Geology of this area

Peña la Vieja is a rock in the sea, which we cannot see now due to the high tide.
There is indeed a sign here with a lot of information about the geology of the area. The beach to our right, the northern part, has a sand color. The beach to our left is black.
The sand on the left is dark in color because it originates from the erosion of volcanic rock. It reaches the beach mainly through the mouth of a ravine and is also swept away by the waves. In contrast, the sand of light and blonde shades tells us about their living past. Grains are the remnants of shells, shellfish, spines, and hard structures of marine organisms. A detailed look at the light sand enables researchers to distinguish the remains of various animals and coccolithophores.

And about the petrified coast: Los Lisos is the name for a beach that has been turned to stone by climate change. The Earth has undergone various extreme climate changes over millions of years that have completely transformed the planet. After the last ice age, when the poles melted for the last time and the sea level rose five meters above its current position, the beach that existed here changed into stone due to chemical changes in the water. That is why today we can see on one hand a fossil beach and on the other hand another beach that constantly shifts its sand.

Loebas