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

  • Annual Author Index

    The Meteoritical Society, 2006-01-01
  • Annual Subject Index

    The Meteoritical Society, 2006-01-01
  • Differentiation and evolution of the IVA meteorite parent body: Clues from pyroxene geochemistry in the Steinbach stony-iron meteorite

    Ruzicka, A.; Hutson, M. (The Meteoritical Society, 2006-01-01)
    We analyzed the Steinbach IVA stony-iron meteorite using scanning electron microscopy (SEM), electron microprobe analysis (EMPA), laser ablation inductively-coupled-plasma mass spectroscopy (LA-ICP-MS), and modeling techniques. Different and sometimes adjacent low-Ca pyroxene grains have distinct compositions and evidently crystallized at different stages in a chemically evolving system prior to the solidification of metal and troilite. Early crystallizing pyroxene shows evidence for disequilibrium and formation under conditions of rapid cooling, producing clinobronzite and type 1 pyroxene rich in troilite and other inclusions. Subsequently, type 2 pyroxene crystallized over an extensive fractionation interval. Steinbach probably formed as a cumulate produced by extensive crystal fractionation (~60-70% fractional crystallization) from a high-temperature (~1450-1490 degrees C) silicate-metallic magma. The inferred composition of the precursor magma is best modeled as having formed by greater than or equal to 30-50% silicate partial melting of a chondritic protolith. If this protolith was similar to an LL chondrite (as implied by O-isotopic data), then olivine must have separated from the partial melt, and a substantial amount (~53-56%) of FeO must have been reduced in the silicate magma. A model of simultaneous endogenic heating and collisional disruption appears best able to explain the data for Steinbach and other IVA meteorites. Impact disruption occurred while the parent body was substantially molten, causing liquids to separate from solids and oxygen-bearing gas to vent to space, leading to a molten metal-rich body that was smaller than the original parent body and that solidified from the outside in. This model can simultaneously explain the characteristics of both stony-iron and iron IVA meteorites, including the apparent correlation between metal composition and metallographic cooling rate observed for metal.
  • Hydrocode modeling of the Sierra Madera impact structure

    Goldin, T. J.; Wünnemann, K.; Melosh, H. J.; Collins, G. S. (The Meteoritical Society, 2006-01-01)
    We present the first hydrocode simulations of the formation of the Sierra Madera structure (west Texas, USA), which was caused by an impact into a thick sedimentary target sequence. We modeled Sierra Madera using the iSALE hydrocode, and here we present two best-fit models: 1) a crater with a rim (final crater) diameter of ~12 km, in agreement with previous authors interpretations of the original structure, and 2) a crater ~16 km in diameter with increased postimpact erosion. Both models fit some of the geologic observational data, but discrepancies with estimates of peak shock pressure, extent of deformation, and stratigraphic displacement remain. This study suggests that Sierra Madera may be a larger crater than previously reported and illustrates some of the challenges in simulating impact deformation of sedimentary lithologies. As many terrestrial craters possess some amount of sedimentary rocks in the target sequence, numerical models of impacts into sedimentary targets are essential to our understanding of target rock deformation and the mechanics of crater formation.
  • Mobile element analysis by secondary ion mass spectrometry (SIMS) of impactite matrix samples from the Yaxcopoil-1 drill core in the Chicxulub impact structure

    Newsom, H. E.; Nelson, M. J.; Shearer, C. K.; Dressler, B. O. (The Meteoritical Society, 2006-01-01)
    The concentrations of the fluid mobile trace elements lithium, beryllium, boron, and barium were measured in samples of the altered matrix of several impactite breccias of the Yaxcopoil-1 drill core using secondary ion mass spectrometry (SIMS) to determine the extent of transport due to aqueous or hydrothermal processes. Three of the elements, Li, Be, and B, have higher concentrations in the upper suevite impact breccias than in the lower impact melt deposits by factors of 3.5, 2.2, and 1.5, respectively. Lithium and B are the most enriched elements up section, and appear to have had the greatest mobility. The similar fractionation of Li and B is consistent with fluid transport and alteration under low-temperature conditions of less than 150 degrees C based on published experimental studies. In contrast to Li, Be, and B, the concentration of Ba in the altered matrix materials decreases upward in the section, and the concentration of Ba in the matrix is an order of magnitude less than the bulk concentrations, likely due to the presence of barite. The origin of the elemental variations with depth may be related to different protolith compositions in the upper versus the lower impactite units. A different protolith in the altered matrix is suggested by the Mg-rich composition of the lower units versus the Al-rich composition of the upper units, which largely correlates with the mobile element variations. The possibility that vertical transport of mobile elements is due to a postimpact hydrothermal system is supported by published data showing that the sediments immediately overlying the impactites are enriched in mobile elements derived from a hydrothermal system. However, the mobile elements in the sediments do not have to originate from the underlying impactites. In conclusion, our data suggests that the impactites at this location did not experience extensive high-temperature hydrothermal processing, and that only limited transport of some elements, including Li, Be, and B, occurred.
  • Petrology and geochemistry of a silicate clast from the Mount Padbury mesosiderite: Implications for metal-silicate mixing events of mesosiderite

