Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ...                                         http://w...
Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ...                       http://www.sciencemag.org....
Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ...                        http://www.sciencemag.org...
Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ...                       http://www.sciencemag.org....
Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ...   http://www.sciencemag.org.ez1.periodicos.capes...
www.sciencemag.org/cgi/content/full/science.1224514/DC1                          Supplementary Materials for  Tissint Mart...
1. Materials and Methods        Oxygen isotope analysis was carried out at the Open University using an infrared laser-ass...
- The natural radioactivity of the rock in the laboratory; the germanium detector isshielded with 30 cm of ultralow radioa...
The system was efficiency calibrated using a variety of certified naturally occurring radioactivestandards, corrected for ...
SEM: images on several polished sections were made at the NHM in London using aZeiss EVO 15LS SEM and in Paris using Zeiss...
temperature steps (~800°C and fusion). The evolved gas was split into two fractions, one fornitrogen isotope analysis and ...
2- Supplementary textField evidence       At about 2 am local time on July 18, 2011, a bright fireball was observed in the...
ferroan zones also occur within the interior of some olivine along fractures. Olivine macrocrysts(FeO/MnO=42-44) are zoned...
Geochemistry       The composition of the black glass was estimated using two approaches: wet chemicalanalysis of the aliq...
its strong variability suggests that it was contributed by a sulphide which volatilised during shockmelting and which is n...
mixed with release of adsorbed terrestrial atmosphere. Although the carbon isotopic compositionof the components is compat...
of Tissint, sulphur is found to be in excess in the black glass relative to the groundmass. Thesame is true for fluorine. ...
3. Supplementary Figures
Fig. S4: BSE image. Notice the fractured olivine macrocryst invaded by the groundmass and its zoning.Maskelynite is dark g...
Wo                              0.5                        0.4                  0.3            0.2      0.10.0En     0    ...
 Fig. S7: BSE image of a black glass pocket, fractured and containing bubbles. The glassshows significant compositional he...
 	  Fig. S8: Tissint Data: Magnetic susceptibility is 1.27±0.2 10-6m3/kg and saturation remanence62±8 mAm2/kg. logMrs in m...
 	  Fig. S9. Oxygen isotope analyses for Tissint and shock glass in Tissint shown in relation toother published laser fluo...
10                                                 EETA                                                79001Asample / chon...
                                                                            	                                             ...
4. Supplementary TablesTable S1: Representative analyses of pyroxene. Structural formula based on 4 cations and 6oxygens.	...
Table S2: Representative analyses of olivine. Structural formula based on 3 cations.	                rim	           rim	  ...
Table S3: Representative compositions of maskelynite               Maskelynite               60 / 1    84 / 3SiO2         ...
Table S5: Representative analyses of sulphides                 8 =7       19 / 1    13 / 1     23 / 1Weight %S            ...
Table S6: Representative analyses of oxides. Structural formula based on 3 cations and 4oxygens.          70 / 1 78 / 1 76...
Table S7: Major element composition              Bulk    Rock       Groundmass           Black Glass           Alberta    ...
Table S8: Chemical analyses, trace elements. All in ppm.           Bulk        Rock       Groundmass          Black Glass ...
Table S9: Oxygen isotope results                       17                       18                  17SAMPLE              ...
Table S11: Nitrogen abundance and isotopic composition in groundmass and black glass.Cosmogenic ages in Ma according to (2...
Table S12. Approximate compositions of carbon- and nitrogen-bearing components inTissint identified by stepped combustion ...
References and Notes1. D. D. Bogard, P. Johnson, Martian gases in an antarctic meteorite? Science 221, 651 (1983).       d...
16. V. Sautter et al., A new Martian meteorite from Morocco: The nakhlite North West Africa        817. Earth Planet. Sci....
31. J. Carignan, P. Hild, G. Mevelle, J. Morel, D. Yeghicheyan, Routine analyses of trace        elements in geological sa...
Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and Atmosphere of Mars
Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and Atmosphere of Mars
Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and Atmosphere of Mars
Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and Atmosphere of Mars
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Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and Atmosphere of Mars

  1. 1. Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ... http://www.sciencemag.org.ez1.periodicos.capes.gov.br/content/early/... ADVANCED AAAS.ORG FEEDBACK HELP LIBRARIANS Science Home Current Issue Previous Issues Science Express Science Products My Science About the Journal Home > Science Magazine > Science Express > Aoudjehane et al. Science www.sciencemag.org.ez1.periodicos.capes.gov.br Published Online October 11 2012 < Science Express Index Science DOI: 10.1126/science.1224514 Leave a comment (0) REPORT Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and Atmosphere of Mars 1,2,* 3 4 2 5 6 7 H. Chennaoui Aoudjehane , G. Avice , J.-A. Barrat , O. Boudouma , G. Chen , M. J .M. Duke , I. A. Franchi , 8 7,9 7 5 10 2 4 J. Gattacecca , M. M. Grady , R. C. Greenwood , C. D. K. Herd , R. Hewins , A. Jambon , B. Marty , 8 9,11,12 10 7 13 10 P. Rochette , C. L Smith , V. Sautter , A. Verchovsky , P. Weber , B. Zanda + Author Affiliations * To whom correspondence should be addressed. E-mail: chennaoui_h@yahoo.fr, h.chennaoui@fsac.ac.ma AB S T R ACT Tissint (Morocco) is the fifth Martian meteorite collected after it was witnessed falling to Earth. Our integrated mineralogical, petrological, and geochemical study shows that it is a depleted picritic shergottite similar to EETA79001A. Highly magnesian olivine and abundant glass containing Martian atmosphere are present in Tissint. Refractory trace element, S and F data for the matrix and glass veins in the meteorite indicate the presence of a Martian surface component. Thus, the influence of in situ Martian weathering can be unambiguously distinguished from terrestrial contamination in this meteorite. Martian weathering features in Tissint are compatible with the results of spacecraft observations of Mars. Tissint has a cosmic ray exposure age of 0.7 ± 0.3 Ma, consistent with those of many other shergottites, notably EETA79001, suggesting that they were ejected from Mars during the same event. Demonstration in the early 1980s that an important group of meteorites was of Martian origin represented a breakthrough in attempts to understand the geological evolution of Mars (1–3). Unfortunately, most of the samples were collected long after their arrival on Earth and thus have experienced variable degrees of terrestrial weathering (4). Even the few Martian meteorites that were collected shortly after their observed fall to Earth have been exposed to organic and other potential contaminants during storage. Here we report on the Tissint Martian meteorite, which fell on 18th July 2011 in Morocco (figs. S1 and S2). This is only the fifth witnessed fall of a meteorite from Mars and therefore provides an opportunity to