I have to admit I am a geeky geologist. I love walking in the mountains, looking at outcrops and imagining how they formed, or how many dinosaurs could have potentially walked there. I wanted to start climbing, perhaps with a slightly different motivation than most people. Malin for example (as most climbers I guess) has the goal of becoming a better climber, she fantasizes about the difficult routes she wants to be able to climb by the end of summer. Her motivation is becoming a stronger, better climber. When I mentioned what my motivation for learning to climb was, I was met with raised eyebrows and suddenly had an idea for a new post.
My strongest motivation for climbing is that it provides another excellent possibility of getting really ‘up close and personal’ to outcropping rocks. I want to climb at different locations and rock-types, and see and experience the difference. I am serious. It might be possible to compare it with a biologist studying an animal from photos vs. actually spending time with the animal? Well, maybe I sound crazy now, and maybe my motivation will change with time, who knows.
Luckily I had the opportunity to go with Malin recently on one of the first real SPRING weekends in the arctic to climb at Brensholmen, Kvaløya. My second motivation for climbing is to get rid of my fear of heights. As I was trying not to look down, I began to wonder about the impact of rock type on difficulty – are there certain rock types that make for difficult climbing? Surely, the answer to that is yes, so in that case where can I go to find the easiest? The way a rock erodes is certainly a factor, as this might determine the amount of places to put feet, the amount of cracks, ledges etc. This post will try to answer some of these questions.
According to Wikipedia in the US, the more popular types of rock to climb on are granite, sandstone and basalt. Unfortunately the Norway list is not very well populated so I can’t be certain but, after checking out the map of climbing locations on Kvaløya from the Tromsø Klatreklubb (rock climbing club) and comparing it to a geology map, I found that on Kvaløya, 17 of 18 sites are located on Granite (and Brensholmen is the 1 of 18 not). Coincidence? Probably not. Granite has a lot of characteristics that make it good for climbing. It is a generally pretty hard rock, so it (probably) won’t just break off underneath your feet, and granite is usually fairly rough (owing to the relatively coarser grain size) which means its easier to grip on to. Basalt is probably popular for similar reasons, but I will probably need to travel outside of Kvaløya to experience that for myself. As a complete novice, I am not really sure, but I imagine that when picking a ‘good’ place to locate bolts and anchors, people would tend to avoid metamorphic rocks like Gneiss which would have planes of weakness meaning it would be harder to secure bolts into the rock. Some others like Quartzite, which is predominately quartz, would be very tough on hands and difficult to grip.
To test the theory I suppose I would need to get a lot better at climbing and then try and climb on all different rock types to see which is the ‘best’ but seeing as that would take a long time I turned to online literature to see what some more experienced people had to say. ‘The Climbing Handbook’ for example states that Rhyolite provides some of the very best and most highly featured rocks for climbing, while sandstones provide good traction. Limestones and conglomerates can have excellent hand holds but are unreliable in terms of rock strength and slate is not recommended as even drilled bolts are not reliable. Sandstone as a ‘safe and reliable’ rock type for climbing confused me for a minute. When I think of sandstone I think of the Auckland North Shore cliffs, for those who know what I am talking about, which are crumbling away into the sea (taking some houses with them) and would be horribly dangerous to attempt to climb. So when it comes to sedimentary rocks I suppose that the amount of pressure they have been subjected to is also a determining factor – more pressure (compaction) generally means harder rock and so sedimentary rocks can have a wide range of ‘strengths’.
So it seems all in all that the weathering process a rock has undergone is what really determines whether it is going to be a good rock for climbing. Foliations in granites cause cracks which can make climbing easy, but also more dangerous as they COULD break off in large slabs. Carbonate rocks can dissolve easily which forms great holds but too much dissolving and the rock becomes too weak – and too much water overall can also weaken rocks through faults and fractures. Possibly why it seems a lot of really excellent climbing locations are in arid areas? Anyway many of these rock types are not found on Kvaløya so I suppose that it is fortunate that granite seems to be a better rock type for climbing. If any climbers are reading this, I would love to know if you have ever considered the rock type while climbing!