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

  • "Comet-tail" ejecta streaks: A predicted cratering landform unique to Titan

    Lorenz, R. D. (The Meteoritical Society, 2004-01-01)
    A model for an impact ejecta landform peculiar to Saturns moon Titan is presented. Expansion of the ejecta plume from moderate-sized craters is constrained by Titans thick atmosphere. Much of the plume is collimated along the incoming bolides trajectory, as was observed for plumes from impacts on Jupiter of P/Shoemaker-Levy-9, but is retained as a linear, diagonal ejecta cloud, unlike on Venus where the plume blows out. On Titan, the blowout is suppressed because the vertically-extended atmosphere requires a long wake to reach the vacuum of space, and the modest impact velocities mean plume expansion along the wake is slow enough to allow the wake to close off. Beyond the immediate ejecta blanket around the crater, distal ejecta is released into the atmosphere from an oblique line source: this material is winnowed by the zonal wind field to form streaks, with coarse radar-bright particles transported less far than fine radar-dark material. Thus, the ejecta form two distinct streaks faintly reminiscent of dual comet tails, a sharply W-E radar-dark one, and a less swept and sometimes comma-shaped radar-bright one.
  • Spectroscopic anatomy of a meteor trail cross section with the European Southern Observatory Very Large Telescope

    Jenniskens, P.; Jehin, E.; Cabanac, R. A.; Laux, C. O.; Boyd, I. D. (The Meteoritical Society, 2004-01-01)
    A meteor spectrum was recorded serendipitously at the European Southern Obrervatory (ESO) Very Large Telescope (VLT) during a long exposure in long-slit spectroscopic mode with FORS1. The -8 magnitude fireball crossed the narrow 1Î x 7î slit during the observation of a high z supernova in normal service mode operation on May 12, 2002. The spectrum covered the range of 6371050 nm, where the meteors air plasma emissions from N2, N, and O dominate. Carbon atom emission was not detected in the relatively unexplored wavelength range above 900 nm, but the observed upper limit was only 3 sigma less than expected from the dissociation of atmospheric CO2. The meteor trail was resolved along the slit, and the emission had a Gaussian distribution with a dimension of FWHM = 7.0 (+/- 0.4) * sin(alpha) * H (km)/90 m, where alpha is the unknown angle between the orientation of the meteor path and slit and H the assumed altitude of the meteor in km. To our knowledge, this is the first observation of a spatially resolved spectrum across a meteor trail. Unlike model predictions, the plasma excitation temperature varied only from about 4,300 to 4,365 K across the trail, based on the ratio of atomic and molecular nitrogen emissions. Unfortunately, we conclude that this was because the meteor at 100 km altitude was out of focus.
  • REE abundances in the matrix of the Allende (CV) meteorite: Implications for matrix origin

    Inoue, M.; Kimura, M.; Nakamura, N. (The Meteoritical Society, 2004-01-01)
    The trace element distributions in the matrix of primitive chondrites were examined using four least-contaminated matrix specimens from the polished sections of the Allende (CV) meteorite. Analysis of rare earth element (REE), Ba, Sr, Rb, and K abundances by isotope dilution mass spectrometry revealed that the elemental abundances of lithophile elements except for alkali metals (K, Rb) in the specimens of the Allende matrix studied here are nearly CI (carbonaceous Orgueil) chondritic (~1 x CI). Compared to refractory elements, all the matrix samples exhibited systematic depletion of the moderately volatile elements K and Rb (0.1-0.5 x CI). We suggest that the matrix precursor material did not carry significant amounts of alkali metals or that the alkalis were removed from the matrix precursor material during the parent body process and/or before matrix formation and accretion. The matrix specimens displayed slightly fractionated REE abundance patterns with positive Ce anomalies (CI-normalized La/Yb ratio = 1.32-1.65; Ce/Ce* = 1.16-1.28; Eu/Eu* = 0.98-1.10). The REE features of the Allende matrix do not indicate a direct relationship with chondrules or calcium-aluminum-rich inclusions (CAIs), which in turn suggests that the matrix was not formed from materials produced by the breakage and disaggregation of the chondrules or CAIs. Therefore, we infer that the Allende matrix retains the REE features acquired during the condensation process in the nebula gas.
  • Impact ejecta in upper Eocene deposits at Massignano, Italy

