Shale weathering: A lysimeter and modelling study for flow, transport, gas diffusion and reactivity assessment in the critical zone

摘要: Abstract Shale weathering was characterized and quantified in a lysimeter modelling study that jointly considered the flow, transport, gas diffusion reactivity processes induced by exposure to atmosphere of recently excavated shale. In this mechanically disaggregated shale presenting preferential pathways for water hydraulic conductivity at saturation 100 cm/day, content seasonal desaturation cycles were identified as main driving mechanisms alteration. The determined gaseous oxygen shale’s unsaturated porosity, which gave rise zonation oxidation pyrite, contained 1 wt% acidification associated with pyrite efficiently buffered calcite but release sulphates, cations, iron trace metals (Pb, Ni, Zn, Co, Cu As, mainly) observed. Besides dissolution, (oxy-)hydroxide formed proved be good phase sorbing metals, whose remained low concentrations drainage water. Seasonal precipitation gypsum also identified, connection summer shallow layers. hydraulic, chemical mineralogical observations made lysimeters reproduced using HP1, reactive transport code, under conditions. It possible account where O2 availability controlled shale, depending on meteorological conditions base lysimeter.