grotte_de_trabuc_cascadeRed Cascades

Then, the Descent into Hell.

The staircase snakes into the red mouth of the very beautiful petrified cascades reminiscent of fine sandy streams.

It is always very surprising to discover so many colours in this world of darkness as they come from the presence of the various mineral salts including iron and manganese with their different tints depending on their state of oxidation and impressively contrasting with the whiteness and purity of deposits.

Streams are characterised by their large facets and their bright aspect. For mineralogists, they result from low alluvial deposits, which explains their growth of monocrystalline type.

On the contrary, when the deposit is too rapid, we get whiter colours as there is less oxidation. Then crystals are polycrystalline aggregates, and their break is saccharoid. Furthermore, their aspect is waxier.

Here, the streams weigh several dozens of tonnes. Tubules make a gash in them as they bear witness to the momentarily aggressive action of waters during infiltrations following periods of heavy rainfall.