Back to article

Figures and Tables

Late accretion history of the terrestrial planets inferred from platinum stable isotopes

J.B. Creech1,2,

1Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
2Institut de Physique du Globe de Paris, Université Sorbonne Paris Cité, Université Paris Diderot, 1 Rue Jussieu, 75328 Paris Cedex 05, France

J.A. Baker3,

3School of Environment, The University of Auckland, Private Bag 92019, Auckland, New Zealand

M.R. Handler4,

4School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand

J.-P. Lorand5,

5Laboratoire de Planétologie et Géodynamique de Nantes, CNRS UMR 6112, Université de Nantes, 2 Rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France

M. Storey6,

6Quadlab, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark

A.N. Wainwright7,

7Laboratoire G-Time, Université Libre de Bruxelles, 50 Avenue F.D. Roosevelt, 1050 Brussels, Belgium

A. Luguet8,

8Steinmann Institut für Geologie Mineralogie und Paläontologie, Rheinische Friedrich-Wilhems-Universität, 53115 Bonn, Germany

F. Moynier2,9,

2Institut de Physique du Globe de Paris, Université Sorbonne Paris Cité, Université Paris Diderot, 1 Rue Jussieu, 75328 Paris Cedex 05, France
9Institut Universitaire de France, 75005 Paris, France

M. Bizzarro1

1Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark

Affiliations  |  Corresponding Author  |  Cite as  |  Funding information

Creech, J.B., Baker, J.A., Handler, M.R., Lorand, J.-P., Storey, M., Wainwright, A.N., Luguet, A., Moynier, F., Bizzarro, M. (2017) Late accretion history of the terrestrial planets inferred from platinum stable isotopes. Geochem. Persp. Let. 3, 94-104.

This research was supported by a Royal Society of New Zealand Marsden Grant to MH and JB and grants from the Danish National Research Foundation (grant number DNRF97) and from the European Research Council (ERC Consolidator grant agreement 616027-STARDUST2ASTEROIDS) to M.B. F.M. acknowledges funding from the European Research Council (ERC Starting grant agreement 637503-Pristine) as well as the financial support of the UnivEarthS Labex program at Sorbonne Paris Cité (ANR-10-LABX-0023 and ANR-11-IDEX-0005-02) and a chaire d’excellence ANR-Idex Sorbonne Paris Cité.

Geochemical Perspectives Letters v3, n1  |  doi: 10.7185/geochemlet.1710
Received 7 September 2016  |  Accepted 19 October 2016  |  Published 8 November 2016
Copyright © 2017 European Association of Geochemistry

Keywords: platinum, stable isotopes, terrestrial planet accretion, late-veneer, magma ocean




Figure 1 Platinum stable isotopes vs. Pt concentrations in achondrite meteorite samples showing increasingly heavy Pt isotopic compositions corresponding with decreasing Pt concentrations, indicating that heavy Pt isotopes are concentrated in the silicate mantle during metal–silicate differentiation. The shaded field represents the mean and 2 sd of chondrites, as given in the text. Error bars on δ198Pt are the 2 sd of combined measurements or the reproducibility of the method as determined by replicate digestions of similar samples, whichever is larger (Supplementary Information). Uncertainties in Pt concentration are negligible on this logarithmic scale. Iron meteorite samples have larger uncertainties in δ198Pt owing to cosmogenic effects, which are discussed further in the Supplementary Information. A regression through the ureilite data gives a slope of –0.108 ‰ per log unit of concentration (r2 ~0.43); excluding ALHA81101, the slope is 0.069 ‰ per log unit of concentration, (r2 ~0.14).
Back to article | Download in Powerpoint



