Welsh Gritstone - Rhinogs (Read 8873 times)

r-man · October 15, 2007, 06:22:43 pm

Saw this photo on UKC - http://www.ukclimbing.com/images/dbpage.html?id=64297

Looks lovely. Anyone know more about this area? Is there anything developed? Is there really a vast unexplored gritstone world, or as the Climbers' Club website would have it, "a whole new Peak District of gritstone outcrops in the most beautiful and quiet mountain environment imaginable"?

Anyone know anything? Got any photos?

Monolith · October 15, 2007, 07:10:55 pm

I'm sure the Welsh would have built Edward I stylee defences around their projects by now if what is stated is true.

Fiend · October 15, 2007, 10:18:35 pm

It's in the Merionydd CC guide. There appears to be a vast amount of outcrops and exploring to do.

I haven't been but I've picked up some beta from friends. Don't expect:

1. To make sense of the guidebook / maps without several hours cross-referencing.

2. Paths, obvious directions, comfortable walk-in terrain or any of those luxuries.

3. Rescue if you fail to bounce when coming off a highball.

Houdini · October 15, 2007, 10:25:19 pm

(Cough)

fatdoc · October 15, 2007, 10:29:29 pm

great cough..

how did you remember that earlier thread??

soooo,

what's the deal?? any good then?? massively well kept secret ... or not really up to much???

Houdini · October 15, 2007, 10:33:06 pm

Quote from: fatdoc on October 15, 2007, 10:29:29 pm

... massively well kept secret ...

Johnny Brown · October 16, 2007, 09:31:08 am

Geologically speaking, these grits are much closer to the Cilan grits and a long way from the Carboniferous 'Millstone' grits of the pennines. Be aware that although we bandy around the term grit all the time what we are actually referring to is a specific group of deposits linked by age and area and, crucially as we are talking about sedimentary rocks, the origin of the sediments. The particle size may be the same but if the particles didn't coming from the right range of now denuded mountains, the rock ain't going to be the same. This helps explain why our pennine grits seem to be pretty much unique worldwide.

Pantontino · October 16, 2007, 09:44:08 am

The stuff at Trawsfynydd feels a bit like a well weathered pennine quarried grit (but in a good way). Nice little crag, well worth a visit. Very sunny (i.e. good in winter), plus only about 5 minute walk in.

Looks a bit short in this pic, but the crag base is undercut. Other bits are quite highball, but mostly it is perfect bouldering height. (Yes that is the power station in the background).

http://www.northwalesbouldering.com/newsitem.asp?nsid=100

Johnny Brown · October 16, 2007, 10:06:32 am

Looks nice!
Judging by the fracture line bottom right, the rock has been more metamorphosed than pennine grit too, which would be expected given its age.

Pantontino · October 16, 2007, 10:16:07 am

I'm guessing that there is more of this sort of thing dotted about the Rhinogs, but access is not easy. Trawsfynydd is right by a major road, whereas the other areas involve long windy approach roads and then long walk ins. It would probably be quicker for me to get to Pex Hill (from Llanberis) than to one of these mythical bouldering crags - that's my excuse for the lack of exploration.

Of course if anybody else discovers a Porth Ysgo hidden in those hills, then I'll be straight down with my lightweight pad and my walking boots!

AndyR · October 16, 2007, 04:57:58 pm

Quote from: Johnny Brown on October 16, 2007, 10:06:32 am

Looks nice!
Judging by the fracture line bottom right, the rock has been more metamorphosed than pennine grit too, which would be expected given its age.

These are Cambrian greywackes aren't they?
Not sure how the fracturing would be affected by age?

andy_e · October 16, 2007, 10:13:21 pm

Can't wait until I actually know enough about rocks to comment... But it's always hard to tell judging from a photo, and anyway, just because of the age doesn't mean the rock is metamorphosed...

richieb · October 16, 2007, 10:44:07 pm

Had an epic day a couple of years ago at what we thought would be one of the most accessible and popular crags, one of the Clip tiers. Although it looks like it from a distance, its no Slipstones. Took us hours to get there. I think we backed off every route we tried. Can backup points 1 and 2 on Fiends list.
I shinned myself falling through a style too.
However theres clearly loads of rock up there and the views are nice. Worth a look for sure, good training for bouldering in Scotland!

Johnny Brown · October 17, 2007, 10:38:19 am

Quote

just because of the age doesn't mean the rock is metamorphosed...

No, but the odds do increase. These are Cambrian, the only older rocks we have in Britain are heavily metamorphosed.
One of the main reasons the pre-cambrian fossil record is so poor is so few sedimentary deposits survive. The other reason, of course, is not much life is thought to have evolved.

andy_e · October 17, 2007, 02:14:35 pm

Quote from: Johnny Brown on October 17, 2007, 10:38:19 am

These are Cambrian, the only older rocks we have in Britain are heavily metamorphosed.

Torridonian Sandstone? One of the oldest sedimentary rocks in the world? Then again, there's no fossils in the Torridonian.

Quote from: Johnny Brown on October 17, 2007, 10:38:19 am

One of the main reasons the pre-cambrian fossil record is so poor is so few sedimentary deposits survive. The other reason, of course, is not much life is thought to have evolved.

What about those found in the flint and chert inclusions in the kent/sussex chalk?

jern · October 17, 2007, 02:30:43 pm

[/quote]

What about those found in the flint and chert inclusions in the kent/sussex chalk?

The chalk is Cretaceous in age, much younger than Pre Cambrian - far more in the way of marine life. Basic geology innit?

(The boulders look good, regardless of fossils)

andy_e · October 17, 2007, 02:37:53 pm

No- the fossils are in the chert & flint inclusions- the pre-cambrian Eukaryotes and Prokaryotes, some of the earliest organisms on earth.

slackline · October 17, 2007, 03:00:52 pm

Quote from: andi_e on October 17, 2007, 02:37:53 pm

No- the fossils are in the chert & flint inclusions- the pre-cambrian Eukaryotes and Prokaryotes, some of the earliest organisms on earth.

The first fossil records of eukaryotes (which evolved from prokaryotes via endosymbiosis) appear some 1 billion years ago, whilst evidence suggests that prokaryotes have been around for ~3.5 billion years.

andy_e · October 17, 2007, 03:02:20 pm

In which case, I was right on both accounts, seeing as how 1 billion years ago was Pre-cambrian.

slackline · October 17, 2007, 03:36:49 pm

Quote from: andi_e on October 17, 2007, 03:02:20 pm

In which case, I was right on both accounts, seeing as how 1 billion years ago was Pre-cambrian.

But perhaps inaccurate in so much as a 2.5 billion year gap between the emergence of two distinct cell types doesn't really qualify the late developer (eukaryotes) as being one of the earliest organisms on earth. Perhaps you were thinking of archaebacteria?

jern · October 17, 2007, 03:43:26 pm

No. The first Eukaryotes and Prokaryotes may well have evolved in the PC - this does not mean that the ones in the flint bands are those very ones. The chert / flint was formed as a primary deposit (at the same time as the chalk)

Anyway I'll shut up now

andy_e · October 17, 2007, 06:28:11 pm

It was still one of the earliest organisms on earth though, there wasn't much around at either time... But that's more an argument about the english language than SCIENCE.