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Tracking continental-scale modification of the Earth’s mantle using zircon megacrysts

J. Woodhead1,

1School of Earth Sciences, The University of Melbourne, VIC 3010, Australia

J. Hergt1,

1School of Earth Sciences, The University of Melbourne, VIC 3010, Australia

A. Giuliani1,2,

1School of Earth Sciences, The University of Melbourne, VIC 3010, Australia
2Department of Earth and Planetary Sciences, Macquarie University, North Ryde, NSW 2019, Australia

J. Hergt1,

1School of Earth Sciences, The University of Melbourne, VIC 3010, Australia

R. Maas1

1School of Earth Sciences, The University of Melbourne, VIC 3010, Australia

Affiliations  |  Corresponding Author  |  Cite as  |  Funding information

Woodhead, J., Hergt, J., Giuliani, A., Phillips, D., Maas, R. (2017) Tracking continental-scale modification of the Earth’s mantle using zircon megacrysts. Geochem. Persp. Let. 4, 1–6.

Research funded by the research group.

Geochemical Perspectives Letters v4  |  doi: 10.7185/geochemlet.1727
Received 08 December 2016  |  Accepted 22 May 2017  |  Published 10 July 2017
Copyright © 2017 European Association of Geochemistry




Figure 1 Schematic map of southern Africa showing kimberlite localities for zircon megacrysts analysed in this and previous studies. The major tectonic domains are also included.
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Figure 2 Age and isotopic composition data for zircon megacrysts. (a) Zircon Hf-isotope data showing a natural compositional subdivision into two distinct groups, further illustrated by Kernel Density estimates. Note the remarkable isotopic homogeneity within each group despite large variations in geographic location and age. All data from this study unless marked: N = Nowell et al. (2004)

Nowell, G.M., Pearson, D.G., Bell, D.R., Carlson, R.W., Smith, C.B., Kempton, P.D., Noble, S.R. (2004) Hf isotope systematics of kimberlites and their megacrysts: new constraints on their source regions. Journal of Petrology 45, 1583–1612.

, G = Griffin et al. (2000)

Griffin, W.L., Pearson, N.J., Belousova, E., Jackson, S.E., van Achterburgh, E., O’Reilly, S.Y., Shee, S.R. (2000) The Hf isotope composition of cratonic mantle: LAM-MC-ICPMS analysis of zircon megacrysts in kimberlites. Geochimica et Cosmochimica Acta 64, 133–147.

. (b) Inset showing a statistically significant correlation between zircon 176Hf/177Hf composition and age. Only zircons for which precise U-Pb Concordia ages are available are used to construct this plot. Literature data with less precise age determinations (greyed out in 2a) are excluded. (c) An equivalent plot to 2b for 143Nd/144Nd isotope variations. (d) A comparison between kimberlite U-Pb perovskite ages, widely used to estimate the timing of magmatism, and U-Pb zircon megacryst ages from the same intrusion. Megacryst ages clearly approximate those of the kimberlite host, at least within the resolution of the perovskite technique.
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Figure 3 A three-step process, summarised in panel (a), proposed to explain the variations within the Nd- and Hf-isotope arrays for zircon megacrysts. (i) A source with prolonged depletion in Lu/Hf and Sm/Nd evolves to highly negative εNd and εHf compositions, depicted here as the source of various lamproites (from Davies et al., 2006

Davies, G.R., Stolz, A.J., Mahotkin, I.L., Nowell, G.M., Pearson, D.G. (2006) Trace element and Sr-Pb-Nd-Hf isotope evidence for ancient, fluid-dominated enrichment of the source of Aldan Shield lamproites. Journal of Petrology 47, 1119–1146.

and references therein) (ii) A carbonate melt, with an isotopic composition similar to OIB pervades this source, preserving the Hf isotopic composition of the source owing to its low Hf content, but overprinting the source rocks with a Nd isotope composition more typical of OIB. In addition to displacing the isotopic composition of the source rocks off the mantle array, this metasomatic process stabilises high Lu/Hf phases. (iii) With time, the isotopic compositions of the source evolve along steep trajectories (shown by the dashed blue arrow in panel (b) owing to their now elevated Lu/Hf and Sm/Nd ratios. Parental melts to zircon megacrysts (red circles for Group A zircons, blue circles represent the possible locations of initial εHfNd for Group B zircons, calculated for a range of potential ages) tap this source periodically, as it evolves to higher εNd and εHf with time. Mantle array line from Vervoort et al. (1999)

Vervoort, J.D., Patchett, P.J., Blichert-Toft, J., Albarède, F. (1999) Relationships between Lu-Hf and Sm-Nd isotopic systems in the global sedimentary system. Earth and Planetary Science Letters, 168, 79–99.

.
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Table 1 Summary data. U-Pb age, Hf and Nd-isotope data for megacryst zircons. All data from this study unless otherwise noted: G = Griffin et al. (2000)

Griffin, W.L., Pearson, N.J., Belousova, E., Jackson, S.E., van Achterburgh, E., O’Reilly, S.Y., Shee, S.R. (2000) The Hf isotope composition of cratonic mantle: LAM-MC-ICPMS analysis of zircon megacrysts in kimberlites. Geochimica et Cosmochimica Acta 64, 133–147.

, N = Nowell et al. (2004)

Nowell, G.M., Pearson, D.G., Bell, D.R., Carlson, R.W., Smith, C.B., Kempton, P.D., Noble, S.R. (2004) Hf isotope systematics of kimberlites and their megacrysts: new constraints on their source regions. Journal of Petrology 45, 1583–1612.

. Where multiple solution analyses are shown from the same kimberlite body these represent different zircon megacrysts.

IN SITU ANALYSESSOLUTION ANALYSES
HostU/Pb age2 sigma176Hf/177Hf2 sigmaSm ppmNd ppm143Nd/144Ndm143Nd/144NdiEpsilon Ndi176Hf/177Hfm176Hf/177HfiEpsilon Hfi

(Ma)










Mukurob57.620.570.2828100.0000240.7340.5650.5130230.5127273.300.2828380.2828373.11

57.62


0.7130.5470.5130600.5127664.050.2828330.2828332.95
Deutche Erde67.940.720.2827700.000033







Silvery Home79.600.240.2827030.000007







Wesselton86.360.450.2827400.000063







Wesselton - Group Bunknown
0.2822200.000011







De Beers87.260.690.2826370.0000101.3321.0870.5130710.5126492.420.2826950.282695-1.23
Du Toitspan87.801.200.2827470.000010







Monastery88.690.500.2827210.000007








88.69
0.282725N0.000006








88.69
0.282703G0.000004







Lethlakane92.010.670.2827320.000008







Bultfontein93.960.490.2826890.0000080.3140.2940.5129830.5125871.480.2827000.282700-0.92

93.96


0.4460.4770.5129520.5126051.780.2826890.282689-1.32

93.96


0.3710.3060.5130450.5125951.560.2826960.282696-1.06
Koffiefontein94.160.530.2827100.0000110.3160.2170.5131550.5126152.020.2827380.2827380.44

