Hans-Rudolf Wenk Explained

Hans-Rudolf Wenk is a Swiss mountaineer, vintner, mineralogist, crystallographer and geologist.

Education and career

Wenk was born in Zürich, Switzerland in 1941 and grew up in Basel. He studied crystallography at the University of Zürich under the direction of Prof. Fritz Laves and obtained a PhD in 1965. In 1966, he went to California, first on a postdoctoral position in experimental rock deformation at UCLA with David Griggs and John Christie and then, in the fall of 1967, assuming a faculty position in mineralogy at the University of California in Berkeley.[1]

Research

Wenk's research interests covered a broad field of topics. His first projects consisted of crystal structure determinations of new minerals such as the silicates wenkite (named after his father, Swiss geologist Eduard Wenk), howieite.[2] and zussmanite, and refining crystal structures from different geological settings such as lunar ilmenite,[3] carbonates and plagioclase.[4] He also used transmission electron microscopy to investigate lattice defects and microstructures of plagioclase and carbonates at high resolution.[5]

Preferred orientation of minerals in both experimentally and naturally deformed rocks remained a focus throughout his career. This involved development and application of new experimental techniques such as neutron diffraction, synchrotron X-ray diffraction and electron back-scatter diffraction. Collaboration with Fred Kocks at Los Alamos National Lab produced research projects that transformed polycrystal plasticity models to low symmetry materials and polyphase aggregates, including recrystallization.[6] [7]

Further studies using diamond anvil cells to reproduce pressures, stresses and temperatures representative of the deep Earth,[8] in combination with the above-stated plasticity models, advanced the understanding of rock deformation and anisotropy in the mantle and core as observed by seismologists.[9]

Wenk combined laboratory experiments and theoretical models with fieldwork, in his teaching and research. His focus has been on the Tertiary Bergell pluton in the Central Alps,[10] [11] and Southern California mylonites[12] and pseudotachylites.[13]

His work quantifying preferred orientation and correlating crystal alignment in shales to seismic anisotropy[14] is used in seismic prospecting for oil and gas. Recent discoveries include extreme preferred orientation in slates,[15] and residual strain in quartz that can be used as a paleo-piezometer of deformed rocks.[16]

Publications

Wenk co-authored works on advanced mineralogy applied to broader topics such as the texture of bones,[17] identifying Hiroshima atomic bomb debris,[18] and the properties of Roman concrete.[19] His research has been reported in over 450 journal publications and 4 books[20] [21]

Awards and achievements

Wenk's research achievements were recognized by awards, including Humboldt Fellowship,[22] Fulbright Fellowship,[23] Berndt Mathias Scholarship (Los Alamos National Lab),[24] Wason Medal of the American Concrete Institute,[25] and the Gottlob Werner Medal of the Deutsche Mineralogische Gesellschaft.His fieldwork was inspired by his passion for mountains where he climbed Mont Blanc, Piz Badile, Finsteraarhorn, Half Dome, Mt. Shasta, Kilimanjaro, Fujiyama, Kinabalu, and Pico di Orizaba.

