WORKSHOP ON THE ISSUE MARTIAN METEORITES: WHERE DO WESTAND AND. WHERE ARE WE GOING? J . ' November 2-4, 1998 Lunar and Planetary Institute, Houston, Texas WORKSHOP ON THEISSUE MARTIAN METEORITES: WHERE DO WE STAND AND WHERE ARE WE GOING? Held at Houston, Texas November 2-4, 1998 Sponsored by National Aeronautics and Space Administration Lunar and Planetary Institute Lunar and Planetary Institute 3600 Bay Area Boulevard Houston TX 77058-1113 LPI Contribution No. 956 Compiled in 1998 by LUNAR AND PLANETARY INSTITUTE The Institute is operated by the Universities Space Research Association under Contract No. NASW-4574 with the National Aeronautics and Space Administration. Material in this volume may be copied without restraintfor library, abstract service, education, or personal research purposes; however, republication of any paper or portion thereof requires the written permission of the authors as well as the appropriate acknowledgment of this publication. Abstracts in this volume may be cited as Author A. B. (1998) Title of abstract.In Workhop on the Issue Martian Meteorites: Where Do We Stand and Where Are We Going? LPI Contribution No. 956. Lunar andPlanetary Institute, Houston. 64 pp. This volume is distributed by ORDER DEPARTMENT Lunarand Planetary Institute 3600 Bay Area Boulevard Houston TX 77 058-1113, USA Phone: 281-486-2172 Fax: 281-486-2186 E-mail: [email protected] Mail order requestors will be invoiced for the cost of shipping and handling. LI Contribution No. 956 iii Preface This volume contains papers that were accepted for presentation at the Workshop on the Issue MartianMeteorites: Where Do We Stand and Where are We Going? The workshop was held November 2-4, 1998, at the Lunar and Planetary Institute in Houston, Texas. Members of the ScientificOrganizing Committee included D. C. Black, Co-Chair (Lunar and PlanetaryInstitute), C. Pilcher, Co-Chair (NASA Headquarters), D. Des Marais (NASA Ames Research Center), M. Drake (University of Arizona), J. Ferris(Rensselaer Polytechnic Institute), J. Longhi (Lamont-Doherty Earth Observatory),D. McCleese (Jet Propul­ sion Laboratory), D. McKay (NASA Johnson Space Center), H. Mcsween (University of Tennessee), M. Meyer (NASA Headquarters), H. Newsom (University of New Mexico), P. Rogers (Smithsonian Institution), and A. Treiman ( Lunar and PlanetaryInstitute). Logistical, administrative, and publications support were provided by the Publications and Program Services Departmentof the Lunar and Planetary Institute. LPI Contribution No. 956 v Contents Gamma-Ray Sterilization of Mars Analog Rocks and Minerals C. C. Allen ..................................................................................................................................... 1 Biomarkers in Carbonate Thermal Springs: Implications for Mars C. C. Allen, S. J. Kivett, and D. S. McKay ..................................................................................... 2 Fluid Inclusions in Allan Hills 84001 and Other Martian Meteorites: Evidence for Volatiles on Mars R. J. Bodnar ................................................................................................................................... 3 Rubidium-StrontiumFormation Age of Allan Hills 84001 Carbonates L. E. Borg, L. E. Nyquist, C.-Y. Shih, H. Wiesmann, Y. Reese, and J. N. Connelly ......................................................................................................................... 5 Rare Potassium-bearing Mica in Allan Hills 84001: Additional Constraints on Carbonate Formation A. J. Brearley ................................................................................................................................. 6 Water on Mars: How Much Was (Is) There, Where Did It Go, and When? M. H. Carr ..................................................................................................................................... 8 On Independent Proof of a Martian Origin for the Shergotty Meteorite Yu. T. Chuburkov, V. P. Pe rely gin, and V. A. Alekseev ................................................................. 9 The Searchfor Early Life on Mars: A European Space Agency Exobiology Science Team Study P. Clancy, A. Brack, B. Hofmann, G. Horneck, G. Kurat, J. Maxwell, G. G. Ori, C. Pillinger, F. Raulin, N. Thomas, F. Westall, and B. Fitton ..................................... 9 Studies of Life on Earth are Important for Mars Exploration D. J. Des Marais .......................................................................................................................... 10 Optimizing the Search for a Fossil Record of Ancient MartianLife J. D. Farmer ................................................................................................................................ 