improve our understanding of processes that operated on that planet at the time the meteorite was ejected from its surface. The largest recovered stones from the Tissint fall are almost fully covered with a shiny black fusion crust (Fig. 1). Internally the meteorite consists of olivine macrocrysts set in a fine-grained matrix of pyroxene and feldspathic glass (maskelynite) (5) (figs. S3 to S6, tables S1 to S6). The matrix is highly fractured and penetrated by numerous dark shock veins and patches filled with black glassy material enclosing bubbles (fig. S7). The petrology of Tissint shows similarities to other picritic shergottites (an important group of olivine-rich Martian basaltic rocks), in particular, lithologies A and C of EETA79001 (2). The grain density and magnetic properties of Tissint (fig. S8) also match previous results from basaltic and picritic shergottites (6). Fig. 1 The Natural History Museum (London) stone. This 1.1 kg stone (BM.2012,M1) exhibits a black fusion crust with glossy olivines. The olivine macrocrysts (pale green) and the numerous black glass pockets and veins, are characteristics of this shergottite. The scale is in cm.1 de 5 11/10/2012 19:11
  2. 2. Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ... http://www.sciencemag.org.ez1.periodicos.capes.gov.br/content/early/... Tissint is an Al-poor ferroan basaltic rock, rich in MgO and other compatible elements (Ni, Cr, Co). Its major element abundances are similar to those of the other picritic shergottites, especially EETA79001. Furthermore, key −3 element ratios (wt%/wt%) such as FeO/MnO (39.7), Al/Ti (7.2), Na/Ti (1.41), Ga/Al (3.9 10 ), Na/Al (0.20) (3, 4, 17 14) and Δ O (+0.301‰) (fig. S9) (7) are also typical of Martian meteorites. The average composition of the black glass (tables S7 and S8) is identical to a mixture of the major phases of the rock (augite, maskelynite and olivine: 50:20:30) with compositional variations reflecting incomplete dissolution of one phase or another (fig. S7). Among minor elements in the black glass, chlorine is always below the detection level of EMPA (100 ppm), whereas fluorine and sulfur exhibit variations in the range 0-4000 ppm and 0-6000 ppm respectively (5). Like most other pictritic shergottites, bulk Tissint displays a marked depletion in light rare earth elements (LREE) and other highly incompatible elements, such as Rb, Li, Be, Nb, Ta, Th and U (Fig. 2). Its Lu/Hf ratio (0.2) is in the range of values measured for EETA79001 and other basaltic shergottites (0.1 to 0.2, e.g., (8)), and lower than those of the picritic shergottites DaG 476/489, SaU 005 and Dhofar 019 (about 0.3, (9-11)). Although the sizes of the two samples analyzed here are somewhat limited (0.49 g and 1.25 g), their trace element abundances are very similar and so are likely to be representative of the whole rock composition, despite the irregular distribution of olivine megacrysts. Fig. 2 REE patterns: Top: Tissint in comparison with other depleted picritic shergottites. Bottom: Black glass and groundmass-rich fraction in comparison with enriched shergottite Zagami. Data from (9-11). CI chondrite normalization values are from (24). In order to evaluate the possible heterogeneity of this stone, we analyzed two additional samples: a groundmass-rich sample (devoid of large olivine crystals, and weighing 181 mg) and a fragment of the same glassy pocket selected for volatile analysis (40 mg). Both samples display markedly higher LREE abundances, with REE patterns generally similar to those of the enriched shergottites, as exemplified by Zagami. However, there is a minor, but analytically valid, positive Ce anomaly (Ce/Ce*=1.1) (Fig. 2) and the La/Nd, La/Nb and Th/La ratios are higher than those of other enriched shergottites (fig. S10). These two samples indicate that a LREE-enriched component, different from those previously recorded in other shergottites, is heterogeneously dispersed throughout the matrix of Tissint. 48 The presence of short-lived V (T½=16 days), among other cosmogenic isotopes, demonstrates that the stones th we analyzed are from the fall of July 18 (table S10). We measured stable cosmogenic isotopes of He, Ne and Ar in three aliquots, consisting of matrix-rich, glass-matrix mixed, and glass-rich separates (table S11). The Cosmic 3 21 38 Ray Exposure ages (CRE ages) computed for He , Ne , and Ar are 1.2 ± 0.4, 0.6 ± 0.2 and 0.9 ± 0.4 Ma c c c respectively, resulting in an average CRE age of 0.7 ± 0.3 Ma for Tissint. This age is in the range of CRE ages of other shergottites, notably that of EETA79001 (0.73 ± 0.15 Ma (2)), suggesting that Tissint and other shergottites were ejected during a single event. Nitrogen isotopes were analyzed together with the noble gases. The glass 15 15 aliquot displayed a well-defined excess of N, which persisted after correction for contribution of cosmogenic N c −13 15 15 (assuming a production rate of 6.7 ± 2.6 × 10 mol N/gMa) (12). This excess N is best explained by trapping 15 40 of a Martian atmospheric component (2). Using a δ N versus Ar/N correlation and taking a Martian atmospheric 15 value from the Viking measurements, of 0.33 ± 0.03 (13), we obtain a δ N value of 634 ± 60 ‰ (1σ), which agrees well with the Viking measurement of 620 ± 160 ‰ (14) (Fig. 3). Fig. 3 Gas analyses of the black glass. Both bulk analyses and step heating analyses plot on a single mixing line between terrestrial atmospheric gas (at left) and Mars atmospheric gas (13), Zagami data from (25). Simultaneous measurement of carbon and nitrogen was carried out by stepped combustion-mass spectrometry on a small chip (21 mg) from the same sample we used for oxygen isotopic analysis (5). The sample had a total 13 15 carbon abundance of 173 ppm and δ C of -26.6 ‰, and contained 12.7 ppm nitrogen with total δ N of -4.5 ‰. At temperatures above 600°C, both carbon and nitrogen were distributed between 3 discrete Martian components (fig. S11, table S12). Below 600°C, readily-resolvable components of organic material combusted; while these may have been introduced during post-fall collection and sample storage, and are an unavoidable consequence of2 de 5 11/10/2012 19:11
  3. 3. Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ... http://www.sciencemag.org.ez1.periodicos.capes.gov.br/content/early/... sample handling procedures, we cannot yet rule out the presence of small quantities of indigenous Martian organic matter (5). At the highest temperatures of the extraction, there was a clear indication of the presence of trapped 13 15 Martian atmosphere, with elevated δ C and δ N (even allowing for a cosmogenic component, blank-corrected 13 15 δ C reaches +16 ‰ and δ N reaches +298 ± 25 ‰). At intermediate temperatures (600 – 800°C), there were 13 15 maxima in both δ C (-14 ‰) and δ N (+110 ‰), suggesting that the component bears some relationship to the Martian atmosphere. In addition, there was clear analytical evidence for a simultaneous release of sulfur (~19 ppm), presumably from either sulphide or sulfate decomposition. This intermediate component probably corresponds to a surface-derived weathering component, as identified in Tissint glass on the basis of REE, S and F data (see below). The third Martian component represents magmatic carbon, which is present in low abundance 13 15 (1.4 ppm with δ C of -26.3 ‰) and is associated with isotopically-light nitrogen (δ N < +10 ‰). Our study demonstrates that Tissint is a picritic shergottite comparable in many respects to EETA79001. The black shock glass resembles lithology C of EETA79001, as well as shock melt pockets commonly found in other shergottites (15). Major elements and oxygen isotope data indicate that this glass represents a melted