Research Outline
As the building blocks of the Earth and the terrestrial planets, minerals and rocks form the medium of Earth’s evolution and dynamics. Their properties control the fluxes of heat and matter between Earth’s surface and deep interior. Geophysical and geochemical observations probe the state and properties of minerals, rocks, and other geomaterials present at depth. These observations, however, are indirectly made from Earth’s surface, and their interpretation requires additional information about the behavior and properties of geomaterials at the conditions of Earth’s deep interior, i.e., at high pressures and high temperatures.
My research focuses on constraining the physical properties of minerals and rocks at the conditions of Earth’s deep interior. I combine high-pressure experiments in diamond anvil cells with material-physical theories to derive models for the physical properties of the minerals that form the rocks in Earth’s mantle. For example, the equation of state (EOS) of a mineral describes the relationship between pressure, temperature, and the volume (or density) of the mineral. The EOS is a fundamental thermodynamic property of a material and can be derived from experiments that determine the unit cell volume of a crystalline material by means of X-ray diffraction as a function of pressure and temperature. At the University of Oxford and as a member of the DEEP-MAPS research team led by Prof. Dr. Hauke Marquardt, I am developing a new class of experiments to better understand how minerals with different elastic properties interact with each other when a rock is exposed to the stress oscillations generated by seismic waves. The results of these experiments will improve our models for the elastic properties of rocks in Earth’s mantle, which are needed to interpret seismic observations in terms of the composition and thermal state of the mantle.
For further examples and illustrations of my research and my academic CV, please visit my research website: https://geophormae.org
View Selected Publications
Buchen, J., Sturhahn, W., Ishii, T. & Jackson, J. M. (2021) Vibrational anisotropy of δ-(Al,Fe)OOH single crystals as probed by nuclear resonant inelastic X-ray scattering. Eur. J. Mineral., 33, 485–502. https://doi.org/10.5194/ejm-33-485-2021
Buchen, J. (2021) Seismic wave velocities in Earth’s mantle from mineral elasticity. In Mantle Convection and Surface Expressions (eds H. Marquardt, M. Ballmer, S. Cottaar & J. Konter) American Geophysical Union, pp. 51–95. https://doi.org/10.1002/9781119528609.ch3
Buchen, J. (2019) Experiments cast light on mantle mineralogy. Nature (News & Views), 565, 168–170. https://doi.org/10.1038/d41586-018-07864-2
Buchen, J., Marquardt, H., Schulze, K., Speziale, S., Boffa Ballaran, T., Nishiyama, N. & Hanfland, M. (2018) Equation of state of polycrystalline stishovite across the tetragonal-orthorhombic phase transition. J. Geophys. Res. Solid Earth, 123, 7347–7360. https://doi.org/10.1029/2018JB015835
Buchen, J., Marquardt, H., Speziale, S., Kawazoe, T., Boffa Ballaran, T. & Kurnosov, A. (2018) High-pressure single-crystal elasticity of wadsleyite and the seismic signature of water in the shallow transition zone. Earth Planet. Sci. Lett., 498, 77–87. https://doi.org/10.1016/j.epsl.2018.06.027
Buchen, J., Marquardt, H., Boffa Ballaran, T., Kawazoe, T. & McCammon, C. (2017) The equation of state of wadsleyite solid solutions: Constraining the effects of anisotropy and crystal chemistry. Am. Mineral., 102, 2494–2504. https://doi.org/10.2138/am-2017-6162
View Extended Publications
Miyajima, N., Buchen, J. & Kawazoe, T. (2022) Twinning in hydrous wadsleyite: symmetry relations, origin, and consequences. Am. Mineral. (in review).
