Table T2. Spinel compositions, Hole 1271B.
Core,
section
Interval
(cm)
Depth
(mbsf)
N
SiO2
TiO2
Al2O3
Cr2O3
Fe2O3
FeO
MnO
MgO
CaO
NiO
Total
Cr#
Mg#
Fe3+#
209-1271B-
Harzburgite
5R1 64–67 28.34 6 0.02 0.02 37.4 33.3 0.43 12.4 0.18 16.6 0.01 0.12 100.5 37.4 70.4 0.5



SD 0.01 0.01 0.4 0.3 0.18 0.3 0.06 0.2 0.01 0.05 0.4 0.5 0.8 0.2
Dunite
4R-1 28–31 26.88 7 0.04 0.02 35.3 33.6 1.58 14.1 0.17 15.1 0.00 0.33 100.3 38.9 65.7 1.7



SD 0.04 0.01 0.4 0.3 0.31 0.5 0.03 0.4 0.01 0.03 0.5 0.4 1.4 0.3
6R-1 30–33 32.5 5 0.07 0.00 33.0 37.1 0.73 14.0 0.19 15.1 0.00 0.21 100.5 43.0 65.8 0.8



SD 0.02 0.01 1.5 1.3 0.19 0.8 0.03 0.7 0.00 0.03 0.9 1.9 2.4 0.2
7R-1 49–54 36.69 13 0.07 0.05 30.9 36.5 3.30 13.8 0.21 15.0 0.00 0.11 100.0 44.2 65.9 3.7



SD 0.02 0.02 1.3 0.7 0.64 0.5 0.04 0.4 0.00 0.05 0.3 1.5 1.4 0.8
8R-1 28–31 40.98 8 0.09 0.04 31.6 36.0 3.26 15.5 0.22 14.1 0.01 0.14 101.0 43.3 61.8 3.6



SD 0.07 0.01 1.1 1.5 0.21 0.6 0.04 0.4 0.01 0.03 0.6 1.9 1.6 0.2
8R-1 83–87 41.53 6 0.06 0.02 34.2 35.0 0.93 13.2 0.19 15.6 0.01 0.10 99.4 40.7 67.7 1.0



SD 0.02 0.02 0.4 0.3 0.29 0.3 0.04 0.2 0.01 0.05 0.6 0.5 0.8 0.3
14R-1 20–24 70 4 0.09 0.40 25.5 41.5 3.04 18.5 0.21 11.8 0.01 0.09 101.1 52.2 53.2 3.5



SD 0.04 0.03 0.4 0.7 0.09 0.9 0.03 0.5 0.01 0.05 0.6 0.8 2.2 0.1
15R-1 23–26 75.03 2 0.06 0.02 19.5 48.8 1.37 18.5 0.22 10.6 0.00 0.04 99.1 62.7 50.6 1.6



SD 0.02 0.00 1.7 1.5 0.45 1.3 0.02 0.9 0.00 0.05 0.7 2.8 3.9 0.6
19R-1 25–28 94.35 5 0.06 0.33 27.0 41.6 0.07 17.6 0.19 12.1 0.01 0.10 99.2 50.8 55.2 0.1



SD 0.03 0.09 0.4 0.9 0.20 1.3 0.04 0.8 0.01 0.09 0.4 0.9 3.5 0.2
20R-1 81–84 99.61 10 0.06 0.35 29.6 39.8 0.28 14.5 0.20 14.4 0.02 0.06 99.2 47.4 63.9 0.3



SD 0.01 0.09 1.8 1.5 0.22 1.3 0.04 1.1 0.03 0.06 0.4 2.4 3.8 0.2
Dunite (impregnated)
10R-1 43–46 50.93 2 0.14 0.05 26.7 42.3 2.64 13.7 0.23 14.8 0.00 0.15 100.6 51.5 65.8 3.0



SD 0.00 0.00 0.3 0.1 0.05 0.0 0.03 0.1 0.00 0.03 0.4 0.2 0.2 0.1
10R-1 82–84 51.32 13 0.02 0.01 25.4 43.9 1.95 15.1 0.23 13.6 0.01 0.06 100.3 53.7 61.5 2.2



