the temperatures over which you'd expect that! Good knowledge JB, I'll go prod around the bridges of Durham for some quartz veining!

Johnny Brown

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Yeah calcite you could understand but quartz is crazy. Maybe it's pre-stressed or summat.  :blink:


Potash

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Not sure how to make that appear as an image.

mark20

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There is actually a 'proper' tufa in the gully on the right of the crag, about 1ft thick and made of limestone, worth a look
And there is a cool tufa ledge you wade across to
the climbing is OK too, honest

Ru

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No, it's the same process, it just occurs far quicker with concrete as the limestone content of the concrete is in much smaller granules, therefore has a higher surface area to allow it to dissolve more readily. As concrete also has a far higher permeability than limestone, there's far more potential to dissolve calcite quicker and reprecipitate it elsewhere quickly.

I thought it was different, as set out in this wikipedia article: https://en.wikipedia.org/wiki/Stalactite - is that wrong?

andy_e

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Ah, to be honest I assumed it was the same process in both and didn't realise that concrete was calcium oxide, I just thought it was crushed calcium carbonate. Essentially though, it's the same reaction, as all you're doing is taking the calcium oxide, formed from calcium carbonate when the concrete was made, and turning it back into calcium carbonate on precipitation due to the presence of CO2. So in effect, the end product is the same for both natural and concrete stalactites.

 

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