SUPPLEMENTARY INFORMATION

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1 SUPPLEMENTARY INFORMATION RECYCLING OF SUBDUCTED CRUSTAL COMPONENTS INTO CARBONATITE MELTS REVEALED BY BORON ISOTOPES Samuel R.W. Hulett 1, Antonio Simonetti 1, E.Troy Rasbury 2, N. Gary Hemming 3 1 Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN USA. 2 Department of Geosciences, Stony Brook University, NY USA. 3 School of Earth and Environmental Science, Queens College, CUNY Queens, NY USA. * simonetti.3@nd.edu NATURE GEOSCIENCE 1

2 SUPPLEMENTARY INFORMATION A B Figure S1. A. World-wide occurrence of carbonatites (black dots) 1, and B. Locations and ages 2,3,4,5 in millions of years before present (Ma) of carbonatite samples investigated in this study. 2 NATURE GEOSCIENCE

3 SUPPLEMENTARY INFORMATION Figure S2. Photos of carbonatite hand specimens from Prairie Lake, Canada (13-1), Iron Hill, USA (13-6), Chemigovka, Ukraine (13-27), and Borden, Canada (13-29). The samples are pristine and lack secondary alteration. NATURE GEOSCIENCE 3

4 SUPPLEMENTARY INFORMATION A B C D F E G H Figure S3. Plane polarized microphotographs of carbonatite samples investigated here. a, b, are 4 NATURE GEOSCIENCE

5 SUPPLEMENTARY INFORMATION from SH13-1 and show fresh, coarse-grained calcite (exhibiting twinning), biotite (brown), apatite (white and no cleavage/twinning), and clinopyroxene (green). c, d, are from sample SH13-11 which display the predominantly calcite-rich nature of the sample; in c, large white, non-twinned crystal is apatite. e, f, are from sample SH13-27 exhibiting the fresh, unaltered nature of this sample since crystal margins and boundaries are crisp and sharp; minerals shown are calcite (exhibiting twinning), biotite (brown), and clinopyroxene (green). g, h, illustrate predominantly fresh calcite and biotite (brown), and apatite (high relief, white grain in bottom left side of panel g) from sample SH All scale bars represent 500 microns. NATURE GEOSCIENCE 5

6 SUPPLEMENTARY INFORMATION Figure S4. Examples of micro-xrf element maps (right column) showing the overall chemical homogeneity of the calcite (represented by the bright green color for Ca) in the carbonatite samples from Prairie Lake (13-1), Iron Hill (13-6), and Borden (13-29). The left column presents a photo mosaic of the petrographic thin section for each sample. 6 NATURE GEOSCIENCE

7 SUPPLEMENTARY INFORMATION Figure S5. Laser ablation-icp-ms results and time-resolved spectra for minerals ablated from sample SH13-27; CC= calcite; AMP= amphibole; BIO= biotite. Minerals investigated in sample SH13-27 are illustrated in Fig. S4 (panels e, f). Based on the 11 B ion signals, the different minerals indicate identical levels of boron, and the calcite analyses were taken (one each) from margin and core regions; both also indicated similar levels of boron abundances. Prior to LA- ICP-MS analysis, the major element compositions of the minerals were determined with a Cameca SX50 Electron Microprobe at the University of Notre Dame under the supervision of Dr. Ian Steele. The EMP is equipped with 4 wavelength-dispersive spectrometers and a highresolution energy-dispersive solid-state detector. EMP analyses were conducted using a 15kV accelerating potential and 30 na incident current. Both natural and synthetic mineral and glass standards were employed for calibration purposes. In-situ B analyses of individual grains were carried out using a UP213 nm laser ablation system coupled to a Thermo-Finnigan Element2 sector field high-resolution ICP-MS at the University of Notre Dame (MITERAC ICP-MS Facility). NIST SRM 612 international glass standard was used for external calibration and 43 Ca ion signal intensities were employed as internal standard to monitor instrumental drift. The content (wt.%) of CaO was determined using EMPA. Standard and sample grains were ablated using a spot size of 55 μm, 5 Hz repetition rate, corresponding to an energy density of ~8 J/cm 2. A typical analysis consisted of a ~60 s background measurement followed by data acquisition and ablation for ~60 s using a dwell time of 8 ms. Of importance, the limit of detection (as determined by the Glitter data reduction software) varied between 0.4 and 0.6 ppm, which NATURE GEOSCIENCE 7

8 SUPPLEMENTARY INFORMATION overlaps with the B abundances determined by solution mode and reported in Supplementary Table 1. 8 NATURE GEOSCIENCE

9 SUPPLEMENTARY INFORMATION Table S1. B abundances and C, O, and B isotope compositions of carbonatites investigated here. Sample Locality Age (Ma) δ 13 C ( ) δ 18 O ( ) B ppb δ 11 B ( ) 13-2 Sukulu, Uganda dup AMD-003 Amba Dongar, India AMD-003 -dup BMR 056 Barmer, India BMR 056- dup. Barmer, India BMR-056- STB Barmer, India MC117 Magnet Cove, USA MC117 - dup MC STB 1.60 TAN 213 Panda Hill, Tanzania TAN 213- dup OKA 4A Oka, Canada OKA 4B Oka, Canada OKA 206 Oka, Canada OKA 203 Oka, Canada OKA 109 Oka, Canada OKA 153 Oka, Canada Kovdor, Russia dup Iron Hill, Colorado dup trip Prairie Lake dup trip STB STB Borden dup trip Chernigovka, Ukraine dup trip Silinjarvi, Finland dup trip STB Samples denoted by STB= identical carbonatite sample powders analyzed at Stony Brook University. The intra-sample B isotope variability results from the phosphate (apatite)-rich NATURE GEOSCIENCE 9