94.16


0.6250.4380.5132040.5126733.160.2827580.2827581.13
Koffiefontein - Group Bunknown
0.2822700.0000470.2320.2790.513226unknownunknown0.282281unknownunknown
Orapa - Group A96.550.730.2827250.000010








96.55
0.28275N0.000007








96.55
0.28271G0.000013







Orapa - Group Bunknown
0.2823200.000031








unknown
0.28233N0.000021








unknown
0.282254G0.000006







Uintjesberg103.420.740.2826600.000023







Frank Smith114.480.830.2826000.000011







Kaalvalie

0.282751N0.000009







Kamfersdam

0.282721N0.000010







Mothae

0.28257N0.000049







Gansfontein

0.282709N0.000005







Leicester

0.28257G0.000049







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Supplementary Figures and Tables


Figure S-1 U-Pb Concordia plots for zircons analysed in this study. Kimberlite megacryst zircons for Group A possess ‘well behaved’ U-Pb systematics allowing the calculation of Concordia ages (upper panel). In contrast all of the Group B zircon megacrysts (lower panel) show evidence of disturbance in the U-Pb system. This implies they are older and have been variably reset during entrainment into the host kimberlite.
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Table S-1 U-Pb isotope and trace element data for zircon samples used in this study. See Materials and Methods for analytical details and Figure S-1 for corresponding Concordia plots.
207Pb/235U2 se206Pb/238U2 seErr. Corr.U ppmTh ppmPb ppmU/Th
Mukurob
0.06410.00500.00890.00030.1713.765.950.132.64
0.06400.00520.00920.00030.0113.336.190.132.54
0.06340.00500.00910.00030.0513.055.920.122.59
0.06480.00780.00900.00030.0641.1614.590.382.96
0.06200.00840.00890.00030.0134.0511.890.263.06
0.06010.00700.00880.00030.0239.0314.070.293.01
0.05880.00720.00890.00030.0539.8314.710.322.97
0.05530.00800.00860.00030.1025.678.260.143.42
0.05570.01120.00900.00040.0517.498.030.162.40
0.05880.01060.00900.00040.1020.6510.680.232.13
0.05940.00980.00910.00040.0121.949.580.222.49
Deutche Erde
0.07240.00480.01040.00030.0215.9511.640.261.86
0.07040.00420.01060.00030.0917.1311.420.281.91
0.06970.00380.01050.00030.1220.9613.570.331.86
0.07190.00560.01080.00040.0420.3611.540.341.83
0.07290.00480.01050.00030.2528.0015.610.491.90
0.07140.00460.01060.00030.1620.4711.090.341.99
0.07570.00440.01050.00030.0925.5013.820.372.02
Silvery Home
0.08300.00140.01250.00010.20345.10375.0014.960.83
0.08330.00130.01250.00010.25406.00430.6018.070.81
0.08330.00190.01240.00020.17157.00127.505.500.99
0.08350.00220.01240.00020.03155.90117.805.291.01
0.08200.00190.01230.00020.21186.3097.004.381.39
0.08040.00260.01230.00020.0979.5045.401.521.88
0.08250.00200.01250.00020.31146.60152.805.871.01
0.08150.00460.01230.00030.0827.636.780.254.25
0.08170.00320.01240.00010.07172.50165.305.791.11
0.08050.00380.01230.00020.06135.40103.033.511.41
0.08250.00300.01240.00020.15202.80173.406.051.26
0.08000.00380.01220.00020.11153.20163.125.581.01
0.07800.00440.01220.00020.05104.1058.191.951.94
0.07960.00480.01250.00020.0586.1552.271.761.77
0.08100.00520.01250.00020.0279.8649.941.651.71
0.08200.00280.01250.00020.06291.30345.7012.380.89
0.08100.00300.01260.00020.13216.70178.406.351.27
0.08360.00320.01240.00020.21260.40255.509.161.06
0.08320.00340.01260.00020.09218.30211.807.561.06
0.08170.00360.01230.00020.16182.90190.606.810.98
0.08020.00440.01230.00020.25143.70125.894.551.16
0.08070.00360.01230.00020.14208.90217.607.710.97
Wesselton - Group B
0.11660.00300.01660.00010.18162.6075.544.112.26
0.11240.00360.01520.00010.25101.3545.672.322.42
0.11520.00240.01510.00010.18209.10102.415.232.33
0.10010.00420.01470.00020.0659.0672.413.140.97
0.10850.00260.01510.00010.16210.30138.516.561.92
0.09900.00340.01450.00020.07109.9087.503.551.69
0.10140.00240.01410.00010.11207.50538.7021.630.54
0.08940.00340.01390.00020.0680.53272.6010.050.43
0.11590.00340.01450.00010.13140.40324.2013.040.64
0.10490.00280.01430.00010.02184.80183.107.371.46
0.10050.00400.01480.00020.0660.0070.062.980.93
0.11940.00400.01600.00020.38186.10104.045.201.99
0.11250.00300.01590.00020.27165.0481.204.092.31
0.10290.00400.01550.00020.1082.4137.531.772.49
0.11860.00340.01580.00020.17134.4060.513.172.50
0.11450.00220.01610.00020.25259.40144.507.541.97
0.13970.00540.01500.00020.31132.67118.616.341.20
0.09840.00360.01460.00020.1088.9695.524.310.98
Wesselton - Group A
0.10150.01720.01350.00050.026.961.850.095.14
0.09350.01640.01390.00050.015.601.170.055.55
0.09500.01880.01370.00050.043.340.510.025.64
0.08810.01080.01380.00040.056.350.920.045.85
0.09310.00380.01340.00010.0648.2421.080.921.92
0.09190.00400.01350.00020.0934.4613.380.582.16
0.08920.00800.01350.00030.0210.091.600.075.28
0.10030.00520.01370.00020.1325.176.040.313.46
0.08990.00520.01360.00020.1330.688.210.383.73
0.08930.00360.01330.00020.1054.0724.561.042.22
0.09080.00660.01360.00030.0116.833.190.135.36
0.08890.00760.01350.00030.0112.252.130.095.90
0.08890.00640.01350.00030.0814.822.860.115.40
0.08770.00420.01330.00020.1433.559.770.433.60
