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

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Recent Submissions

  • Northwest Africa 2526: A partial melt residue of enstatite chondrite parentage

    Keil, K.; Bischoff, A. (The Meteoritical Society, 2008-01-01)
    NWA 2526 is a coarse-grained, achondritic rock dominated by equigranular grains of polysynthetically twinned enstatite (~85 vol%) with frequent 120 triple junctions and ~10-15 vol% of kamacite + terrestrial weathering products. All other phases including troilite, daubreelite, schreibersite, and silica-normative melt areas make up <~1 vol% of the rock. Oxygen isotopic analyses are well within the range of those for enstatite chondrites and aubrites. We show that the "enstatite achondrite" (Russell et al. 2005) Northwest Africa (NWA) 2526 is actually a partial melt residue of an enstatite chondrite-like lithology that experienced ~20 vol% partial melting. We suggest that the heat source was internal to the parent body. The FeS-Fe,Ni and plagioclase-enstatite partial melts were removed from the parent lithology, leaving NWA 2526 as a residue highly depleted in troilite and lacking plagioclase. Sub-solidus slow cooling and annealing is responsible for the coarsegrained, recrystallized texture of the rock. We also suggest that the parent lithology of NWA 2526, prior to partial melting, experienced a shock event which formed the curvilinear trails of blebs of minor troilite and rare metal that are enclosed in enstatite crystals; thus, these represent relicts. After partial melting and annealing, NWA 2526 experienced a second, relatively mild impact event (<~20 GPa) that caused formation of the polysynthetic twinning in the enstatite. We suggest that the meteorite Zakłodzie, which has been referred to as a "primitive enstatite achondrite" (Przylibski et al. 2005), did not form from a magma of internal origin, but that it is an impact-melt breccia of enstatite chondrite-like parentage, as previously discussed by Burbine et al. (2000) and Keil (2007). Finally, the "metal-rich enstatite meteorite with achondritic texture" Itqiy (Patzer et al. 2001) formed by processes very similar to those responsible for formation of NWA 2526 and is also the residue of ~20 vol% partial melting of an enstatite chondrite-like parent lithology, with the FeS-Fe,Ni and plagioclase-enstatite partial melts having been removed from the residue. It also experienced an impact event after partial melting that was responsible for the formation of the mixed Mg-Mn-Fesulfides and the shock stage S3 features of the enstatite. These similarities indicate that NWA 2526 and Itqiy may have formed on the same parent body. This body was different from the EH, EL, Shallowater and aubrite parent bodies, and NWA 2526 and Itqiy may represent samples from yet another, fifth enstatite meteorite parent body.
  • Petrogenetic linkages among Martian basalts: Implications based on trace element chemistry of olivine

    Shearer, C. K.; Burger, P. V.; Papike, J. J.; Borg, L. E.; Irving, A. J.; Herd, C. (The Meteoritical Society, 2008-01-01)
    The shergottites exhibit a range of major and trace element compositions, crystallization ages, and initial Sr, Nd, Hf, and Pb isotopic compositions. To constrain the physical mechanisms by which shergottites obtain their compositional characteristics, we examined the major and trace element record preserved in olivine in the more primitive shergottites. Based on such characteristics as the Mg#, V zoning, calculated DNi,Co, the olivine in Y-980459 are most likely phenocrysts. Many of these same characteristics indicate that the olivines in other shergottites are not in equilibrium with the adjacent melt. However, in most cases they are not xenocrystic, but additions of olivine from the same basaltic system. Elephant Moraine (EET) A79001 may be an exception with the olivine data suggesting that it is xenocrystic. In this case, the olivine crystallized from a reduced and LREEdepleted melt and was incorporated into an oxidized and enriched basalt. Vanadium and CaO in olivine appear to record the appearance of spinel and pyroxene on the liquidus of most of the shergottites. Most of the olivine shergottites represent basalts produced by melting of reduced (IW to IW + 1), depleted mantle sources. Olivine data indicate that many of the primary melts derived from this source had similar Ni, Co, and Mn. Shergottites such as Northwest Africa (NWA) 1110/1068 and perhaps Roberts Massif (RBT) 04261 that appear to be derived from more enriched sources have distinctly different olivine. In the case of NWA 1110/1068, the olivine data suggests that the enriched component was added to system prior to olivine crystallization.
  • Aragonite in the Murray (CM2) carbonaceous chondrite: Implications for parent body compaction and aqueous alteration

