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Growth of upper plate lithosphere controls tempo of arc magmatism: Constraints from Al-diffusion kinetics and coupled Lu-Hf and Sm-Nd chronology

E.J. Chin1,2,

Department of Earth Science, Rice University, Houston, Texas, USA
Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, Rhode Island, USA

C.-T.A. Lee1,

Department of Earth Science, Rice University, Houston, Texas, USA

J. Blichert-Toft1,3

Department of Earth Science, Rice University, Houston, Texas, USA
Ecole Normale Supérieure de Lyon and Université Lyon 1, Laboratoire de Géologie de Lyon, CNRS UMR 5276, Lyon, France

Affiliations  |  Corresponding Author  |  Cite as

Chin, E.J., Lee, C.-T.A., Blichert-Toft, J. (2015) Growth of upper plate lithosphere controls tempo of arc magmatism: Constraints from Al-diffusion kinetics and coupled Lu-Hf and Sm-Nd chronology. Geochem. Persp. Let. 1, 20-32.

Geochemical Perspectives Letters v1, n1  |  doi: 10.7185/geochemlet.1503
Received 10 January 2015  |  Accepted 13 March 2015  |  Published 8 April 2015
Copyright © 2015 European Association of Geochemistry


Figure 1 (A) Sample locality map. (B) Vertical architecture of the lithosphere beneath the central Sierra Nevada as sampled by xenoliths (see text for references). (C) Wavelength-dispersive (WDS) elemental map of Al intensity in an orthopyroxene containing garnet and amphibole lamellae in garnet peridotite 1026V from 3 GPa (~90 km). Spots labelled as wt.% Al2O3 correspond to individual, quantitative WDS spot measurements.
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Figure 2 Orthopyroxene Al diffusion modelling of the Al halo transect shown in Figure 1C. Quantitative WDS spot analyses along the transect are plotted as white circles. (A-C) show diffusion profiles at selected times (0.1, 1, 5, 10, 20 Ma) using an activation energy E of 375 kJ/mol and D0 = 10-10 m2/s. Three different cooling scenarios are shown, with e-fold timescales of cooling τ of 3, 7, and 50 Myr. (D) through (F) shows the residual (XAl(observed) – XAl(modelled)) as a function of distance for each of the models, where XAl = atomic Al/2, and Al is the number of cations in the formula for orthopyroxene on a 6 oxygen basis.
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Figure 3 (A) Lu-Hf and (B) Sm-Nd isochrons of Sierran garnet pyroxenite xenoliths. Isochrons were calculated using a MatLab least-squares software by F. Albarède (version 6.0, 2013).
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Figure 4 (A) Top panel: U-Pb zircon ages from the Sierra Nevada Batholith (Paterson et al., 2014) showing a major peak at ~95 Ma. Bottom panel: Thermobarometrically constrained depth versus radiometric age of Sierran pyroxenite xenoliths. The vertical bars represent the range of final P, T recorded by several mineral rim pairs in each xenolith (except for BCX, where average REE concentrations were used); the symbols represent the average P, T. (B) Cartoon illustrating the formation of shallow low-MgO pyroxenite (top) and deep high-MgO websterite (bottom). (C) Temperature versus depth diagram showing the initial condition of conductive cooling modelling of a 100-km thick lithosphere at 0 Myr (initial condition) and re-equilibration to a new ambient geotherm after 70 Myr. Thermal diffusivity is 10-6 m2/s. (D) Temperature versus time diagram of depth slices ranging from 40 to 99 km. Superimposed on the diagram are the three cooling scenarios evaluated in the Al-diffusion modelling.
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Supplementary Figures and Tables