0.08820.00360.01340.00020.0841.4713.930.603.16
0.08890.00320.01340.00020.1147.5420.410.892.55
DeBeers
0.09140.00600.01340.00040.189.743.310.113.63
0.09060.00680.01340.00040.118.953.130.083.55
0.09090.00600.01350.00040.2111.533.970.103.54
0.08960.00580.01310.00040.1112.324.040.143.54
0.09130.00600.01340.00040.189.773.310.113.63
0.09090.00680.01340.00040.118.983.140.083.55
0.09090.00600.01350.00040.2111.553.970.103.55
0.09210.00540.01380.00020.1774.9337.071.372.12
0.09110.00980.01420.00040.0526.4113.500.482.14
0.09790.01140.01420.00040.0224.3412.810.482.18
0.08240.01160.01320.00040.0721.308.390.213.40
0.09200.01080.01310.00040.0531.1612.200.293.46
0.09400.01300.01320.00050.0218.567.380.193.31
0.09600.01140.01330.00040.0425.059.290.293.33
0.08520.00800.01390.00040.0420.926.330.243.37
0.08720.00860.01380.00040.1222.086.700.283.36
0.09060.01140.01410.00040.0217.975.280.253.47
0.08670.01280.01390.00050.0115.274.520.173.46
0.08970.01360.01390.00050.0216.394.780.193.49
0.08370.00960.01350.00040.0315.804.730.203.41
0.09590.01360.01390.00040.0110.623.180.123.39
0.08320.01200.01380.00050.0210.643.210.133.35
0.08280.01460.01360.00060.0212.343.740.153.33
Dutiotspan
0.09950.01100.01340.00070.034.131.490.033.16
0.09180.01220.01360.00070.014.321.510.063.20
0.10440.01380.01320.00070.093.831.370.043.09
0.09900.01080.01320.00060.024.291.540.043.02
0.09280.01180.01360.00070.034.291.330.043.36
0.10900.06000.01360.00070.044.271.440.072.98
0.09000.04400.01400.00130.083.771.310.052.89
0.09300.04400.01360.00140.124.011.360.062.95
0.08800.02800.01410.00090.064.111.410.052.93
0.10600.05000.01420.00110.004.361.470.062.97
0.08340.01920.01400.00070.054.841.620.063.03
0.10200.02600.01380.00070.034.681.570.063.00
0.09700.02400.01390.00060.045.051.670.063.03
0.08400.02000.01380.00060.014.801.600.052.99
0.07900.02600.01380.00090.015.131.690.073.01
Monastery
0.09990.00820.01370.00060.056.723.220.092.72
0.10080.00640.01370.00040.0710.755.250.152.77
0.09600.00640.01380.00050.059.955.100.142.69
0.09210.00620.01360.00040.1010.485.320.142.72
0.08430.01320.01360.00040.015.461.350.054.11
0.08680.01420.01380.00050.075.801.470.054.08
0.09820.01280.01380.00040.066.652.160.082.83
0.08630.01100.01380.00040.026.191.970.072.78
0.08410.01360.01400.00050.016.691.660.084.06
0.08830.01540.01400.00050.005.461.380.053.99
0.09930.01920.01400.00070.035.251.400.054.00
0.08230.01740.01380.00060.145.141.120.054.86
0.08700.01500.01370.00050.014.691.050.044.30
0.09030.01620.01390.00050.004.300.900.044.58
0.10000.02000.01400.00060.023.060.600.034.91
0.09280.01700.01400.00050.024.070.930.044.28
0.09270.01340.01390.00050.066.431.620.054.03
0.09820.01260.01360.00040.038.123.070.122.63
0.09860.01700.01400.00050.065.011.230.054.15
0.09490.01500.01400.00050.045.491.210.064.58
0.09630.01380.01380.00050.026.171.470.074.18
0.09410.01060.01380.00040.068.323.330.132.51
0.09590.01500.01420.00050.065.941.460.054.11
0.09120.01540.01400.00050.055.981.480.074.06
0.09650.01700.01420.00050.005.181.200.054.35
0.10050.01620.01400.00050.055.391.350.064.00
0.09670.01660.01410.00050.014.951.210.054.14
0.08990.01520.01370.00050.015.391.290.064.26
0.09040.01240.01380.00050.026.321.750.073.69
0.09310.01180.01400.00050.007.481.930.083.92
0.09010.00960.01350.00040.045.912.070.093.17
0.08500.00980.01380.00040.045.151.930.082.99
0.08650.00940.01380.00040.027.072.630.112.81
Lethlakane
0.09630.00460.01460.00040.2722.936.670.253.93
0.09650.00520.01450.00040.0917.944.870.154.18
0.09910.00580.01450.00040.0117.014.600.164.07
0.09820.00540.01440.00040.0516.634.180.144.26
0.09100.01000.01420.00040.0225.486.480.264.00
0.08730.01200.01420.00050.1917.714.090.154.41
0.08710.01040.01430.00040.0224.626.530.263.84
0.08740.00920.01450.00040.0030.778.900.373.58
0.09070.00980.01440.00040.0127.217.540.293.77
0.08790.01080.01440.00040.0322.165.680.244.03
0.08920.00840.01430.00040.0035.7010.740.403.45
0.09190.00840.01430.00040.0135.6810.690.433.43
0.09300.01020.01440.00040.0629.157.280.304.10
Bultfontein
0.09880.00280.01460.00020.1374.9034.001.622.03
0.09840.00280.01470.00020.2880.9042.101.821.82
0.09740.00360.01480.00030.2349.8018.010.872.63
0.09660.00500.01470.00020.0481.0038.071.712.06
0.09770.00800.01480.00030.1023.106.430.293.48
0.09360.00560.01460.00030.1348.5716.170.742.84
0.09450.00500.01450.00030.1254.4419.860.932.60
0.09630.00640.01450.00030.0560.1623.221.042.46
0.09810.00380.01480.00020.0294.3049.762.191.79
0.10030.00460.01480.00020.0673.7031.251.352.25
Koffiefontein - Group B
0.12830.00980.01740.00040.0811.356.920.391.56
0.11610.00820.01670.00030.0311.526.750.361.61
0.11510.00860.01550.00040.0010.215.300.281.81
0.12920.00960.01910.00040.049.985.380.341.73
0.10520.00840.01570.00030.0010.735.710.291.76
0.11690.00860.01580.00030.0810.503.110.183.18
0.10910.00720.01540.00030.0416.274.550.243.36
0.10860.00640.01530.00030.0316.694.870.263.25
0.12680.00760.01780.00030.1016.304.490.273.44
0.11010.00620.01530.00020.0417.195.040.263.24
0.12510.01980.01590.00070.0010.094.950.272.02