Figure 2 Platinum stable isotope results for terrestrial and meteorite samples. Error bars on δ198Pt for NiS digested samples are the 2 sd of combined replicates or the reproducibility of the method as determined by replicate digestions of similar samples, whichever is larger (Supplementary Information). Extended error bars illustrate the additional uncertainty arising from the potential presence of small amounts of analytical blank (further details are given in the Supplementary Information). The dashed vertical line and grey box represent the mean and 2 sd of chondrites as discussed in the text. For one Kaapvaal sample where the variability in replicate digestions exceeded the reproducibility of the technique (interpreted as reflecting real isotopic heterogeneity on the scale of these samples) all three replicates are shown enclosed in a dashed box, where the size of the box represents the 2 sd of the three replicates. Large uncertainties on iron meteorite samples are attributed to cosmic ray exposure effects, which are expected to shift δ198Pt to more negative values; further discussion is given in the Supplementary Information.
Back to article | Download in Powerpoint


Figure 3 Model of the effect of addition of chondritic late-veneer on the abundance and isotopic composition of Pt in the mantle. (a) The calculated mantle concentration of Pt from the addition of chondrite to the pre-late-veneer mantle. The vertical line represents the Pt concentration of primitive upper mantle (PUM; 7.6 ppb; Becker et al., 2006

Becker, H., Horan, M.F., Walker, R.J., Gao, S., Lorand, J.-P., Rudnick, R.L. (2006) Highly siderophile element composition of the Earth’s primitive upper mantle: Constraints from new data on peridotite massifs and xenoliths. Geochimica et Cosmochimica Acta 70, 4528–4550.

), and the dashed horizontal line marks the intercept of the mantle concentration with PUM, indicating the amount of late-veneer required to reproduce the Pt abundance of PUM. (b) The Pt isotopic composition of the mantle resulting from mixing late-veneer with hypothetical pre-late-veneer mantle, with black and blue lines representing mixtures with initial pre-late-veneer mantle Pt concentrations of ≤0.001 ng g-1 and 0.144 ng g-1, relating to core formation at low- or high-pressures and -temperatures, respectively (Supplementary Information). Shaded boxes represent the composition of the post-Archean mantle and inferred composition of the Archean mantle sources of Isua and Kaapvaal (based on the range of values defined by the sample KBD4, which is taken to represent the most pristine pre-late-veneer signature). Note that the latter was not used to constrain the model, as Pt concentrations may not relate solely to depletion during core-formation.
Back to article | Download in Powerpoint

Back to article

Supplementary Figures and Tables


Figure S-1 Demonstration of correction for blank Pt on δ198Pt data for (a) mixtures of blank Pt from NiS digested blanks and IRMM-010 Pt isotope standard (δ198Pt = 0 ‰) and (b) the peridotite BC1 (δ198Pt = -0.09 ± 0.15 ‰), where three samples have been prepared by combining digestions of relatively small amounts of material, thus creating a high blank-to-sample ratio. In each case, uncorrected data are shown in blue and the same data with a blank correction applied are shown in green.
Back to article | Download in Powerpoint


Figure S-2 Pt stable isotope data for individual replicates processed from iron meteorites. The dashed horizontal line and grey field represent the mean and 2 sd of chondrite data. The arrow indicates the expected direction of influence of cosmic ray exposure on DS-corrected Pt stable isotope data.
Back to article | Download in Powerpoint


Table S-1 Terrestrial Pt stable isotope and concentration results from double-spike MC-ICPMS, PGE concentrations from ID-ICPMS, and Re–Os isotope data determined by N-TIMS.
SampleRock typeLocalityTotal sample processed (g)total Pt (ng)Pt conc.
(ng g–1)
(n)δ198Pt
(‰)
±2σBlank proportion (%)Magnitude of blank correction (‰)
Subcontinental Lithospheric Mantle Xenoliths
BC1LherzoliteBatchelor's Crater. Queensland. Australia15.01036.82-0.250.040.8-0.01
  replicate

17.71176.61-0.140.030.8-0.01
  average





-0.190.15


BC7LherzoliteBatchelor's Crater. Queensland. Australia15.6785.21-0.050.031.1-0.02
MQ1LherzoliteMount Quincan. Queensland. Australia7.2486.61-0.070.041.7-0.03
MQ14LherzoliteMount Quincan. Queensland. Australia15.01036.82-0.170.030.8-0.01
  replicate

