Table S1. Unit cell parameters calculated from d-spacings of (240),(040) and (141) and volume - pressure results calculated for given temperatures of each experiment

B068 / B069 / B070 / B071 / B072
a (Å) / 5.592 / 5.622 / 5.590 / 5.596 / 5.575
b (Å) / 11.160 / 11.180 / 11.064 / 11.152 / 11.184
c (Å) / 8.108 / 8.053 / 8.158 / 8.145 / 8.094
V (Å3)a / 506.0 / 506.2 / 504.6 / 508.3 / 504.6
T (K) / 2070 / 2060 / 2140 / 2040 / 2200
Pb (GPa) / 20.1 / 20.0 / 21.0 / 19.0 / 21.3

a Uncertainty in the unit cell volume is ± 2 Å3

b Calculated using Mie-Grüneisen-Debye EOS parameters in Stixrude and Lithgow-Bertelloni 2011 for 10% Fe-bearing wadsleyite

Table S2. Extrapolated average equivalent stress at given strain rates

Experiment: / B069 / B070 / B071 / B072
Strain rate (s−1) / 5.6 x 10−6 / 9.7 x 10−6 / 4.6 x 10−6 / 6.6 x 10−6
a (pseudo-steady state stress) / 2.40 / 1.74 / 1.57 / 0.63
b / 4262.18 / 15.90 / 186.11 / 92.55
Strain rate (s−1) / 1.7 x 10−5 / 2.4 x 10−5 / 1.9 x 10−5 / 1.6 x 10−5
a (pseudo-steady state stress) / 3.00 / 2.15 / 2.36 / 1.41
b / 282.94 / 70.68 / 264.87 / 35.63
Strain rate (s−1) / 4.2 x 10−5 / 4.2 x 10−5 / - / 6.4 x 10−5
a (pseudo-steady state stress) / 3.60 / 2.37 / - / 2.00
b / 744.36 / 416.12 / - / 42.57
Stress exponent,
n / 4.9 / 4.5 / 3.7 / 1.0, 4.6

a,b are parameters obtained from a best fit to the data using the equation σ ̅eqv=a(1-exp(-b*εeqv)) to the data, and for subsequent strain-rate steps the equation becomes: σ ̅eqv=a(1-exp(-b*(εeqv0-ε2,3)))