0.09810.01640.01530.00060.0610.134.400.212.29
0.10790.01820.01500.00060.0612.194.980.212.45
0.14460.01900.02130.00080.0411.334.920.332.31
0.09590.01540.01560.00060.0212.345.320.232.33
0.11200.01740.01650.00060.1111.275.840.271.94
0.10060.01780.01530.00060.0010.805.510.201.99
0.08870.01520.01480.00050.0512.524.780.192.68
0.08960.01440.01540.00060.1113.725.650.222.49
0.09720.01340.01540.00050.0918.6411.590.431.65
Koffiefontein - Group A
0.11600.01180.01510.00040.0610.494.900.192.46
0.10780.00860.01490.00030.0417.158.230.312.45
0.11560.01160.01520.00040.0211.655.430.212.54
0.10810.00900.01500.00030.0216.507.660.292.56
0.11870.01020.01510.00030.0618.605.370.274.05
0.10770.00780.01520.00030.0320.475.840.253.92
0.10350.00700.01500.00030.0321.656.430.263.68
0.10570.00720.01480.00030.0721.478.740.362.62
0.10070.00480.01480.00020.0940.5517.680.692.38
0.11010.01020.01510.00030.0311.844.430.212.73
0.07860.01500.01440.00060.039.503.450.152.64
0.08900.01420.01450.00060.0311.894.220.182.68
0.09580.01660.01460.00060.019.513.350.142.72
0.09640.01700.01440.00060.0110.263.580.122.75
0.08880.01580.01450.00060.0210.763.240.133.20
0.09200.01540.01470.00060.0010.503.180.113.21
Orapa - Group A
0.09610.00600.01440.00040.1621.833.560.144.31
0.10750.01140.01520.00040.066.981.490.074.70
0.10630.01220.01520.00040.027.531.610.084.70
0.10320.00680.01490.00030.0119.094.900.233.89
0.10370.01260.01520.00040.068.181.910.094.32
0.11240.00820.01500.00030.0814.854.360.203.41
0.10670.01280.01510.00050.038.051.380.075.83
0.10960.01000.01490.00040.0312.403.490.163.59
0.11170.00840.01500.00030.0318.045.850.273.10
0.11140.01700.01550.00050.115.841.160.065.08
0.11060.01380.01510.00040.037.811.860.104.23
0.10510.00860.01510.00030.0315.063.680.184.12
0.10430.01200.01500.00040.029.742.120.114.63
0.11820.01180.01520.00040.119.291.980.144.70
0.10760.01340.01480.00040.017.781.840.094.25
0.10940.01140.01510.00040.0710.851.800.096.07
0.10490.01140.01490.00030.1110.561.720.076.18
0.10440.01020.01500.00040.037.062.080.112.92
0.10970.01180.01490.00040.046.812.030.092.92
Orapa - Group B
0.09680.00500.01430.00040.0829.736.010.274.22
0.11580.00920.01700.00030.0814.974.230.223.55
0.13050.01100.01880.00040.0614.363.880.223.73
0.11670.01020.01590.00040.0015.334.060.203.79
0.12080.00920.01550.00030.0215.734.530.243.50
0.15540.01080.02100.00040.1614.064.280.283.28
0.11740.00860.01570.00030.0114.294.300.213.36
0.16310.01120.01580.00030.1917.439.020.551.95
0.25600.02400.01700.00040.4811.3710.170.701.13
0.11180.00920.01550.00030.0512.287.160.301.73
0.16000.01020.02290.00040.1417.694.720.303.79
0.29050.01240.03780.00070.3216.584.590.453.64
0.15120.01020.02130.00040.0114.074.180.243.43
0.10280.00540.01500.00020.0530.6417.150.701.81
0.10440.00540.01520.00020.0627.8712.500.502.26
0.11550.00720.01640.00030.0918.367.450.342.51
Uintjesberg
0.10730.00520.01620.00040.1217.026.760.263.01
0.11040.01060.01630.00070.004.491.170.044.53
0.10920.00460.01630.00030.1529.7012.610.582.48
0.10640.00440.01590.00040.1333.2014.750.692.33
0.10780.00580.01610.00040.1219.466.010.263.33
0.11410.01300.01640.00090.036.901.990.073.53
0.14480.01960.01640.00080.328.691.950.144.50
0.10880.01480.01600.00060.0810.303.340.162.77
0.10660.01360.01600.00050.0111.493.730.222.74
0.10950.01480.01610.00050.0510.953.370.182.84
0.10140.01400.01620.00050.0110.883.470.202.72
0.09980.01360.01590.00050.0611.683.880.232.61
0.09310.01780.01630.00070.046.722.100.112.78
0.11000.02000.01650.00080.066.741.900.103.12
0.10430.01320.01640.00050.0413.524.460.242.70
0.12290.01840.01660.00060.1911.953.110.193.48
0.13300.01640.01630.00060.1012.164.300.252.62
0.09800.02400.01610.00080.075.001.410.063.37
0.10730.01940.01590.00070.108.492.300.103.60
Frank Smith
0.11570.00540.01770.00050.0921.074.470.254.42
0.11970.00660.01750.00050.0715.683.250.184.35
0.12420.00720.01760.00050.0616.603.180.204.57
0.12060.00680.01750.00060.0718.183.350.224.58
0.11330.01220.01780.00050.0513.003.050.134.26
0.12030.01140.01790.00040.0815.963.790.214.23
0.11890.01460.01820.00060.0412.562.960.164.23
0.12820.01260.01800.00050.0113.753.260.164.23
0.12100.01420.01830.00050.0111.252.670.134.22
0.13200.02000.01820.00050.0113.773.300.194.19
0.12350.01460.01790.00050.1013.013.080.174.20
0.11230.01480.01830.00060.0415.443.600.204.26
0.11780.01240.01790.00050.0113.323.120.164.26
0.12240.01600.01810.00060.0210.612.500.114.25
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Table S-2 Hf-isotope data for megacryst zircons. All data from this study unless otherwise noted: Griffin et al. (2000) or Nowell et al. (2004). Given the relatively small datasets involved, a Tukey Biweight robust mean has been employed to determine the central tendency in the Hf-isotope ratios for each suite. Parent daughter ratios are unsuited to this approach due to their inherently more scattered nature, the result of magmatic zonation: here a simple arithmetic mean is employed.
176Lu/177Hf2 seMean176Hf/177Hf2 seMean95 % conf.178Hf/177Hf2 seLu interferenceYb interferenceHf Beam