mixture of the surrounding bulk rock, composed of olivine, maskelynite and clinopyroxene (5). However, this glass is substantially different from the bulk meteorite and igneous groundmass in that it has a variable, but generally high 15 S and F content; a distinct LREE-enriched composition; and a high δ N value indicative of trapped Martian atmosphere. The LREE-enriched composition of the glass is somewhat enigmatic. Phosphates are often invoked as a carrier of REE. However, the P content of the black glass relative to bulk rock is not consistent with enrichment in phosphates. One possibility to explain the LREE composition of the glass might be selective crustal contamination prior to final emplacement of the Tissint magma. Although LREE-enriched magmatic rocks have been generated on Mars, as exemplified by the Nakhlites and Chassignites, these do not exhibit anomalous Ce abundances (16, 17). In addition, crustal contamination of magma is unlikely to result in REE ratio variations at the sub-centimeter 4+ scale, as observed here. Decoupling of Ce from the other REE, indicates partial oxidation to Ce , a process that requires oxidising conditions, such as those that prevail in the near-surface environment of Mars. Surface weathering caused by leaching of phosphates by acid aqueous fluids, the process that is responsible for terrestrial alteration of eucritic meteorites in Antarctica (18), would also explain the LREE-enriched composition of the Tissint 15 glass The high δ N value of the Tissint glass, as well as its enrichment in S and F, demonstrates that it has been contaminated by Martian surface components. In view of this evidence, the most likely explanation for the relatively LREE-enriched composition of the glass, and the origin of the Ce anomaly, is that these features also reflect the presence of a near-surface Martian component in Tissint. A Martian soil component was previously suggested for EETA79001 lithology C, which also contains Martian atmospheric gases (19). However, because this meteorite is a find, rather than a fresh fall like Tissint, there’s the possibility of terrestrial contamination, which complicates the interpretation (20). We propose the following scenario in order to explain the composite nature of Tissint. A picritic basalt was emplaced at or near the surface of Mars. After some period, the rock was weathered by fluids, which had leached elements from the Martian regolith. Subsequently, these fluids deposited mineral phases within fissures and cracks. The Martian weathering products are the most likely source of the required LREE, incompatible and volatile elements. Upon impact, preferential, shock-induced melting occurred in the target rock along fractures where weathering products were concentrated. This melting produced the black glass and retained in it chemical signatures characteristic of the Martian surface. Shock melting also trapped a component derived from the Martian atmosphere, as revealed by stepped combustion-mass spectrometry. About 0.7 Ma ago, the sample was ejected from Mars and eventually landed on Earth in July 2011. The Martian weathering features in Tissint described here are compatible with spacecraft observations on Mars, including those made by the NASA Viking landers, MER Spirit rover and ESA’s Mars Express orbiter (5, 21–23). Supplementary Materials www.sciencemag.org/cgi/content/full/science.1224514/DC1 Materials and Methods Supplementary Text Figs. S1 to S11 Tables S1 to S13 References (26–35) Received for publication 9 May 2012. Accepted for publication 25 September 2012. References and Notes 1. D. D. Bogard, P. Johnson, Martian gases in an antarctic meteorite? Science 221, 651 (1983). Abstract/FREE Full Text 2. R. H. Becker, R. O. Pepin, The case for a Martian origin of the shergottites: Nitrogen and noble gases in EETA 79001. Earth Planet. Sci. Lett. 69, 225 (1984). CrossRef Web of Science 3. A. H. Treiman, J. D. Gleason, D. D. Bogard, The SNC meteorites are from Mars. Planet. Space Sci. 48, 1213 (2000). CrossRef Web of Science 4. G. Crozaz, M. Wadhwa, The terrestrial alteration of Saharan shergottites Dar al Gani 476 and 489: A case study of weathering in a hot desert environment. Geochim. Cosmochim. Acta 65, 971 (2001). CrossRef Web of Science 5. Supplementary materials are available on Science Online 6. P. Rochette et al., Matching Martian crustal magnetization and magnetic properties of Martian meteorites. Meteorit. Planet. Sci. 40, 529 (2005). CrossRef Web of Science 7. I. A. Franchi, I. P. Wright, A. S. Sexton, C. T. Pillinger, The oxygen-isotopic composition of Earth and Mars. Meteorit. Planet. Sci. 34, 657 (1999). Search Google Scholar3 de 5 11/10/2012 19:11
  4. 4. Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ... http://www.sciencemag.org.ez1.periodicos.capes.gov.br/content/early/... 8. J. Blichert-Toft, J. D. Gleason, P. Télouk, F. Albarède, The Lu-Hf isotope geochemistry of shergottites and the evolution of the Martian mantle-crust system. Earth Planet. Sci. Lett. 173, 25 (1999). CrossRef Web of Science 9. G. Dreibus et al., Chemistry of a new shergottite: Sayh Al Uhaymir 005. Meteorit. Planet. Sci. 35, A49 (2000). Search Google Scholar 10. J. A. Barrat, J. Blichert-Toft, R. W. Nesbitt, F. Keller, Bulk chemistry of Saharan shergottite Dar al Gani 476. Meteorit. Planet. Sci. 36, 23 (2001). CrossRef Web of Science 11. C. R. Neal, L. A. Taylor, J. C. Ely, J. C. Jain, M. A. Nazarov, Detailed geochemistry of new shergottite, Dhofar 019. Lunar Planet. Sci. 32, 1671 (2001). Search Google Scholar 12. B. Marty, K. Hashizume, M. Chaussidon, R. Wieler, Nitrogen isotopes on the moon: Archives of the solar and planetary contributions to the inner solar system. Space Sci. Rev. 106, 175 (2003). CrossRef Web of Science 13. T. Owen et al., The composition of the atmosphere at the surface of Mars. J. Geophys. Res. 82, 4635 (1977). CrossRef 14. A. O. Nier, M. B. McElroy, Composition and structure of Mars upper atmosphere: Results from the Neutral Mass Spectrometers of Viking 1 and 2. J. Geophys. Res. 82, 4341 (1977). CrossRef 15. J.-A. Barrat et al., Petrology and chemistry of the Picritic Shergottite North West Africa 1068. Geochim. Cosmochim. Acta 66, 3505 (2002). CrossRef Web of Science 16. V. Sautter et al., A new Martian meteorite from Morocco: The nakhlite North West Africa 817. Earth Planet. Sci. Lett. 195, 223 (2002). CrossRef Web of Science 17. P. Beck et al., Petrography and geochemistry of the chassignite Northwest Africa 2737 (NWA 2737). Geochim. Cosmochim. Acta 70, 2127 (2006). CrossRef Web of Science 18. D. W. Mittlefehldt, M. M. Lindstrom, Geochemistry of eucrites: Genesis of basaltic eucrites, and Hf and Ta as petrogenetic indicators for altered Antarctic eucrites. Geochim. Cosmochim. Acta 67, 1911 (2003). CrossRef Web of Science 19. M. N. Rao, L. E. Borg, D. S. McKay, S. J. Wentworth, Martian soil component in impact glasses in a Martian meteorite. Geophys. Res. Lett. 26, 3265 (1999). CrossRef Medline Web of Science 20. E. L. Walton, P. J. Jugo, C. D. K. Herd, M. Wilke, Martian regolith in Elephant Moraine 79001 shock melts? Evidence from major element composition and sulfur speciation. Geochim. Cosmochim. Acta 74, 4829 (2010). CrossRef Web of Science 21. R. E. Arvidson, J. L. Gooding, H. J. Moore, The Martian surface as imaged, sampled, and analyzed by the Viking landers. Rev. Geophys. 