Dr Sheng Fan, Our people, Department of Geology, University of Otago, New Zealand

Sheng Fan image 2021 @1x PhD (Otago)

Ice deformation (creep) experiments
Ice microstructure and mechanics
Cryogenic electron backscatter diffraction (cryo-EBSD) and fabric analyzer
Cryo-seismology

Google Scholar: Sheng Fan
ResearchGate: Sheng Fan
ORCID: orcid.org/0000-0002-0404-1374
MTEX code page: grain boundary irregularity

Research interests

My current research focuses on (1) understanding the deformation mechanism of ice under terrestrial conditions (warm, low stress) and planetary settings (cold, high stress), and (2) understanding high-temperature deformation mechanism of minerals using ice as an analogue. I use high-quality electron backscatter diffraction (EBSD) data to quantify the microstructural statistics. I use these microstructural statistics to understand the origin, kinetics and dynamics of deformation mechanisms and/or processes and link them to the large-scale tectonic processes.

Microstructural change and mechanical weakening (enhancement)

Flowing glaciers and ice sheets play key roles in shaping planetary surfaces, and form important feedbacks with climate, both on Earth and elsewhere in the solar system. Ice deformation is a significant component of ice flow. Ice becomes mechanically weaker during the deformation—the rate of ice flow accelerates as the deformation progresses from low to high strain, at a constant temperature. The correlation between ice microstructural change and the mechanical weakening is well known but poorly quantified. This knowledge gap prevents us from better quantifying the acceleration rate of polar ice flow, which contribute directly to the sea level rise, under global warming. I analyse the mechanical and microstructural data collected from ice deformation experiments and natural ice cores, aiming at quantifying the contribution of microstructural changes (e.g., crystallographic axis alignment, grain size reduction) to the weakening of ice. (Fan et al. (2020): Temperature and strain controls on ice deformation mechanisms: insights from the microstructures of samples deformed to progressively higher strains at −10, −20 and −30 °C)

Sheng fan profile 1

Quantify the progress of dynamic recrystallization

Dynamic recrystallization involves the migration and/or formation of grain boundaries, through which a crystalline aggregate lowers its free energy during plastic deformation and thus lead to weakening. Ice usually deforms at temperatures very close to its melting point under terrestrial settings. Attempts to understand high temperature microstructures and recrystallization are hampered by challenges in identifying newly-formed recrystallized grains. I attempt to use statistics of grain boundary irregularity to reliably identify recrystallized grains in ice and, furthermore, gives insight into the physical processes (e.g., nucleation, grain boundary migration) driving microstructural evolution in ice at high temperatures. (Fan et al. (2021a): Using grain boundary irregularity to quantify dynamic recrystallization in ice)

Sheng fan profile 2

Use subgrain structure to understand the nature of grain boundary formation

Subgrain rotation is an important process of dynamic recrystallization, and it occurs via the progressive misorientation of low-angle intragranular boundaries, which eventually become high-angle intragranular boundaries. The enclosure of high-angle intragranular boundaries leads to the formation of new recrystallized grains. I am very interested in understanding the origin of subgrain rotation – in other words, does the progressive subgrain rotation involve the change of misorientation axes? I attempt to explore this scientific question using misorientation and geometrically necessary dislocation statistics collected from intragranular boundaries. (Fan et al. (2021b): Kinking facilitates grain nucleation and modifies crystallographic preferred orientations during high-stress ice deformation)

Sheng Fan profile 3

Appointments

2021–2022 Postdoctoral Research Fellow, University of Otago, New Zealand
2019 Visiting Researcher, University of Liverpool, UK
2018–2019 Visiting Researcher, University of Pennsylvania, USA
2018 Visiting Researcher, University of Tübingen, Germany
2018 Visiting Researcher, University of Mainz, Germany
2015-2017 Geological Engineer, China National Offshore Oil Corporation, PRC
2014-2015 Research Assistant, State Key Lab of Petroleum Resources and Prospecting, PRC
2013-2014 Assistant Geological Engineer, China National Petroleum Corporation, PRC

Honours, awards and research funding

New Zealand Antarctic Research Institute (NZARI) Early Career Researcher Seed Grant
Antarctic Science Platform research grant from New Zealand Ministry of Business, Innovation and Employment (to David Prior and Sheng Fan)
Exceptional Doctoral Thesis. 2021.
Best poster of Early Career Researcher or Student, Antarctic Science Conference, 2021.
New Zealand Antarctic Research Institute Early Career Researcher Grant, 2021.
Antarctica New Zealand Doctoral Scholarship, 2018-2019.
PERT polar research seed funding, 2017-2018.
University of Otago Doctoral Scholarship, 2017-2020.
Third prize of “Science and Technology Forum of CNOOC”, 2016.
Second prize of “Science and Technology Forum of CNOOC”, 2015.
Honour of “Outstanding Graduate” (Master’s student), 2015.
Third prize of “National Doctoral Forum-Oil & Gas Resources and Exploration”, 2014.
Sino Geophysical Co., Ltd. Enterprise Scholarship, 2013-2014.
Honour of “Merit Student” (outstanding in study, attitude and health), 2013-2014.
China University of Petroleum Master Student Scholarship, 2012-2015.