(unweighted)

(Robust-Tukey)


(ppm on 176)(ppm on 176)(volts)
Mukurob
0.0000880.00000050.0000630.2828160.0000340.2828100.0000241.4673690.0000643101365112.2
0.0000770.0000007
0.2827940.000029

1.4673770.0000532721167412.4
0.0001060.0000007
0.2828380.000034

1.4673630.0000613721668611.9
0.0000380.0000005
0.2827890.000031

1.4673770.000053133621312.3
0.0000370.0000006
0.2828170.000030

1.4674030.000055130602012.5
0.0000330.0000005
0.2827870.000036

1.4673840.000063118550912.4
Deutche Erde
0.0000290.00000050.0000310.2827620.0000280.2827700.0000331.4673470.000054103493715.5
0.0000350.0000004
0.2827720.000033

1.4673740.000060125604915.4
0.0000310.0000005
0.2827590.000037

1.4673340.000062111540415.2
0.0000410.0000004
0.2828010.000034

1.4674260.000066144711215.3
0.0000210.0000004
0.2827530.000032

1.4673710.00006174358915.1
Silvery Home
0.0001530.00000030.0001400.2827140.0000360.2827030.0000071.4675150.0000635312438014.3
0.0001320.0000004
0.2827080.000042

1.4674260.0000714592130012.0
0.0001350.0000003
0.2827060.000039

1.4674960.0000714702146212.4
0.0000510.0000002
0.2827140.000031

1.4674730.000057181940117.4
0.0001650.0000002
0.2826670.000035

1.4674790.0000645702788114.3
0.0000750.0000003
0.2826770.000039

1.4674530.0000732651169412.8
0.0001640.0000002
0.2826840.000035

1.4674840.0000605662857013.4
0.0001680.0000003
0.2826910.000037

1.4674550.0000665792984012.3
0.0002090.0000003
0.2827220.000032

1.4674460.0000627183556014.2
0.0000520.0000002
0.2827370.000033

1.4674510.000062184951417.2
0.0001400.0000005
0.2826640.000032

1.4674100.0000664872628014.7
0.0001640.0000005
0.2826890.000035

1.4674640.0000655682872013.7
0.0001910.0000005
0.2826820.000037

1.4674580.0000696573357214.0
0.0002650.0000005
0.2827090.000040

1.4674220.0000668974865014.1
0.0000400.0000006
0.2827050.000032

1.4674050.000057141652015.3
0.0001280.0000005
0.2827020.000032

1.4674400.0000584452302915.0
0.0001570.0000004
0.2826920.000033

1.4674250.0000565432906014.2
0.0001560.0000006
0.2826930.000030

1.4674240.0000545382871814.2
0.0001470.0000005
0.2827440.000031

1.4674120.0000635092774014.9
0.0002150.0000010
0.2827240.000035

1.4674250.0000657383776014.3
0.0000840.0000004
0.2827320.000032

1.4674060.0000592951580416.9
0.0000810.0000004
0.2827030.000032

1.4674210.0000592821512916.8
Wesselton - Group B
0.0002100.00000020.0001420.2822350.0000340.2822200.0000111.4673770.0000677243387014.8
0.0002100.0000002
0.2822220.000033

1.4674320.0000657243345016.5
0.0002180.0000003
0.2822350.000041

1.4674300.0000707503538116.0
0.0001480.0000002
0.2822010.000041

1.4673660.0000725142441613.0
0.0000410.0000002
0.2822010.000035

1.4673580.000068145628115.9
0.0001160.0000003
0.2822310.000033

1.4673370.0000644061835716.9
0.0001680.0000003
0.2822060.000042

1.4674540.0000745832694513.9
0.0000760.0000001
0.2822170.000035

1.4674150.0000692671178119.1
0.0001020.0000002
0.2822040.000034

1.4674180.0000653591588417.8
0.0001970.0000003
0.2822340.000038

1.4674560.0000686793125716.4
0.0001190.0000005
0.2822180.000032

1.4673640.0000604151840618.0
0.0001040.0000005
0.2822630.000037

1.4674460.0000673651676617.4
Wesselton - Group A
0.0000440.00000050.0000300.2827680.0000340.2827400.0000631.4674210.000066155702314.7
0.0000330.0000004
0.2827440.000031

1.4673310.000060118518315.4
0.0000130.0000004
0.2827160.000034

1.4673740.00006047209914.9
De Beers
0.0000490.00000040.0000400.2826180.0000310.2826370.0000331.4673450.000058173787114.5
0.0000410.0000007
0.2826390.000030

1.4673640.000062146650214.5
0.0000330.0000005
0.2826320.000031

1.4674000.000062117528913.7
0.0000310.0000004
0.2826490.000031

1.4673760.000056111498814.1
0.0000160.0000004
0.2826330.000033

1.4673770.00006357245914.8
0.0000300.0000005
0.2826550.000032

1.4673970.000060105448514.7
0.0000370.0000005
0.2826590.000031

1.4674010.000059131595011.8
0.0000710.0000006
0.2826180.000039

1.4673810.0000622501114011.1
0.0000510.0000006
0.2826330.000034

1.4673960.000060180815211.0
0.0000430.0000006
0.2826390.000038

1.4673980.000068152669911.5
DuToitspan
0.0000070.00000010.0000090.2827580.0000390.2827470.0000101.4674060.00007725117620.0
0.0000070.0000002
0.2827500.000031

1.4673960.00006625125118.3
0.0000080.0000002
0.2827560.000029

1.4674010.00005627129419.7
0.0000080.0000002
0.2827530.000037

1.4673960.00006827133318.1
0.0000080.0000002
0.2827670.000027

1.4673840.00005629140620.1
0.0000070.0000001
0.2827340.000035

1.4673810.00007224116220.8
0.0000070.0000002
0.2827730.000031

1.4674530.00006224115221.6
0.0000070.0000002
0.2827570.000034

1.4673730.00006824119318.6
0.0000080.0000002
0.2827500.000038

1.4673700.00006928139217.8
0.0000080.0000002
0.2827630.000035

1.4674120.00006529138617.7
0.0000070.0000003
0.2827320.000029

1.4673910.00005625128321.6
0.0000040.0000002
0.2827280.000031

1.4673490.0000631362521.1
0.0000190.0000003
0.2827180.000037

1.4673770.00006668320015.9
0.0000210.0000004
0.2827130.000032

1.4673540.00006175347615.6
0.0000100.0000003
0.2827430.000030

1.4673470.00006236180017.8
0.0000100.0000003
0.2827550.000033

1.4673660.00006237187017.3
Monastery
0.0000370.00000020.0000140.2827030.0000310.2827210.0000071.4674800.000057130625218.0
0.0000370.0000002
0.2827130.000035

1.4674670.000064132630918.1
0.0000360.0000002
0.2827000.000033

1.4674280.000061126619316.2
0.0000270.0000002
0.2827090.000026

1.4674790.00005995459418.0
0.0000210.0000002
0.2827040.000031

1.4674720.00005773352519.0
0.0000160.0000002
0.2827130.000027

1.4675190.00005658276719.8
0.0000050.0000002
0.2827390.000035

1.4674670.0000641887018.3
0.0000050.0000002
0.2827150.000031

1.4675260.0000521886121.2
0.0000130.0000002
0.2827400.000032

1.4675120.00005948227119.8
0.0000130.0000002
0.2827320.000031

1.4674790.00005546222618.5
0.0000060.0000003
0.2827210.000033

1.4674240.0000652091218.0
0.0000060.0000002
0.2827450.000032

1.4674420.00005822100319.6
0.0000050.0000002
0.2827220.000030

1.4674460.0000601989618.8
0.0000050.0000002
0.2827310.000037

1.4674040.0000721988116.7
0.0000050.0000002
0.2827120.000032

1.4673980.0000592090416.6
0.0000050.0000002
0.2827480.000036

1.4673930.0000661985518.6
0.0000050.0000003
0.2827020.000031

1.4673410.0000571885916.7
0.0000050.0000004
0.2827260.000030

1.4673930.0000582090716.7
0.0000060.0000002
0.2827230.000039

1.4675520.0000662099312.2
0.0000130.0000003
0.2827320.000040

1.4675950.00007645229712.1
Monastery - Nowell et al. (2004)
0.000006
0.0000090.2827240.0000060.2827250.000006




0.000007

0.2827350.000006






0.000010

0.2827280.000006






0.000001

0.2827130.000006






0.000001

0.2827160.000006






0.000005

0.2827370.000006






0.000011

0.2827230.000006






0.000010

0.2827300.000006






0.000020

0.2827180.000006






0.000022

0.2827230.000006






Monastery - Griffin et al. (2000)
0.000006
0.0000090.2827120.0000140.2827030.000004