Figure S-1  Al2O3 (wt. %) in orthopyroxene cores and rims in garnet websterites and garnet peridotite. Cores have higher Al contents.
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Figure S-2  Plane-polarised light photograph of thick section (~200 μm) of high-MgO websterite BC98-5.
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Figure S-3  Plane-polarised light photograph of thick section (~200 μm) of high-MgO websterite BC98-7. (IND51), Nagrasu (IND54), Rudraprayag (IND57-59) and Srinagar (IND62, 64, 65, 72 and 73). Flow is from top to bottom of the image. Vertical exaggeration is 3x.
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Figure S-4  Plane-polarised light photograph of thick section (~200 μm) of low-MgO garnet clinopyroxenite BCX.
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Figure S-5  Representative “clean” clinopyroxene and garnet separates from BC98-5.
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Figure S-6  The thermobarometre of Harley and Green (1982) parameterised as a function of XAl on M1 site of opx versus temperature at constant pressure (top) and XAl on M1 site of opx versus pressure at constant temperature (bottom).
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Figure S-7  Modelled Al-diffusion profiles at various times at different values of D0 and constant E (375 kJ/mol), using starting T = 1275 °C, final T = 750 °C. Each column shows models performed at a different cooling scenario.
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Figure S-8  Norm of residual of Al-diffusion models (E = 375 kJ/mol, D0 = 10-10 m2/s) at 0.1, 1, 5, 10, and 20 Ma and at different cooling scenarios.
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Figure S-9  Modelled Al-diffusion profiles at various times at different values of D0 and constant E (375 kJ/mol), using starting T = 1100 °C, final T = 750 °C.
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Table S-1 Major element compositions (wt. %) of orthopyroxene profile in sample 1026V in Figure 1C.
ID 1b#71b#81b#91b#101b#111b#121b#131b#141b#151b#161b#171b#181b#191b#201b#211b#221b#231b#241b#251b#26
Xmm32.238432.239432.240432.241432.242432.243432.244432.245432.246432.247432.248432.249432.250432.251432.252432.253432.254432.255432.256432.2574
Ymm26.096726.097226.097726.098226.098726.099226.099726.100226.100726.101226.101726.102226.102726.103226.103726.104226.104726.105226.105726.1062
  at contact with garnet lamella
SiO257.5357.3757.1356.8657.4457.0056.9757.1057.2257.0356.5956.4156.6557.2556.9057.2057.1657.0856.7756.57
TiO20.0130.0220.0280.0020.0140.0050.0350.0350.0170.0230.010.0190.0230.00500.0240.0290.0230.0290.001
Al2O30.991.091.271.371.521.601.711.741.691.741.851.881.841.821.781.831.821.791.881.87
Cr2O30.310.290.350.470.490.600.650.500.550.540.570.500.510.430.580.420.370.520.360.47
FeOT5.845.585.455.395.345.455.645.755.525.485.685.745.645.685.365.685.535.745.835.91
MnO0.160.100.110.130.090.160.140.090.150.100.110.110.080.050.130.110.080.110.140.12
MgO35.2834.9134.9034.6534.7134.7934.5834.6334.6434.2632.5731.7634.5034.9534.6934.6934.7134.5634.5534.47
CaO0.100.100.110.130.140.130.130.110.120.120.110.140.120.110.110.110.110.110.110.13
Na2O0.0220.0320.0070.0070.0030.0070.00100.0090.0150.0110.0070.0110.02600.0230000.005
NiO0.060.100.070.060.020.060.050.080.060.070.020.080.170.100.010.140.140.050.140.08
Total100.2999.5999.4299.0699.7699.7999.91100.0499.9899.3897.5196.6599.54100.4299.56100.2199.9499.9899.8099.61
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Table S-2 Orthopyroxene major element compositions (wt. %) in Sierran garnet pyroxenites.
  BC98-7 BC98-5
IDBC987_01-opxRBC987_02-opxCBC987_07-opxRBC987_08-opxCBC985_03-opxRBC985_04-opxCBC985_07-opxRBC985_08-opxCBC985_17-opxRBC985_18-opxC
 rimcorerimcorerimcorerimcorerimcore
x (μm)128711279365727337313919-122-9676317345
y (μm)134161378585998825231912342926133258782788927423
 
