ABOUT THIS COLLECTION

Meteoritics & Planetary Science is an international monthly journal of the Meteoritical Society—a scholarly organization promoting research and education in planetary science. Topics include the origin and history of the solar system, planets and natural satellites, interplanetary dust and interstellar medium, lunar samples, meteors and meteorites, asteroids, comets, craters, and tektites.

Meteoritics & Planetary Science was first published in 1935 under the title Contributions of the Society for Research on Meteorites. In 1947, the publication became known as Contributions of the Meteoritical Society and continued through 1951. From 1953 to 1995, the publication was known as Meteoritics, and in 1996, the journal's name was changed to Meteoritics & Planetary Science or MAPS. The journal was not published in 1952 and from 1957 to 1964.

This archive provides access to Meteoritics & Planetary Science Volumes 37-44 (2002-2009).

Visit Wiley Online Library for new and retrospective Meteoritics & Planetary Science content (1935-present).

ISSN: 1086-9379

QUESTIONS?

Contact the University Libraries Journal Team with questions.

Recent Submissions

  • Petrology of silicate inclusions in the Sombrerete ungrouped iron meteorite: Implications for the origins of IIE-type silicate-bearing irons

    Ruzicka, A.; Hutson, M.; Floss, C. (The Meteoritical Society, 2006-01-01)
    The petrography and mineral and bulk chemistries of silicate inclusions in Sombrerete, an ungrouped iron that is one of the most phosphate-rich meteorites known, was studied using optical, scanning electron microscopy (SEM), electron microprobe analysis (EMPA), and secondary ion mass spectrometry (SIMS) techniques. Inclusions contain variable proportions of alkalic siliceous glass (~69 vol% of inclusions on average), aluminous orthopyroxene (~9%, Wo1-4Fs2535, up to ~3 wt% Al), plagioclase (~8%, mainly An7092), Cl-apatite (~7%), chromite (~4%), yagiite (~1%), phosphaterich segregations (~1%), ilmenite, and merrillite. Ytterbium and Sm anomalies are sometimes present in various phases (positive anomalies for phosphates, negative for glass and orthopyroxene), which possibly reflect phosphate-melt-gas partitioning under transient, reducing conditions at high temperatures. Phosphate-rich segregations and different alkalic glasses (K-rich and Na-rich) formed by two types of liquid immiscibility. Yagiite, a K-Mg silicate previously found in the Colomera (IIE) iron, appears to have formed as a late-stage crystallization product, possibly aided by Na-K liquid unmixing. Trace-element phase compositions reflect fractional crystallization of a single liquid composition that originated by low-degree (~48%) equilibrium partial melting of a chondritic precursor. Compositional differences between inclusions appear to have originated as a result of a filter-press differentiation process, in which liquidus crystals of Cl-apatite and orthopyroxene were less able than silicate melt to flow through the metallic host between inclusions. This process enabled a phosphoran basaltic andesite precursor liquid to differentiate within the metallic host, yielding a dacite composition for some inclusions. Solidification was relatively rapid, but not so fast as to prevent flow and immiscibility phenomena. Sombrerete originated near a cooling surface in the parent body during rapid, probably impact-induced, mixing of metallic and silicate liquids. We suggest that Sombrerete formed when a planetesimal undergoing endogenic differentiation was collisionally disrupted, possibly in a breakup and reassembly event. Simultaneous endogenic heating and impact processes may have widely affected silicate-bearing irons and other solar system matter.
  • Erratum

    The Meteoritical Society, 2006-01-01
  • Erratum

    Bhandari, N. (The Meteoritical Society, 2006-01-01)
  • Thermodynamic constraints on fayalite formation on parent bodies of chondrites

    Zolotov, M. Yu.; Mironenko, M. V.; Shock, E. L. (The Meteoritical Society, 2006-01-01)
    Thermochemical equilibria are calculated in the multicomponent gas-solution-rock system in order to evaluate the formation conditions of fayalite, (Fe0.881.0Mg0.120)2SiO4, Fa88100, in unequilibrated chondrites. Effects of temperature, pressure, water/rock ratio, rock composition, and progress of alteration are evaluated. The modeling shows that fayalite can form as a minor secondary and transient phase with and without aqueous solution. Fayalite can form at temperatures below ~350 degrees C, but only in a narrow range of water/rock ratios that designates a transition between aqueous and metamorphic conditions. Pure fayalite forms at lower temperatures, higher water/rock ratios, and elevated pressures that correspond to higher H2/H2O ratios. Lower pressure and water/rock ratios and higher temperatures favor higher Mg content in olivine. In equilibrium assemblages, fayalite usually coexists with troilite, kamacite, magnetite, chromite, Ca-Fe pyroxene, and phyllosilicates. Formation of fayalite can be driven by changes in temperature, pressure, H2/H2O, and water/rock ratios. However, in fayalite-bearing ordinary and CV3 carbonaceous chondrites, the mineral could have formed during the aqueous-to-metamorphic transition. Dissolution of amorphous silicates in matrices and/or silica grains, as well as low activities of Mg solutes, favored aqueous precipitation of fayalite. During subsequent metamorphism, fayalite could have formed through the reduction of magnetite and/or dehydration of ferrous serpentine. Further metamorphism should have caused reductive transformation of fayalite to Ca-Fe pyroxene and secondary metal, which is consistent with observations in metamorphosed chondrites. Although bulk compositions of matrices/chondrites have only a minor effect on fayalite stability, specific alteration paths led to different occurrences, quantities, and compositions of fayalite in chondrites.
  • Petrographic studies of "fallout" suevite from outside the Bosumtwi impact structure, Ghana