11 Bacterial Mineral Precipitation and the Making of Microfossils F. G. Ferris .................................................................................................................................. 12 Organic Carbon in Carbonate and Rim fromAllan Hills 84001 G. J. Flynn, L. P. Keller, C. Jacobsen, and S. Wirick ................................................................. 13 Chains of Magnetite Crystals in Allan Hills 84001: Evidence of Biological Origin E. I. Friedmann, J. Wierzchos, and C. Ascaso ............................................................................ 14 vi Workhop on Martian Meteorites Biomimetic butAbiotic Carbonates: New Geochemical Markers for Primitive Environments J. M. Garcia-Ruiz ........................................................................................................................ 16 How Do the Properties of Allan Hills 84001 Compare with Accepted Criteria for Evidence of Ancient Life? E. K. Gibson Jr., D.S. McKay, K. Thomas-Keprta, F. Westall, and C. A. Romanek ...................................................................................................................... 17 Xenon and Argon Isotopes in Irradiated, Etched Nakhla: Characterizingthe Host of Martian Atmospheric Xenon J. D. Gilmour, J. A. Whitby, R. Burgess, and G. Turner............................................................. 18 Formation of Carbonates in Allan Hills 84001 by Impact Metasomatism: Cooking with Gas R. P. Harvey................................................................................................................................. 20 Recovering More Antarctic Martian Meteorites: Answers to Common Questions R. P. Harvey and W. A. Cassidy .................................................................................................. 22 Estimates of Oxygen Fugacity in the Basaltic Shergottites fromElectron Microprobe Oxygen Analysis C. D. K. Herd and J. J. Papike .................................................................................................... 23 Implications of Hydrous Weathering Product on Mars forFuture Exploration L. E. Kirkland and K. C. Herr ..................................................................................................... 24 The Signature of Life: Is It Legible? A. H. Knoll.............. ..................................................................................................................... 25 Martian Biogenic Activity: Looking for Viruses and DNA Traces Instead of Extant Bacteria Traces L. V. Ksanfomality............... ........................................................................................................ 26 The Structure of Findings in Allan Hills 84001 May Hint at Their Inorganic Origin L_. V. Ksanfomality ............._. ...................... ................................................................................... 26 Constraints on Martian Volatile History from Studies of Martian Meteorites: Lessons Learnedand Open Questions L. A. Leshin .................................................................................................................................. 27 The Future Search for Life on Mars: An Unambiguous Martian Life Detection Experiment G. V. Levin ................................................................................................................................... 28 LP/ Contribution No. 956 vii Curation of U.S. Martian Meteorites Collected in Antarctica M. Lindstrom, C. Satterwhite, J. Allton, and E. Stansbery.......................................................... 29 Principal Component Analysis for Biosignature Detection in Extraterrestrial Samples G.D. McDonald and M. C. Storrie-Lombardi ............................................................................ 30 Evidence for Ancient Lifein Mars Meteorites: Lessons Learned D. S. McKay ................................................................................................................................. 31 Key Research: Martian Meteorites and Their Relationships to Planetary Geology and Perhaps Biology H. Y. McSween Jr . ....................................................................................................................... 33 What Were the Major Factors That Controlled Mineralogical Similarities and Differencesof Basaltic, Lherzolitic, and Clinopyroxenitic Martian Meteorites Within Each Group? T. Mikouchi, M. Miyamoto, and G. A. McKay ............................................................................ 34 Genesis of the Mars Pathfinder "Sulfur-Free"Rock fromSNC Parental Liquids M. E. Minitti and M. J. Rutherford................... ........................................................................... 36 Recognizing Lifeand Its Evolution Through