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Publications

Fan, S., Wheeler, J., Prior, D. J., Negrini, M., Cross, A. J., Hager, T. F., … Wallis, D. (2022). Using misorientation and weighted Burgers vector statistics to understand intragranular boundary development and grain boundary formation at high temperatures. Journal of Geophysical Research: Solid Earth, 127, e2022JB024497. doi: 10.1029/2022JB024497

Platt, J. P., Mitchell, T. M., Prior, D. J., Negrini, M., Fan, S., Jefferd, M., & Winnard, B. (2022). Stress sensitivity of high-temperature microstructures in ice, with potential applications to quartz. Journal of Structural Geology, 154, 104487. doi: 10.1016/j.jsg.2021.104487

Prior, D., Fan, S., Thomas, R., & Wang, T. (2021). Ice mechanics: What do we still need to know to model ice sheets? In A. V. Zernack & J. Palmer (Eds.), Geoscience Society of New Zealand Miscellaneous Publication. 158, (pp. 220). Wellington, New Zealand: Geoscience Society of New Zealand. [Abstract]

MacClure, Z., Prior, D., Fan, S., Purdie, H., & Craw, L. (2021). Microstructural responses to shear localisation in the lateral margin of the Haupapa/Tasman Glacier. In A. V. Zernack & J. Palmer (Eds.), Geoscience Society of New Zealand Miscellaneous Publication. 158, (pp. 165). Wellington, New Zealand: Geoscience Society of New Zealand. [Abstract]

Lutz, F., Prior, D., Thomas, R., & Fan, S. (2021). How well can seismology measure ice anisotropy? A calibration experiment at the Priestley Glacier. In A. V. Zernack & J. Palmer (Eds.), Geoscience Society of New Zealand Miscellaneous Publication. 158, (pp. 163). Wellington, New Zealand: Geoscience Society of New Zealand. [Abstract]

Journal - Research Article

Craw, L., Treverrow, A., Fan, S., Peternell, M., Cook, S., McCormack, F., & Roberts, J. (2021). The temperature change shortcut: Effects of mid-experiment temperature changes on the deformation of polycrystalline ice. Cryosphere, 15, 2235-2250. doi: 10.5194/tc-15-2235-2021

Journal - Research Article

Fan, S., Cross, A. J., Prior, D. J., Goldsby, D. L., Hager, T. F., Negrini, M., & Qi, C. (2021). Crystallographic Preferred Orientation (CPO) development governs strain weakening in ice: Insights from high-temperature deformation experiments. Journal of Geophysical Research: Solid Earth, 126(12), e2021JB023173. doi: 10.1029/2021JB023173

Journal - Research Article

Fan, S., Prior, D. J., Cross, A. J., Goldsby, D. L., Hager, T. F., Negrini, M., & Qi, C. (2021). Using grain boundary irregularity to quantify dynamic recrystallization in ice. Acta Materialia, 209, 116810. doi: 10.1016/j.actamat.2021.116810

Journal - Research Article

Fan, S., Prior, D. J., Hager, T. F., Cross, A. J., Goldsby, D. L., & Negrini, M. (2021). Kinking facilitates grain nucleation and modifies crystallographic preferred orientations during high-stress ice deformation. Earth & Planetary Science Letters, 572, 117136. doi: 10.1016/j.epsl.2021.117136

Journal - Research Article

King, A., Lepine, P., Gorman, A. R., Prior, D. J., Lukács, A., Bowman, M. H., Fan, S., Robertson, A., Lutz, F., … Schjins, H. (2021). Shallow seismic reflection imaging of the Alpine Fault through late Quaternary sedimentary units at Whataroa, New Zealand. New Zealand Journal of Geology & Geophysics, 64(4), 505-517. doi: 10.1080/00288306.2020.1823433

Journal - Research Article

Monz, M. E., Hudleston, P. J., Prior, D. J., Michels, Z., Fan, S., Negrini, M., Langhorne, P. J., & Qi, C. (2021). Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: A case study, Storglaciären, Sweden. Cryosphere, 15, 303-324. doi: 10.5194/tc-15-303-2021

Journal - Research Article

Fan, S., Hager, T. F., Prior, D. J., Cross, A. J., Goldsby, D. L., Qi, C., Negrini, M., & Wheeler, J. (2020). Temperature and strain controls on ice deformation mechanisms: Insights from the microstructures of samples deformed to progressively higher strains at −10, −20 and −30 ºC. Cryosphere, 14(11), 3875-3905. doi: 10.5194/tc-14-3875-2020

Journal - Research Article

Lutz, F., Eccles, J., Prior, D. J., Craw, L., Fan, S., Hulbe, C., Forbes, M., Still, H., … Mandeno, D. (2020). Constraining ice shelf anisotropy using shear wave splitting measurements from active-source borehole seismics. Journal of Geophysical Research: Earth Surface, 125(9), e2020JF005707. doi: 10.1029/2020JF005707

Journal - Research Article

Qi, C., Prior, D. J., Craw, L., Fan, S., Llorens, M.-G., Griera, A., Negrini, M., … Goldsby, D. L. (2019). Crystallographic preferred orientations of ice deformed in direct-shear experiments at low temperatures. Cryosphere, 13(1), 351-371. doi: 10.5194/tc-13-351-2019

Journal - Research Article

Monz, M. E., Hudleston, P. J., Prior, D. J., Michels, Z., Fan, S., Negrini, M., Langhorne, P. J., & Qi, C. (2020). Electron backscatter diffraction (EBSD) based determination of crystallographic preferred orientation (CPO) in warm, coarse-grained ice: A case study, Storglaciären, Sweden. Cryosphere Discussions. doi: 10.5194/tc-2020-135

Journal - Research Other

Fan, S., Prior, D. J., Goldsby, D. L., Hager, T. F., Cross, A. J., & Negrini, M. (2021). The control of crystallographic preferred orientation (CPO) development and grain size reduction on ice mechanical weakening. Proceedings of the New Zealand Antarctic Science Conference: Connecting through change. (pp. 69). Retrieved from https://www.antarcticanz.govt.nz/nzasc21