From Soils to Shallow Groundwater: The Influence of Clays on the Critical Zone
Clays, hydroxides, and related minerals exert a strong influence on biogeochemical cycling and physical properties in the critical zone, the area where interactions between minerals, water, gases, and organisms regulate life-sustaining processes. In particular, reactive minerals in the CZ strongly affect nutrient availability, contaminant fate and transport, carbon cycling, permeability, and susceptibility to erosion. Burgeoning research on the influence of microbes on minerals, and vice versa, is expanding understanding of mineral reactivity, sorption, and elemental cycling. Precise mineralogical characterization allows prediction of water vapour adsorption as it relates to clay content, composition, texture, specific surface area and other hydro-physical properties, and knowledge in this area is notably lacking for soils in arid and tropical climates. Research on soil toposequences and chronosequences records the effects of geomorphic and hydrologic factors on soil mineralogy as well as the role of soil age and kinetic factors in controlling soil composition. Pedogenic clays record past biotic and climatic regimes when preserved in paleosols, and research on earth’s CZ informs understanding of the surface of Mars. In summary, this session seeks to attract a multidisciplinary group of presentations to foster analysis of ways in which clays improve knowledge and modeling of processes in the CZ — present, past and future.
Conveners: Abdelmonem Amer (Menoufia University, Egypt), Peter Ryan (Middlebury College, USA), Jeff Wilson (Hutton Institute, Scotland)