Characterization of Interfacial Processes in Soils with High Resolution Transmission Electron Microscopy and Focused Ion Beam Technology
Characterization of Interfacial Processes in Soils with High Resolution Transmission Electron Microscopy and Focused Ion Beam Technology
Previously Published Material: Some of results were shown last year at the Goldschmidt conference but without any conclusions. A paper has been submitted to the journal "Geology"
Abstract ID#: 34917
English Abstract:
High resolution transmission electron microscopy (HRTEM) and focused ion beam (FIB) technology are used to characterize mineral surface coatings in upper soil horizons. The combination of both techniques allows deciphering past abiotic and biotic soil processes and thus the reading of environmental records preserved on the nanoscale. Key to the preservation of a rarely observed mineralogy and chemistry in the surface coatings are limited diffusion of elements in Fe-hydroxide coatings in combination with silicification events of nano- to micrometer size confined pore and interface spaces. The most intriguing features include petrified cocci in proximity to a structural analogue of green rust, pockets of jarosite encapsulated by amorphous silica and chains of biogenic magnetite. The observations in this study indicate that chemical processes in confined pore and interface spaces are often in disequilibrium with the bulk soil and that, Fe-silica-bearing coatings are excellent tracking tools for the evolution of the chemistry of soils and sediments.