The hydrosphere and lithosphere intersect in a zone a few kilometres wide at the earth s surface, resulting in the formation of magmas, metamorphic rocks and mineral deposits, and placing important controls on the evolution of landscapes. This interaction imparts chemistry to waters and provides the essential environment for ecosystems to flourish. It affects the transport and fate of pollutants in groundwater and surface water systems, influences the stability of landscapes and sub-surface structures and provides an important feedback mechanism for controlling carbon dioxide levels in the...