Water-rock interactions during the weathering of pelitic schist - its role in the development of landslides

摘要

We characterize a weathering zone within pelitic schist, which is one of the typical bedrock types associated with landslides, and discuss the processes and mechanisms of the weathering in relation to landslides by using carefully drilled cores from a landslide body. Oxidation of pyrite and the formation of sulfuric acid at the oxidation front are found to be the dominant chemical processes of weathering. Chlorite is transformed into Al-vermiculite at the oxidation front. Pyrite oxidation and subsequent processes may deteriorate the pelitic schist and foster the rock shearing and the formation of a sliding zone below the oxidation front.