    Tamaki, M.; Yamaguchi, A.; Misawa, K.; Ebihara, M.; Takeda, H. (The Meteoritical Society, 2006-01-01)
    Petrological and bulk geochemical studies were performed on a large silicate clast from the Mount Padbury mesosiderite. The silicate clast is composed mainly of pyroxene and plagioclase with minor amounts of ilmenite, spinel, and other accessory minerals, and it shows subophitic texture. Pyroxenes in the clast are similar to those in type 5 eucrites and could have experienced prolonged thermal metamorphism after rapid crystallization from a near-surface melt. Ilmenite and spinel vary chemically, indicating growth under disequilibrium conditions. The clast seems to have experienced an episode of rapid reheating and cooling, possibly as a result of metal-silicate mixing. Abundances of siderophile elements are obviously higher than in eucrites, although the clast is also extremely depleted in highly siderophile elements. The fractionated pattern can be explained by injection of Fe- FeS melts generated by partial melting of metallic portions during metal-silicate mixing. The silicate clast had a complex petrogenesis that could have included: 1) rapid crystallization from magma in a lava flow or a shallow intrusion; 2) prolonged thermal metamorphism to equilibrate the mineral compositions of pyroxene and plagioclase after primary crystallization; 3) metal-silicate mixing probably caused by the impact of solid metal bodies on the surface of the mesosiderite parent body; and 4) partial melting of metal and sulfide portions (and silicate in some cases) caused by the collisional heating, which produced Fe-FeS melts with highly fractionated siderophile elements that were injected into silicate portions along cracks and fractures.
  • Estimating shock pressures based on high-pressure minerals in shock-induced melt veins of L chondrites

    Xie, Z.; Sharp, T. G.; De Carli, P. S. (The Meteoritical Society, 2006-01-01)
    Here we report the transmission electron microscopy (TEM) observations of the mineral assemblages and textures in shock-induced melt veins from seven L chondrites of shock stages ranging from S3 to S6. The mineral assemblages combined with phase equilibrium data are used to constrain the crystallization pressures, which can be used to constrain shock pressure in some cases. Thick melt veins in the TenhamL6 chondrite contain majorite and magnesiowstite in the center, and ringwoodite, akimotoite, vitrified silicate-perovskite, and majorite in the edge of the vein, indicating crystallization pressure of ~25 GPa. However, very thin melt veins (5-30 micrometers wide) in Tenham contain glass, olivine, clinopyroxene, and ringwoodite, suggesting crystallization during transient low-pressure excursions as the shock pressure equilibrated to a continuum level. Melt veins of Umbarger include ringwoodite, akimotoite, and clinopyroxene in the vein matrix, and Fe2SiO4-spinel and stishovite in SiO2-FeO-rich melt, indicating a crystallization pressure of ~18 GPa. The silicate melt veins in Roy contain majorite plus ringwoodite, indicating pressure of ~20 GPa. Melt veins of Ramsdorf and Nakhon Pathon contain olivine and clinoenstatite, indicating pressure of less than 15 GPa. Melt veins of Kunashak and La Lande include albite and olivine, indicating crystallization at less than 2.5 GPa. Based upon the assemblages observed, crystallization of shock veins can occur before, during, or after pressure release. When the assemblage consists of high-pressure minerals and that assemblage is constant across a larger melt vein or pocket, the crystallization pressure represents the equilibrium shock pressure.
  • A study of Mg and K isotopes in Allende CAIs: Implications to the time scale for the multiple heating processes

    Ito, M.; Nagasawa, H.; Yurimoto, H. (The Meteoritical Society, 2006-01-01)
    The measurements of magnesium and potassium isotopic compositions of refractory minerals in Allende calcium-aluminum-rich inclusions (CAIs), 7R-19-1, HN3-1, and EGG3 were taken by secondary ion mass spectrometry (SIMS). The 7R-19-1 contains 16O-rich and 16O-poor melilite grains and define a single isochron corresponding to an initial 26Al/27Al ratio of (6.6 +/- 1.3) x 10^(-5). The Al-Mg isochron, O isotope measurements and petrography of melilite in 7R-19-1 indicate that 16O-poor melilite crystallized within 0.4 Myr after crystallization of 16O-rich melilite, suggesting that oxygen isotopic composition of the CAI-forming region changed from 16O-rich to 16O-poor within this time interval. The 16O-poor melilite is highly depleted in K compared to the adjacent 16Orich melilite, indicating evaporation during remelting of 7R-19-1. We determined the isochron for 41Ca-41K isotopic systematics in EGG3 pyroxene with (4.1 +/- 2.0) x 10^(-9) (2-sigma) as an initial ratio of 41Ca/40Ca, which is at least two times smaller than the previous result (Sahijipal et al. 2000). The ratio of 41Ca/40Ca in the EGG3 pyroxene grain agrees within error with the value obtained by Hutcheon et al. (1984). No evidence for the presence of 41K excess (decay product of a short-lived radionuclide 41Ca) was found in 7R-19-1 and HN3-1. We infer that the CAI had at least an order of magnitude lower than canonical 41Ca/40Ca ratio at the time of the CAI formation.
  • Carbon and nitrogen in carbonaceous chondrites: Elemental abundances and stable isotopic compositions

