Supporting Online Material for

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1 Supporting Online Material for Identification of Carbonate-Rich Outcrops on Mars by the Spirit Rover Richard V. Morris,* Steven W. Ruff, Ralf Gellert, Douglas W. Ming, Raymond E. Arvidson, Benton C. Clark, D. C. Golden, Kirsten Siebach, Göstar Klingelhöfer, Christian Schröder, Iris Fleischer, Albert S. Yen, Steven W. Squyres *To whom correspondence should be addressed. This PDF file includes: SOM Text Figs. S1 and S2 Tables S1 and S2 References Published 3 June 2010 on Science Express DOI: /science

2 Supporting Online Material Identification of carbonate-rich outcrops on Mars by the Spirit rover Richard V. Morris, Steven W. Ruff, Ralf Gellert, Douglas W. Ming, Raymond E. Arvidson, Benton. C. Clark, D. C. Golden, Kirsten Siebach, Göstar Klingelhöfer, Christian Schröder, Iris Fleischer, Albert S. Yen, and Steven W. Squyres Laboratory Studies Mössbauer, chemical, and thermal emissivity data were acquired for 10 terrestrial low-ca carbonate samples, and Mössbauer and chemical data were acquired on 3 terrestrial high-ca carbonates (Table S1). Mössbauer and chemical data were acquired on 5 synthetic samples (Table S1), which were carbonate globules prepared as analogues (S1) for the carbonate globules in Martian meteorite ALH (S2, S3). Transmission Mössbauer spectra were obtained at 295 K (S4). The Martian data obtained at 200 to 260 K and the laboratory data obtained at ~295 K can be directly compared because the difference in temperature between the source radiation and the target is within ~10 K in both cases and because E Q is only weakly dependent on temperature in the interval 200 to 295 K (S5, S6). Major element compositions for the terrestrial samples, expressed as mole fraction siderite (Sd; FeCO 3 ), magnesite (Mc; MgCO 3 ), calcite (Cc; CaCO 3 ), and rhodochrosite (Rh; MnCO 3 ), were determined on carbon-coated thick sections of epoxy grain mounts (500 to1000 µm size fraction) using a Cameca SX100 electron microprobe and well-characterized minerals as standards. For the synthetic samples, epoxy blocks remaining after thin sectioning were used. Thermal emission spectra were obtained between 200 and 2000 cm -1 on the 500 to 1000 µm size fraction of the low-ca terrestrial carbonates (Fig. S1) after heating the samples overnight at ~80 C (S7). The thermal emission spectra are consistent with those published over a narrower wavenumber interval (400 to 1800 cm -1 ) (S8). Spectral Unmixing of Mini-TES spectra Linear least squares spectral unmixing (S9) employed a library of laboratory mineral spectra tailored for consistency with APXS and MB data. Library spectra for Fe-Mg carbonates (Fig. S1) were acquired during this study, as discussed above. Following the practice of (S10), the spectral range used in the calculations (~380 to 570 cm -1 and ~780 to 1350 cm -1 ) excludes contributions from atmospheric CO 2 and the noisiest portions of the Mini-TES spectra. In addition to mineralogic phases, the library included spectra representing Martian dust, a slope spectrum to account for any temperature determination errors, and a blackbody spectrum to account for differences in spectral contrast between the laboratory and Mini-TES spectra. The results of the calculations are normalized to the mineralogic endmembers to give their relative contribution to the spectrum (i.e., area % of the target) (Table S2). Pancam Multispectral Spectroscopy Pancam spectra for target Yackeschi (p2590) on Comanche Spur (Fig. 2) were obtained by first defining four regions of interest (ROI) based on the value of R* (lambert albedo) at 03 µm between 0.10 and 0 in intervals of Each of these ROIs were then intersected with ROIs defined by the spectral slope between µm and 04 µm with values between to 0.25 in intervals of The plotted spectra are averages of those with the extreme values of the spectral slope under the constraint that >100 spectra are used for the average. Error bars are one standard deviation of average values. Two distinct spectral shapes are evident and are independent of albedo at 03 µm (Fig. S2). One shape is characterized by reflectance maximum at 0.67 to 0.75 µm, a ferric absorption edge between the maximum and 0.44 µm and 0.67 µm, and a negative trending spectral slope between the maximum and µm. This shape is the Pancam signature of olivine (S11), which was 1

3 also detected by both MB and Mini-TES (Fig. 3). The other shape is characterized by a ferric absorption edge between ~0.44 µm and 6 µm and a relatively flat spectral slope between there and µm and is interpreted as nanophase ferric oxide. No spectral signature of Fe 2+ in carbonate was detected, but one was not expected because the carbonate Fe 2+ absorption bands occur at wavelengths longer than µm (S12, S13). Supporting Figures Emissivity IG SICBL1 CD SMCAID1 SIDCL02 SIDCL03 CMSCAW1 BB Wavenumber (cm -1) Fig. S1. Laboratory thermal emission spectra for the 500 to 1000 µm size fraction of low-ca carbonates (Cc < 0.17 mole fraction). The low wavenumber limit for Mini-TES is ~384 cm Pancam R* Pancam R* R* at 03 m: 0.20 to 0.25 R* at 03 m: 0.10 to B Slope = [R*(04)-R*(0.673)]/0.231 Slope Wavelength (x1000 nm) A R* at 03 m: 0.25 to 0 slope: to slope: 0.15 to 0.20 R* at 03 m: 0.15 to 0.20 Fig. S2. Pancam spectra for regions of interest (ROI) in the target Yackeschi (p2590) on Comanche Spur (Fig. 2). (A) Green spectra: average spectra from the intersection of ROI having R* in the interval between 0.20 to 0.25 at 03 µm and the two ROIs having the maximum and minimum spectral slopes between µm and 04 µm (R* R* )/0.231). Blue spectra: same as green spectra except the R* interval at 03 µm is 0.10 to (B) Red and yellow spectra: same as green spectra except that the R* intervals at 03 µm are 0.25 to 0 and 0.15 to Spectra with square symbols (negative slopes between and 03 µm) have the spectral signature olivine. Spectra with circle symbols (positive slopes) have wide ferric absorption edges characteristic of nanophase ferric oxide. Spectral signatures of Fe 2+ in Febearing carbonate are not evident, because those absorptions occur at wavelengths longer than µm. 2

