Spent the morning caving with Snorri — the world under the lava fields is even crazier than the surface!
The texture of the caves (or more accurately lava/magma tubes) is extremely different to the water-formed caves back in the UK. There is a crazy mixture of jagged edges and smooth edges, caused by the magma cooling at different rates.
The layered structure of the systems is as obvious in macro as it is close up — the smallest rocks have clearly defined layers, as do the caves themselves. Often it looks like the roof is in mid-collapse as one layer peels off another; on a rock shelf pieces of smooth ceiling rock lie centimetres from their original position.
Although it looks scary to have pieces of ceiling lying around, in reality this is all pretty much frozen in place, as most of the collapsing will have taken place within a year after the cave’s formation, thousands of years ago.
The colours are as striking and numerous as the shapes. It’s a pity they’re all locked up where light seldom reaches — caves are colour prisons.