27, 39 (1989). Search Google Scholar 22. L. A. Haskin et al., Water alteration of rocks and soils on Mars at the Spirit rover site in Gusev crater. Nature 436, 66 (2005). CrossRef Medline 23. A. Gendrin et al., Sulfates in Martian layered terrains: The OMEGA/Mars Express view. Science 307, 1587 (2005). Abstract/FREE Full Text 24. J. A. Barrat et al., Geochemistry of CI chondrites: Major and trace elements, and Cu and Zn isotopes. Geochim. Cosmochim. Acta 83, 79 (2012). CrossRef Web of Science 25. K. Marti, J. S. Kim, A. N. Thakur, T. J. McCoy, K. Keil, Signatures of the martian atmosphere in glass of the Zagami meteorite. Science 267, 1981 (1995). Abstract/FREE Full Text 26. Y. Gonin, J. Busto, J.-L. Vuilleumier, The “La Vue-des-Alpes” Underground Laboratory. Rev. Sci. Instrum. 74, 4663 (2003). CrossRef Web of Science 27. G. Bonino, G. Cini Castagnoli, N. Bhandari, Measurement of cosmogenic radionuclides in meteorites with a sensitive gamma-ray spectrometer. Nuovo Cim. 15, 99 (1992). CrossRef 28. C. Arpesella, A low background counting facility at Laboratori Nazionali del Gran Sasso. Appl. Radiat. Isot. 47, 991 (1996). CrossRef Web of Science 29. A. Jambon et al., Petrology and mineralogy of the Angrite Northwest Africa 1670. Meteorit. Planet. Sci. 43, 1783 (2008). CrossRef Web of Science 30. H. K. Cooper, M. J. M. Duke, A. Simonetti, G. Chen, Trace element and Pb isotope provenance analyses of native copper in northwestern North America: Results of a recent pilot study using INAA, ICP-MS, and LA-MC-ICP-MS. J. Archaeol. Sci. 35, 1732 (2008). CrossRef Web of Science 31. J. Carignan, P. Hild, G. Mevelle, J. Morel, D. Yeghicheyan, Routine analyses of trace elements in geological samples using flow injection and low pressure on-line liquid chromatography coupled to ICP-MS: A study of geochemical reference materials BR, DR-N, UB-N, AN-G and GH. Geostand. Newsl. 25, 187 (2001). CrossRef 32. B. Marty, P. Robert, L. Zimmermann, Nitrogen and noble gases in micrometeorites. Meteorit. Planet. Sci. 40, 881 (2005). Search Google Scholar 33. A. B. Verchovsky et al., C, N and noble gas isotopes in grain size separates of presolar diamonds from Efremovka. Science 281, 1165 (1998). Abstract/FREE Full Text 34. H. Chennaoui Aoudjehane, A. Jambon, B. Reynard, P. Blanc, Silica as shock index in shergottites, a cathodoluminescence study. Meteorit. Planet. Sci. 40, 967 (2005). CrossRef Web of Science 35. R. J. Macke, D. T. Britt, G. J. Consolmagno, Density, porosity, and magnetic susceptibility of achondritic meteorites. Meteorit. Planet. Sci. 46, 311 (2011). CrossRef Web of Science 36. Acknowledgments: Authors acknowledge: Dean N. Menegas and family for their generous donation enabling the acquisition of Tissint (BM.2012,M1), Mohamed Aoudjehane for fieldwork, Adam Aaranson for field information, Jenny Gibson for her assistance with oxygen isotope analysis, Luc Labenne for providing and loan of a sample, and Tony Irving for 400 mg powdered sample. This study was funded at Hassan II University Casablanca, FSAC by CNRST, Morocco and CNRS France, PICS SDU 01/10, and CMIFMP Volubilis (MA/11/252); CRPG, Nancy, France by the CNES, the CNRS, and the ERC under the ECSFP (FP7/2007-2013 no. 267255); UBO-IUEM, Plouzané, France by the PNP, INSU; Open University, by STFC grant to the Planetary and Space Sciences Discipline; and University of Alberta, by NSERC grant 261740-03.4 de 5 11/10/2012 19:11
  5. 5. Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and ... http://www.sciencemag.org.ez1.periodicos.capes.gov.br/content/early/... Leave a comment (0)5 de 5 11/10/2012 19:11
  6. 6. www.sciencemag.org/cgi/content/full/science.1224514/DC1 Supplementary Materials for Tissint Martian Meteorite: A Fresh Look at the Interior, Surface, and Atmosphere of Mars H. Chennaoui Aoudjehane,* G. Avice, J.-A. Barrat, O. Boudouma, G. Chen, M. J. M. Duke, I. A. Franchi, J. Gattacecca, M. M Grady, R. C. Greenwood, C. D. K. Herd, R. Hewins, A. Jambon, B. Marty, P. Rochette, C. L Smith, V. Sautter, A. Verchovsky, P. Weber, B. Zanda*To whom correspondence should be addressed. E-mail: chennaoui_h@yahoo.fr, h.chennaoui@fsac.ac.ma Published 11 October 2012 on Science Express DOI: 10.1126/science.1224514This PDF file includes: Materials and Methods Supplementary Text Figs. S1 to S11 Tables S1 to S13 References (26–35)
  7. 7. 1. Materials and Methods Oxygen isotope analysis was carried out at the Open University using an infrared laser-assisted fluorination system (7). Whole-rock chips of Tissint, with a total mass of approximately100 mg, were powdered and homogenized and from this ~2 mg of powder was loaded for eachreplicate analysis. In addition, fragments of black shock glass were hand picked under abinocular microscope and then loaded without further treatment. Oxygen was liberated from thesample by laser-heating in the presence of BrF5. After fluorination the O2 released was purifiedby passing it through two cryogenic nitrogen traps and over a bed of heated KBr. O2 wasanalyzed using a MAT 253 dual-inlet mass spectrometer. Analytical precision (2σ), based onreplicate analysis of international (NBS-28 quartz, UWG-2 garnet) and internal standards, isapproximately ±0.08‰ for δ17O; ±0.16‰ for δ18O; ±0.05‰ for Δ17O (7). The quoted precision(2σ) for Tissint is based on the results obtained on replicate analyses. Results for the oxygen isotope analysis of Tissint are reported in standard δ notation,where δ18O has been calculated as: δ18O = [(18O /16Osample)/(18O /16Oref)-1] × 1000 (‰) andsimilarly for δ17O using the 17 O /16O ratio. Δ17O, which represents the deviation from theterrestrial fractionation line, has been calculated as: Δ17O = δ17O – 0.52 δ18O (Fig. S9). Measurements of short-lived cosmogenic nuclides by gamma-ray spectroscopy wereperformed in La Chaux de Fonds (La Vue-des-Alpes underground laboratory) (26) and theUniversity of Alberta on 29 g and 58 g specimens, respectively. The Germanium detector in the "la Vue-des-Alpes Underground Laboratory" is shieldedfrom: - The cosmic exposure, thank to the 600 meters water-equivalent above the detector; theneutron flux is thus reduced by a factor 10000.
  8. 8. - The natural radioactivity of the rock in the laboratory; the germanium detector isshielded with 30 cm of ultralow radioactivity Cu and 30 cm of ultraslow radioactivity Pb. - The radon contained in the air; nitrogen is flushed into the detection volume, in order toreplace the air and avoid a radon counting into the detector. The gamma analysis starts when nitrogen completely replaced the air. These shieldingmethods allow gamma counting of samples with a very low background: - The detector background at 320.1keV (51Cr peak) is 0.24+/-0.43 counts/day - The detector background at 983.5keV (48V peak) is 0.19+/-0.16 counts/day Moreover, in order to get quantitative activity values of the measured cosmogenicisotopes, a Monte-Carlo simulation, based on the GEANT3 code from CERN, is run.This simulation takes into account the samples chemical composition, density, and its geometry(self-absorption). The detector efficiency of measuring a gamma from the sample is thencalculated for each peak energies. Unlike gamma-ray spectrometer systems specifically designed to measure cosmogenicradionuclides in meteorites (27-28) the University of Alberta SLOWPOKE Reactor Facilitygamma-ray spectrometer utilized to measure the cosmogenic radionuclides of the Tissintmeteorite sample is typically used for measuring naturally occurring radionuclides in terrestrial 54 22 26samples. Consequently, determining the cosmogenic radionuclides Mn, Na, and Al in theTissint meteorite, with acceptable statistical uncertainties, required counting the sample for anextended period (1,250,000 s, i.e., 14.4676 d). The University of Alberta γ-ray spectroscopysystem utilized consists of a 41% efficient ORTEC FX Profile hyperpure Ge detector, with 210carbon end-window, housed in a 15 cm Pb cave (the inner 5 cm consisting of ‘old’, Pb-poor,lead) with a Cu lining. The detector is attached to an ORTEC DSPEC Pro digital spectrometer.
