Intrinsic paleointensity bias and the long-term history of the geodynamo

advances.sciencemag.org/cgi/content/full/3/2/e1602306/DC1

Supplementary Materials for

Intrinsic paleointensity bias and the long-term history of the geodynamo

Aleksey V. Smirnov, Evgeniy V. Kulakov, Marine S. Foucher, Katie E. Bristol

Published 15 February 2017, Sci. Adv. 3, e1602306 (2017) DOI: 10.1126/sciadv.1602306

This PDF file includes:

 Supplementary Results

 fig. S1. Typical dependences of low-field magnetic susceptibility versus temperature.

 fig. S2. Magnetic hysteresis properties.

 table S1. Paleointensity results obtained using the conventional Thellier method by fitting the high- and low-temperature segments of the Arai plots.

 table S2. Paleointensity results obtained using the LTD-Thellier method by fitting

the high- and low-temperature segments of the Arai plots.

fig. S1. Typical dependences of low-field magnetic susceptibility (κ) versus temperature. Data

measured from magnetite powders with the mean grain size of 0.75 μm (A) and 250 μm (B). Red and

blue lines represent the heating and cooling curves, respectively.

fig. S2. Magnetic hysteresis properties. (A, B, C) Typical magnetic hysteresis loops after paramagnetic slope correction measured from the M0.35 (A), M1.5 (B), and M250 (C) samples. (D) A Day plot (21) with data for all measured samples. Green symbols represent the data from M0.35, M0.75, M1.5, M5, M12, M30, and M250 samples; red symbols represent the data from the MIX samples. Abbreviations are:

M

, saturation remanence; M

, saturation magnetization; H

, coercivity; H

, coercivity of remanence; SD

single-domain; PSD, pseudo-single-domain; MD, multidomain. Gray lines represent SD-MD mixing

models (24).

table S1. Paleointensity results obtained using the conventional Thellier method by fitting the high- and low-temperature segments of the Arai plots. H and dH are the paleointensity value and its standard deviation; N – the number of successive data points used for fitting; f – the fraction of NRM, g - gap factor, q - quality factor (18); d(CK) is the maximum pTRM check deviation within and below the selected Arai segment, normalized to the "true" TRM, which is determined from the intersection of the linear fit with the x-axis (47).

High-temperature fit (525-585°C)* Low-temperature fit (100-450°C)

