- Brand: Francia
- Product Code: PA112
- Availability: In Stock
Location: Coiron, Ardèche, France.
Leaf measures: 6,5 cm x 2 cm
Diatomite leaf. Diatomite is a siliceous sedimentary rock, formed by diatom microfossils, which are unicellular aquatic algae that secrete a siliceous skeleton called a frustule.
This piece belongs to an old collection, which, together with the rest of the specimens, represents a complete collection of the flora of the Coiron massif.
The Coiron is an ancient basalt plateau located in the Ardèche, where a dozen "maars" (name given to volcanic crater lakes) were formed. Diatom deposits that have accumulated at the bottom of lakes have solidified into a rock called diatomite.
This deposit is 8 million years old, that is, in the Tortonian stage during the Miocene.
There are few diatom deposits in the world. Fortunately, this deposit was saved from the glacial erosion of the Quaternary thanks to a basalt shield formed after the volcanic eruptions and which, by covering the layers, protected them.