  9. 9. The system was efficiency calibrated using a variety of certified naturally occurring radioactivestandards, corrected for natural background. Fortuitously, the Tissint sample analyzed wassimilar in both shape and mass to the standards used for efficiency calibration. Consequently, nocorrections were applied for differing counting geometries, or possible gamma-ray self-attenuation effects. Natural long-lived radiogenic elements (238U, 232 Th and 40 K and their decay products)were observed in addition to 26Al and 22Na, and up to four other short-lived cosmogenic isotopes(Table S10). These data however cannot be directly compared to those from Martian meteoritesbecause there are no measurements of short-lived cosmogenic isotopes for other Martianmeteorites. The average 22Na/26Al ratio at the time of fall for the two determinations is 2.05 (±0.17). Differences in the specific activities of the cosmogenic radionuclides may be due to thepre-break-up size of the meteorite and location of the analyzed samples in the original meteorite.The consistency of the ratio of the University of Alberta/La Chaux de Fond 26Al, 22Na, and 54Mndeterminations (1.7 ± 0.1) supports this explanation. Electron Microprobe Analysis (EMPA): All major and minor mineral phases have beenanalyzed by EMPA with a Cameca SX100 electron microprobe in Paris according to theprocedures presented in (29) and are reported in Tables S1-6. In particular the FeO/MnO ofpyroxene (30±5) and olivine (50±12) despite significant variability correlate with their Mg# andare characteristic of a Martian composition. The detection limits for F and Cl are 200 and 100ppm respectively. Furthermore, P, F, Cl and S were analysed in the black glass. We report inTable S7 the average composition obtained for 150 data points and range. The detection limitsfor these elements are 100, 200, 100 and 100 ppm respectively. No correlation between F and Feis observed as would be the case if Fe-L line and F-K line were not properly resolved.
  10. 10. SEM: images on several polished sections were made at the NHM in London using aZeiss EVO 15LS SEM and in Paris using Zeiss ULTRA 55VP (Fig. S4-S5-S7). Chemicalmapping was performed in London using an EDX spectrometer (Oxford Instruments INCAsystem).Bulk Elemental Composition: Analyses were obtained by ICP-MS at University of Alberta on a 400 mg subsample of a1.25 g homogenized interior sample according to the procedure described in (30), by ICP-AESand ICP-SFMS at UBO in Brest following the procedure described in (24). Finally, a 5 mg ofblack glass was analyzed by ICP-AES and ICP-MS at CRPG in Nancy, following the proceduredescribed in (31). All these procedures are well established, and the same geostandards (e.g.,BIR-1 and BHVO-2) were used during the sessions in order to avoid any systematic biasbetween the three laboratories. Based on replicate standards, the 1-σ analytical uncertainties forabundances are better than 5 % for all the elements. Trace element ratios are often determinedwith a much better accuracy. In the case of the Ce/Ce* (where Ce* is the expected Ceconcentration for a smooth CI-normalized REE pattern, such that Ce*n=(Lan x Prn)1/2), the 1σanalytical uncertainties are about 1 % or better, even at low REE abundances, as exemplified bythe USNM3529 Allende standard (see Table 4 in ref. 24).For N-noble gas analysis, mg-sized aliquots were loaded in a laser chamber, outgassed undervacuum at 100 °C overnight, and then left under high vacuum for several days to decrease thebackground. Each sample was heated with a continuous mode infrared CO2 laser (10.6 nmwavelength) for 5 min in static vacuum. Modulating the power of the laser permitted to apply 2
  11. 11. temperature steps (~800°C and fusion). The evolved gas was split into two fractions, one fornitrogen isotope analysis and one for noble gas analysis, and sequentially analyzed with a staticmass spectrometer (see (32) for further details).Carbon and nitrogen analyses were carried out at the Open University. They were extracted byCO2 laser step-heating of mg sized samples, and analysed using the FINESSE isotope ratio massspectrometer (33). A small chip of 21 mg was wrapped in platinum foil, then heated under excessoxygen in increments from room temperature to 1400°C. System blanks were < 4 ng carbon and< 1 ng nitrogen per increment for temperatures below 600°C, and < 10 ng carbon and < 2 ngnitrogen per increment for temperatures above 600°C. Data are shown in Figure S11 andsummarized in Table S12.
  12. 12. 2- Supplementary textField evidence At about 2 am local time on July 18, 2011, a bright fireball was observed in the region ofthe Oued Drâa valley, SE of Tata, Morocco. One eyewitness reported that it illuminated the entire area, before splitting into two parts.Two sonic booms were also reported. In October 2011, after a thorough search, nomads began tofind fresh, fusion-crusted stones in a remote area, centred about 50 km ESE of Tata and 48 kmSSW of Tissint, both N and S of the Oued El Gsaïb valley and near El Ga’ïdat plateau. Theweather in this desert area is very dry, especially in summer, when rain is exceptionally rare. Itwasn’t until December 2011 that the Martian origin of the fall was realised. The first pieces werecollected at the end of October and sold in Erfoud. A few pieces weighing between 2 kg and 0.1kg have been recovered, but the largest number consists in thousands of smaller pieces, crustedor splintered from larger stones. The total meteorite mass recovered, as of the end of February2012, is estimated at about 17 kg (Fig. S1-S2). A number of large specimens are now preservedin national or public institutions (Table S13).Mineralogy and Petrography: When broken open, the crust reveals a pale grey interior, with pale yellow olivinemacrocrysts (up to 2 mm across) and microphenocrysts, which comprise up about 16 vol. % ofthe rock. The finer groundmass is composed of light grey pyroxene (about 50 vol%) and darker,mostly, but not totally amorphized plagioclase (maskelynite) 18±2 vol % (Fig. 1, Fig. S3-S5).All olivines are of the same composition with no difference between large and small crystals;they exhibit thin ferroan rims against groundmass and contain small chromite inclusions. Narrow
  13. 13. ferroan zones also occur within the interior of some olivine along fractures. Olivine macrocrysts(FeO/MnO=42-44) are zoned from the core (Fa16-20) to the rim (Fa43-60, FeO/MnO=50-55) whereit reaches a Fa value similar to olivine interstitial microcrysts, (cores Fa29-30, FeO/MnO=45-46;rims up to Fa53, FeO/MnO=53), (Fig. S3-S6). Augite/pigeonite exhibits patchy zoning as isobserved in e.g. QUE 94201 with orthopyroxene cores (Fs24-24Wo4-5, FeO/MnO=30-32),pigeonite (Fs26 -52Wo12-17, FeO/MnO=31-35) and sub-calcic augite (Fs22-23Wo25-24,FeO/MnO=26-28), rims (Fig. S4-S6). Plagioclase (maskelynite, An61-64Or0.5-0.4) is slightly zonedbut does not include silica or mixed silica rich glass, it shows a relict of twin lamella (Fig.S5)(34). Minor phases are Ti-poor chromite, ilmenite, titanomagnetite (modal abundance of oxidesis less than 1%), pyrrhotite, apatite and merrillite.Physical properties: Grain density of 3.41±0.03, measured on a 28 g sample, exceeds that measured in othershergottite falls (3.28; (35)) in agreement with a more mafic composition of Tissint comparedwith other shergottites. Magnetic properties, measured on 29 samples from different stones ofvarious origins, exhibit particularly low variability. They are in agreement with data obtained onother shergottites whose magnetization is carried by pyrrhotite (6), although it appears that asignificant fraction of magnetization is carried by Fe rich oxides (Fig. S8). Natural remanencemeasurement of a number of uncrusted fragments reveals that the majority have been tested witha magnet. Extra-terrestrial field estimate from remaining fragments is lower than previous datafrom shergottite falls.
