11th International GeoRaman Conference (2014) 5004.pdf Spectroscopic comparison of Lafayette & MIL 03346 vein-filling materials. K. E. Kuebler [email protected] Introduction: The primary goal of this project is to 2004 with a few modifications made per 1, 2]. At characterize the phyllosilicate alteration products in present, the database contains > 100 phyllosilicate Lafayette (or Nakhla) using correlated Raman Raman spectra (Figs. 1, 2), most of which are supported spectroscopic and EMP traverses much like those [1, 2] by EMPA and some by IR (some samples donated by performed on ALHA 77005 and MIL 03346. These ASU [7]). We would like to collect XRD patterns, more data are compared to the MIL traverses of [1]. IR spectra (several from each major group), and append Preliminary Raman traverses were collected on the database (especially the clays). We anticipate that Lafayette by [3, data reused here] but this work is this data will lead to 2 or 3 new mineral calibrations hindered by traces of a former carbon coat and need to (e.g., biotite and chlorite – per [8, 9]); Tschermak, AlIV be recollected. and AlVI, F/OH substitutions will have to be explored. These data reflect the status of the phyllosilicate Major Raman spectral features of phyllosilicates: database initiated by the Planetary Surface Materials Wang et al. [8] discuss the major features of Research Group at Washington University during the dioctahedral and trioctahedral phyllosilicates using four development of the MMRS [4–6, originally compiled in spectral regions: < 600 cm-1, 600 – 800 cm-1, 800 – -1 -1 standard biotite and chlorite spectra 1150 cm , and 3000 – 3800 cm . Bridging oxygen -1 phlogopite peaks (Si-Ob-Si) occur in the 600 – 800 cm region, 679 3714 non-bridging oxygen peaks (Si-Onb) in the 800 – 1150 191 OH -1 -1 cm region, OH and H2O peaks in the 3000 – 3800 cm 337 283 554 782 1085 512 1037 3300 3700 region. The number of OH peaks, their positions, and relative intensities are controlled by the number and type annite 714 668 3658 of crystalographically equivalent OH groups and the 760 OH 164 cations surrounding the OH sites; e.g., N, I, V type 935 522 225 1015 888 1050 264 395 hydrogen bonds [8, 10]. 355 3300 3700 Most trioctahedral phyllosilicates have strong peaks -1 lepidomelane between 180 and 250 cm , one or more strong Si-Ob-Si 3599 OH 3651 -1 751 182 716 557 peaks between 670 and 700 cm , and one or more weak 681 158 138 peaks in the Si-Onb region [8]. Lepidolite is the only 910 3300 3700 394 1092 trioctahedral phyllosilicate with a Si-Ob-Si peak position > 700 cm-1 because Li+ is so light [8, 11]. Fe3+ bearing biotite, BUR-840 721 3685 phyllosilicates have broad, multi-component peaks of OH 3660 680 769 -1 184 moderate strength near 550 cm (attr. to vibrations 143 552 VI 509 408 280 920 involving Al by [9], confirmed by the spectra in our 1086 3300 3700 database) while Mg-phyllosilicates have weak to -1 200 400 600 800 1000 1200 1400 moderate peaks between 325 and 370 cm . The character and peak positions of the Si-O -Si peaks clinochlore b OH & H O 2 3588 3682 change with cation composition [8]. 204 3445 683 551 Comparison of Lafayette and MIL 03346 357 1057 alteration products: The MIL alteration products 128 472 284 3300 3700 appear smooth in thin section but those of Lafayette chamosite have a micaceous habit (Fig. 3; same thin section as that H O 3646 548 2 3563 pictured in [12]). The conversion of smooth alteration 3431 671 522 products into micaceous morphologies is apparent in the 1053 790 896 202 363 429 278 3300 3700 Lafayette sections studied by [13]. The vein-filling chlorite, WAR 1924 alteration products of MIL were identified as 3579 H2O stilpnomelane by [1] and presumably formed at 3680 206 3440 552 681 pressures akin to that of low grade diagenesis. The 355 132 1049 Raman spectra of the Lafayette alteration products (see 3300 3700 Fig. 4) are more consistent with vermiculite [3] but 200 400 600 800 1000 1200 1400 