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O: Fachverband Oberflächenphysik
O 63: Oxides and Insulator Surfaces: Adsorption and Reaction of Small Molecules II
O 63.4: Talk
Wednesday, March 19, 2025, 11:15–11:30, H25
Cleaved feldspar surfaces under dry and humid conditions: an AFM study — •Luca Lezuo1, Sandra Boigner1, Rainer Abart2, Michael Schmid1, Ulrike Diebold1, and Giada Franceschi1 — 1Inst. of Applied Physics, TU Wien, 1040 Wien, Austria — 2Dep. of Lithospheric Research, Universität Wien, 1090 Wien, Austria
The Earth’s surface is largely shaped by the interaction between water and the minerals of its crust. Feldspars, the most common aluminosilicates, are made of a framework of corner-sharing silica and alumina tetrahedra, enclosing cations such as potassium (K+), sodium (Na+), and calcium (Ca2+). The chemical reactions at the feldspar-water interface contribute to geological processes such as erosion and weathering [1], clay formation [2], and ice nucleation [3], with implications for geology, agriculture, atmospheric chemistry, and climate science.
We exposed cleaved surfaces of different feldspars to air and Ar with defined humidity and examined the evolution of their mesoscale morphology with atomic force microscopy (AFM). Overlayers with distinct patterns develop over time. They remain stable after rinsing the surface with ultrapure water, suggesting a permanent alteration of the surface morphology. We attribute the distinct patterns to local chemistry differences and different cation leaching rates [1].
[1] Brantley and White, Chem. Weath. Rates of Sil. Min. (2018)
[2] Bleam., Clay Min. and Chem., 87-146 (2017)
[3] Atkinson, et al., Nature 498, 355-358 (2013)
Keywords: mineral surface chemistry; feldspars; AFM; dissolution; leaching