  14. 14. Geochemistry The composition of the black glass was estimated using two approaches: wet chemicalanalysis of the aliquot of glass used for gas analysis and taking the average composition fromtwo sets of EMPA data from 150 and 127 individual spots. Data from the wet chemical analysisand from one of the EPMA data sets are reported in Table S7. An indication of sample variabilityis given by the range of composition in Table S7. Several points relevant to the origin of theTissint black glass merit further discussion here. The agreement between the two methods isfair, especially when the compositional variability is considered. The major element compositionis equivalent to a mixture of approximately 30% olivine, 50% pyroxene and 20% maskelyniteand the variability is explained by imperfect mixing/melting of the major phases (Fig. S7).Among the minor elements, F, P, S and Cl are of particular significance. Fluorine is estimatedfrom EMPA analyses as having an average value of 720 ppm, with 45% of the data below thedetection limit of EMPA (200 ppm). Modal mineralogy of the rock indicates 0.5 % merrillitecorresponding to about 0.25 % P2O5, which is in the same range as that measured in the blackglass (0.5-0.25 %) using both bulk chemical analysis and EMPA. Modal mineralogy alsosuggests the presence of <0.1% troilite, whereas the amount of S measured by EMPAcorresponds to an equivalent of 0.7 % FeS. A similar observation was made by Rao et al. (19) inEETA79001. Chlorine has a low abundance (<200 ppm), and 97% of the results are below theEPMA detection limit for Cl. Chlorine is essentially absent. Rao et al. (19) noticed a similarlylow level of Cl in EETA79001 lithology C, despite the presence of excess S. P is present atlevels expected from bulk rock melting. This point is important, as phosphate is a potentialcarrier phase of REE. The overabundance of S compared with that contained in the bulk rock and
  15. 15. its strong variability suggests that it was contributed by a sulphide which volatilised during shockmelting and which is now present in the shock-melted, glass veins and pockets. Fluorine is alsoclearly overabundant compared to the bulk rock value. The only common phase of thegroundmass, which could carry F, is merrillite. Its measured F abundance however is alwaysbelow the detection limit of EMPA (Table S4). We must, therefore, conclude that the black glassveins and pockets contain an S and F-rich component which is absent from the groundmass andwhich is irregularly distributed in the veins and pockets. Oxygen isotope analysis results for both bulk Tissint and black shock glass are given inTable S9 and plotted in Fig. S9. The results are shown in Fig. S9 in relation to the MarsFractionation Line (7) and other published Martian meteorite oxygen isotope analyses obtainedby laser fluorination. The analysis of bulk Tissint in Fig. S9 plots close to the Mars FractionationLine (MFL) and within the broad field occupied by other shergottitic meteorites, thus confirmingthat it is a member of the Martian meteorite group. Also shown in Fig. S9 is the mean analysis ofblack shock glass in Tissint. This has a similar δ18O value to the bulk meteorite, but displays asignificantly greater level of heterogeneity with respect to Δ17O, with a 2σ value of ± 0.090 ‰compared to ± 0.002 ‰ for the bulk meteorite. The stepped combustion profiles (Fig. S11) indicate that both carbon and nitrogen aredistributed between several discrete components (Table S12). The data are interpreted in thefollowing way: below 600°C, the abundance histograms clearly show that there are two separatecomponents, the first of which combusts between 200-400°C, with δ13C ~ -28‰, δ15N ~ -10‰and a variable C/N of between ~10-30. The second component has a slightly higher δ13C, at ~ -26‰, but similar δ15N ~ -10‰ and variable C/N of ~10-30. Almost all of the carbon andnitrogen released below 600 °C is believed to emanate from combustion of organic material
  16. 16. mixed with release of adsorbed terrestrial atmosphere. Although the carbon isotopic compositionof the components is compatible with interpretation of its having a terrestrial origin, this by itselfis insufficient to rule out the presence of small quantities of indigenous Martian organic matter.Three additional components of presumed Martian origin were identified as combusting (orbeing released) at temperatures above 600 °C; they are described in the main text. Based on the production rate of cosmogenic 15N (see “cosmogenic isotopes” section) thecontribution of the component, if it is all released at 1100oC, is about 60‰. The amount of sulphur released between 650 and 800oC is calculated based on the totalpressure of CO2+SO2 measured by baratron and the amount of CO2 measured as mass 44 peakintensity in the mass spectrometer.Tissint results compared to spacecraft remote-sensing dataEvidence described in this paper for a Martian weathering component in Tissint is consistentwith observations made by both orbital spacecraft and landers on Mars. The fact that S is a majorcomponent in the Martian soil was first demonstrated by the NASA Viking landers (21). TheNASA Spirit MER rover undertook a detailed compositional analysis of rocks and soils at Gusevcrater (22). These showed clear evidence for the interaction of water and volcanic rocks atGusev, with anomalously high concentrations of sulphur, chlorine and bromine. In addition,multilayer coatings on the surface of rocks at Gusev have high ferric (Fe3+) ion enrichmentsconsistent with a highly oxidizing environment. This latter feature is clearly relevant to theevidence presented in our paper for partial oxidation of Ce to Ce4+ under oxidising conditions,which prevail at the surface of Mars. A range of hydrated sulphate minerals have been detectedon Mars by the OMEGA hyperspectral imager on ESA’s Mars Express orbiter (23). In the case
  17. 17. of Tissint, sulphur is found to be in excess in the black glass relative to the groundmass. Thesame is true for fluorine. High levels of halogens have been detected in the Martian soil (bromineand chlorine), but as yet evidence for high levels of fluorine is not as strong. Chlorine, which ispresent in the soil is not found at a significant level in the black glass. Our conclusion istherefore that contamination is not from soil incorporation, which would concern all elements (Sand Cl) but rather contamination by infiltration. On this point it is interesting to note that theSpirit MER rover data indicates: “decoupling of sulphur, chlorine and bromine concentrations intrench soils compared to Gusev surface soils, indicating chemical mobility and separation.”(22).Discussion: Tissint is an olivine-phyric shergottite; the olivine macrocrysts are likely to havebeen accumulated into a more evolved liquid. Nevertheless, it seems clear that Tissint hasaffinities to the depleted mantle source on Mars, based on its REE composition. It is possiblyrelated (and possibly launched paired) with EETA79001, which displays the same Lu/Hf ratio.The numerous patches and veins of black glass are the result of shock melting.
  18. 18. 3. Supplementary Figures
  19. 19. Fig. S4: BSE image. Notice the fractured olivine macrocryst invaded by the groundmass and its zoning.Maskelynite is dark grey, oxides and sulfides apear white. The variable grey otherwise correspondsmostly to patchy zoning of pyroxene; small olivines are slightly normally zoned are light grey.
  20. 20. Wo 0.5 0.4 0.3 0.2 0.10.0En 0 0.2 0.4 0.6 0.8 1 Fs EETA79001Fo Fa 0 0.2 0.4 0.6 0.8 1 Fig. S6. Composition of pyroxene and olivine in Tissint compared to those in the shergottite EETA79001.
  21. 21.  Fig. S7: BSE image of a black glass pocket, fractured and containing bubbles. The glassshows significant compositional heterogeneity due to variable melting of olivine, pyroxeneand plagioclase.
  22. 22.    Fig. S8: Tissint Data: Magnetic susceptibility is 1.27±0.2 10-6m3/kg and saturation remanence62±8 mAm2/kg. logMrs in mAm2/kg versus logc in 10-9 m3/kg for pyrrhotite and magnetitedominant shergottites, circles and triangles, highlighting Tissint in red and falls in bold.
  23. 23.    Fig. S9. Oxygen isotope analyses for Tissint and shock glass in Tissint shown in relation toother published laser fluorination analyses of SNC meteorites. Error bars for bulk Tissint andTissint shock glass are 2σ. MFL: Mars Fractionation Line (5). TFL: Terrestrial FractionationLine.
