[SA Chris]

Was wondering after a visit to Rocher Fin, as some of the rock there seems remarkably similar (in texture and features) to Quartzite I have climbed on in Oz, SA and the US? Can any geologists shed some light?

[Bonjoy]

 Quartzite is metamorphosed sandstone. I wouldn't be surprised if some of the marbley hard stuff could class as this. I'd imagine it forms as a result of pressure (or heat). But that's pure guesswork, I'm no geologist.

[SA Chris]

Yup, I know quartzite is metamorphosed sandstone, and is altered by heat and/or pressure. But like you, that's where my knowldege ends. I had previously assumed it was all sandstone.

[Lostboy]

my housemate is a geologist, I shall return with more details later  :D

[AndyR]

Yup, I know quartzite is metamorphosed sandstone, and is altered by heat and/or pressure. But like you, that's where my knowldege ends. I had previously assumed it was all sandstone.

You're talking about metaquartzite (which is almost all of the quartzite you ever find).
Some of the stuff at font is presumably orthoquartzite, which is a very pure sandstone (i.e. the grains are almost all made of quartz - you'd be surprised how much 'sand' isn't quartz in normal sandstones - grit included), often with a quartz secondary cement that binds the grains together - hence it's quartzite, but just formed by normal sedimentary and diagenetic processes - no P/T required.

Well, you did ask.

[SA Chris]

And that's just the answer I was looking for, thanks. How did the ski season end Andy, or is it still going strong?

[andy_e]

I presume the light colour means it is pure quartz, whereas old red sandstone isn't quartz?

[SA Chris]

I think colours are more to do with oxides and base material than quality of sanstone? Grampians feel like font quality stuff, and they are bright red.

[andy_e]

There are a lot of iron oxides in gritstone, hence the mainly brown colour.

[AndyR]

And that's just the answer I was looking for, thanks. How did the ski season end Andy, or is it still going strong?

Nae bother - was in Whistler at the weekend - still great conditions up top, and plenty of new snow up there, but small hills on the north shore are closed now.
Time to put the board away and dust off the rack.....

[Bubba]

Andy, get into downhill mtb ffs - Vancouver's North Shore and Whistler are home to a lot of the best freeriding on the planet.

[AndyR]

Andy, get into downhill mtb ffs - Vancouver's North Shore and Whistler are home to a lot of the best freeriding on the planet.

I will - I need to get some new forks for my bike - though to be honest, a lot of the stuff on the north shore is just too hardcore for me - I would need to rap down some of the stuff they ride down......
Also, talking to guys who do it, its just a question of time until you break your collar bone, arm, leg etc, even with full body armour.
But, there is more do-able stuff on Seymour, and Whistler are putting in some more intermediate style tracks this year, so theres more to do there.
The weather is just too good at the mo though - I think of mtbing as a bad weather activity.
Are you going to get yourself over here and do some north shore action?

[Bubba]

Yeah, hoping to get over for a trip when I ever get enough of money...and when i'm riding bigger and faster, it'd be a bit of a waste at the moment.

[saltbeef]

andy you been to squamish? what will it be like in july?

[AndyR]

andy you been to squamish? what will it be like in july?

Yep, been up a couple of times in the last few weeks - the weather has been great here recently - it was too hot on the apron boulders a week or so ago, but fine (pretty cold actually) in the forest.
I think it'll be OK, but reasonably warm in the forest in July - a lot of the problems have pretty slopey holds, so don't expect the friction to be the greatest - if you can get up earlyish, the chief keeps the grand wall boulders in the shade until mid-morning.
There's lots of other things to do as well......

[SA Chris]

and when i'm riding bigger and faster, it'd be a bit of a waste at the moment.

I though you had been riding "big" for a while now 

[Bubba]

I meant the drops, not me 

I've actually got a bit of helmet cam from yesterday which I'll put up as soon as I can find somewhere to put it that won't completely screw my bandwidth...

[hongkongstuey]

find somewhere to put it that won't completely screw my bandwidth...

Bubba - I've plenty spare if you need somewhere to sling it for a while