0.000007

0.2827070.000011






0.000007

0.2826990.000017






0.000006

0.2827250.000014






0.000006

0.2827170.000012






0.000008

0.2827150.000013






0.000007

0.2827140.000013






0.000012

0.2826960.000015






0.000012

0.2827160.000015






0.000014

0.2826850.000018






0.000015

0.2827000.000019






0.000014

0.2826960.000020






0.000004

0.2826940.000020






0.000003

0.2826930.000018






0.000010

0.2827170.000012






0.000007

0.2826910.000015






0.000005

0.2827000.000016






0.000013

0.2827400.000015






0.000013

0.2827230.000015






0.000007

0.2827220.000022






0.000004

0.2827070.000019






0.000005

0.2826610.000020






0.000004

0.2826960.000012






0.000004

0.2826980.000015






0.000006

0.2826960.000010






0.000013

0.2827050.000030






0.000005

0.2826850.000017






0.000005

0.2826840.000019






0.000012

0.2827020.000017






0.000003

0.2826850.000024






0.000014

0.2826740.000017






0.000014

0.2827060.000016






0.000018

0.2827030.000017






0.000004

0.2827080.000022






0.000007

0.2827310.000015






0.000011

0.2827100.000022






0.000004

0.2827040.000013






0.000017

0.2827170.000024






0.000014

0.2826950.000020






0.000006

0.2827060.000017






0.000006

0.2826910.000017






0.000012

0.2826790.000014






Lethlakane
0.0000190.00000020.0000190.2827430.0000350.2827320.0000081.4673540.00007067292917.2
0.0000160.0000002
0.2827330.000042

1.4673630.00007256247614.4
0.0000210.0000002
0.2827290.000033

1.4673760.00006676338315.8
0.0000210.0000002
0.2827560.000037

1.4674190.00006776338417.2
0.0000200.0000002
0.2827420.000036

1.4674130.00006972307817.5
0.0000210.0000003
0.2827580.000036

1.4673880.00006674324517.9
0.0000240.0000003
0.2827480.000035

1.4674280.00006684374817.5
0.0000200.0000002
0.2827550.000037

1.4673690.00006772315017.2
0.0000220.0000003
0.2827340.000038

1.4673800.00007478347515.8
0.0000260.0000003
0.2827370.000040

1.4673530.00007492436113.8
0.0000270.0000003
0.2827470.000041

1.4673970.00007496421612.4
0.0000170.0000004
0.2827320.000025

1.4674510.00005460263017.2
0.0000160.0000004
0.2827130.000030

1.4674050.00006056248317.4
0.0000170.0000004
0.2826960.000028

1.4674010.00005461275619.5
0.0000100.0000003
0.2827160.000027

1.4674550.00005337165820.1
0.0000140.0000004
0.2827280.000029

1.4673980.00005549219417.8
0.0000150.0000004
0.2827250.000030

1.4674580.00006354236117.9
Bultfontein
0.0000230.00000050.0000360.2826660.0000380.2826890.0000081.4674270.00007780356915.3
0.0000160.0000005
0.2826720.000033

1.4674330.00006358261615.9
0.0000460.0000006
0.2826700.000030

1.4673830.000060164731315.3
0.0000330.0000005
0.2826800.000028

1.4674260.000053118513415.4
0.0000150.0000005
0.2826900.000032

1.4673810.00006052230915.2
0.0000160.0000006
0.2826690.000031

1.4674250.00005958261315.0
0.0000300.0000002
0.2826850.000053

1.4673020.000092106472416.6
0.0000670.0000002
0.2826870.000053

1.4673300.0001002361122816.1
0.0000230.0000002
0.2826900.000059

1.4673100.00011081403017.0
0.0000130.0000002
0.2826850.000051

1.4673420.00009845208518.4
0.0000340.0000002
0.2827120.000046

1.4673940.000091120526017.5
0.0000620.0000003
0.2827300.000058

1.4672900.0001002191045617.8
0.0000590.0000003
0.2827070.000051

1.4673430.000095209997317.5
0.0000240.0000002
0.2826940.000043

1.4673740.00008786379016.3
0.0000160.0000002
0.2827070.000053

1.4673300.00011056263218.1
0.0000720.0000002
0.2826630.000057

1.4672800.0001002551184715.0
0.0000350.0000003
0.2826400.000062

1.4674200.000110125543116.2
0.0000100.0000003
0.2826670.000046

1.4673500.00009136164018.5
0.0000280.0000003
0.2826970.000049

1.4673710.00009099440817.3
0.0000640.0000003
0.2826690.000052

1.4673580.0000972251007615.7
0.0000440.0000003
0.2826880.000051

1.4673010.000099154697914.9
0.0000550.0000003
0.2826950.000049

1.4672960.000097194884814.6
0.0000090.0000002
0.2827390.000051

1.4673040.00009834180421.2
0.0000140.0000002
0.2827430.000054

1.4673490.00009549234218.4
0.0001130.0000003
0.2826770.000047

1.4673730.0000973951947316.1
0.0000490.0000003
0.2826990.000067

1.4673800.000120172795917.6
0.0000090.0000002
0.2827280.000073

1.4672500.00014032170022.0
0.0000380.0000003
0.2826800.000043

1.4672820.000079135618214.4
0.0000200.0000002
0.2826870.000042

1.4673590.00007872339017.5
0.0000360.0000003
0.2826720.000060

1.4673100.000110128591614.0
0.0000400.0000003
0.2827200.000054

1.4673030.000097142678815.7
0.0000410.0000003
0.2827070.000042

1.4673320.000082147678913.3
0.0000350.0000002
0.2826660.000046

1.4673730.000080124540615.5
0.0000460.0000002
0.2826620.000044

1.4673210.000086163741914.5
Koffiefontein - Group A
0.0000190.00000050.0000260.2827120.0000310.2827100.0000111.4673610.00005966303916.5
0.0000190.0000004
0.2827210.000031

1.4673770.00006069316416.3
0.0000130.0000004
0.2827060.000027

1.4674030.00005346202415.9
0.0000130.0000004
0.2827040.000032

1.4673710.00005848212315.9
0.0000130.0000002
0.2826930.000032

1.4674210.00005848210019.1
0.0000160.0000002
0.2826770.000035

1.4673840.00006658268821.6
0.0000350.0000002
0.2827260.000032

1.4674340.000052123545817.8
0.0000240.0000002
0.2826960.000032

1.4674200.00005784354218.4
0.0000160.0000002
0.2827200.000035

1.4674220.00006756244722.5
0.0000620.0000002
0.2826870.000037

1.4674050.000072219979118.5
0.0000540.0000002
0.2827220.000039

1.4674620.000069191837118.3
Koffiefontein - Group B
0.0000140.00000020.0000130.2823140.0000370.2822700.0000471.4674480.00007351201320.1
0.0000200.0000003
0.2823070.000055

