• http://www.lpi.usra.edu/meetings/sncs2002/sncs2002.1st.html

        Chemical, Isotopic, and Petrologic
        Componensts of the Martian Meteorites
        October 11-13, 2002
        Houston Texas
        May 2002
        Lunar and Planetary Institute
        Allan H. Treiman                  Christopher D. K. Herd
        Lunar and Planetary Institute     Lunar and Planetary Institute
        Phone: 281-486-2117               Phone: 281-244-2021
        E-mail: treiman@lpi.usra.edu      E-mail: herd@lpi.usra.edu
        John Jones, NASA Johnson Space Center
        David Mittlefehldt, NASA Johnson Space Center

    When and Where

    A workshop on Unmixing the SNCs will be held on October 11-13,
    2002, at the Lunar and Planetary Institute (LPI). The LPI is
    housed in the Center for Advanced Space Studies, 3600 Bay Area
    Boulevard, Houston, Texas.

    Purpose and Scope

    Martian meteorites,
    pite being all basalts or their
    derivatives, show an enormous range of chemical and isotopic
    compositions. In some respects this breadth is greater than that
    of all basaltic rocks on Earth. Much of the compositional
    variability can be modeled as mixtures of chemical and isotopic
    components, and some components have been assigned to specific
    geological/chemical reservoirs: mantle, crust, atmosphere,
    regolith, and hydrosphere. If mixing components in the SNCs can be
    characterized, we will gain insight into hidden aspects of martian
    geology and geochemistry – hitherto unsampled rock types and/or
    poorly characterized processes and geological environments.

    But just what are the components that make up the martian
    meteorites? What are their chemical and isotopic properties? Do
    they represent recognizable source rocks, reservoirs, or
    geochemical processes? Are physical traces of them, mineral
    grains, or xenoliths recognizable in the meteorites? And how have
    they come to be mixed?

    * Among the shergottites, many seemingly unrelated chemical and
    isotopic parameters are strongly correlated: e.g., oxygen
    fugacity, initial Sr and Nd isotope ratios, and La/Yb ratio.
    These correlations suggest that the martian basalts are
    mixtures of distinct chemical/isotopic components (rock types
    or chemical reservoirs), the end members of which may not be
    represented among the meteorites themselves. Do these
    components represent mantle sources, crustal contaminants,
    metasomatic influxes, or what?

    * More than 10 years ago, it was shown that some radioisotope
    parameters in the shergottites could be represented as
    mixtures from several reservoirs, one of which is consistent
    with the source material of the nakhlites. Can other
    radioisotope systems be explained by these same components,
    are different components required, or are additional
    components required?

    * The heavy noble gases in the martian meteorites are
    interpretable as mixtures of discrete components, including
    atmosphere, primitive mantle, and fractionated atmosphere.
    Are these noble gas components associated with components
    defined by other chemical and isotopic systems (e.g., an
    atmospheric signature of high D/H and high D17O)?

    * The bulk chemical compositions of some shergottite basalts
    are represented well as mixtures of lherzolites and other
    shergottites. Could this relationship imply that these
    shergottites are impact melts?

    * Shock melts in the shergottites can contain the high
    concentrations of a surface component – the martian
    atmosphere. Are other surface components detectable in the
    shock melts or elsewhere in the meteorites? For instance, it
    has been proposed that that shock melts contain traces of
    regolith or dust. Can this be confirmed or extended? How else
    might the martian meteorites retain clues to the nature of
    martian regolith?

    If these many proposed mixing components can be characterized, we
    will gain insight into hidden aspects of martian geology and
    geochemistry – hitherto unsampled rock types and/or poorly
    characterized processes and geological environments. While
    important to the petrologist and geochemist, this knowledge could
    be useful in interpreting spacecraft data about Mars. For
    instance, if mantle components can be defined, they will help in
    interpreting geophysical data on the martian interior (as from the
    MOLA and magnetometer instruments on MGS) by constraining the
    chemical and thermal states of the mantle. If crustal and regolith
    components can be recognized, they may be critical in interpreting
    chemical and mineralogical data for the martian surface, as from
    the TES instrument on MGS and the Gamma-Ray Spectrometer on Mars
    Odyssey, or data obtained in situ at the surface by rovers such as
    MER. In this way, unmixing the martian meteorites can strengthen
    the ties between sample science and remote sensing science, and
    further demonstrate the importance of laboratory sample analyses
    to our deeper understanding of the solar system.