10.7656.12-0.070.021.2-0.02
  average





-0.120.14



Ophiolites/transitional lherzolites
L 213LherzoliteSezia Lanzo HP zone. Alps. Italy17.61116.31-0.130.030.8-0.01
LI 138LherzoliteInternal Liguride Ophiolite. Italy15.11087.33-0.130.060.7-0.01

Off craton basalt-hosted xenoliths
Mtf37LherzoliteMontferrier. Massif Central. France15.11036.83-0.030.020.8-0.01

Continental orogenic peridotites
TUR 7LherzoliteTuron de Técouère. Pyrénées. France16.51197.21-0.100.040.7-0.01

Cratonic xenoliths (Kaapvaal craton)
BGLherzoliteKimberley. South Africa15.0211.42-0.200.053.7-0.07
BG2HarzburgiteKimberley. South Africa13.1564.220.160.031.4-0.02
KBD4HarzburgiteKimberley. South Africa15.3271.720.270.063.0-0.04
  replicate

15.1261.720.260.053.1-0.04
  replicate

15.6301.920.460.042.8-0.03
  average





0.330.22


LMA2HarzburgiteMatsoku kimberlite. Lesotho11.9292.42-0.080.042.8-0.05
LTP20LherzoliteThaba Putsoa kimberlite. Lesotho7.440.610.080.1218.2-0.33

Isua
460203MetabasaltIsua Supracrustal Belt. Greenland20.25673.330.130.091.6-0.02
460204Ultramafic schistIsua Supracrustal Belt. Greenland22.551406.220.120.020.9-0.01
460217MetabasaltIsua Supracrustal Belt. Greenland20.58803.910.160.161.4-0.02
460218MetabasaltIsua Supracrustal Belt. Greenland25.071104.420.110.021.2-0.02
  duplicate

20.69813.910.070.071.4-0.02
  average





0.090.05


460219MetabasaltIsua Supracrustal Belt. Greenland25.221124.420.130.071.2-0.02
460258MetabasaltIsua Supracrustal Belt. Greenland25.161154.62-0.080.061.2-0.02
  duplicate

20.53723.520.040.021.5-0.02
  average





-0.020.17


460275MetabasaltIsua Supracrustal Belt. Greenland20.40824.010.110.051.3-0.02
460276Ultramafic schistIsua Supracrustal Belt. Greenland20.42773.820.090.081.4-0.02

SampleOs
(ng g–1)
Ir
(ng g–1)
Ru
(ng g–1)
Pt
(ng g–1)
Pd
(ng g–1)
Re
(ng g–1)
Re/Os187Os/188Os 187Re/188OsTMA (Ma)TRD (Ma)
Subcontinental Lithospheric Mantle Xenoliths
BC1











BC7










MQ1a1.46



0.214

0.707113113
MQ14a2.11



0.192

0.439265

Ophiolites/transitional lherzolites
L 213b3.252.895.665.784.470.261

0.387

LI 138c3.043.065.457.155.95






Off craton basalt-hosted xenoliths
Mtf37d5.244.67.58.36.60.156

0.144


Continental orogenic peridotites
TUR 7b4.033.597.227.26.540.341

0.408


Cratonic xenoliths (Kaapvaal craton)
BG2.372.263.261.580.490.2170.0910.106610.43882
3091
BG24.594.457.012.720.060.0230.0050.108650.0243029862823
KBD42.562.162.841.830.060.0600.0230.106780.1127641073069
  replicate










  replicate










  average










LMA24.193.385.002.230.660.0420.0100.107240.0486333763008
LTP204.423.155.790.440.080.1700.0390.106990.1849651953041

Pt stable isotope compositions given are weighted means of the number of analyses (n) of each digestion, with the uncertainties reflecting the errors on the weighted means. Where multiple replicates were processed, the mean and 2 sd (n ≤ 2) or weighted mean (n ≥ 3) is also shown along with the values for each replicate. Details of analytical blanks and blank corrections are given in the Supplementary Information. All Re–Os ages for Kaapvaal samples calculated to PUM with a 187Os/188Os of 0.1296 and a 187Re/188Os of 0.435 after Becker et al. (2006). Model ages (TMA) for Kaapvaal samples are overestimated due to the presence of metasomatic sulphides that affect the Re/Os ratio. PGE and Re–Os data for MQ1, MQ14, L 213, LI 138, Mtf37 and TUR 7 are from the following references: aHandler et al. (2005); bBecker et al. (2006); cLuguet et al. (2004); dAlard et al. (2011).

