Extended Data Table 2 Composition and calculated density and viscosity of the North China lavas, MORB and Hawaii OIB

SiO₂ (wt%)

41.76

1.45

^46.91

^1.72

39.93

^47.92

^50.49

TiO₂ (wt%)

2.68

0.21

^2.18

^0.32

2.85

^2.45

^1.42

Al₂O₃ (wt%)

11.81

0.91

^13.99

^0.68

11.57

^13.15

^15.48

Fe₂O₃ (wt%)

15.03

0.77

^12.43

^0.78

16.57

^12.50

^10.39

MnO (wt%)

0.20

0.02

^0.16

^0.01

0.22

^0.18

^0.17

MgO (wt%)

10.09

1.66

^9.81

^1.32

9.85

^9.89

^7.84

CaO (wt%)

10.59

1.22

^9.27

^0.71

12.25

^11.21

^11.52

Na₂O (wt%)

4.54

0.69

^3.05

^0.60

3.63

^2.16

^2.71

K₂O (wt%)

2.18

0.40

^1.63

^0.34

2.04

^0.31

^0.18

P₂O₅ (wt%)

1.13

0.19

^0.56

^0.15

1.09

^0.24

^0.13

Na₂O + K₂O (wt%)

^6.72

^0.84

^4.68

^0.63

5.67

^2.47

^2.89

Fe/Mn ratio

^68.3

^6.0

^69.2

^4.9

^68.0

^61.8

^54.9

Y/Yb ratio

^20.81

^1.40

^14.36

^0.98

^21.87

^13.51

¹⁰

Melt extraction depth (km)

¹⁴⁹

¹¹

⁹⁸

⁸

¹⁵⁸

⁹¹

⁶³

Melt density (g/cm³)

^3.291

^3.096

^3.351

^3.086

^2.942

^{Melt viscosity [log η (Pa s)]}

^0.988

^1.412

^0.851

^1.460

^1.730

Solid mantle density (g/cm³)

^3.328

^3.280

^3.334

^3.273

^3.246

^{Melt mobility (Δρ/η)}

^0.085

^0.130

^−0.02

^0.128

^0.175