1.4674400.00011071349113.6
0.0000170.0000002
0.2822700.000071

1.4674000.00013059331817.1
0.0000080.0000004
0.2822160.000030

1.4673690.00005627120118.3
0.0000070.0000004
0.2822470.000029

1.4673660.00005624109118.8
0.0000150.0000001
0.2822380.000032

1.4674220.00006252238022.8
Orapa - Group A
0.0000180.00000020.0000150.2827400.0000330.2827250.0000101.4674540.00006265274518.1
0.0000140.0000002
0.2827350.000036

1.4674430.00006450210916.3
0.0000190.0000002
0.2827670.000034

1.4675050.00006468285519.1
0.0000080.0000002
0.2827290.000032

1.4674490.00006329125117.3
0.0000090.0000002
0.2827230.000034

1.4673860.00006634147917.0
0.0000110.0000002
0.2827560.000034

1.4674950.00006238165417.5
0.0000150.0000002
0.2827600.000034

1.4674570.00006454235118.7
0.0000200.0000002
0.2827320.000032

1.4674360.00005973308419.5
0.0000130.0000003
0.2827420.000033

1.4674120.00005946195919.2
0.0000120.0000002
0.2827360.000035

1.4674210.00006343183118.9
0.0000150.0000004
0.2827080.000027

1.4673910.00005755254118.6
0.0000180.0000005
0.2827120.000031

1.4674070.00005963292017.8
0.0000090.0000004
0.2827140.000032

1.4674220.00006034155318.2
0.0000090.0000004
0.2827100.000029

1.4673590.00005431142518.4
0.0000240.0000004
0.2827020.000031

1.4673760.00006084384016.0
0.0000250.0000005
0.2826940.000030

1.4674130.00006290420415.3
0.0000030.0000005
0.2826670.000029

1.4673640.0000531156820.0
0.0000130.0000006
0.2827010.000032

1.4674260.00006046206617.9
0.0000190.0000004
0.2827040.000029

1.4673960.00005468303317.9
0.0000050.0000003
0.2826870.000027

1.4673650.0000501779418.8
0.0000150.0000004
0.2826880.000028

1.4673550.00005553231416.5
0.0000160.0000006
0.2827240.000030

1.4673880.00005555235012.6
0.0000090.0000001
0.2827300.000040

1.4674410.00007731133920.3
0.0000090.0000001
0.2827670.000038

1.4674490.00007031135724.8
0.0000270.0000001
0.2827280.000036

1.4674310.00006695416319.1
0.0000310.0000002
0.2827490.000034

1.4674280.000067110457420.2
0.0000280.0000002
0.2827220.000036

1.4674160.00006898446619.0
0.0000050.0000002
0.2827290.000037

1.4674560.0000691877920.9
0.0000140.0000002
0.2827700.000031

1.4674500.00006051220023.2
0.0000190.0000002
0.2827520.000034

1.4673980.00006468288517.5
0.0000060.0000002
0.2826950.000031

1.4674180.0000572390817.3
Orapa - Group B
0.0000120.00000020.0000110.2823000.0000340.2823200.0000311.4674590.00006243186620.1
0.0000100.0000003
0.2822540.000078

1.4674000.00013034183714.7
0.0000210.0000003
0.2823470.000066

1.4674200.00012074398614.1
0.0000170.0000002
0.2822630.000075

1.4674200.00014060320113.4
0.0000070.0000002
0.2823370.000069

1.4674700.00013026141215.2
0.0000040.0000003
0.2823460.000056

1.4674400.0001101470713.6
0.0000030.0000002
0.2823620.000041

1.4674790.0000751251623.8
0.0000050.0000001
0.2823810.000033

1.4674620.0000631982424.7
0.0000190.0000001
0.2823400.000034

1.4674260.00006466284420.6
0.0000080.0000001
0.2822950.000034

1.4674250.00005929127224.4
Orapa - Group A - Nowell et al. (2004)
0.000024
0.0000200.2827660.0000080.2827500.000007




0.000031

0.2827450.000010






0.000016

0.2827520.000011






0.000017

0.2827550.000008






0.000019

0.2827450.000014






0.000016

0.2827380.000012






0.000021

0.2827500.000006






0.000021

0.2827780.000008






0.000027

0.2827240.000010






0.000036

0.2827600.000007






0.000015

0.2827570.000012






0.000019

0.2827630.000012






0.000018

0.2827540.000019






0.000018

0.2827630.000014






0.000021

0.2827550.000011






0.000025

0.2827440.000013






0.000008

0.2827260.000013






0.000005

0.2827230.000010






0.000023

0.2827620.000014






0.000017

0.2827320.000011






Orapa - Group B - Nowell et al. (2004)
0.000007
0.0000090.2823660.0000100.2823300.000021




0.000006

0.2823610.000007






0.000008

0.2823430.000011






0.000014

0.2823590.000010






0.000007

0.2823030.000014






0.000011

0.2823050.000015






0.000008

0.2823140.000014






0.000006

0.2822930.000015






0.000009

0.2823390.000011






0.000010

0.2823540.000016






Orapa - Group A - Griffin et al. (2000)
0.000009
0.0000430.2827280.0000140.2827100.000013




0.000009

0.2827260.000024






0.000017

0.2827110.000018






0.000015

0.2827090.000024






0.000020

0.2826820.000022






0.000012

0.2827070.000034






0.000013

0.2827230.000015






0.000039

0.2827330.000017






0.000031

0.2825520.000022






0.000028

0.2825590.000030






0.000004

0.2826790.000020






0.000007

0.2827070.000019






0.000246

0.2831260.000030






0.000156

0.2830410.000024






Orapa - Group B - Griffin et al. (2000)
0.000007
0.0000150.2823470.0000240.2822540.000006




0.000006

0.2823280.000018






0.000027

0.2822590.000026






0.000027

0.2822490.000020






0.000014

0.2822510.000024






0.000009

0.2822560.000020






Uintjiesberg
0.0000130.00000020.0000280.2825490.0000320.2826600.0000231.4674160.00006147185016.3
0.0000060.0000002
0.2825570.000038

