QUANTIFYING CLIMATE CONTROLS ON SHALE WEATHERING IN THE CRITICAL ZONE

Comprising 25% of the continental landmass, Shale acts as a major sink of atmospheric CO₂ and source of bicarbonate to the ocean. To explore how climate controls shale weathering we link meteorological (NLDAS-2), land-surface hydrological (Flux-PIHM), and geochemical (WITCH) models to project solute fluxes from the critical zone. To explore the effects of climate variables we compared soils on the sun-facing and shaded hillslopes of the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO). By predicting the observed soil water Mg⁺ concentration, WITCH successfully captured the weathering of the Mg-rich clay minerals (i.e., Illite and Chlorite) found in Shale. Our next steps will be to explore how climate evolution controls shale weathering by comparing soils along a shale ridge top climosequence that spans from Wales to Puerto Rico (Dere et al. 2013). The eventual goal is to utilize our understanding of the climatic controls on shale weathering profiles and solute chemistry from these explorations to “earthcast” the next hundred years.