    Glass, B. P.; Liu, S.; Montanari, A. (The Meteoritical Society, 2004-01-01)
    Previous workers have shown that an impact ejecta layer at Massignano, Italy contains a positive Ir anomaly, flattened spheroids (pancake spherules), Ni-rich spinel crystals, and shocked quartz with multiple sets of planar deformation features. Because of sample sizes and work by different investigators, it was not clear if the shocked quartz is associated with the Ir anomaly and pancake spherules or if it belongs to a separate impact event. To address this problem, we carried out a high-resolution stratigraphic study of this ejecta layer. The ejecta layer was sampled continuously at 1 cm intervals in two adjacent columns. The carbonate was removed with dilute HCl, and the noncarbonate fraction was gently sieved. Pancake spherules were recovered from the 250-500 micrometers size fraction and counted. At the peak abundance, the number of pancake spherules in the 250-500 micrometers size fraction is about 67/g of sample. The pancake spherules removed from the 250-500 micrometers size fraction are mostly translucent to opaque pale green, but some have a grey color or dark opaque patches due to a coating of Ni- and Cr-rich spinel crystals. Energy-dispersive X-ray analysis and Xray diffraction data indicate that the green spherules are composed of iron-rich smectite, probably nontronite. Black opaque spinel stringers (dark spinel-rich pancake spherules), usually 200 micrometers across, can be seen in a polished section of a block that includes the ejecta layer. None of the dark spinel-rich pancake spherules were recovered from the sieved non-carbonate fraction due to their fragile nature, but we believe that they are from the same impact event as the green pancake spherules. The <250 micrometers size fractions from both columns were disaggregated using ultrasonics and re-sieved. The 63-125 micrometers size fractions were then searched for shocked quartz using a petrographic microscope. At the peak-abundance level, the number of shocked quartz grains in the 63-125 micrometers size fraction is about 7/g of sample. Some of the shocked quartz grains have a toasted appearance. These grains have a brownish color and contain a patchy distribution of faint, densely spaced planar deformation features (PDFs). Polymineralic fragments containing one or two shocked quartz grains with one or two sets of PDFs were observed. They appear to have an organic matrix and are probably fragments of agglutinated foraminiferal tests. We searched for, but did not find, coesite or shocked zircons. We found that the peak abundance of the shocked quartz is within a centimeter of the peak abundance of the green pancake spherules. We conclude that the pancake spherules are diagenetically altered clinopyroxene-bearing spherules and that the shocked quartz, green (and presumably the dark spinel-rich) pancake spherules, and Ir anomaly all belong to the same impact event. This conclusion is consistent with previous suggestions that the cpx spherule layer may be from the 100 km-diameter Popigai impact crater in northern Siberia.
  • An anthropogenic origin of the "Sirente crater," Abruzzi, Italy

    Speranza, F.; Sagnotti, L.; Rochette, P. (The Meteoritical Society, 2004-01-01)
    In this paper, we review the recent hypothesis, based mostly on geomorphological features, that a ~130 m-wide sag pond, surrounded by a saddle-shaped rim from the Sirente plain (Abruzzi Italy), is the first-discovered meteoritic crater of Italy. Sub-circular depressions (hosting ponds), with geomorphological features and size very similar to those exhibited by the main Sirente sag, are exposed in other neighboring intermountain karstic plains from Abruzzi. We have sampled presentday soils from these sag ponds and from the Sirente sags (both the main crater and some smaller ones, recently interpreted as a crater field) and various Abruzzi paleosols from excavated trenches with an age range encompassing the estimated age of the "Sirente crater." For all samples, we measured the magnetic susceptibility and determined the Ni and Cr contents of selected specimens. The results show that the magnetic susceptibility values and the geochemical composition are similar for all samples (from Sirente and other Abruzzi sags) and are both significantly different from the values reported for soils contaminated by meteoritic dust. No solid evidence pointing at an impact origin exists, besides the circular shape and rim of the main sag. The available observations and data suggest that the Sirente crater, together with analogous large sags in the Abruzzi intermountain plains, have to be attributed to the historical phenomenon of transumanza (seasonal migration of sheep and shepherds), a custom that for centuries characterized the basic social-economical system of the Abruzzi region. Such sags were excavated to provide water for millions of sheep, which spent summers in the Abruzzi karstic high pasture lands, on carbonatic massifs deprived of natural superficial fresh water. Conversely, the distribution of the smaller sags from the Sirente plain correlates with the local pattern of the calcareous bedrock and, together with the characteristics of their internal structure, are best interpreted as natural dolines. In fact, reported radiocarbon ages for the formation of the main sag pond and of the smaller sags differ (significantly) by more than two millennia, thus excluding that they were all contemporaneously formed by a meteoritic impact.
  • The fall, recovery, and classification of the Park Forest meteorite

