What are hornfels in geology ?
Hornfels - Metamorphism
Its mineralogical composition varies according to the nature of the host rocks :
- pelitic rocks give micaceous hornfels with andalusite and cordierite, evolving into feldspathic hornfels
- marl-limestone rocks and calcareous pelites give calcic hornfels, called tactites, of variable mineralogical composition, usually rich in garnet, epidote and hornblende.
- carbonate rocks give skarns and marbles
- the other rocks evolve according to their original mineralogical composition (for example, for quartzose sandstones the hornfel ones will be quartzites).