Have you ever walked on a mountain trail, passing past outcrops of rocks and noticed that many rocks appear to be split along a well-defined orientation? If you have, you might have seen one of the most important structures in metamorphic rocks – called foliation. The term ‘foliation’ derives from the Latin folium, meaning ‘leaf’. A rock with a foliation looks like a pile of R ...[Read More]
Features from the field: Foliation
Jurassic slate in La Grave (Hautes-Alpes, France). These rocks easily split along foliation surfaces that dip towards the left of the image. Don’t believe me? Try to hammer them! Photo © Samuele Papeschi