    Simon, S. B.; Grossman, L.; Clayton, R. N.; Mayeda, T. K.; Schwade, J. R.; Sipiera, P. P.; Wacker, J. F.; Wadhwa, M. (The Meteoritical Society, 2004-01-01)
    On the night of March 26, 2003, a large meteorite broke up and fell upon the south suburbs of Chicago. The name Park Forest, for the village that is at the center of the strewnfield, has been approved by the nomenclature committee of the Meteoritical Society. Satellite data indicate that the bolide traveled from the southwest toward the northeast. The strewnfield has a southeast-northwest trend; however, this is probably due to the effects of strong westerly winds at high altitudes. Its very low 56Co and very high 60Co activities indicate that Park Forest had a preatmospheric mass that was at least ~900 kg and could have been as large as ~7 x 10^3 kg, of which only ~30 kg have been recovered. The average compositions of olivine and low-Ca pyroxene, Fa24.7 +/- 1.1 and Fs20.8 +/- 0.7, respectively, and its bulk oxygen isotopic composition, delta-18O = +4.68 ppm, delta-17O = +3.44 ppm, show that Park Forest is an L chondrite. The ferromagnesian minerals are well equilibrated, chondrules are easily recognized, and maskelynite is mostly less than or equal to 50 micrometers across. Based on these observations, we classify Park Forest as type 5. The meteorite has been strongly shocked, and based on the presence of maskelynite, mosaicism and planar deformation features in olivine, undulatory extinction in pyroxene, and glassy veins, the shock stage is S5. The meteorite is a monomict breccia, consisting of light-colored, angular to rounded clasts in a very dark host. The light and dark lithologies have essentially identical mineral and oxygen isotopic compositions. Their striking difference in appearance is due to the presence of a fine, pervasive network of sulfide veins in the dark lithology, resulting in very short optical path lengths. The dark lithology probably formed from the light lithology in an impact that formed a sulfide-rich melt and injected it into cracks.
  • Spectral reflectance-compositional properties of spinels and chromites: Implications for planetary remote sensing and geothermometry

    Cloutis, E. A.; Sunshine, J. M.; Morris, R. V. (The Meteoritical Society, 2004-01-01)
    Reflectance spectra of spinels and chromites have been studied as a function of composition. These two groups of minerals are spectrally distinct, which relates largely to differences in the types of major cations present. Both exhibit a number of absorption features in the 0.3-26 micrometer region that show systematic variations with composition and can be used to quantify or constrain certain compositional parameters, such as cation abundances, and site occupancies. For spinels, the best correlations exist between Fe2+ content and wavelength positions of the 0.46, 0.93, 2.8, Restrahelen, 12.3, 16.2, and 17.5 micrometer absorption features, Al and Fe3+ content with the wavelength position of the 0.93 micrometer absorption feature, and Cr content from the depth of the absorption band near 0.55 micrometers. For chromites, the best correlations exist between Cr content and wavelength positions of the 0.49, 0.59, 2, 17.5, and 23 micrometer absorption features, Fe2+ and Mg contents with the wavelength position of the 1.3 micrometer absorption feature, and Al content with the wavelength position of the 2 micrometer absorption feature. At shorter wavelengths, spinels and chromites are most readily distinguished by the wavelength position of the absorption band in the 2 m region (<2.1 micrometers for spinels, >2.1 micrometers for chromite), while at longer wavelengths, spectral differences are more pronounced. The importance of being able to derive compositional information for spinels and chromites from spectral analysis stems from the relationship between composition and petrogenetic conditions (pressure, temperature, oxygen fugacity) and the widespread presence of spinels and chromites in the inner solar system. When coupled with the ability to derive compositional information for mafic silicates from spectral analysis, this opens up the possibility of deriving petrogenetic information for remote spinel- and chromite-bearing targets from analysis of their reflectance spectra.
  • Accessory silicate mineral assemblages in the Bilanga diogenite: A petrographic study

    Domanik, K.; Kolar, S.; Musselwhite, D.; Drake, M. J. (The Meteoritical Society, 2004-01-01)
    The petrographic relationships in diogenites between orthopyroxene and minor phases such as chromite, troilite, diopside, plagioclase, and silica are often obscured by the intense brecciation that characterizes these meteorites. Although brecciated, Bilanga preserves numerous clasts displaying primary textural relations between orthopyroxene and these minor phases that are large enough to analyze by electron microprobe. In this study, we focus on the distribution, composition, and origin of the minor phases in Bilanga to provide new insights into the crystallization and metamorphic history of these rocks. The samples examined consist mainly of orthopyroxene grains plus five types of assemblages containing diopside + a Fe-rich phase (chromite, troilite, and/or Fe-Ni metal) +/- plagioclase +/- silica. We interpret type 1 assemblages as being remnants of intercumulus melt trapped in the interstices between orthopyroxene grains after crystal settling in a magma chamber. Type 2 assemblages appear to have formed by heterogeneous exsolution during thermal metamorphism. Type 3 assemblages are believed to be remnants of other assemblages that have been shocked, melted, and rapidly recrystallized by impact events. Type 4 assemblages consist of veins that also appear to have formed from trapped intercumulus melt. Regions of silica-rich mesostasis (type 5) appear to be larger patches of more evolved intercumulus melt that have been significantly affected by late-stage impact melting. Finally, large clasts containing plagioclase diopside are interpreted to be exotic fragments of a different but possibly related rock type incorporated in the Bilanga breccia.
  • Experimental study of the degradation of polymers: Application to the origin of extended sources in cometary atmospheres