Back to article | Download in Excel


Table S-2 Platinum stable isotope and concentration results for meteorite samples measured by double-spike MC-ICPMS.
SampleGroupTotal sample processed (g)total Pt
(µg)
Pt conc. (µg g–1)Ref. Pt conc.
(µg g–1)
δ198Pt (‰)±2σ(n)Blank proportion (%)Magnitude of blank correction (‰)CRE age (Myr)Structural type‡Kamacite
bandwidth‡ (mm)
Ordinary chondrites
BovedyL30.520.521.00
-0.150.0330.20.00


BegaaLL30.480.250.52
-0.150.0330.30.00


Talbachat n'aït IsfoulLL30.960.220.23
-0.140.0240.4-0.01


  replicate
0.490.190.39
-0.190.0430.4-0.01


  average




-0.170.077




SAH 97172L51.361.000.79
-0.160.0440.10.00



Enstatite chondrites
SAH 97096EH30.470.631.33
-0.150.0340.10.00


  replicate
0.470.601.27
-0.170.0110.10.00


  average




-0.160.03





SAH 97159EH31.241.471.12
-0.140.04
0.10.00



Carbonaceous chondrites
AllendeCV31.001.261.261.36a-0.100.0430.10.00


  replicate
1.141.451.27
-0.100.0730.10.00


  replicate
1.041.241.20
-0.130.0150.10.00


  replicate
1.021.301.29
-0.120.0450.10.00


  replicate
1.051.221.16
-0.170.0220.10.00


  average


1.24
-0.120.06





GujbaCB30.482.134.42
-0.080.0430.00.00


NWA 1232CO30.540.520.98
-0.080.0330.20.00


NWA 763CO30.480.491.02
-0.170.0430.20.00


NWA 1559CK30.660.320.49
-0.170.0440.30.00


NWA 1563CK50.500.350.68
-0.080.0340.20.00


NWA 723CV30.440.511.16
-0.240.0330.20.00


SaU 290CH30.640.500.78
-0.160.0330.20.00



Primitive achondrites
Dho 125Acapulcoite0.861.241.45
-0.090.0240.10.00


  replicate
0.861.251.45
-0.090.0230.10.00


  average




-0.090.01





NWA 2871Acapulcoite0.881.992.27
-0.040.0330.00.00


Tierra BlancaWinonaite0.310.250.82
0.010.0310.30.00


ALH 84136Ureilite1.200.310.260.28b-0.050.0630.30.00


ALHA77257Ureilite1.540.230.150.19b-0.010.0330.3-0.01


ALHA78019Ureilite0.270.250.901.54b-0.210.0430.3-0.01


ALHA81101Ureilite1.230.080.060.06b0.170.1331.0-0.02


EET 87517Ureilite1.090.540.490.59b-0.050.0630.10.00


EET 96042Ureilite1.470.690.470.57b-0.040.0630.10.00


GRA 95205Ureilite1.000.540.540.83b-0.150.0930.10.00


GRA 98032Ureilite1.070.260.250.41b-0.130.1130.30.00


GRO 95575Ureilite1.450.540.370.31b0.100.1430.10.00


NWA 2234Ureilite0.690.180.26
0.000.0440.4-0.01


PCA 82506Ureilite1.780.470.260.47b-0.190.0230.20.00


META 78008Ureilite0.740.270.361.04b-0.110.0710.30.00



Iron meteorites
Canyon DiabloIAB

6.098.0c-0.240.051

540dOg2
  replicate


6.73
-0.100.038




  average




-0.170.20





TolucaIAB

7.305.47e-0.180.032

600fOg1.4
  replicate


5.39
-0.170.054




  replicate


2.96
-0.130.021




  average




-0.160.05





HenburyIIIAB

15.2418.31e-0.310.032

700fOm0.9
  replicate


16.55
-0.240.037




  replicate


15.44
-0.180.048




  average




-0.240.13





Savik (Cape York)IIIAB


11.85e-0.270.026

82gOg1.2
  replicate




-0.280.053




  average




-0.280.01





GibeonIVA

3.906.91e-0.220.027

400Of0.3
  replicate


3.90
-0.090.022




  average




-0.160.18





ChingaIVB/ung

7.619.56e-0.190.017

845D
  replicate


9.39
-0.090.037




  average




-0.140.14