    Boamah, D.; Koeberl, C. (The Meteoritical Society, 2006-01-01)
    Field studies and a shallow drilling program carried out in 1999 provided information about the thickness and distribution of suevite to the north of the Bosumtwi crater rim. Suevite occurrence there is known from an ~1.5 km^2 area; its thickness is less than or equal to 15 m. The present suevite distribution is likely the result of differential erosion and does not reflect the initial areal extent of continuous Bosumtwi ejecta deposits. Here we discuss the petrographic characteristics of drill core samples of melt-rich suevite. Macroscopic constituents of the suevites are melt bodies and crystalline and metasedimentary rock (granite, graywacke, phyllite, shale, schist, and possibly slate) clasts up to about 40 cm in size. Shock metamorphic effects in the clasts include multiple sets of planar deformation features (PDFs), diaplectic quartz and feldspar glasses, lechatelierite, and ballen quartz, besides biotite with kink bands. Basement rock clasts in the suevite represent all stages of shock metamorphism, ranging from samples without shock effects to completely shock-melted material that is indicative of shock pressures up to ~60 GPa.
  • New observations on shatter cones in the Vredefort impact structure, South Africa, and evaluation of current hypotheses for shatter cone formation

    Wieland, F.; Reimold, W. U.; Gibson, R. L. (The Meteoritical Society, 2006-01-01)
    Shatter cones have been described from many meteorite impact structures and are widelyregarded as a diagnostic macroscopic recognition feature for impact. However, the origin of thismeso- to macroscopic striated fracture phenomenon has not yet been satisfactorily resolved, and thetiming of shatter cone formation in the cratering process still remains enigmatic. Here, previousresults from studies of shatter cones from the Vredefort impact structure and other impact structuresare discussed in the light of new field observations made in the Vredefort Dome. Contrary to earlier claims, Vredefort cone fractures do not show uniform apex orientations at any given outcrop, nor do small cones show a pattern consistent with the previously postulated master cone concept. Simple back-rotation of impact-rotated strata to a horizontal pre-impact position also does not lead to a uniform centripetal-upward orientation of the cone apices. Striation patterns on the cone surfaces are variable, ranging from the typically diverging pattern branching off the cone apex to subparallel-to parallel patterns on almost flat surfaces. Striation angles on shatter cones do not increase with distance from the center of the dome, as alleged in the literature. Instead, a range of striation angles is measured on individual shatter cones from a specific outcrop. New observations on small-scale structures in the collar around the Vredefort Dome confirm the relationship of shatter cones with subparallel sets of curviplanar fractures (so-called multipli-striated joint sets, MSJS). Pervasive, meter-scale tensile fractures cross-cut shatter cones and appear to have formed after the closely spaced MSJ-type fractures. The results of this study indicate that none of the existing hypotheses for the formation of shatter cones are currently able to adequately explain all characteristics of this fracturing phenomenon. Therefore, we favor a combination of aspects of different hypotheses that includes the interaction of elastic waves, as supported by numerical modeling results and which reasonably explains the variety of shatter cone shapes, the range of striation geometries and angles, and the relationship of closely spaced fracture systems with the striated surfaces. In the light of the currently available theoretical basis for the formation of shatter cones, the results of this investigation lead to the conclusion that shatter cones are tensile fractures and might have formed during shock unloading, after the passage of the shock wave through the target rocks.
  • Spatial heterogeneity of 26Al/27Al and stable oxygen isotopes in the solar nebula