    Fray, N.; Bénilan, Y.; Cottin, H.; Gazeau, M.-C.; Minard, R. D.; Raulin, F. (The Meteoritical Society, 2004-01-01)
    This paper presents some preliminary results concerning the degradation of refractory nitrogenated polymers, which could be responsible for the CN extended source in comets. We are studying hexamethylenetetramine (HMT) and HCN polymers. Both compounds have been irradiated or heated to simulate the degradation processes they undergo in the cometary atmosphere. We show that, even if both compounds are quite stable under photolysis, the heating leads to a much more efficient degradation with the formation of HCN, NH3, and other heavier compounds. Moreover, the thermal degradation of HCN polymers appears to be more efficient than that of HMT. Thus, the HCN polymers seem to be better candidates for the CN extended source. We are now developing a new reactor to quantify the production of gaseous molecules and to detect in situ CN radicals.
  • The frequency of compound chondrules and implications for chondrule formation

    Ciesla, F.J.; Lauretta, D. S.; Hood, L. L. (The Meteoritical Society, 2004-01-01)
    The properties of compound chondrules and the implications that they have for the conditions and environment in which chondrules formed are investigated. Formulae to calculate the probability of detecting compound chondrules in thin sections are derived and applied to previous studies. This reinterpretation suggests that at least 5% of chondrules are compounds, a value that agrees well with studies in which whole chondrules were removed from meteorites. The observation that adhering compounds tend to have small contact arcs is strengthened by application of these formulae. While it has been observed that the secondaries of compound chondrules are usually smaller than their primaries, these same formulae suggest that this could be an observation bias. It is more likely than not that thin section analyses will identify compounds with secondaries that are smaller than their primaries. A new model for chondrule collisional evolution is also developed. From this model, it is inferred that chondrules would have formed, on average, in areas of the solar nebula that had solids concentrated at least 45 times over the canonical solar value.
  • Petrogenesis of lunar highlands meteorites: Dhofar 025, Dhofar 081, Dar al Gani 252, and Dar al Gani 400

    Cahill, J. T.; Floss, C.; Anand, M.; Taylor, L. A.; Nazarov, M. A.; Cohen, B. A. (The Meteoritical Society, 2004-01-01)
    The petrogenesis of four lunar highlands meteorites, Dhofar 025 (Dho 025), Dhofar 081 (Dho 081), Dar al Gani 262 (DaG 262), and Dar al Gani 400 (DaG 400) were studied. For Dho 025, measured oxygen isotopic values and Fe-Mn ratios for mafic minerals provide corroboratory evidence that it originated on the Moon. Similarly, Fe-Mn ratios in the mafic minerals of Dho 081 indicate lunar origin. Lithologies in Dho 025 and Dho 081 include lithic clasts, granulites, and mineral fragments. A large number of lithic clasts have plagioclase AN# and coexisting mafic mineral Mg# that plot within the "gap" separating ferroan anorthosite suite (FAN) and high-magnesium suite (HMS) rocks. This is consistent with whole rock Ti-Sm ratios for Dho 025, Dho 081, and DaG 262, which are also intermediate compared to FAN and HMS lithologies. Although ion microprobe analyses performed on Dho 025, Dho 081, DaG 262, and DaG 400 clasts and minerals show far stronger FAN affinities than whole rock data suggest, most clasts indicate admixture of less than or equal to 12% HMS component based on geochemical modeling. In addition, coexisting plagioclase-pyroxene REE concentration ratios in several clasts were compared to experimentally determined plagioclase-pyroxene REE distribution coefficient ratios. Two Dho 025 clasts have concordant plagioclase-pyroxene profiles, indicating that equilibrium between these minerals has been sustained despite shock metamorphism. One clast has an intermediate FAN-HMS composition. These lunar meteorites appear to represent a type of highland terrain that differs substantially from the KREEP-signatured impact breccias that dominate the lunar database. From remote sensing data, it is inferred that the lunar far side appears to have appropriate geochemical signatures and lithologies to be the source regions for these rocks; although, the near side cannot be completely excluded as a possibility. If these rocks are, indeed, from the far side, their geochemical characteristics may have far-reaching implications for our current scientific understanding of the Moon.