I don’t know if you’ve noticed, but all the mountains in NZ are more or less the same shape – peaky with steep sides (at 33 degrees if you want to know, according to my iPhone theodolite). And with plenty of rock screes, landslips and the like.
Well, it’s all to do with what the mountains are made of. Here it is:
This is the stuff at the top. Called ‘greywacke’ as you might expect. This was underwater only recently – it’s basically flooring material. Stands to reason that if you make mountains of it – which is basically sandy stuff with stones in it, then they aren’t going to last. And they don’t, they simply fall apart. You won’t get more than a couple of million years out of shoddy material like this.
In fact they reckon that in the last 15 million years the mountains have risen 20,000 metres, but because of erosion they are still only 4,000 metres high.
Quality, mate, quality is what matters. Just imagine if they had used granite instead of this rubbish. Mountains 20 km high by now. Everest phooey. I rest my case.
Bloody fascinating mate I’ll try to get Kate to read it!
Yep, it’s not what you expect. Things are happening fast in NZ. In fact the top of Mt Cook was underwater less than 1 million years ago. The mountains are rising at the rate of about 1 metre per 100 years. Which means in 200,000 years they rise 200 metres. Not a lot of time in geologial terms.