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Supporting Information Supporting Information Holst et al. 10.1073/pnas.1300383110 SI Materials and Methods background were 30 s. Minerals with known chemical compo- Identification of FUN Inclusions. An ∼3 kg fragment of the Allende sitions were used as standards. Matrix effects were corrected CV meteorite (carbonaceous chondrite of the Vigarano type) using procedures described in Pouchou and Pichoir (2). was cut into numerous 3-mm–thick sections using a 250-μm diamond-coated wire saw that was operated dry to expose the fresh Petrology, Mineralogy, and Mineral Chemistry of the STP-1 FUN CAI. surface of the meteorite. High-resolution photographic images STP-1 is a coarse-grained igneous CAI composed of pure an- were produced for each section and these were characterized vi- orthite, gehlenitic melilite (Åk6−28), and igneously zoned Al,Ti- = − = − sually to identify all igneous calcium–aluminum-rich (CAI)-like diopside (Al2O3 17.7 28.5 wt %, TiO2 0.03 8.7 wt %), all inclusions. Igneous CAI-like inclusions greater than 2 mm in di- poikilitically enclosing euhedral compositionally pure spinel – ameter and present on at least two sections were sampled grains (Table S1). Lath-shaped hibonite grains and spinel using a Micromill sampling device fittedwith300-μm–di- hibonite intergrowths occur in the outermost portion of the in- − ameter diamond-coated microdrills. The sampled material clusion. The hibonite grains have low contents of MgO (0.2 1.7 − was transferred to Savillex beakers and digested using HF– wt %) and TiO2 (0.09 3.2 wt %). The Ti-poor compositions observed in some rare pyroxene grains are found in crystals lo- HNO3 acid mixtures on a hotplate at 130 °C for 48 h. After complete dissolution, a 5% aliquot of the sample was taken for cated at the boundary between melilite and anorthite (dmis- Al/Mg ratio determination to 5% accuracy using the Thermo- teinbergite) and appears to have crystallized at the eutectic point Fisher X-Series II inductively coupled plasma source mass spec- between these minerals from the last portion of melt. This prob- trometer (ICPMS) at the Centre for Star and Planet Formation in ably explains the low Ti abundances in these pyroxenes. No mul- Copenhagen, to discard inclusions with low Al/Mg ratios such as tilayered Wark–Lovering rim sequence is observed around STP-1 chondrules and amoeboid olivine aggregates. All samples with Al/ (Figs. S2 and S5). The inclusion experienced only a small degree of Mg ratio higher than 1.5 were classified as potential CAIs, which secondary alteration resulting in formation of nepheline, sodalite, constitute about 50% of the sampled inclusions. For these sam- and Fe-bearing Al-rich, Ti-poor pyroxene (FeO, 2.5−6.3 wt %, − − ples, we purified the magnesium by ion-exchange chromatogra- Al2O3,5.1 16.2 wt %, TiO2,0.10 0.27 wt %), and enrichment of phy and analyzed its isotopic composition using a ThermoFisher spinel in FeO (up to 19.5 wt %) in its peripheral portion (Table S1, Neptune multiple collector inductively coupled plasma source Figs. S1–S5). In addition, melilite crystals are cross-cut by thin mass spectrometer following protocols outlined in Bizzarro et al. veins of grossular, Al-rich, Ti-poor diopside, and Na-bearing pla- − (1). Out of ∼220 bona fide CAIs analyzed, only one inclusion was gioclase (0.35 0.89 wt % Na2O). Primary coarse anorthite crystals typified by a resolvable deficit in 26Mg* of ∼300 ppm as well as show no evidence for replacement by secondary minerals, but astableMg–isotope composition enriched in the heavy isotopes by display cleavage planes, occasionally filled by grossular (Fig. S5D). ∼1%/amu, which is characteristic of many known fractionation and unidentified nuclear effects (FUN) inclusions. Based on this Bulk Trace Elements Determination (Rare-Earth Element and Uranium). observation, this inclusion, named STP-1, was classified as a FUN Rare-earth element (REE) abundances were determined on the ∼ CAI and selected for further analysis. Present on the surfaces of Thermo X-Series II ICPMS from a separate 5.5-mg bulk aliquot μ two 3-mm–thick sections, the STP-1 FUN CAI is a spherical in- of STP-1, of which 0.5% of the total solution, dissolved in 400 L clusion of ∼10 mm diameter. It was liberated from the Allende 2% HNO3, was used for the analysis. The sample was bracketed matrix using a variable-speed Dremel fitted with either cone-shaped by analyses of a synthetic REE standard solution with a concen- diamond-coated cutting tools or dental drill bits. Once the in- tration of 1 ppb, and the data were reduced in Iolite (3) using the “ clusion was liberated, the easily identified dark matrix was carefully TraceElements data reduction scheme with the semi-quantita- ” removed from all surfaces using the Dremel. A ∼200-μm–thick tive setting. Based on measurements under similar conditions of section was made from the extracted