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Sheng Fan image 2021 @1xPhD (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.

Publications

Qi, C., Wang, Q., Fan, S., Richards, D., Prior, D. J., & Worthington, R. (2023). Evolution of crystallographic preferred orientations of ice sheared to high strains by equal-channel angular pressing. Proceedings of the American Geophysical Union (AGU) Fall Meeting: Wide. Open. Science. MR31A-0044. Retrieved from https://www.agu.org Conference Contribution - Published proceedings: Abstract

Fan, S., & Prior, D. J. (2023). Cool ice with hot properties. Nature Geoscience, 16(12), 1073. doi: 10.1038/s41561-023-01330-z Journal - Research Other

German, T., Prior, D., Pooley, B., Fan, S., & Woolley, R. (2023). Understanding ice dynamics through natural ice air bubbles and their deformation. In G. E. Frontin-Rollett & S. D. Nodder (Eds.), Geoscience Society of New Zealand Miscellaneous Publication. 164A, (pp. 86). Wellington, New Zealand: Geoscience Society of New Zealand. [Abstract] Conference Contribution - Published proceedings: Abstract

Fleming, M., Prior, D., Fan, S., Worthington, R., Pooley, B., & Bowman, H. (2023). Ice deformation mechanisms: Effect of grain size and sample size on ice rheology. Proceedings of the New Zealand-Australia Antarctic Science Conference (NZAASC): Latitudes of Change. (pp. 98-99). Retrieved from https://www.nzaasc.org Conference Contribution - Published proceedings: Abstract

MacClure, Z., Prior, D., Purdie, H., Fan, S., Still, H., & Craw, L. (2023). Structural and microstructural responses to shear in the lateral margin of the Haupapa/Tasman Glacier. Proceedings of the New Zealand-Australia Antarctic Science Conference (NZAASC): Latitudes of Change. (pp. 94). Retrieved from https://www.nzaasc.org Conference Contribution - Published proceedings: Abstract

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