Tuesday, May 5, 2020

Caves in Nuuksio's Katajasuo

Research pays off! I wanted to explore more boulder caves, but where to find boulders? I kept looking for data, and it turns out the geologic research institute had made a listing of the most valuable boulder fields in Finland. One of them was nearby, in Nuuksio, so I headed out to investigate on Sunday. No caves had been listed at that spot, but the report already made some promises about cave-like holes between the rocks. And a 50 meters wide and 10 meters deep field! I was hooked. Although it turned out the location was listed after all in the book of cave in Finland (albeit with a different name).

It turned out that there indeed are some caves. I have not gone through the entire space yet, but there are at least 8-9 caves, maybe more. None of them are big, but some of them are quite cave like. The one that I like the most is maybe 4.5 meters long path from on one entrance to another, and has a maybe 3 meters by 3 meters room inside.

The boulders have fallen down from a collapsed part of a cliff that is 20-25 meters high. There's still room for more collapses in the coming millennia :-) as there's a thin slice of a rock still standing, with the uppermost part that it at least 5-10 meters long and maybe 2 meters thick sitting loose at the top.

I also explored the main cave underneath the cliff. This is a roof cave, under a high, 10 meter-wide roof that extends on its furthest part 2.5 meters out of the cliff base. Under the roof there are some boulders, and under them is a second layer of cave, the main one being 2.6x1.5m.

Oddly, the book of caves in Finland ("Suomen luolat") does indeed list caves in this location, just that it calls them "Kattilajärven onkalot". Kattilajärvi is a lake a bit further away, behind some other lakes, so the name confused me. Particularly when there are cliffs and boulder fields also in Kattilajärvi.


The research report, "Kansallisesti arvokkaat kivikot", is available here.

I have to say though, that the report is woefully incomplete. Clearly, it had new information for me. But it is nowhere complete with regards to reporting different boulder fields. For instance, two major boulder fields that I'm familiar with -- Korkberget and the large boulders by the Korso high school -- are not mentioned. From Uusimaa just a couple of boulder fields are listed.

While the research is quite extensive on the ones that are mentioned, I need to assume that most of what's out there isn't actually listed. Can anyone help me? Any of you work with maps or geology, and would know where to get more complete information about boulder fields in Finland?

Main cave views:

The loose part of the cliff hanging high up:

Cave 1 views, first the entrances as seen from inside:

The map:

Inside cave 1:

Cave 2:

More pictures of the main cave:

Side cave 1:

Side cave 2:

The author:

This article has also been published at TGR. See more caving stories at Planetcaver.net, and all Planetskier and Planetcaver stories at Blogspot and TGR! This article, pictures and videos is (c) 2020 by Jari Arkko. All rights reserved.

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