This geosite refers to an outcrop located next to the road of Chão de Espinho. It is a section representing a still early stage in the evolution of the orthogonal fracturing of the quartzite massif. The network of joints of this body divides it into bigger and smaller blocks, looking like rough parallelepipeds. The weathering is steeper in these plans of joints, due to the intense circulation of water infiltration in this place. Once the weathering degree is superior in the vertexes than in the edges, the blocks tend to become increasingly round and apart from each other. It is possible to clearly observe the phenomenon of onion peel disjunction, where the most external surface is very sandy in contrast to the less modified quartzdiorite in the block core.
Location: Arouca
Location: Arouca