    Lee, M. R.; Ellen, R. (The Meteoritical Society, 2008-01-01)
    The matrix of the CM2 carbonaceous chondrite Murray contains rare micrometer-sized prismatic crystals of aragonite that formed during late-stage parent body aqueous alteration. The aragonite was identified by X-ray microanalysis coupled with electron backscatter diffraction (EBSD), TEM selected area electron diffraction and cathodoluminescence spectroscopy. The sixteen crystals found all occur within loose and elongate submillimeter-sized clusters and one cluster is present in each of the two thin sections studied. Orientation determinations using EBSD show that the c axes of aragonite crystals within each cluster lie roughly in a plane, itself aligned approximately parallel to the long axis of the host cluster. Aragonite is inferred to have crystallized after calcite but before completion of static/impact-related compaction. The clusters developed by growth of aragonite within films of aqueous fluids that had a relatively high Mg/Ca ratio. These fluids were focused within zones of high porosity and permeability along a weak compactional fabric in the matrix and this fabric is also likely to have influenced the orientations of aragonite crystals as they grew. These results suggest that aragonite probably occurs in most of those carbonaceous chondrites that have undergone moderate degrees of parent body aqueous alteration and may provide further insights into the evolution of pore fluid compositions and volumes and the chronology of asteroidal evolution.
  • New impact-melt rock from the Roter Kamm impact structure, Namibia: Further constraints on impact age, melt rock chemistry, and projectile composition

    Hecht, L.; Reimold, W. U.; Sherlock, S.; Tagle, R.; Koeberl, C.; Schmitt, R.-T. (The Meteoritical Society, 2008-01-01)
    A new locality of in situ massive impact-melt rock was discovered on the southsouthwestern rim of the Roter Kamm impact structure. While the sub-samples from this new locality are relatively homogeneous at the hand specimen scale, and despite being from a nearby location, they do not have the same composition of the only previously analyzed impact-melt rock sample from Roter Kamm. Both Roter Kamm impact-melt rock samples analyzed to date, as well as several suevite samples, exhibit a granitic-granodioritic precursor composition. Micro-chemical analyses of glassy matrix and Al-rich orthopyroxene microphenocrysts demonstrate rapid cooling and chemical disequilibrium at small scales. Platinum-group element abundances and ratios indicate an ordinary chondritic composition for the Roter Kamm impactor. Laser argon dating of two sub-samples did not reproduce the previously obtained age of 3.7 +/- 0.3 (1-sigma) for this impact event, based on 40Ar/39Ar dating of a single vesicular impact-melt rock. Instead, we obtained ages between 3.9 and 6.3 Ma, with an inverse isochron age of 4.7 +/- 0.3 Ma for one analyzed sub-sample and 5.1 +/- 0.4 Ma for the other. Clearly a post-5 Ma impact at Roter Kamm remains indicated, but further analytical work is required to better constrain the currently best estimate of 4-5 Ma. Both impactor and age constraints are clearly obstructed by the inherent microscopic heterogeneity and disequilibrium melting and cooling processes demonstrated in the present study.
  • Bulk chemical composition of lherzolitic shergottite Grove Mountains 99027—Constraints on the mantle of Mars