10 SUPPLEMENTARY INFORMATION nature for some samples (e.g., 13-1, Prairie Lake, Canada). A digestion technique involving the use of cold 2N double-distilled HNO 3 acid was employed so as to minimize the amount of phosphate processed through the ion exchange chemistry 6. B aliquots were measured as ~100 ppb solutions using the NPII MC-ICP-MS instrument at the University of Notre Dame, whereas those analyzed at Stony Brook were either 25 ppb (13-1-STB-1, 13-1-STB-2, 13-11) or 50 ppb (BMR 056, MC117). Table S2. Boron blank levels in different MITERAC laboratories (University of Notre Dame) and of main reagents used in B separation chemistry Total B (ng) pg/hour Room Clean Lab (97 hours) Clean Lab Extrac. Hood (97 hours) ICP-MS Lab (97 hours) MC-ICP-MS Lab (97 hours) ICP-MS Lab Hood (97 hours) Reagents MQ H 2 O Acetate Double distilled HNO 3 below detection (<0.08 ppb) below detection (<0.08 ppb) below detection (<0.08 ppb) 10 NATURE GEOSCIENCE

11 SUPPLEMENTARY INFORMATION Figure S6. Boron isotope values for marine carbonates (data points) through the Phanerozoic 7,8,9,10 show an overall trend of increasing values towards present day. Also plotted is an estimate of the ph for the oceans (horizontal line with shaded grey area) 11. The different colored data points represent average δ 11 B values of marine carbonates for specific time intervals; light blue is from 7, orange and purple from 8, black is taken from 9. The uneven (vertical) line in the early Jurassic marks the 'Mid-Mesozoic revolution 11 when the widespread occurrence of calcareous nanoplankton occurred, and provided a much tighter control of the entire ocean s alkalinity, rather than just within shelf areas. (є= Cambrian; O=Ordovician; S=Silurian; D=Devonian; C=Carboniferous; P=Permian; T R =Triassic; J=Jurassic; K=Cretaceous). NATURE GEOSCIENCE 11

12 SUPPLEMENTARY INFORMATION Previous studies have documented and reported protocols to reduce or eliminate dry-down steps in order to mitigate B loss and thus potential isotope fractionation 6. Thus, a carbonatite sample with known B abundance was doped with a known quantity of the NIST SRM 951a B isotope standard, and yields were calculated subsequent dry-down and B ion exchange chemistry. The recovery yields listed in Table S3 indicate no loss of B during these steps in the sample processing and chemistry 6. Note recoveries in Table S3 are slightly higher than 100% due to minor heterogeneity in the low (~64 ppb) B abundance within the different powder aliquots of carbonatite sample PH951 doped with ~100 ng of the NIST SRM 951a standard. Table S3. B recovery tests subsequent dry-down and ion exchange chemistry 12 NATURE GEOSCIENCE

13 SUPPLEMENTARY INFORMATION References 1. Woolley, A. R. & Kjarsgaard, B. A. Carbonatite occurrences of the world: map and database (Geological Survey of Canada, Ottawa, 2008). 2. Woolley, A. R. The spatial and temporal distribution of carbonatites: Carbonatites: Genesis and Evolution Ch. 1 (Unwin Hyman, London, 1989). 3. Rukhlov, A. S. & Bell, K. Geochronology of carbonatites from the Canadian and Baltic Shields, and the Canadian Cordillera: clues to mantle evolution. Mineralogy and Petrology 98, (2010). 4. Bell, K., Blenkinsop, J., Cole, T.J.S. & Menagh, D.P. Evidence from Sr isotopes for long-lived heterogeneities in the upper mantle. Nature 298, (1982). 5. Simonetti, A., Goldstein, S. L., Schmidberger, S. S. & Viladkar, S. G. Geochemical and Nd, Pb, and Sr isotope data from Deccan alkaline complexes inferences for mantle sources and plume lithosphere interaction. Journal of Petrology 39, (1998). 6. Lemarchand, D., Gaillardet, J., Göpel, C. & Manhes, G. An optimized procedure for boron separation and mass spectrometry analysis for river samples. Chemical Geology 182, (2002). 7. Joachimski, M.M., Simon, L., vangeldern, R. & Lecuyer. C. Boron isotope geochemistry of Paleozoic brachiopod calcite: Implications for a secular change in the boron isotope geochemistry of seawater over the Phanerozoic. Geochimica et Cosmochimica Acta 69, (2005). NATURE GEOSCIENCE 13

14 SUPPLEMENTARY INFORMATION 8. Lecuyer, C., Grandjean, P., Reynard, B., Albarede, F. & Telouk, P. B-11/B-10 analysis of geological materials by ICP-MS Plasma 54: Application to the boron fractionation between brachiopod calcite and seawater. Chemical Geology 186, (2002). 9. Hemming, N.G. Boron isotope systematics of natural and laboratory grown calcium carbonate (PhD dissertation, SUNY Stony Brook, 1993). 10. Pearson, P.N. & Palmer, M.R. Atmospheric carbon dioxide concentrations over the past 60 million years. Nature 406, (2000). 11. Ridgwell, A. A Mid Mesozoic revolution in the regulation of ocean chemistry. Marine Geology 217, (2005). 14 NATURE GEOSCIENCE