  24. 24. 10 EETA 79001Asample / chondrite Tissint (W.R.) 1 1.25 g sample 0.492 g sample SaU 005 DaG 476 Zagami 10 Tissint W.R. 1 black glass "groundmass" Y Zr Ba U La Pr Eu Tb Ho Tm Lu Hf Nb Th Ce Nd Sm Gd Dy Er Yb Fig. S10. Trace element pattern: Top: Whole-rock trace element systematics of Tissint in comparison with other depleted picritic (olivine-bearing) shergottites. Bottom: Black glass and groundmass-rich fraction in comparison with Tissint whole rock and Zagami. Notice the Ce anomaly in the black glass and groundmass which is not observed in Zagami. Data from (7-9). CI chondrite normalization values are from (18).
  25. 25.        Fig. S 11: Stepped combustion data acquired from a 21 mg chip of Tissint (from the NaturalHistory Museum, London, specimen). (a) carbon; (b) nitrogen and (c) atomic C/N ratio. In (a)and (b), the histograms are the amount of material released, normalised to the width of thetemperature step, whilst the line profiles are isotopic composition. Errors in isotopic compositionare less than the size of the symbol unless shown otherwise.
  26. 26. 4. Supplementary TablesTable S1: Representative analyses of pyroxene. Structural formula based on 4 cations and 6oxygens.   Pigeonite       Augite       86/20   86/174   85/17   82/98   85/130  SiO2   54.04   48.60     52.67   49.89   52.02  Al2O3   0.56   0.69     0.82   0.90   1.98  MgO   24.41   12.51     18.26   9.94   14.59  FeO   16.27   29.15     15.64   21.36   11.93  MnO   0.56   0.85     0.48   0.60   0.42  CaO   2.89   5.71     9.77   14.13   16.75  Na2O   0.07   0.06     0.09   0.17   0.13  K2O   0.00   0.01     0.00   0.03   0.01  TiO2   0.07   0.70     0.16   1.18   0.35  Cr2O3   0.47   0.15     0.50   0.13   0.98  NiO   0.00   0.00     0.00   0.00   0.09  Total   99.35   98.43     98.38   98.34   99.24  Mg#   0.73   0.43     0.68   0.45   0.69  FeO/MnO   28.84   34.29     32.58   35.49   28.27                Si   1.99   1.94     2.00   1.98   1.97  Al   0.02   0.03     0.04   0.04   0.09  Mg   1.34   0.75     1.03   0.59   0.82  Fe   0.50   0.97     0.50   0.71   0.38  Mn   0.02   0.03     0.02   0.02   0.01  Ca   0.11   0.25     0.40   0.60   0.68  Ti   0.00   0.02     0.00   0.04   0.01  Cr   0.01   0.00     0.01   0.00   0.03                En   0.66   0.37     0.52   0.30   0.41  Fs   0.25   0.46     0.27   0.39   0.22  Wo   0.05   0.10     0.19   0.30   0.31  
  27. 27. Table S2: Representative analyses of olivine. Structural formula based on 3 cations.   rim   rim   core   core     85/351   89 / 93   89 / 41   37 / 1  SiO2   33.45   35.12   38.31   38.98  Al2O3   0.03   0.01   0.03   0.07  MgO   16.18   23.67   36.47   41.16  FeO   49.53   40.38   25.09   19.02  MnO   0.81   0.69   0.55   0.29  CaO   0.35   0.33   0.26   0.21  Na2O   0.05   0.02   0.01   0.01  K2O   0.00   0.00   0.00   0.00  TiO2   0.05   0.00   0.00   0.00  Cr2O3   0.03   0.05   0.25   0.21  NiO   0.00   0.01   0.19   0.14  Total   100.48   100.27   101.16   100.09            Mg#   0.37   0.51   0.72   0.79  FeO/MnO   61.1   58.5   45.9   65.4            Si 1.00   1.00   1.00   1.00  Mg 0.72   1.01   1.42   1.57  Fe 1.24   0.96   0.55   0.41  Mn 0.02   0.02   0.01   0.01  Ca 0.01   0.01   0.01   0.01  Cr 0.00   0.00   0.01   0.00  
  28. 28. Table S3: Representative compositions of maskelynite Maskelynite 60 / 1 84 / 3SiO2 51.83 56.78Al2O3 30.39 26.42MgO 0.13 0.05FeO 0.65 0.68MnO 0.04 0.02CaO 13.66 9.90Na2O 3.42 5.13K 2O 0.04 0.50TiO2 0.04 0.08Cr2O3 0.01 0.00NiO 0.00 0.00Total 100.21 99.55Si 2.36 2.58Al 1.63 1.42Ca 0.67 0.48Na 0.30 0.45K 0.00 0.03Table S4: Representative analyses of merrillite 18 / 1 14 / 1 6/1SiO2 0.21 0.17 0.39Al2O3 0.04 0.03 0.24MgO 1.94 2.69 3.07FeO 3.99 2.96 2.05MnO 0.20 0.14 0.08CaO 46.00 46.57 46.55Na2O 0.80 0.92 0.98TiO2 0.04 0.11 0.13Cr2O3 0.02 0.01 0.05P 2O 5 46.19 46.04 45.45SO2 0.01 0.54 0.01Cl 0.00 0.00 0.02F 0.00 0.00 0.00Total 99.43 100.19 99.02
  29. 29. Table S5: Representative analyses of sulphides 8 =7 19 / 1 13 / 1 23 / 1Weight %S 38.43 37.22 37.65 38.35Fe 58.00 55.54 54.80 52.55Co 0.04 0.08 0.10 0.12Ni 1.38 2.81 4.53 6.02Cu 0.06 0.15 0.03 0.00Zn 0.05 0.07 0.00 0.06Total 97.96 95.86 97.11 97.11mol%S 52.97 52.58 52.54 53.33Fe 45.89 45.04 43.91 41.96Co 0.03 0.06 0.08 0.09Ni 1.04 2.16 3.45 4.57Cu 0.04 0.11 0.02 0.00Zn 0.03 0.05 0.00 0.04 100.00 100.00 100.00 99.99