    Lin, Y.; Qi, L.; Wang, G.; Xu, L. (The Meteoritical Society, 2008-01-01)
    We report the concentration of 50 elements, including rare earth elements (REEs) and platinum group elements (PGEs) in bulk samples of the Grove Mountains (GRV) 99027 lherzolitic shergottite. The abundances of REEs are distinctly lower than those of Allan Hills (ALH) A77005 and other lherzolitic shergottites, indicating that GRV 99027 is not paired with them. It may, nevertheless, sample the same igneous unit as the others (Lin et al. 2005b; Wang and Chen 2006). The CInormalized elemental pattern of GRV 99027 reveals low (0.004-0.008 x CI) and unfractionated PGEs (except for Pd of 0.018 x CI) without depletion of W or Ga relative to lithophile element trends. Fractionation between siderophile and lithophile elements become less pronounced with increase of volatility, except for high abundances of Ni and Co. These characteristics are probably representative of the mantle of Mars, which is consistent with previous work that the Martian mantle formed in a deep magma ocean followed by a later accretion of chondritic materials.
  • Mid-infrared spectroscopy of refractory inclusions (CAIs) in CV and CO chondrites

    Morlok, A.; Köhler, M.; Grady, M. M. (The Meteoritical Society, 2008-01-01)
    We present laboratory mid-infrared absorption spectra (2.5 micrometers to 16.0 m) of powdered calcium-aluminum-rich inclusions (CAIs) and matrix separated from the carbonaceous chondrites Allende (CV3.2), Vigarano (CV3.3), and Ornans (CO3.3). Two groups of spectra with different features were found for the CAI: in the first group spectra are dominated by spinel, pyroxene, and sodalite nepheline, where main features occur at 9.3 micrometers, 10.3 micrometers, and 11.3 micrometers. In the second group, characteristic minerals are spinel and melilite with typical band maxima at 11.0 micrometers and 12.3 micrometers, and a broad feature between 14.0 micrometers and 15.0 micrometers. The position of the broad spinel feature probably depends on its iron content. Comparison of band positions in spectra from the CAI components to observed circumstellar emission spectra indicates the potential occurrence of CAI-like material. Pyroxene- and spinel-rich features could occur in spectra of dust around the Herbig Ae star HD104237, the T Tauri star Hen3-600 and the post-AGB star R Sge. Melilite- and spinel-rich components possibly appear in the spectrum of HD104237, Hen3-600, 04187_1927, R Sge, and the planetary nebula Hb 12. There is also indication for a spinel component in dust from the Herbig Ae/Be star HD179218. The spectra of the AGB stars R Cas and Aps show no features of CAI-type spinel.
  • Impact melt rocks from the Paasselkä impact structure (SE Finland): Petrography and geochemistry

    Schmieder, M.; Moilanen, J.; Buchner, E. (The Meteoritical Society, 2008-01-01)
    Recently, samples of allochthonous melt rocks from the v10 km and less than or equal to 1.9 Ga Paasselkä impact structure, SE Finland, were obtained. In this study, we present a first detailed petrographic and geochemical description of clast-rich Paasselkä impact melt rocks. Shock metamorphic features comprise shocked feldspar grains, intensely shocked and toasted quartz, marginally molten and recrystallized clasts thought to have been diaplectic quartz glass, largely fresh and recrystallized feldspar glasses, decomposed biotite flakes, recrystallized fluidal silica glass (originally probably lechatelierite) in partially molten sandstone clasts, all set into a glassy to cryptocrystalline melt matrix. The degree of shock metamorphism of clasts suggests initial whole-rock melting at peak shock pressures of greater than or equal to 35 GPa and post-shock temperatures of up to ~1500 degrees C. Glass components vary in geochemical composition corresponding to the mixed character of the crystalline target rock (i.e., representing different monomineralic and mixed-mineral melts). Feldspar glasses and the fresh glassy to cryptocrystalline melt matrix indicate that the Paasselkä melt rocks are not intensely altered. The geochemical composition of the Paasselkä impact melt rocks is roughly consistent with the compositions of melt rocks from a number of impact structures located within the crystalline basement of the Baltic Shield.
  • Fe-Ni metal in primitive chondrites: Indicators of classification and metamorphic conditions for ordinary and CO chondrites