SD 0.02 0.01 1.2 1.0 0.19 0.7 0.03 0.6 0.01 0.03 0.6 1.7 2.1 0.2
13R-1 70–73 65.8 6 0.12 0.28 29.1 38.4 2.90 16.5 0.23 13.4 0.01 0.13 101.1 46.9 59.0 3.3



SD 0.06 0.03 0.3 0.4 0.35 1.2 0.04 0.8 0.01 0.09 0.5 0.4 3.3 0.4
18R-1 110–113 90.2 6 0.10 0.09 21.5 46.4 2.55 19.0 0.25 10.8 0.01 0.12 100.9 59.1 50.3 3.0



SD 0.03 0.01 0.4 0.4 0.41 0.5 0.04 0.3 0.01 0.04 0.5 0.6 1.3 0.5
Troctolite
11R-1 70–75 56.2 5 0.02 0.34 22.7 43.4 2.52 20.0 0.28 10.1 0.00 0.07 99.4 56.3 47.2 3.0



SD 0.02 0.22 0.4 0.4 0.48 0.8 0.04 0.4 0.00 0.04 0.3 0.3 2.0 0.6
17R-1 32–35 84.82 8 0.03 0.69 26.0 40.9 2.39 15.0 0.21 13.9 0.00 0.17 99.3 51.3 62.3 2.8



SD 0.02 0.14 1.7 1.3 0.45 1.0 0.05 0.7 0.01 0.07 0.4 2.4 2.8 0.5
Olivine gabbro
12R-1 17–22 60.27 7 0.04 0.68 23.8 40.3 4.49 19.2 0.26 11.0 0.01 0.08 99.8 53.2 50.4 5.3



SD 0.02 0.05 0.5 0.5 0.29 0.6 0.03 0.4 0.01 0.03 0.5 0.8 1.6 0.3
12R-1 68–72 60.78 5 0.09 2.29 19.5 39.6 5.46 22.3 0.26 9.3 0.00 0.17 99.0 57.6 42.7 7.0



SD 0.03 0.67 1.0 1.1 0.47 0.7 0.03 0.3 0.01 0.09 0.4 1.7 1.2 0.6
12R-1 96–99 61.06 4 0.03 1.22 20.8 42.0 5.21 20.7 0.31 10.1 0.01 0.09 100.4 57.5 46.6 6.4



SD 0.01 0.15 0.4 0.7 0.18 0.8 0.07 0.5 0.02 0.06 0.7 0.7 2.1 0.2
12R-1 115–120 61.25 6 0.09 0.98 22.1 40.7 4.67 20.4 0.26 10.2 0.00 0.09 99.4 55.3 47.1 5.7



SD 0.05 0.18 0.6 0.7 0.44 0.6 0.03 0.3 0.01 0.02 0.4 1.0 1.4 0.5
13R-1 27–30 65.37 4 0.04 1.03 22.5 41.3 2.93 21.3 0.27 9.5 0.01 0.11 99.0 55.2 44.3 3.6



SD 0.08 0.46 3.4 2.7 0.33 2.0 0.05 1.5 0.00 0.07 0.4 5.7 6.2 0.5
17R-1 22–25 84.72 5 0.16 1.06 23.7 42.0 2.68 19.4 0.25 11.4 0.01 0.09 100.7 54.3 51.1 3.2



SD 0.08 0.22 1.5 0.7 0.43 1.2 0.03 1.0 0.01 0.04 0.9 1.9 3.7 0.5
Olivine gabbronorite
18R-1 27–30 89.37 5 0.04 1.03 22.5 41.3 2.93 21.3 0.27 9.5 0.01 0.11 99.0 46.3 65.2 0.3



SD 0.01 0.42 0.8 1.0 0.58 1.3 0.05 0.9 0.01 0.07 0.6 1.3 3.8 0.7

Notes: N = number of analyses making up the average composition. Cr# = (Cr x 100)/(Cr + Al); Mg# = (Mg x 100)/(Mg + Fe2+); Fe3+# = (Fe3+ x 100)/(Al + Cr + Fe3+); SD = one standard deviation.