Table T3. Amphibole composition, Hole 1271B.
Core,
section
Interval
(cm)
Depth
(mbsf)
N
SiO2
TiO2
Al2O3
Cr2O3
FeO
MnO
MgO
NiO
CaO
Na2O
K2O
Total
Mg#
Si
Na + K
209-1271B-
Dunite
7R-1 49–54 36.69 1 45.5 0.31 11.9 2.40 2.91 0.07 19.0 0.05 12.6 2.98 0.00 97.6 0.921 6.43 0.82
Troctolite
11R-1 70–75 56.2 3 52.4 0.22 6.0 0.93 3.10 0.06 21.0 0.10 11.9 1.89 0.04 97.7 0.923 7.28 0.52



SD 1.8 0.05 1.5 0.43 0.20 0.03 0.7 0.05 0.4 0.38 0.01 0.6 0.007 0.19 0.10
12R-1 17–22 60.27 3 47.7 0.17 10.4 1.32 3.61 0.10 19.7 0.12 11.9 2.83 0.07 97.8 0.907 6.70 0.79



SD 1.9 0.12 2.1 0.08 0.21 0.03 0.9 0.04 0.3 0.15 0.00 0.8 0.009 0.20 0.05
Olivine gabbro
12R-1 68–72 60.78 2 46.6 0.08 11.2 1.48 3.88 0.03 19.2 0.10 11.8 2.95 0.07 97.4 0.898 6.60 0.82



SD 0.5 0.04 0.7 0.24 0.17 0.01 0.2 0.03 0.2 0.01 0.01 0.4 0.005 0.05 0.00
12R-1 115–120 61.25 1 47.4 0.04 11.0 0.87 3.97 0.13 19.2 0.04 12.0 2.73 0.08 97.5 0.896 6.69 0.76
13R-1 27–30 65.37 1 47.9 0.23 9.5 1.20 3.84 0.14 19.9 0.16 11.7 2.66 0.09 97.3 0.902 6.77 0.75
16R-1 3–8 79.53 3 49.6 0.73 8.6 0.30 4.66 0.10 19.4 0.02 12.2 2.32 0.10 98.0 0.881 6.95 0.65



SD 1.4 0.44 1.5 0.44 0.31 0.06 0.7 0.04 0.1 0.26 0.04 0.1 0.010 0.17 0.08
Brown amphibole gabbro
3R-1 34–39 17.25 12 53.5 1.37 5.34 0.03 4.33 0.08 21.1 0.06 11.8 1.69 0.03 99.3 0.897 7.08 0.45



SD 1.78 0.41 1.95 0.03 0.46 0.03 0.56 0.05 0.21 0.36 0.02 0.3 0.010 0.21 0.10
3R-1 84–90 17.85 16 49.9 2.30 7.65 0.01 4.38 0.07 19.2 0.10 11.5 2.47 0.06 97.7 0.887 7.00 0.68



SD 2.7 0.89 2.16 0.01 0.60 0.03 1.2 0.05 0.2 0.55 0.02 0.6 0.020 0.31 0.16
4R-1 21–24 26.81 13 51.0 1.49 6.72 0.05 4.24 0.07 20.2 0.09 11.6 1.94 0.04 97.5 0.894 7.14 0.53



SD 3.1 0.83 3.10 0.06 0.38 0.04 0.8 0.04 0.4 0.76 0.02 0.4 0.009 0.38 0.21
4R-1 69–72 27.29 11 48.6 2.68 8.17 0.04 5.41 0.09 18.5 0.08 11.7 2.80 0.06 98.2 0.859 6.84 0.77



SD 1.3 0.79 1.18 0.05 0.37 0.04 0.3 0.03 0.4 0.17 0.01 0.5 0.008 0.18 0.05
14R-1 8–10 69.88 5 49.9 1.90 6.67 0.02 6.85 0.11 18.2 0.13 11.7 1.98 0.04 97.6 0.826 7.08 0.55



SD 2.0 0.68 1.53 0.03 0.54 0.02 0.9 0.03 0.3 0.57 0.02 0.3 0.018 0.25 0.16

Notes: Depth is based on expanding the curated recovery to fill the drilled interval. N = number of analyses making up averaged compositions; Mg# = Mg/(Mg + Fe); Si = molecular Si on 23 oxygens; Na + K = molecular Na and K on 23 oxygens; SD = one standard deviation.