    Kimura, M.; Grossman, J. N.; Weisberg, M. K. (The Meteoritical Society, 2008-01-01)
    We report the results of our petrological and mineralogical study of Fe-Ni metal in type 3 ordinary and CO chondrites, and the ungrouped carbonaceous chondrite Acfer 094. Fe-Ni metal in ordinary and CO chondrites occurs in chondrule interiors, on chondrule surfaces, and as isolated grains in the matrix. Isolated Ni-rich metal in chondrites of petrologic type lower than type 3.10 is enriched in CO relative to the kamacite in chondrules. However, Ni-rich metal in type 3.15-3.9 chondrites always contains less CO than does kamacite. Fe-Ni metal grains in chondrules in Semarkona typically show plessitic intergrowths consisting of submicrometer kamacite and Ni-rich regions. Metal in other type 3 chondrites is composed of fine- to coarse-grained aggregates of kamacite and Ni-rich metal, resulting from metamorphism in the parent body. We found that the number density of Ni-rich grains in metal (number of Ni-rich grains per unit area of metal) in chondrules systematically decreases with increasing petrologic type. Thus, Fe-Ni metal is a highly sensitive recorder of metamorphism in ordinary and carbonaceous chondrites, and can be used to distinguish petrologic type and identify the least thermally metamorphosed chondrites. Among the known ordinary and CO chondrites, Semarkona is the most primitive. The range of metamorphic temperatures were similar for type 3 ordinary and CO chondrites, despite them having different parent bodies. Most Fe-Ni metal in Acfer 094 is martensite, and it preserves primary features. The degree of metamorphism is lower in Acfer 094, a true type 3.00 chondrite, than in Semarkona, which should be reclassified as type 3.01.
  • Crystallization experiments on a Gusev Adirondack basalt composition

    Filiberto, J.; Treiman, A. H.; Le, L. (The Meteoritical Society, 2008-01-01)
    Until recently, the SNC meteorites represented the only source of information about the chemistry and petrology of the Martian surface and mantle. The Mars Exploration Rovers have now analyzed rocks on the Martian surface, giving additional insight into the petrology and geochemistry of the planet. The Adirondack basalts, analyzed by the MER Spirit in Gusev crater, are olivine-phyric basaltic rocks which have been suggested to represent liquids, and might therefore provide new insights into the chemistry of the Martian mantle. Experiments have been conducted on a synthetic Humphrey composition at upper mantle and crustal conditions to investigate whether this composition might represent a primary mantle-derived melt. The Humphrey composition is multiply saturated at 12.5 kbar and 1375 degrees C with olivine and pigeonite; a primary anhydrous melt derived from a "chondritic" mantle would be expected to be saturated in orthopyroxene, not pigeonite. In addition, the olivine and pigeonite present at the multiple saturation are too ferroan to have been from a Martian mantle as is understood now. Therefore, it seems likely that the Humphrey composition does not represent a primary anhydrous melt from the Martian mantle, but was affected by mineral/melt fractionations at lower (crustal) pressures.
  • 39Ar-40Ar dating of the Zagami Martian shergottite and implications for magma origin of excess 40Ar