material for petrographic the BCR-2 (Basalt, Columbia River) and BHVO-2 (Basalt, Ha- characterization and in situ 26Al–26Mg and O–isotope work. waiian Volcanic Observatory) rock standards, we estimate the accuracy of our REE results to be 23% (2 SD), apart for Eu, Gd, X-Ray Elemental Mapping and Electron Probe Microanalysis. STP-1 Tb, Dy, and Ho for which we estimate the relative accuracy to be was exposed in three sequential polished sections (1–3), which 45% (2 SD) because of the low count rates obtained for these were studied in reflected light using optical microscopy. Part of elements. The REE data of a bulk rock aliquot of STP-1, reported the central portion of the CAI was possibly lost during cutting. in absolute concentration as well as normalized to the CI chon- Each section was mapped in Mg, Ca, Al, Si, Ti, Na, K, Cl, and Fe drite data of Palme and Jones (4), are presented in Table S2. Kα X-rays with a resolution of 5 μm/pixel using the University of The uranium content of an object of known age can be cal- Hawaii (UH) field-emission electron microprobe JEOL JXA- culated from the amount of radiogenic 206Pb present today, 8500F operating at 15-kV accelerating voltage, 100-nA beam which, in turn, is determined from the total amount of Pb, its Pb current and 3-μm beam size, and studied in backscattered elec- isotopic composition, and the initial Pb isotopic composition at trons with 25-nA beam current and fully focused beam. To in- the time of formation. In a companion study, we analyzed the Pb vestigate the distribution of primary and secondary minerals in isotopic compositions of a number of fractions of the STP-1 STP-1, (i) Mg, Ca, and Al, (ii) Cl, Na, and Mg, and (iii) Ti, Ca, FUN CAI spiked with an equal atom 202Pb–205Pb tracer of and Al X-ray maps were combined using a red-green-blue color known concentration following a stepwise cleaning and dissolu- scheme. These elements and color scheme allow one to distin- tion procedure of a 23.0-mg fragment of this object. Eight of the guish spinel, hibonite, melilite, Al,Ti-diopside, anorthite, neph- 14 fractions analyzed defined a linear array in 204Pb/206Pb vs. eline, and sodalite (Figs. S1, S3, and S4). Electron microprobe 207Pb/206Pb space, with the remaining 6 fractions plotting slightly analyses of individual minerals were performed with the JEOL below the line. The line regresses through the isotopic compo- JXA-8500F operated at 15-kV accelerating voltage, 15-nA beam sition of the Solar System as estimated by Tatsumoto et al. (5). current, and fully focused beam using five wavelength spec- Points falling below the line are attributed to a small amount trometers. For each element, counting times on both peak and of terrestrial Pb contamination in these fractions that was not Holst et al. www.pnas.org/cgi/content/short/1300383110 1of12 removed during the precleaning steps. Subtracting sufficient standards including Burma spinel, Madagascar hibonite, Miya- terrestrial Pb from these 6 fractions to transpose them onto the kejima anorthite, synthetic melilite glass, and synthetic Al,Ti- linear array in 204Pb/206Pb vs. 207Pb/206Pb space defined by the 8 diopside glass. Excess or deficit of radiogenic 26Mg (δ26Mg*) was fractions results in Pb isotopic compositions for all 14 fractions calculated using an exponential law with a mass fractionation that represent binary mixtures of initial Pb and radiogenic Pb. exponent of 0.511. The reported uncertainties include both the An estimate of 5.36 pg of radiogenic 206Pb in the fragment an- internal precision of an individual analysis and the external re- alyzed is calculated by arithmetically combining the Pb in all 14 producibility for standard measurements during a given analytical fractions and subtracting the initial Pb component (based on the session. The relative sensitivity factors for aluminum and mag- + + 204Pb/206Pb ratio of the Solar System initial). This corresponds to nesium were determined from the 27Al /24Mg ratios measured an average concentration of 0.38 ppb of U in STP-1. This con- by SIMS and the Al/Mg ratios measured previously by electron centration is 91–140 times lower than the U contents of three microprobe for each standard mineral. The 27Al/24Mg and Mg recently analyzed canonical CAIs from the chondrite Efremovka isotope data are reported in Table S4 in the δ-notation, which (6). Given the limited amount of material available for STP-1, reflect permil deviations from the terrestrial composition. this concentration is well below the minimum required for a sufficiently precise U isotopic measurement to calculate Analytical Protocols for Tungsten Isotope Measurements. Following a meaningful absolute Pb–Pb age. removal from the Allende slab and cleaning, the bulk STP-1 inclusion was gently crushed in an agate mortar under distilled Analytical Protocols for in Situ Oxygen Isotope Measurements.
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