    Boss, A. P. (The Meteoritical Society, 2006-01-01)
    The degree of isotopic spatial heterogeneity in the solar nebula has long been a puzzle, with different isotopic systems implying either large-scale initial spatial homogeneity (e.g., 26Al chronometry) or a significant amount of preserved heterogeneity (e.g., ratios of the three stable oxygen isotopes, 16O, 17O, and 18O). We show here that in a marginally gravitationally unstable (MGU) solar nebula, the efficiency of large-scale mixing and transport is sufficient to spatially homogenize an initially highly spatially heterogeneous nebula to dispersions of ~10% about the mean value of 26Al/27Al on time scales of thousands of years. A similar dispersion would be expected for 17O/16O and 18O/16O ratios produced by ultraviolet photolysis of self-shielded molecular CO gas at the surface of the outer solar nebula. In addition to preserving a chronological interpretation of initial 26Al/27Al ratios and the self-shielding explanation for the oxygen isotope ratios, these solar nebula models offer a self-consistent environment for achieving large-scale mixing and transport of thermally annealed dust grains, shock-wave processing of chondrules and refractory inclusions, and giant planet formation.
  • Titan's damp ground: Constraints on Titan surface thermal properties from the temperature evolution of the Huygens GCMS inlet

    Lorenz, R. D.; Niemann, H. B.; Harpold, D. N.; Way, S. H.; Zarnecki, J. C. (The Meteoritical Society, 2006-01-01)
    A simple thermal model is developed to determine the temperature history of the inlet tube of the Huygens probe gas chromatograph mass spectrometer (GCMS) after its fortuitous emplacement on the surface of Saturns moon Titan. The model parameters are adjusted to match the recorded temperature history of a nearby heater, taking into account heat losses by conduction to the rest of the probe and to Titans cold atmosphere. The model suggests that after impact when forced convective cooling ceased, the inlet temperature rose from ~110 K to an asymptotic value of only ~145 K. This requires that the inlet was embedded in a surface that acted as an effective heat sink, most plausibly interpreted as wet or damp with liquid methane. The data appear inconsistent with a tar or dry, fine-grained surface, and the inlet was not warm enough to devolatilize methane hydrate.
  • Acrylic embedding of Stardust particles encased in aerogel

    Matrajt, G.; Brownlee, D. E. (The Meteoritical Society, 2006-01-01)
    Ultramicrotomy of samples embedded in epoxy resin is a standard method for preparing ultra-thin sections for electron microscopy. In this report we describe a new embedding technique that uses acrylic resin instead of epoxy. This method offers several important advantages for sectioning small extraterrestrial samples. One is that the acrylic resin is soluble and can be removed after ultramicrotomy to leave a sample that is free of the mounting media. This is important for studying carbon and insoluble organic components. A second major advantage of acrylic is that, when combined with pre-embedding compression, it provides a very effective method of mounting samples collected in silica aerogel. Acrylic embedding is currently being used to mount comet particles collected by NASA's Stardust mission. Combined with a flattening process, the acrylic embedding and sectioning preserves all pieces of collected samples in their collection matrix. In addition to Stardust, acrylic may be applied to other samples collected in aerogel such as those from the Russian Mir space station (Hörz et al. 2000) and future missions such as Sample Collection for Investigation of Mars (SCIM) (Leshin 2003), a proposed mission to collect atmospheric dust particles from Mars.
  • Geochemical identification of projectiles in impact rocks

    Tagle, R.; Hecht, L. (The Meteoritical Society, 2006-01-01)
    The three major geochemical methods for impactor identification are evaluated with respect to their potential and limitations with regards to the precise detection and identification of meteoritic material in impactites. The identification of a projectile component in impactites can be achieved by determining certain isotopic and elemental ratios in contaminated impactites. The isotopic methods are based on Os and Cr isotopic ratios. Osmium isotopes are highly sensitive for the detection of minute amounts of extraterrestrial components of even <<0.05 wt% in impactites. However, this only holds true for target lithologies with almost no chemical signature of mantle material or young mantle-derived mafic rocks. Furthermore, this method is not currently suitable for the precise identification of the projectile type. The Cr-isotopic method requires the relatively highest projectile contamination (several wt%) in order to detect an extraterrestrial component, but may allow the identification of three different groups of extraterrestrial materials, ordinary chondrites, an enstatite chondrites, and differentiated achondrites. A significant advantage of this method is its independence of the target lithology and post-impact alteration. The use of elemental ratios, including platinum group elements (PGE: Os, Ir, Ru, Pt, Rh, Pd), in combination with Ni and Cr represents a very powerful method for the detection and identification of projectiles in terrestrial and lunar impactites. For most projectile types, this method is almost independent of the target composition,especially if PGE ratios are considered. This holds true even in cases of terrestrial target lithologies with a high component of upper mantle material. The identification of the projectile is achieved by comparison of the “projectile elemental ratio” derived from the slope of the mixing line (target-projectile) with the elemental ratio in the different types of possible projectiles (e.g., chondrites). However, this requires a set of impactite samples of various degree of projectile contamination.