4 Supporting Tables Table S1. Composition and Mössbauer parameters (295 K) for Mg-Fe-Ca-Mn carbonates. Mole Fraction Carbonate a Mössbauer b Sample, mm/s E Q, mm/s Comments High-Ca Carbonates (Cc > 0.46) BTEMT Terrestrial, Butte, MT, USA (S14) AMLI Terrestrial, unspecified location (S15) FLRW Terrestrial, Ladysmith, WI, USA (S14) CAMB-UN Terrestrial, unspecified location (S15) Ankerite Terrestrial, Stolzembourg, Luxembourg (S16) Ankerite Terrestrial, Ersberg Mine, Austria (S17) AMNH Terrestrial, Minas Gerais, Brazil (S15) AMNH Terrestrial, Erzberg, Styria, Austria (S15) CH271A Terrestrial, Charlemont, MA, USA (S14) Fe:CaCO Synthetic (S18) Low-Ca Carbonates (Cc < 0.18) BB Terrestrial, Brumado, Bahia, Brazil (S14) Fe:MgCO Synthetic (S18) Experiment Synthetic (S1, S14) CMSCWA Terrestrial, Stevens City, WA, USA (S14) SIDCL Terrestrial, Copper Lake, Nova Scotia, Canada (S14) SIDCL Terrestrial, Copper Lake, Nova Scotia, Canada (S14) Experiment Synthetic (S1, S14) Experiment Synthetic (S1, S14) SMCAID Terrestrial, Coeur D Alene, ID, USA (S14) PGMSTX Terrestrial, unknown location (S14) CD Terrestrial, unknown location, Canada (S14) SICBL Terrestrial, Solavi, Bolivia (S14) IG Terrestrial, Ivigttut, Greenland (S14) Siderite Terrestrial, Ersberg Mine, Austria (S17) FD-L Synthetic (S14, S19) a Mc = magnesite (MgCO 3 ); Sd = siderite (FeCO 3 ); Cc = calcite (CaCO 3 ); Rh = rhodochrosite (MnCO 3 ). b Mössbauer parameters: = isomer shift = (v2-v1)/2 and E Q = quadrupole splitting = v2 v1, where v1 and v2 are the peak positions numbered from low to high velocity. Zero velocity is the center position of the spectrum of metallic Fe foil at room temperature. Uncertainties for and E Q are 0.02 mm/s. 3

5 Table S2. Spectral components derived from leastsquares unmixing of Mini-TES spectra presented as area percent. Comanche Saupitty Component Complete, % Normalized, % Olivine (Fo 68 ) 6 34 Amorphous silicate 6 33 Mg-Fe carbonate a 6 34 Surface dust 4 0 Other dust b 3 0 Slope 19 0 Blackbody 67 0 Total a CMSCWA1 (Table S1; Fig. S1). b Formerly described as a sky component (S10), now recognized as another possible manifestation of surface dust (S20). References and Notes. S1. D. C. Golden et al., Meteorit. Planet. Sci. 35, 457 (2000). S2. D. W. Mittlefehldt, Meteoritics 29, 214 (1994). S3. A. H. Treiman, Meteoritics 30, 294 (1995). S4. R. V. Morris et al., J. Geophys. Res. 105, 1757 (2000). S5. R. V. Morris et al., J. Geophys. Res. 111, E02S13, doi: /2005je (2006). S6. R. V. Morris et al., J. Geophys. Res. 113, E12S42, doi: /2008je (2008). S7. S. W. Ruff et al., J. Geophys. Res. 102, 14,899 (1997). S8. M. D. Lane and P. R. Christensen, J. Geophys. Res. 102, 25,581 (1997). S9. M. S. Ramsey and P. R. Christensen, J. Geophys. Res. 103, 577 (1998). S10. S. W. Ruff, J. Geophys. Res. 111, E12S18, doi: /2006je (2006). S11. R. Sullivan et al., J. Geophys. Res. 113, E06S07,doi: /2008JE (2008). S12. S. J. Gaffey, Amer. Mineral. 71, 151 (1986). S13. S. J. Gaffey, J. Geophys. Res. 92, 1429 (1987). S14. This study. S15. R. J. Reeder and W. A. Dollase, Amer. Mineral. 74, 1159 (1989). S16. E. De Grave and R. Vochten, Phys. Chem. Minerals 12, 108 (1985). S17. B. B. Ellwood et al., J. Geophys. Res. 94, 7321 (1989). S18. K. K. P. Srivastava, J. Phys. C: Solid State Phys. 16, L1137 (1983). S19. C. Jimenez-Lopez and C. S. Romanek, Geochim. Cosmochim. Acta 68, 557 (2004). S20. S. W. Ruff and J. L. Bandfield, Lunar and Planetary Science XVI, Abstract #2411, March 1-5, 2010, Houston TX (CD-ROM) (2010). 4