    Bogard, D. D.; Park, J. (The Meteoritical Society, 2008-01-01)
    The Zagami shergottite experienced a complex, petrogenetic formation history (McCoy et al. 1992, 1999). Like several shergottites, Zagami contains excess 40Ar relative to its formation age. To understand the origin of this excess 40Ar, we made 39Ar-40Ar analyses on plagioclase and pyroxene minerals from two phases representing different stages in the magma evolution. Surprisingly, all these separates show similar concentrations of excess 40Ar, ~1 x 10^(-6) cm^(3)/g. We present arguments against this excess 40Ar having been introduced from the Martian atmosphere as impact glass. We also present evidence against excess 40Ar being a partially degassed residue from a basalt that actually formed ~4 Gyr ago. We utilize our experimental data on Ar diffusion in Zagami and evidence that it was shock-heated to only ~70 degrees C, and we assume this heating occurred during an ejection from Mars ~3 Myr ago. With these constraints, thermal considerations necessitates either that its ejected mass was impossibly large, or that its shock-heating temperature was an order of magnitude higher than that measured. We suggest that this excess 40Ar was inherited from the Zagami magma, and that it was introduced into the magma either by degassing of a larger volume of material or by early assimilation of old, K-rich crustal material. Similar concentrations of excess 40Ar in the analyzed separates imply that this magma maintained a relatively constant 40Ar concentration throughout its crystallization. This likely occurred through volatile degassing as the magma rose toward the surface and lithostatic pressure was released. These concepts have implications for excess 40Ar in other shergottites.
  • In situ micro-Raman and X-ray diffraction study of diamonds and petrology of the new ureilite UAE 001 from the United Arab Emirates

    Hezel, D. C.; Dubrovinsky, L.; Nasdala, L.; Cauzid, J.; Simionovici, A.; Gellissen, M.; Schönbeck, T. (The Meteoritical Society, 2008-01-01)
    A new olivine-pigeonite ureilite containing abundant diamonds and graphite was found in the United Arab Emirates. This is the first report of a meteorite in this country. The sample is heavily altered, of medium shock level, and has a total weight of 155 g. Bulk rock, olivine (Fo79.881.8) and pyroxene (En73.9-75.2, Fs15.5-16.9, Wo8.8-9.5) compositions are typical of ureilites. Olivine rims are reduced with Fo increasing up to Fo96.1-96.8. Metal in these rims is completely altered to Fehydroxide during terrestrial weathering. We studied diamond and graphite using micro-Raman and in situ synchrotron X-ray diffraction. The main diamond Raman band (LO=TO mode at ~1332 cm^(-1)) is broadened when compared to well-ordered diamond single crystals. Full widths at half maximum (FWHM) values scatter around 7 cm^(-1). These values resemble FWHM values obtained from chemical vapor deposition (CVD) diamond. In situ XRD measurements show that diamonds have large grain sizes, up to 5 micrometers. Some of the graphite measured is compressed graphite. We explore the possibilities of CVD versus impact shock origin of diamonds and conclude that a shock origin is much more plausible. The broadening of the Raman bands might be explained by prolonged shock pressure resulting in a transitional Raman signal between experimentally shock-produced and natural diamonds.
  • Molecular study of insoluble organic matter in Kainsaz CO3 carbonaceous chondrite: Comparison with CI and CM IOM

    Remusat, L.; Le Guillou, C.; Rouzaud, J.-N.; Binet, L.; Derenne, S.; Robert, F. (The Meteoritical Society, 2008-01-01)
    Kainsaz CO3 insoluble organic matter (IOM) was studied using Curie point pyrolysis, electronic paramagnetic resonance (EPR), and high-resolution transmission electron microscopy (HRTEM) to determine the effect of thermal metamorphism on molecular chondritic fingerprints. Pyrolysis released a very low amount of products that consist of one- and two-ring aromatic units with methyl, dimethyl, and ethyl substituents. Moreover, Kainsaz IOM contains two orders of magnitude fewer radicals than Orgueil, Murchison, and Tagish Lake IOM. In addition, no diradicaloids were found in Kainsaz, although they are thought to constitute a specific signature for weakly organized extraterrestrial organic compounds in contrast to terrestrial ones. HRTEM reveals a very heterogeneous structure, with microporous disordered carbon, mesoporous graphitic carbons and graphite. Graphitization likely occurs and explains the differences between Kainsaz and CI or CM IOM. Heating stress experienced by Kainsaz IOM, on the parent body and/or prior its accretion, is likely responsible for the differences in molecular and structural organizations compared with those of CI and CM IOM.