    Pearson, V. K.; Sephton, M. A.; Franchi, I. A.; Gibson, J. M.; Gilmour, I. (The Meteoritical Society, 2006-01-01)
    We have undertaken a comprehensive study of carbon and nitrogen elemental abundances and isotopic compositions of bulk carbonaceous chondrites. A strategy of multiple analyses has enabled the investigation of hitherto unconstrained small-scale heterogeneities. No systematic differences are observed between meteorite falls and finds, suggesting that terrestrial processing has a minimal effect on bulk carbon and nitrogen chemistry. The changes in elemental abundance and isotopic composition over the petrologic range may reflect variations in primary accreted materials, but strong evidence exists of the alteration of components during secondary thermal and aqueous processing. These changes are reflected within the CM2 and CO3 groups and follow the published alteration scales for those groups. The nitrogen isotope system appears to be controlled by an organic host, which loses a 15N-rich component with progressive alteration. This study recommends caution, however, over the use of bulk carbon and nitrogen information for classification purposes; variance in relative abundance of different components in carbonaceous chondrites is significant and reflects intrameteorite heterogeneities.
  • Paleomagnetism and petrophysics of the Jänisjärvi impact structure, Russian Karelia

    Salminen, J.; Donadini, F.; Pesonen, L. J.; Masaitis, V. L.; Naumov, M. V. (The Meteoritical Society, 2006-01-01)
    Paleomagnetic, rock magnetic, and petrophysical results are presented for impactites and target rocks from the Lake Jänisjärvi impact structure, Russian Karelia. The impactites (tagamites, suevites, and lithic breccias) are characterized by increased porosity and magnetization, which is in agreement with observations performed at other impact structures. Thermomagnetic, hysteresis, and scanning electron microscope (SEM) analysis document the presence of primary multidomain titanomagnetite with additional secondary titanomaghemite and ilmenohematite. The characteristic impact-related remanent magnetization (ChRM) direction (D = 101.5 degrees, I = 73.1 degrees, alpha-95 = 6.2 degrees) yields a pole (Lat. = 45.0mdegrees N, Long. = 76.9 degrees E, dp = 9.9 degrees, dm = 11.0 degrees). Additionally, the same component is observed as an overprint on some rocks located in the vicinity of the structure, which provides proofs of its primary origin. An attempt was made to determine the ancient geomagnetic field intensity. Seven reliable results were obtained, yielding an ancient intensity of 68.7 +/- 7.6 micro-T (corresponding to VDM of 10.3 +/- 1.1 x 10^22 Am^2). The intensity, however, appears to be biased toward high values mainly because of the concave shape of the Arai diagrams. The new paleomagnetic data and published isotopic ages for the structure are in disagreement. According to well-defined paleomagnetic data, two possible ages for magnetization of Jänisjärvi rocks exist: 1) Late Sveconorwegian age (900-850 Myr) or 2) Late Cambrian age (~500 Myr). However, published isotopic ages are 718 +/- 5 Myr (K-Ar) and 698 +/- 22 Myr (39Ar-40Ar), but such isotopic dating methods are often ambiguous for the impactites.
  • Olivine zoning and retrograde olivine-orthopyroxene-metal equilibration in H5 and H6 chondrites

    Reisener, R. J.; Goldstein, J. I.; Petaev, M. I. (The Meteoritical Society, 2006-01-01)
    Electron microprobe studies of several H5 and H6 chondrites reveal that olivine crystals exhibit systematic Fe-Mg zoning near olivine-metal interfaces. Olivine Fa concentrations decrease by up to 2 mol% toward zoned taenite + kamacite particles (formed after relatively small amounts of taenite undercooling) and increase by up to 2 mol% toward zoneless plessite particles (formed after ~200 degrees C of taenite undercooling). The olivine zoning can be understood in terms of localized olivine-orthopyroxene-metal reactions during cooling from the peak metamorphic temperature. The silicate-metal reactions were influenced by solid-state metal phase transformations, and the two types of olivine zoning profiles resulted from variable amounts of taenite undercooling at temperatures <700 degrees C. The relevant silicate-metal reactions are modeled using chemical thermodynamics. Systematic olivine Fe-Mg zoning adjacent to metal is an expected consequence of retrograde silicate-metal reactions, and the presence of such zoning provides strong evidence that the silicate and metallic minerals evolved in situ during cooling from the peak metamorphic temperature.