1.4674480.0000672393418.5
0.0000400.0000003
0.2826320.000040

1.4674030.000070143607711.0
0.0000430.0000004
0.2826410.000040

1.4673230.000070153745011.0
0.0000220.0000003
0.2826720.000037

1.4674440.00007076345011.8
0.0000760.0000006
0.2827000.000037

1.4674410.0000682661143014.0
0.0000100.0000003
0.2826860.000033

1.4674210.00006136151814.6
0.0000410.0000003
0.2826730.000042

1.4674290.000077144609311.9
0.0000440.0000003
0.2827020.000042

1.4673920.000076155726911.3
0.0000340.0000003
0.2826780.000033

1.4674090.000060122588813.5
0.0000370.0000006
0.2826830.000034

1.4674320.000063131624313.4
0.0000100.0000003
0.2826620.000036

1.4674170.00006736170918.3
0.0000210.0000004
0.2826940.000031

1.4674270.00005576365417.8
0.0000110.0000004
0.2826550.000029

1.4673860.00005240190918.5
0.0000120.0000004
0.2826750.000032

1.4674160.00006242205218.5
Frank Smith
0.0000260.00000030.0000270.2826000.0000390.2826000.0000111.4674070.00006892388613.3
0.0000250.0000002
0.2825930.000033

1.4674300.00006387370614.1
0.0000250.0000003
0.2826110.000035

1.4673190.00006190383712.7
0.0000270.0000003
0.2825990.000038

1.4673590.00006997417311.9
0.0000240.0000003
0.2825630.000039

1.4673470.00007384360413.1
0.0000320.0000004
0.2826170.000043

1.4674380.000077114481913.2
0.0000290.0000003
0.2826320.000039

1.4674460.000065102432913.7
0.0000300.0000003
0.2826300.000037

1.4674350.000068107451113.7
0.0000300.0000003
0.2826020.000033

1.4674340.000066106443514.0
0.0000260.0000003
0.2826120.000038

1.4673880.00007494399113.6
0.0000320.0000006
0.2825760.000031

1.4673460.000056115496712.0
0.0000220.0000006
0.2825980.000031

1.4673980.00005679349912.3
0.0000280.0000006
0.2825880.000035

1.4673700.00006399432912.3
0.0000250.0000006
0.2825770.000031

1.4673520.00005888389912.3
0.0000270.0000005
0.2825990.000031

1.4673360.00006197424512.0
0.0000240.0000005
0.2825750.000032

1.4673180.00005985372912.3
Kaalvallie - Nowell et al. (2004)
0.000004
0.0000100.2827380.0000170.2827510.000009




0.000004

0.2827170.000017






0.000004

0.2827180.000018






0.000003

0.2827340.000015






0.000008

0.2827480.000022






0.000008

0.2827720.000024






0.000007

0.2827700.000020






0.000007

0.2827280.000021






0.000006

0.2827720.000025






0.000006

0.2827370.000024






0.000010

0.2827170.000025






0.000016

0.2827580.000004






0.000016

0.2827450.000004






0.000018

0.2827630.000003






0.000017

0.2827520.000004






0.000013

0.2827510.000004






0.000013

0.2827540.000005






0.000018

0.2827740.000005






0.000017

0.2827740.000006






0.000016

0.2827730.000004






0.000015

0.2827630.000003






0.000006

0.2827480.000004






0.000006

0.2827470.000004






Kamfersdam - Nowell et al. (2004)
0.000022
0.0000220.2827210.0000100.2827210.000010




Mothae pipe - Nowell et al. (2004)
0.000008
0.0000120.2827110.0000070.2827180.000008




0.000015

0.2827180.000007






0.000007

0.2827230.000007






0.000019

0.2827180.000007






Gansfontein - Nowell et al. (2004)
0.000009
0.0000120.2827010.0000060.2827090.000006




0.000010

0.2827100.000004






0.000019

0.2827270.000007






0.000015

0.2827120.000006






0.000015

0.2827150.000005






0.000010

0.2827050.000004






0.000008

0.2827040.000008






0.000010

0.2827020.000010






Leicester - Griffin et al. (2000)
0.000006
0.0000240.2825670.0000220.2825700.000049




0.000006

0.2825670.000022






0.000006

0.2825360.000022






0.000039

0.2826660.000022






0.000046

0.2826680.000024






0.000020

0.2826340.000028






0.000006

0.2824950.000026






0.000005

0.2825340.000017






0.000005

0.2825270.000019






0.000083

0.2824540.000026






0.000040

0.2826190.000026






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Table S-3 Calculated temperatures based on Ti-in-zircon using the formulation of Ferry and Watson (2007). See Materials and Methods and Figure S-2 for further information and our interpretation of these results.
SampleTi (ppm)log Ti (ppm)log aSiO2log aTiO2
~log XTi in rutile
Ferry and Watson (2007) extrapolated to P =




or ~log XTi in ilmenite 4+ site1 GPa2 GPa3 GPa4 GPa5 GPa6 GPa





T (°C)T (°C)T (°C)T (°C)T (°C)T (°C)



minimum aSiO2






Koffiefontein8.90.95-0.71-0.05611661711761811861
Koffiefontein15.61.19-0.71-0.05652702752802852902
Koffiefontein9.40.97-0.71-0.05614664714764814864
Mukurob4.10.61-0.71-0.05559609659709759809
Mukurob14.71.17-0.71-0.05648698748798848898
Bultfontein63.31.8-0.71-0.057758258759259751025
Bultfontein24.21.38-0.71-0.05688738788838888938
Bultfontein3.70.57-0.71-0.05552602652702752802
De Beers10.71.03-0.71-0.05624674724774824874














maximum aSiO2






Koffiefontein8.90.95-1.01-0.05565615665715765815
Koffiefontein15.61.19-1.01-0.05602652702752802852
Koffiefontein9.40.97-1.01-0.05568618668718768818
Mukurob4.10.61-1.01-0.05518568618668718768
Mukurob14.71.17-1.01-0.05598648698748798848
Bultfontein63.31.8-1.01-0.05711761811861911961
Bultfontein24.21.38-1.01-0.05634684734784834884
Bultfontein3.70.57-1.01-0.05512562612662712762
De Beers10.71.03-1.01-0.05577627677727777827














intermediate aSiO2






Koffiefontein8.90.95-0.86-0.05587637687737787837
Koffiefontein15.61.19-0.86-0.05627677727777827877
Koffiefontein9.40.97-0.86-0.05591641691741791841
Mukurob4.10.61-0.86-0.05538588638688738788
Mukurob14.71.17-0.86-0.05622672722772822872
Bultfontein63.31.8-0.86-0.05742792842892942992
Bultfontein24.21.38-0.86-0.05660710760810860910
Bultfontein3.70.57-0.86-0.05532582632682732782
De Beers10.71.03-0.86-0.05600650700750800850
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Figure S-2 Calculated temperature intervals for zircon megacrysts. Temperature values calculated at variable pressure using the Ti-in-zircon thermometer of Ferry and Watson (2007) and Ti concentrations of megacrysts in southern African archetypal kimberlites. Note that, if the Ti-in-zircon temperatures truly reflect the equilibration conditions of zircon megacrysts and assuming a typical cratonic mantle geotherm of 40–42 mW/m2, the zircon megacrysts could only be in equilibrium with the ambient mantle at P of 2.5–3.0 GPa.
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