Text Box: Volcanic Cave, Calhau, Săo Vicente, Cape Verde       


I'm currently in Cape Verde, a cluster of islands 460 km west of Senegal, in the Atlantic Ocean. I’m here on fieldwork on the island of Săo Vicente but I have had the odd hour or two free to wander and to discover its delights. My work is at the Cape Verde Atmospheric Observatory, near the village of Calhau on the east coast of the island. The site is perched on a shelf of volcanic rock between two small, extinct volcanoes and the Atlantic Ocean.

Cape Verde Atmospheric Observatory, showing the 30 m tower and a few of the shipping container laboratories

On a rare sunny afternoon (it’s often cloudy) when the scientific equipment was all behaving itself (it’s often not) I decided it was time to escape from the converted shipping container which has been my laboratory for a few weeks. I had heard talk, from a colleague who had been here previously, that there were some “insignificant” caves in the area, which were “not much to speak of”. In my speleologically-starved state that was more than enough to pique my interest. I had it in mind to wander up one of the volcanoes and see the sights from the top, and to keep an eye open for holes in the ground as I went, just in case.

The rock is like pumice, full of little holes, and sharp. A colleague here told me that a cut from the rock can quickly turn septic, thanks to some microscopic life form that lives on the rock. “I’ll put my safety boots on”. (I find safety boots, like a helmet or a harness, always inspire confidence, however misplaced).

As I wandered up from the site I found sinuous formations in the rock, winding down in solidified streams from the volcano to the sea. In between these formations are patches where the rock has been eroded into rubble by wind (during the windy season, which it is now) and rain (during the rainy


season, which I have to look forward to when I return in August). The smooth, flowing sections were much nicer to walk on, so I followed them up the hill.


                Sharp and porous volcanic rock


Lava flow with some very hardy plants, from the top of the 30 m tower


In places it looks like huge bubbles of air have been trapped beneath the lava as it solidified, some remaining as smooth humps, and some breaking at the dome. 



‘Bubbles’ in the rock, taken at the coast in front of the site

I came across many open-ended tubes running up-and-down hill, the sort of size a rabbit or fox could have got along quite happily, but not really the stuff for a full-grown speleologist (not even for a seasoned Scottish digger, which I’m not). “These can’t be the caves they meant, surely?” The roofs of these tubes, thin and crumbling, were the easy ground that I had been following. I quickly revised that strategy.

Tube in the rock. The roof is about 6 inches thick.

Disappointed (they really weren’t caves after all, though they were nice enough to look at) I wandered on and resolved to walk up the volcano. No sooner had I thought this thought than I almost fell into a sink hole and, low and behold, there was a proper cave!

I confess I dithered at this point. I had told my colleagues at the site that I was “going for a short


walk” and “wouldn’t be long” - I hadn’t mentioned caves. I didn’t have kneepads, and I really didn’t want to get gangrene. This also looked like exactly the sort of cave I would choose for a home if I was a small mammal (I’ve heard all about angry badgers in caves). But, I reasoned, I could just about see the site from the cave entrance, and they would probably come looking for me before too long. I remembered, too, that there weren’t any small mammals native to Săo Vicente, only cats, dogs, and a mouse or two. And I had my safety boots on. I gingerly stepped down the pile of rocks to the entrance and peered inside. It wasn’t exactly cavernous, but the light at the other end suggested a miniature through trip was on the cards, and that was just about the most exciting thing I’d found so far on the whole island. 

I took a couple of photographs then excitedly went to look for the other end. I found it a few metres away, scrambled down over the little boulders, and carefully went inside. The floor was covered in very fine yellow sand or dust, with a single footprint in it, others probably having been erased by wind or water. The strong sunlight coming through both entrances, and through a skylight, brought out some lovely colours in the rock.  I completed the tiny gem of a through trip, 10 or 15 metres long and stooping height throughout, and went looking for other caves big enough to get inside. Sadly I didn’t find any others, and it was time to go back to work.

You may laugh at my delight at this tiny cave. The Berger it is not, but it was a great antidote to hanging about in a crowded shipping container, it’s better than anything in the guidebook, and any caving is better than none at all. I’ll be back for more fieldwork in August. It can’t be the only cave on the island, can it?

Hannah Walker


The cave entrance



Inside the Cave

The other entrance


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