Pt stable isotope compositions are weighted means of the number of analyses (n) of each digestion, with the uncertainties reflecting the errors on the weighted means. Where multiple replicates were processed, the mean and 2 sd is also shown along with the values for each replicate. Details of analytical blanks and blank corrections are given in the Supplementary Information. No blank correction was applied to iron meteorite data due to different digestion methods (Supplementary Information). Greater uncertainty in iron meteorite data may reflect cosmogenic effects in these samples, as discussed in the Supplementary Information. §CRE age given is weighted average for group. aFischer-Gödde et al. (2010); bRankenburg et al. (2008); cCrocket (1972); dMichlovich et al. (1994); ePetaev and Jacobsen (2004); fScherstén et al. (2006); gMathew and Marti (2009).

Back to article | Download in Excel


Table S-3 Determination of Pt blanks from replicate NiS blank digestions.
#digestionsamount of 'sample' (g)total blank (ng)blank per 15g digestion (ng)
1125.611.570.92
2240.374.721.75
3115.010.220.22
4115.100.230.23
5115.001.201.20
6115.011.041.04
7115.000.540.54
8115.000.490.49
9115.140.460.46
10115.070.760.76
11460.374.491.12
12120.101.310.98


mean0.81

median0.84

max1.75
Back to article | Download in Excel


Table S-4 Isotopic composition of blanks from replicate, double-spiked, NiS blank digestions.
 Total 'sample' digested (g)digestionsδ198Pt (‰)±total blank (ng)blank per 15g digestion (ng)
DS blank 160.3740.830.254.481.11
DS blank 220.111.580.391.310.98
Back to article | Download in Excel


Table S-5 Pt isotope data and NiS blank correction of mixtures of IRMM-010 and NiS blank Pt.
 blank Pt proportion (%)δ198Pt (‰)±δ198PtBC (‰)
IRMM-01000.000.030.00
IRMM-010–blank mixture #1100.120.070.02
IRMM-010–blank mixture #2300.330.070.00
Back to article | Download in Excel


Table S-6 Pt isotope data and NiS blank correction of low-Pt replicate digestions of peridotite BC1, compared with normal digestions of the same sample.
 Total sample processed (g)digestionsδ198Pt (‰)±total Pt
(ng)
Pt conc.
(ng g-1)
blank per digestion (ng)total blank (ng)blank Pt proportion (%)δ198PtBC (‰)
BC1 low-Pt #12.830.170.07196.61.54.620–0.18
BC1 low-Pt #23.030.180.07206.61.75.020–0.17
BC1 low-Pt #33.230.000.07185.60.72.010–0.17











BC115.01–0.250.041036.81.01.01–0.27
BC117.71–0.140.031176.61.01.01–0.16
Back to article | Download in Excel


Table S-7 Model parameters used in preparing Figure 3.
Reservoir
DPtmet/silPt conc. (ng g-1)δ198Pt (‰)
Pre-late-veneer mantle– Low P-T≥106<1.44 x 10-5

– High P-T1040.144





Post-veneer-mantle

7.63–0.10 ± 0.10
Late-veneer (chondrite)

982–0.19 ± 0.14
Back to article | Download in Excel


Table S-8 Thermal neutron capture cross sections for isotopes in the mass range of platinum. aIsotopic abundances from Berglund and Wieser (2011). bThermal neutron capture cross sections from Mughabghab (2003).
Isotope190Pt191Ir192Pt193Ir194Pt195Pt196Pt197Au198Pt
Relative abundancea (%)0.0137.270.7862.7332.9733.8325.241007.16
Cross-sectionb (barns)14795410111~128~0.6993.66
Back to article | Download in Excel