MR012-01
Clay minerals are structured in four dimensions

Tuesday, 15 December 2020: 17:30
Virtual
Michael Whittaker, Lawrence Berkeley National Laboratory, Earth and Environmental Sciences Area, Berkeley, United States, David Ren, University of California, Berkeley, Department of Electrical Engineering and Computer Sciences, Berkeley, CA, United States, Colin Ophus, Lawrence Berkeley National Laboratory, National Center for Electron Microscopy, Berkeley, United States, Yugang Zhang, Brookhaven National Laboratory, NSLS-II, Upton, United States, Laura Nielsen Lammers, University of California Berkeley, Department of Environmental Science, Policy and Management, Berkeley, CA, United States, Laura Waller, University of California Berkeley, Department of Electrical Engineering and Computer Sciences, Berkeley, CA, United States, Benjamin Gilbert, Lawrence Berkeley National Laboratory, Berkeley, CA, United States and Jillian F Banfield, University of California, Berkeley, Berkeley, CA, United States
Recorded Presentation
Abstract:
Clay minerals played putative roles in the origin of life1 and today mediate phenomena such as seismic slip2-4, soil carbon and water storage5,6, stability of CO2 and radionuclide geological waste repositories7,8, and sedimentary lithium accumulation9. Accurate microstructural models of clay minerals are needed to understand how the properties of clay-rich media evolve over time, but have remained elusive due to the nanoscale dimensions of clay layers and their rapid dynamics when hydrated. Here, we show that clay minerals exhibit unexpected structure both in space and in time, arising from the tight coupling of charge, hydration, and curvature at the layer interface. Three dimensional structures of lithium montmorillonite suspensions from Ångstrom to micron scales in aqua obtained using cryo electron tomography reveal pervasive curvature of layers and their associated electrolyte cloud over a range of concentrations. Curvature promotes interfacial charge segregation to opposing sides of a layer, an unstable state that drives avalanche transitions between domains with distinct structures. We introduce a free energy landscape for hydrated layered minerals that is applicable to a broad range of mineral types, solution compositions and layer geometries, which predicts layered mineral microstructures and their evolution over time.

References

  1. Grew, E. S. et al. Lithium mineral evolution and ecology: comparison with boron and beryllium. European Journal of Mineralogy 31, 755-774, doi:10.1127/ejm/2019/0031-2862 (2019).
  2. Carpenter, B. M., Marone, C. & Saffer, D. M. Weakness of the San Andreas Fault revealed by samples from the active fault zone. Nature Geoscience 4, 251-254, doi:10.1038/ngeo1089 (2011).
  3. Ikari, M. J., Ito, Y., Ujiie, K. & Kopf, A. J. Spectrum of slip behaviour in Tohoku fault zone samples at plate tectonic slip rates. Nature Geoscience 8, 870-874, doi:10.1038/ngeo2547 (2015).
  4. Hüpers, A. et al. Release of mineral-bound water prior to subduction tied to shallow siesmogenic slip off Sumatra. Science 356, 841-844 (2017).
  5. Hemingway, J. D. et al. Mineral protection regulates long-term global preservation of natural organic carbon. Nature 570, 228-231, doi:10.1038/s41586-019-1280-6 (2019).
  6. Rempe, D. M. & Dietrich, W. E. Direct observations of rock moisture, a hidden component of the hydrologic cycle. Proc Natl Acad Sci U S A 115, 2664-2669, doi:10.1073/pnas.1800141115 (2018).
  7. Tournassat, C. & Steefel, C. I. Reactive Transport Modeling of Coupled Processes in Nanoporous Media. Reviews in Mineralogy and Geochemistry 85, 75-109, doi:10.2138/rmg.2019.85.4 (2019).
  8. Sellin, P. & Leupin, O. X. The Use of Clay as an Engineered Barrier in Radioactive-Waste Management – A Review. Clays and Clay Minerals 61, 477-498

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