Leçon :
Histoire et définition : Un schiste est une roche qui a pour particularité d'avoir un aspect feuilleté et de se débiter en plaques fines ou « feuillets rocheux » : on dit qu'elle présente une schistosité. Il peut s'agir d'une roche sédimentaire argileuse ou d'une roche métamorphique. Les schistes tirés des terrils houillers, servent à la réalisation des assises de chaussées.
Variétés et caractéristiques : Il en existe deux types :
- les rouges résultant d'une cuisson à l'intérieur de terrils entrés spontanément en combustion, ce qui leur a donné une meilleure résistance mécanique
- les noirs, à l'état naturel, plus friables et plus gras.

Bon Géocaching à tous 😎
🇬🇧
With Flo, we share a great passion for geocaching: EarthCaches 🥰. We are intense rock hunters! 🪨😄 You could even say it’s a real crush 🤢. Our second geocaching passion is GeoArt 🤩. So we pushed ourselves a bit and decided to mix the two. A big headache to set up 😵, but in the end, totally doable.

Questions : Locate the blue dot in the photo above and answer the following:
1 - What are the two different types of rock besides shale ?
2 - Based on your observation, what color is this slab of shale ?
3 - What is its appearance ?
4 - Take a photo in this narrow street, with your geocaching username visible, and make a 🤙 sign with your hand.
EarthCache Rules: "Log this "Found it" cache and send me your suggested answers either via my profile or via email, and I will contact you if there is a problem."
Lesson :
History and definition : Shale is a rock characterized by its layered appearance and its tendency to split into thin slabs or "rock flakes": it is said to exhibit schistosity. It can be a clayey sedimentary rock or a metamorphic rock. Shale extracted from coal spoil heaps is used in the construction of road bases.
Varieties and characteristics : There are two types :
- Red shale, resulting from firing inside spoil heaps that spontaneously combusted, which gave it greater mechanical strength.
- Black shale, which occurs naturally, is more crumbly and oilier.
Happy Géocaching everyone 😎