    Through this LPI workshop, we seek to assemble experts and
    researchers in martian geochemistry and petrology to share and
    diversify their knowledge of martian meteorites and of Mars. Among
    the questions we will consider are:

    * How many chemical/isotopic components can be recognized, and
    are some meteorites purely a single component?

    * What are the chemical and isotopic characteristics that
    define the different components?

    * Do these components correspond to recognizable rock types or

    * Do their chemical/isotopic characteristics suggest specific
    geologic or tectonic settings?

    * Are these components predicted by (or consistent with)
    postulated events in Mars’ history, like a magma ocean, a
    warm wet epoch, or mantle plumes?

    Workshop Format

    The intent of the workshop is to bring new and existing results on
    chemical and isotopic components of the martian basalts to a
    single forum through oral and poster presentations. We envision a
    few invited talks, and many contributed talks with time scheduled
    for minimally moderated discussion. Poster presentations will have
    high visibility through short summary presentations and scheduled
    time for viewing and discussion.

    Abstracts are welcome from all disciplines related to the
    chemical, isotopic, or petrologic characteristics of martian
    basalts and their precursor components. Studies related to martian
    meteorites are expected to dominate, but we welcome contributions
    based on remote sensing data or in situ investigations.

    Contingent on review, accepted abstracts will be published in a
    referenceable abstract volume that will be distributed to workshop
    participants. Given sufficient interest, the organizers will
    arrange for a collection of papers derived from the workshop to be
    published together in a peer-reviewed journal. The workshop
    abstracts and preliminary program will also be available in
    electronic format and will be posted on the meeting Web site on or
    before August 30, 2002. These files will be in PDF format,
    viewable with version 4.0 or higher of Adobe Acrobat Reader.

    Call For Abstracts

    The deadline for electronic submission of abstracts will be August
    8, 2002.

    Abstracts should not exceed two pages (including text, figures,
    and tables). Abstracts should be submitted using the electronic
    submission form by 5:00 p.m. August 8, 2002, U.S. Central Daylight
    Savings Time (the abstract submission form will be available by
    July 1, 2002). Abstracts can be submitted in a variety of formats.
    Templates and detailed instructions for formatting and submitting
    your abstract are provided.

    Note that electronic submission of files is not always
    instantaneous; gateways can be shut down temporarily, local
    routers can fail, network traffic can be heavy, etc. Because your
    file must be received at the LPI by 5:00 p.m. CDT, it is in your
    best interest to submit early to allow for possible technical
    problems or delays in transmission. Please DO NOT wait until the
    last minute to access the system; access to the Web form will
    terminate at 5:00 p.m. CDT.


    A registration fee of $50.00 ($25.00 for students) is required of
    each participant to cover catering and related costs. The
    registration fee does not include meals, travel, lodging, etc. You
    must register and pay by September 3, 2002, to avoid a late fee of

    To preregister, please return the downloadable preregistration
    form with your payment by September 3, 2002, or you may use the
    electronic preregistration form if paying by credit card. Non-U.S.
    participants who state on the preregistration form that they have
    a currency exchange problem may pay in cash at the meeting and
    avoid the late fee.

    Hotel Reservations

    Participants are responsible for making their own travel and hotel
    reservations. For your convenience, we have provided a list of
    local hotels and a local area map showing their locations.

    Additional Information

    For more information regarding the scientific objectives of this
    workshop, contact one of the organizers listed at the top of this
    announcement. For information regarding logistics, contact the LPI
    meeting coordinator, Paula Walley (phone: 281-486-2144;
    e-mail:walley@lpi.usra.edu). For more information regarding
    abstracts, contact the LPI abstract coordinator, Reneé Dotson
    (phone: 281-48-2188; e-mail:dotson@lpi.usra.edu).