  30. 30. Table S6: Representative analyses of oxides. Structural formula based on 3 cations and 4oxygens. 70 / 1 78 / 1 76 / 1 41 / 1 74 / 1 51 / 1 49 / 1 54 / 1 43 / 1 83 / 1SiO2 0.17 0.22 0.15 0.29 0.04 0.02 0.03 0.05 0.06 0.08Al2O3 7.22 7.29 7.13 8.46 5.61 5.59 4.51 3.60 2.57 1.31MgO 3.59 5.11 4.72 3.43 1.48 2.14 2.19 1.78 1.17 0.37MnO 0.00 0.00 0.00 0.02 0.21 0.23 0.35 0.47 0.65 0.57FeO 29.04 27.06 27.46 29.37 43.02 45.34 46.71 51.89 54.03 63.04CaO 0.00 0.00 0.03 0.09 0.04 0.07 0.10 0.05 0.06 0.16TiO2 0.75 0.73 0.72 1.28 10.67 11.86 19.29 20.85 24.64 31.20Cr2O3 58.16 59.37 59.75 53.30 38.90 32.28 24.99 20.48 13.97 0.36Total 98.93 99.79 99.95 96.24 99.98 97.53 98.17 99.16 97.15 97.09Si 0.006 0.008 0.006 0.010 0.001 0.001 0.001 0.002 0.002 0.003Ti 0.020 0.019 0.019 0.035 0.287 0.325 0.528 0.569 0.693 0.888Al 0.301 0.298 0.291 0.360 0.237 0.240 0.194 0.154 0.113 0.058Cr 1.625 1.627 1.641 1.520 1.101 0.929 0.720 0.587 0.413 0.010Fe 0.858 0.784 0.797 0.886 1.288 1.380 1.423 1.575 1.690 1.995 3+Fe 0.022 0.022 0.019 0.029 0.085 0.180 0.027 0.117 0.083 0.149 2+Fe 0.836 0.762 0.778 0.857 1.202 1.200 1.396 1.458 1.607 1.846Mg 0.189 0.264 0.245 0.184 0.079 0.116 0.119 0.096 0.065 0.021Ca 0.000 0.000 0.001 0.003 0.001 0.003 0.004 0.002 0.003 0.006Mg# 18.46 25.74 23.91 17.71 6.14 8.82 7.84 6.21 3.91 1.11Spin 15.22 14.92 14.58 18.68 11.83 12.29 9.86 7.77 5.84 3.00Chrom 82.15 81.53 82.08 78.98 55.04 47.62 36.66 29.60 21.27 0.54Usp 1.98 1.89 1.89 3.63 28.74 33.30 53.82 57.39 71.33 91.48Mgt 1.09 1.10 0.94 1.52 4.27 9.25 1.39 5.88 4.28 7.70
  31. 31. Table S7: Major element composition Bulk Rock Groundmass Black Glass Alberta UBO UBO CRPG EMPA rangeMass 1250 mg 492 mg 181 mg 5 mg n=150 n=150SiO2 44.86 45.74 35-55TiO2 0.63 0.65 0.67 0.56 0.36 0-1.5Al2O3 4.86 5.50 6.37 4.09 3.58 0-18FeO 21.15 20.87 18.80 21.84 20.24 9-26MnO 0.52 0.53 0.49 0.51 0.53 0.3-0.7MgO 17.06 17.92 15.09 19.99 20.91 10-35CaO 6.53 7.31 7.16 6.03 5.68 0.3-14Na2O 0.72 0.77 1.13 0.63 0.46 0-2.2K 2O 0.02 0.02 0.09 0.04 0.02 0-0.2P 2O 5 0.48 0.56 0.44 0.46 0.24 0-5Cr2O3 0.41 0.78 0.70 0.81 0.71 0.2-1.5NiO 0.03 0.02 0.02 0.03 0.05 0-0.2S 0.27 0-1F 0.07 0-0.4Cl 0.00 0-0.03Total 99.85 98.80 98-101Mg# 0.59 0.60 0.59 0.62 0.65 0.56-0.71FeO/MnO 41 39 38 42 38 28-44
  32. 32. Table S8: Chemical analyses, trace elements. All in ppm. Bulk Rock Groundmass Black Glass Alberta UBO UBO CRPGMass 1.25 g 0.492 g 0.181 g 0.005 gppmLi 2.18 2.00 4.60Be 0.031 0.097P 2074 2285 1906K 200 235 771Sc 39.38 36.49 38.3Ti 3789 4044 3732V 194 219 205 200Cr 3042 5323 4756 5549Co 58.1 58.5 47.7 63.2Ni 269 262 199 268Cu 13.8 9.80 9.94 23Zn 63.0 63.2 55.0 87.3Ga 12.05 11.32 11.25 9.29Rb 0.376 0.305 2.52 1.36Sr 34.78 31.79 43.40 25.07Y 14.91 13.22 12.82 8.21Zr 23.14 19.69 24.73 20.1Nb 0.28 0.219 0.771 0.226Cs 0.0153 0.0710 0.184Ba 3.54 2.50 36.57 5.91La 0.315 0.283 2.62 1.20Ce 1.16 0.945 6.19 2.81Pr 0.237 0.192 0.745 0.324Nd 1.63 1.37 3.37 1.58Sm 1.07 0.877 1.13 0.673Eu 0.503 0.405 0.452 0.271Gd 1.85 1.70 1.79 1.05Tb 0.364 0.333 0.331 0.196Dy 2.38 2.22 2.17 1.24Ho 0.504 0.466 0.453 0.266Er 1.48 1.30 1.24 0.764Tm 0.204Yb 1.30 1.17 1.10 0.772Lu 0.190 0.160 0.15 0.11Hf 1.01 0.81 0.96 0.67Ta 0.0138 0.0533W 0.041 0.094Pb 0.25 0.15 0.74U 0.0070 0.100 0.123Th 0.0240 0.915 0.323
  33. 33. Table S9: Oxygen isotope results 17 18 17SAMPLE δ O‰ 1σ δ O‰ 1σ Δ O‰ 1σBulk BM 1 2.69 4.58 0.30Bulk BM 2 2.61 4.43 0.30Bulk BM 3 2.49 4.22 0.30Mean BM 2.60 0.10 4.41 0.18 0.30 0.00black glass 1 2.54 4.37 0.26black glass 2 2.52 4.21 0.33black glass 3 2.51 4.29 0.28black glass 4 2.62 4.45 0.30black glass 5 2.47 4.18 0.29black glass 6 2.51 4.28 0.29black glass 7 2.54 4.35 0.28Mean BlackGlass 2.53 0.05 4.31 0.10 0.29 0.02Table S10: Radiogenic isotopes at the time of fall. La Chaux de Fonds Univ. of Alberta Isotope T(1/2) dpm/kg ± 1σ dpm/kg ± 1σ 238U 2.24 0.80 232Th 2.10 0.45 40K 262 19 391 99 26Al 0.717 My 23.9 2.2 38.6 4.2 22Na 2.60 y 46.1 2.7 83.9 4.6 51Cr 27.7 d 161 62 7Be 53.3 d 192 60 54Mn 312.2 d 47.0 2.7 77.1 4.4 48V 16.0 d 5460 2030
  34. 34. Table S11: Nitrogen abundance and isotopic composition in groundmass and black glass.Cosmogenic ages in Ma according to (2). δ15NAIR, 14 3 21 38Sample N ppm ‰ T( Hec) T( Nec) T( Arc) ± ± ± ± ±Groundmass #1(5.252 mg)≈800 °C 0.181 0.005 9 16≈1000 °C 0.059 0.002 4 28Total 0.241 0.005 7 22 1.07 0.10 0.57 0.03 0.61 0.02Groundmass #2(6.262 mg)≈800 °C 0.322 0.009 10 6≈1000 °C 0.164 0.005 27 11Total 0.486 0.010 19 5 1.30 0.13 0.54 0.03 0.88 0.02Black Glass(3.845 mg)≈800 °C 0.042 0.002 -53 49≈1000 °C 0.135 0.004 133 15Total 0.176 0.004 100 13 1.31 0.13 0.72 0.04 1.17 0.03
  35. 35. Table S12. Approximate compositions of carbon- and nitrogen-bearing components inTissint identified by stepped combustion Component Temp. [C] δ 13C [N] δ 15N C/N (° C) (ppm) (‰) (ppm) (‰) (atom)1. Organic 200-400 73 -28.7 5.5 -8.7 152. Organic 400-600 95 -25.8 6.7 -5.6 163. Intermediate 600 - 800 2.3 > -17 0.1 +63 25 (soil?)4. Magmatic 800 - 1000 1.4 -26.3 0.2 < +10 125. Martian > 1000 < 1.2 < +16 < 0.04 < +300 40 atmosphereTable S13. Specimens list in national institutions as of July 2012. Institution   Mass (g)   NHM London, UK   1099 + 79 + 25   NHM Wien, Austria   990   ASU Carleton B. Moore Meteorite collection USA   370   Smithsonian Institution, Washington DC, USA   159.46   University of New Mexico, Albuquerque, USA   108   University of Alberta, Edmonton, Canada   58   University of Washington, USA   30.3   Centre culturel AGM, Marrakesh, Morocco   23   Université P. et M. Curie, Paris, France   3.5   University of Tokyo, Japan   1.26   MNHN Paris, France   1.28  
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