IV -1 saponite (smectite) generally contains far less Al and Raman shift (cm ) AlVI than vermiculite, which is more consistent with our Fig. 1) Raman spectra of several trioctahedral phyllosilicate EMP data [14]. The vein-filling materials of MIL and standards. Lafayette have similar SiO2 contents but the Abstract for 11th GeoRaman International Conference, June 15-19, 2014, St. Louis, Missouri, USA 11th International GeoRaman Conference (2014) 5004.pdf H2O of MIL. Perhaps the vermiculite can be explained as an 554 615 188 vermiculite alteration product of the stilpnomelane. Vermiculite is 672 332 390 758 935 3300 3700 1075 usually inferred to be a weathering or hydrothermal alteration product of chlorite and biotite [15]. H2O 552 675 zonalite Acknowledgements: The WU database was 190 established by the Planetary Surface Materials Research 765 (anhydrous) 354 1080 927 430 3300 3700 Group during the development of the MMRS; use of the data acknowledged by Alian Wang. H O & OH 680 2 552 vermiculite 191 References: [1] Kuebler (2013a) JGR, 118, 347- 520 778 354 var. jeffersite 1075 908 1030 368, doi: 10.1029/2012JE004244; [2] Kuebler (2013b) 428 3300 3700 277 JGR, 118, 803-830, doi: 10.1029/2012JE004243; [3] H2O & OH 555 Kuebler et al. (2004) LPSC XXXV, Abstract #1704; [4] 354 674 DuVal 187 392 618 428 vermiculite Wang et al. (2003) JGR 108, E1, 5005, doi: 265 752 1088 905 290033003700 10.1029/2002 JE001902; [5] Kuebler et al. (2006) LPSC XXXVII, Abstract # 1907; [6] Wang et al. (2014) H2O in progress; [7] R. Ruff website: http://rruff.info/ 676 547 1087 vermiculite 191 352 711 793 3300 3700 (accessed 12/20/13); [8] Wang et al. (2002) LPSC 275 XXXIII, Abstract #1374; [9] Prieto et al. (1991) Clays H2O and Clay Minerals, 39, 5, 531-539; [10] Vedder (1964) 675 187 vermiculite Am. Min., 49, 736-768; [11] Klein and Hurlbut (1985) 355 549 1054 3300 3700 431 277 Manual of Mineralogy. John Wiley & Sons, NY; [12] 825 Treiman et al (2005) Chemie der Erde, 65, 203-270; 200 400 600 800 1000 1200 1400 [13] Changela and Bridges (2010) MAPS, 45, 12, 1847- Raman shift (cm-1) 1867; [14] Deer, Howie, and Zussman (1992) An Introduction to the Rock Forming Minerals, Prentice Fig. 2) Raman spectra of several vermiculite standards. Hall, Harlow, England; [15] Calle and Suquet (1988) stilpnomelane has 10 wt % more FeO, 7 wt % less MgO, Chap. 12, RIM 19, MSA, Washington, D.C. and less than < 0.5 wt % Al2O3. The stilpnomelane in Fig. 4) Raman spectral comparison of the fine and coarse grained MIL has less Al2O3 than the Lafayette vein-filling -1 alteration in Lafayette to the vein-filling materials of MIL materials [1]. The relatively strong 550 cm peak in the 033346. fine-grained alteration of Lafayette may reflect the mobilization of Al during their conversion. Spectra of the alteration products in Lafayette The Raman peaks of the MIL stilpnomelane are fine grained alteration 555 606 3617 670 broad (because the structure is modulated) and their 518 peak positions differ slightly from our standard 392 966 318 920 187 1035 3400 3800 stilpnomelane but do not resemble dioctahedral or 1112 trioctahedral phyllosilicates. The major MIL -1 coarse alteration stilpnomelane peak is ~100 cm lower than the Si-Ob-Si 658 710 peak positions of most trioctahedral phyllosilicates and 546 -1 774 853 916 > 50 cm lower than the coarse alteration products of 963 246 309 Lafayette [1, 3]. 387 Conclusions: We hope to obtain fresh samples (never carbon coated or exposed to acetone) of Smooth alteration products in MIL 03346 Lafayette or Nakhla, study their alteration products, and stilp + olivine+ jarosite elucidate their relationship to the vein-filling materials 586 508 432 454 816 843 392 688 960 1004 302 Fig. 3A) Lafayette’s micaceous alteration products. 1128 B) The vein-filling materials in MIL03346,177 are smooth. 250 500 750 1000 1250 1500 Raman shift (cm-1) Abstract for 11th GeoRaman International Conference, June 15-19, 2014, St. Louis, Missouri, USA .