SiO254.1354.2954.9454.1055.1954.6455.1254.4754.8653.72
TiO20.0430.020.0340.020.020.01300.0340.0280.01
Al2O31.801.991.502.050.741.220.761.490.921.68
Cr2O30.130.110.100.200.080.110.080.090.080.11
FeOT12.8012.8512.9213.0712.3212.3812.7113.1413.1913.55
MnO0.140.140.170.150.110.110.110.150.160.16
MgO30.8030.5731.1430.7631.4531.0731.3230.4530.5330.18
CaO0.250.210.200.160.120.170.100.190.200.20
Na2O0.0140.0250.0140.0170.0120.0020.0050.0120.0060
Total100.09100.22101.02100.53100.0499.70100.21100.0299.9899.61
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Table S-3 Clinopyroxene major element compositions (wt. %) in garnet pyroxenites.
  BCX BC98-7 BC98-5
IDBCX_03-cpxBCX_05-cpxBCX_08-cpxBC987_05-cpxRBC987_06-cpxCBC987_09-cpxRBC987_10-cpxCBC985_05-cpxRBC985_06-cpxCBC985_11-cpxRBC985_12-cpxCBC985_15-cpxRBC985_16-cpxC
rim next to gtrim next to gtrim next to gtrimcorerimcorerimcorerimcorerimcore
x (μm)-6-5075-4444126861265676984946755089-470-29974548124
y (μm)-15851-6058-13636141521442088749171238472447926791272892817028080
SiO254.8554.8054.5353.7953.6254.4553.8654.3553.5954.3153.4154.0652.98
TiO20.180.190.210.150.240.090.140.050.150.050.130.040.13
Al2O39.349.429.243.914.493.564.031.974.192.324.421.664.70
Cr2O30.040.000.000.440.440.450.440.260.220.270.290.260.36
FeOT4.144.174.193.734.043.503.653.604.183.594.223.484.37
MnO0.0020.0290.0370.0840.0560.0330.0370.0760.0980.0370.0510.0410.057
MgO10.5710.5710.6015.0014.5015.1614.9616.1714.7716.0314.7316.3714.41
CaO17.0416.7616.9721.8121.3821.8321.6123.2221.9722.9522.1223.2522.08
Na2O4.614.704.531.611.671.651.710.901.231.031.360.791.36
Total100.78100.64100.30100.51100.44100.72100.44100.59100.40100.58100.7299.93100.46
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Table S-4 Garnet major element compositions (wt. %) in Sierran garnet pyroxenites.
  BC98-5 BCX BC98-7
IDBC985_01-GT1BC985_02-GT1BC985_09-GTrBC985_10-GTcBC985_13-GTcBC985_14-GTrBCX_01-GTCBCX_02-GTrBCX_04-GTrBCX_06-GTrBCX_07-GTCBCX_09-GTBC987_03-GTCBC987_04-GTrBC987_11-GT1BC987_12-GT2
rimcorecorerimcorerimrimrimcorecorerim
x (μm)36393671-308-5937284736637938008338-4877-4680-497611863121525760
y (μm)228922283526127263582803428111-12444-12849-16003-5904-5797-13521139951389198559811
 
SiO240.1540.1340.0140.2339.7740.0039.3539.1639.3139.0839.0539.1940.2340.3040.2839.96
TiO20.0440.0930.0480.1040.1040.0170.140.0730.160.050.1070.0930.0770.0530.0620.058
Al2O322.9422.8622.8422.6222.5822.6022.2022.1022.5622.5822.2522.4622.7222.9022.8422.81
Cr2O30.340.370.420.340.390.3800.0400.030.020.020.470.520.510.49
FeOT18.0018.1618.9718.0918.9419.2022.7321.1420.7320.6920.9620.7417.9318.7918.4518.43
MnO0.560.570.530.420.540.570.660.560.530.560.530.600.560.570.530.57
MgO13.1012.9412.3112.8112.2812.149.437.417.957.407.487.3613.4212.7013.1413.21
CaO5.615.615.615.655.515.506.269.899.5810.3810.1710.465.195.225.225.29
Na2O0.020.0250.0140.020.0050.0190.0560.0240.0670.0030.0390.020.0140.0120.020.002
Total100.76100.75100.75100.27100.11100.42100.82100.41100.88100.77100.60100.94100.62101.07101.05100.81
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Table S-5 Sm-Nd and Lu-Hf concentrations and isotope compositions of Sierran pyroxenites.
gt = garnet
cpx = clinopyroxene
wr = whole-rock
kgt = kelyphite-rimmed garnet
SampleSm (ppm)Nd (ppm)147Sm/144Nd143Nd/144NdLu (ppm)Hf (ppm)176Lu/177Hf176Hf/177Hf
BC98-7 gt0.5630.2951.1520.5130680.0000080.4550.08520.75810.2835960.000044
BC98-7 cpx2.006.500.18580.5125660.0000040.006280.9120.00097660.2827370.000005
BC98-7 wr0.7692.130.21780.5125620.0000040.1340.3600.052850.2830940.000005
BC98-5 kgt0.7270.5330.82570.5128770.0000060.7690.1860.58710.2837280.000014
BC98-5 cpx2.346.510.21730.5125260.0000050.009461.070.0012520.2827160.000004
BC98-5 wr1.484.040.22150.5125230.0000050.1580.8170.027490.2828410.000014
BCX gt3.502.190.96390.5129560.0000051.220.3440.50370.2837740.000010
BCX gt dupl1.25
BCX cpx1.111.800.37180.5126300.0000120.01971.100.0025290.2827670.000003
BCX cpx dupl0.01971.090.002574
BCX wr2.794.730.35630.5127020.0000040.5140.9360.077950.2829130.000004
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