Sample H dH N f g q d(CK) H dH N f

M0.35-1 48.79 0.29 6 0.830 0.710 97.66 2.71 61.07 2.18 6 0.089

M0.35-2 49.02 0.32 6 0.831 0.709 91.03 1.37 56.14 3.45 6 0.084

M0.35-3 49.66 0.14 6 0.834 0.709 215.05 2.49 56.74 5.31 6 0.077

SD Mean 49.16 0.45 57.98 2.69

M0.75-1 46.02 0.20 6 0.789 0.601 122.22 3.09 87.46 3.25 6 0.132

M0.75-2 45.03 0.15 6 0.800 0.599 141.50 2.83 91.24 4.79 6 0.135

M0.75-3 46.40 1.30 6 0.799 0.610 17.63 1.95 70.15 10.40 6 0.098

M0.75 Mean 45.82 0.71 82.95 11.25

M1.5-1 44.03 0.14 6 0.774 0.604 146.21 1.25 107.30 11.13 6 0.190

M1.5-2 44.10 0.39 6 0.816 0.713 65.18 1.63 99.26 6.80 6 0.155

M1.5-3 43.39 0.92 6 0.834 0.722 28.55 1.83 105.66 11.47 6 0.197

M1.5 Mean 43.84 0.39 104.07 4.25

M5-1 40.47 0.81 6 0.805 0.715 28.64 2.02 117.11 7.51 6 0.202

M5-2 39.78 1.14 6 0.805 0.736 20.75 2.68 121.71 8.21 6 0.213

M5-3 38.87 1.25 6 0.788 0.733 17.99 2.82 142.95 11.47 6 0.244

M5 Mean 39.71 0.80 127.26 13.78

M12-1 35.18 1.48 6 0.772 0.754 13.85 1.54 145.19 14.20 6 0.277

M12-2 35.79 0.61 6 0.678 0.721 28.51 2.70 104.65 11.06 6 0.327

M12-3 36.55 1.65 6 0.781 0.745 12.87 2.00 137.67 13.60 6 0.258

M12 Mean 35.84 0.69 129.17 21.57

M30-1 28.15 1.24 6 0.626 0.753 10.71 2.80 116.31 12.24 6 0.402

M30-2 28.51 1.99 6 0.725 0.757 7.85 3.40 139.28 8.18 6 0.325

M30-3 29.39 1.85 6 0.717 0.755 8.58 2.72 132.32 7.57 6 0.315

M30 Mean 28.68 0.64 129.30 11.78

M250-1* 20.74 1.57 5 0.677 0.726 6.48 2.95 184.65 15.61 6 0.420

M250-2* 20.99 1.77 5 0.670 0.731 5.81 3.04 180.66 15.35 6 0.420

M250-3* 21.24 2.21 5 0.641 0.688 4.24 1.82 206.86 8.78 6 0.385

M250 Mean* 20.99 0.25 190.72 14.12

MIX-1 43.13 1.35 6 0.822 0.743 19.57 1.81 104.37 6.22 6 0.174

MIX-2 44.74 1.01 6 0.824 0.736 26.97 2.85 92.55 6.18 6 0.153

MIX-3 45.34 0.85 6 0.825 0.732 32.09 3.43 87.60 5.56 6 0.144

MIX Mean 44.40 1.14 94.84 8.62

* The 540-585°C range was used for the M250 samples.

table S2. Paleointensity results obtained using the LTD-Thellier method by fitting the high- and low-temperature segments of the Arai plots. H and dH are the paleointensity value and its standard deviation; N – the number of successive data points used for fitting; f – the fraction of NRM, g - gap factor, q - quality factor (18); d(CK) is the maximum pTRM check deviation within and below the selected Arai segment, normalized to the "true" TRM, which is determined from the intersection of the linear fit with the x-axis (47).

High-temperature fit (525-585°C)* Low-temperature fit (100-450°C)

Sample H dH N f g q d(CK) H dH N f

M0.35-1 49.30 0.26 6 0.835 0.711 112.47 1.64 55.24 2.41 6 0.075

M0.35-2 49.73 0.24 6 0.838 0.708 122.42 2.04 53.02 1.88 6 0.077

M0.35-3 50.05 0.08 6 0.842 0.71 386.58 0.9 50.16 0.09 6 0.07

SD Mean 49.69 0.38

M0.75-1 50.32 0.27 6 0.805 0.595 89.282 2.26 57.87 2.88 6 0.078

M0.75-2 49.93 0.18 6 0.808 0.587 134.04 2.21 51.49 3.64 6 0.069

M0.75-3 49.54 0.62 6 0.805 0.604 39.01 1.89 59.39 5.84 6 0.076

M0.75 Mean 49.93 0.39

M1.5-1 49.13 0.16 6 0.791 0.609 149.09 2.22 54.64 3.81 6 0.09

M1.5-2 49.51 0.58 6 0.826 0.714 50.244 2.51 52.77 5.18 6 0.077

M1.5-3 48.58 0.37 6 0.831 0.713 77.11 1.44 61.14 3.56 6 0.097

M1.5 Mean 49.07 0.47

M5-1 48.33 0.31 6 0.832 0.717 93.89 1.47 62.85 2.25 6 0.091

M5-2 47.01 0.45 6 0.823 0.727 62.88 1.81 75.88 7.97 6 0.114

M5-3 47.78 0.41 6 0.829 0.719 70.06 1.91 68.92 6.10 6 0.1

M5 Mean 47.71 0.66

M12-1 45.19 0.80 6 0.848 0.736 37.94 3.84 80.91 12.66 6 0.12

M12-2 44.49 0.93 6 0.766 0.722 26.48 1.79 82.21 5.97 6 0.163

M12-3 44.96 0.41 6 0.824 0.723 64.78 3.7 73.81 3.03 6 0.11

M12 Mean 44.88 0.36

M30-1 34.26 1.57 6 0.8 0.735 12.8 3.25 136.33 5.34 6 0.22

M30-2 33.69 1.79 6 0.73 0.762 10.45 1.58 122.48 3.63 6 0.199

M30-3 35.00 1.58 6 0.717 0.758 12.03 1.9 110.39 3.02 6 0.184

M30 Mean 34.32 0.66

M250-1* 21.92 1.34 5 0.676 0.733 8.08 2.49 157.51 12.60 6 0.388

M250-2* 22.13 1.25 5 0.641 0.739 8.376 1.56 159.52 12.63 6 0.391

M250-3* 22.83 2.01 5 0.644 0.688 5.023 1.89 173.42 6.38 6 0.374

M250 Mean* 22.29 0.48

MIX-1 47.84 0.62 6 0.827 0.724 45.87 2.12 72.71 3.88 6 0.107

MIX-2 48.28 0.36 6 0.835 0.718 80.56 2.81 66.15 1.93 6 0.101

MIX-3 48.73 0.26 6 0.835 0.715 112.19 2.13 103.26 5.14 6 0.185

MIX Mean 48.28 0.45 80.71 19.81

* The 540-585°C range was used for the M250 samples.