Immoor, J., Miyagi, L., Liermann, H.-P., Speziale, S., Schulze, K., Buchen, J., Kurnosov, A. & Marquardt, H. (2021) Weak cubic CaSiO3 perovskite in the Earth’s mantle. Nature, 603, 276–279. https://doi.org/10.1038/s41586-021-04378-2
Buchen, J., Sturhahn, W., Ishii, T. & Jackson, J. M. (2021) Vibrational anisotropy of δ-(Al,Fe)OOH single crystals as probed by nuclear resonant inelastic X-ray scattering. Eur. J. Mineral., 33, 485–502. https://doi.org/10.5194/ejm-33-485-2021
Buchen, J. (2021) Seismic wave velocities in Earth’s mantle from mineral elasticity. In Mantle Convection and Surface Expressions (eds H. Marquardt, M. Ballmer, S. Cottaar & J. Konter) American Geophysical Union, pp. 51–95. https://doi.org/10.1002/9781119528609.ch3
Wang, X., Chen, Q.-F., Niu, F., Wei, S., Ning, J., Li, J., Wang, W., Buchen, J. & Liu, L. (2020) Distinct slab interfaces imaged within the mantle transition zone. Nat. Geosci., 13, 822–827. https://doi.org/10.1038/s41561-020-00653-5
Satta, N., Marquardt, H., Kurnosov, A., Buchen, J., Kawazoe, T., McCammon, C. & Boffa Ballaran, T. (2019) Single-crystal elasticity of iron-bearing phase E and seismic detection of water in Earth’s upper mantle. Am. Mineral., 104, 1526–1529. https://doi.org/10.2138/am-2019-7084
Buchen, J. (2019) Experiments cast light on mantle mineralogy. Nature (News & Views), 565, 168–170. https://doi.org/10.1038/d41586-018-07864-2
Buchen, J., Wesemann, V., Dehmelt, S., Gross, A. & Rytz, D. (2019) Twins in YAl3(BO3)4 and K2Al2B2O7 crystals as revealed by changes in optical activity. Crystals, 9, 8. https://doi.org/10.3390/cryst9010008
Saki, M., Thomas, C., Cobden, L., Abreu, R. & Buchen, J. (2019) Causes for polarity reversals of PP precursor waves reflecting off the 410 km discontinuity beneath the Atlantic. Phys. Earth Planet. Inter., 286, 111–126. https://doi.org/10.1016/j.pepi.2018.11.007
Marquardt, H., Buchen, J., Mendez, A. S. J., Kurnosov, A., Wendt, M., Rothkirch, A., Pennicard, D. & Liermann H.-P. (2018) Elastic softening of (Mg0.8Fe0.2)O ferropericlase across the iron spin crossover measured at seismic frequencies. Geophys. Res. Lett., 45, 6862–6868. https://doi.org/10.1029/2018GL077982
Buchen, J., Marquardt, H., Schulze, K., Speziale, S., Boffa Ballaran, T., Nishiyama, N. & Hanfland, M. (2018) Equation of state of polycrystalline stishovite across the tetragonal-orthorhombic phase transition. J. Geophys. Res. Solid Earth, 123, 7347–7360. https://doi.org/10.1029/2018JB015835
Immoor, J., Marquardt, H., Miyagi, L., Lin, F., Speziale, S., Merkel, S., Buchen, J., Kurnosov, A. & Liermann, H.-P. (2018) Evidence for {100}<011> slip in ferropericlase in Earth’s lower mantle from high-pressure/high-temperature experiments. Earth Planet. Sci. Lett., 489, 251–257. https://doi.org/10.1016/j.epsl.2018.02.045
Buchen, J., Marquardt, H., Speziale, S., Kawazoe, T., Boffa Ballaran, T. & Kurnosov, A. (2018) High-pressure single-crystal elasticity of wadsleyite and the seismic signature of water in the shallow transition zone. Earth Planet. Sci. Lett., 498, 77–87. https://doi.org/10.1016/j.epsl.2018.06.027
Buchen, J., Marquardt, H., Boffa Ballaran, T., Kawazoe, T. & McCammon, C. (2017) The equation of state of wadsleyite solid solutions: Constraining the effects of anisotropy and crystal chemistry. Am. Mineral., 102, 2494–2504. https://doi.org/10.2138/am-2017-6162
Schulze, K., Buchen, J., Marquardt, K. & Marquardt, H. (2017) Multi-sample loading technique for comparative physical property measurements in the diamond-anvil cell. High Pressure Res., 37, 159–169. https://doi.org/10.1080/08957959.2017.1299719
Kawazoe, T., Buchen, J. & Marquardt, H. (2015) Synthesis of large wadsleyite single crystals by solid-state recrystallization. Am. Mineral., 100, 2336–2339. https://doi.org/10.2138/am-2015-5400