Prof. David Dobson [University College London, UK]

Title: Extreme Anisotropic Diffusion Creep in Post-Perovskite: A New Paradigm for Mantle Flow in D''

Language:  English presentation

Time: 9:30 - 11:00 AM, Monday, August 5, 2024

Place:  Onsite：Conference room 410, HPSTAR (Shanghai)

            Online: https://meeting.tencent.com/dm/kAWO599byi72   #Meeting ID：904-259-607

Host: Prof. Ho-kwang Mao

Abstract:

Post-perovskite is thought to form a significant component of much of the Earth's lowermost mantle in the D'' region.  We have shown through a combination of high-pressure experiment and ab initio simulation that chemical diffusivity in silicate post perovskite is extremely anisotropic, with 8 orders of magnitude difference between the fastest and slowest diffusing directions.  This has significant implications for the rheological behavior of post perovskite, ultimately leading to a strong strain weakening rheology in lattice diffusion creep.  This in turn helps to explain several anomalous seismic features of D'' and might be important for the long-term stability and short-term temporal variability of plume source regions.

Biography of the Speaker:

Career Hostory

1991 BSc Bristol University. 1996 Ph.D University of London. 1996-1997 Post Doctoral Research Assistant. UCL;  1997-2000  NERC Fellow. UCL; 2000-2002 Alexander von Humboldt Fellow Bayerisches Geoinstitut; 2002-2009;  Royal Society University Research Fellow UCL; 2007-2011 Reader in Mineralogical Geophysics UCL; 2011- Professor of Earth Materials UCL.

Prizes and Honours

1999 Geological Society of London President's Award; 2004 Philip Leverhulme Prize; 2005 European Union of Geosciences Outstanding Young Scientist Medal; 2005 European Mineralogical Union Research Excellence Medal; 2010 Bullerwell Lecturer of the British Geophysical Association; 2010-2011 Mineralogical Society of America Distinguished Lecturer.  

2014 Friedrich Wilhelm Bessel Research Award of the Alexander von Humboldt Foundation.

Contionuous NERC funding since 2002.

£1.85 M as PI since 2011; £4.85 M as CoI since 2011.

£2.3M current total funding (FEC)

Publications:

Over 120 ISI listed papers; 9 in Nature/Science; H-index 33 (WoS).