Pyrite in Sliding Mud： A Potential Indicator of Landslide Development

A new principle of geochemical conditions within a landslide slip zone is presented based on the concept of a self-sealing closed system for which newly formed pyrite should be considered as a potential indicator. Once slip zones occur, a series of water-rock interactions may take place, particularly, a change in redox conditions simultaneously with progression of the landslide. This change induces weathering of the debris and bed rocks, and leads to accumulation of newly formed sliding mud within the slip zone. Pyrite formation along with clay mineral accumulation occurs under a weak alkaline-strong reducing environment along with landslide development. Thus, formation of neogenetic pyrite, iron speciation, and clay mineralization are all important factors for a better understanding of landslide progression.