Notes and References

  1. Web site: Hans-Rudolf WENK . Earth and Planetary Science . 8 June 2020 . en.
  2. Wenk, H.-R. (1974). Howieite, a new type of chain silicate, Am. Mineral., 59, 86-97
  3. Raymond, K.N., Wenk, H.-R. (1971). Lunar ilmenite (refinement of the crystal structure), Contrib. Mineral. Petrol., 30, 135-340
  4. Wenk, H.-R., Kroll, H. (1984). Analysis of P, I  and C plagioclase structures, Bull. Mineral, 107, 467-487
  5. Wenk, H.-R., Edit. (1976). Electron Microscopy in Mineralogy, Springer-Verlag, Berlin-Heidelberg-New York, 564 pp
  6. Wenk, H.-R., Canova, G., Brechet, Y., Flandin, L. (1997). A deformation-based model for recrystallization of anisotropic materials. Acta mater. 45, 3283-3296
  7. Kocks, U.F., Tome, C., Wenk, H.-R. (2000). Texture and Anisotropy. Preferred Orientations in Polycrystals and Their Effect on Materials Properties. 2nd paperback edition. Cambridge University Press, 676pp
  8. Wenk, H.-R., Lonardelli, I., Pehl, J., Devine, J., Prakapenka, V., Shen G., Mao H.-k. (2004). In situ observation of texture development in olivine, ringwoodite, magnesiowuestite and silicate perovskite at high pressure. Earth Planet. Sci. Lett. 226, 507-519 [doi:10.1016/j.epsl.2004.07.033]
  9. Romanowicz, B., Wenk, H.-R. (2017). Anisotropy in the deep Earth. PEPI (Review paper), 269, 58-90 [doi:10.1016/j.pepi.2017.05.005]
  10. Wenk, H.-R., (1973). The structure of the Bergell Alps, Eclogae Geol. Helv., 66, 255-291
  11. Wenk, H.-R., S.C. Cornelius (1978). Geologischer Atlas der Schweiz, Blatt Sciora 1296 Atlasblatt 70, Schweiz. Geol. Komm. Basel
  12. H.R. Wenk (1998). Deformation of mylonites in Palm Canyon, California, based on xenolith geometry. J. Struct. Geol. 20, 559-571
  13. Wenk, H.-R., Johnson, L.R., Ratschbacher, L. (2000). Pseudotachylites in the eastern Peninsular ranges of California. Tectonophysics 321, 253-277
  14. Wenk, H.-R., Voltolini, M., Kern, H., Popp, H., Mazurek, M. (2008). Anisotropy of Mont Terri Opalinus Clay. The Leading Edge 27, 742-748
  15. Wenk, H.-R., Yu, R., Cardenes, V., Lopez-Sanchez, M.A., Sintubin, M (2020). Review: Fabric and anisotropy of slates: From classical studies to new experimental results. J. Struct. Geol.
  16. Wenk, H.-R., Chandler, C.B., Chen, K., Li, Y., Tamura, N., Yu, R (2020). Residual strain in quartzites as a paleo-piezometer. Geoph. J. Int. (in press)
  17. Hedegaard, C., Wenk, H.-R. (1998). Microstructure and texture patterns of mollusc shells. J. Mollusc. Studies 64, 133-136
  18. Wannier, M.A., Urreiztieta, M., Wenk, H.-R., Stan, C.V., Tamura, N., Yue, B. (2019). Fallout melt debris and aerodynamically-shaped glasses in beach sands of Hiroshima Bay, Japan. Anthropocene, 25, 100196, [doi:10.1016/j.ancene.2019.100196]
  19. Jackson, M.D., Landis, E.N., Brune, P.F., Vitti, M., Chen, H., Li, Q., Kunz, M., Wenk, H.-R., Monteiro, P.J.M., Ingraffea, A.R. (2014). Mechanical resilience and cementitious processes in Imperial Roman architectural mortar. Proc. Natl. Acad. Sci. 111, 18484-18489 [doi/10.1073/pnas.1417456111]
  20. Web site: HANS-RUDOLF WENK PUBLICATIONS. 2020-06-06. eps.berkeley.edu.
  21. Wenk, H.-R., Bulakh, A. (2016). Minerals. Their Constitution and Origin. 2nd Edn. Cambridge University Press, 621pp.
  22. Web site: American Friends of the Alexander von Humboldt Foundation. 2020-06-07. www.americanfriendsofavh.org. en.
  23. Web site: Hans-Rudolf Wenk Fulbright Scholar Program. 2020-06-07. www.cies.org.
  24. Book: Gates, Alexander E.. A to Z of Earth Scientists. 2009. Infobase Publishing. 978-1-4381-0919-0. en.
  25. Web site: Paper Awards. 2020-06-07. www.concrete.org.

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