Isotopic compositions,nitrogen functional chemistry,and low‐loss electron spectroscopy of complex organic aggregates at the nanometer scale in the carbonaceous chondrite Renazzo     

Christian Vollmer  Jan Leitner  Demie Kepaptsoglou  Quentin M. Ramasse  Henner Busemann  Peter Hoppe 《Meteoritics & planetary science》2020,55(6):1293-1319

Organic matter (OM) was widespread in the early solar nebula and might have played an important role for the delivery of prebiotic molecules to the early Earth. We investigated the textures, isotopic compositions, and functional chemistries of organic grains in the Renazzo carbonaceous chondrite by combined high spatial resolution techniques (electron microscopy–secondary ion mass spectrometry). Morphologies are complex on a submicrometer scale, and some organics exhibit a distinct texture with alternating layers of OM and minerals. These layered organics are also characterized by heterogeneous ¹⁵N isotopic abundances. Functional chemistry investigations of five focused ion beam‐extracted lamellae by electron energy loss spectroscopy reveal a chemical complexity on a nanometer scale. Grains show absorption at the C‐K edge at 285, 286.6, 287, and 288.6 eV due to polyaromatic hydrocarbons, different carbon‐oxygen, and aliphatic bonding environments with varying intensity. The nitrogen K‐edge functional chemistry of three grains is shown to be highly complex, and we see indications of amine (C‐NH_x) or amide (CO‐NR₂) chemistry as well as possible N‐heterocycles and nitro groups. We also performed low‐loss vibrational spectroscopy with high energy resolution and identified possible D‐ and G‐bands known from Raman spectroscopy and/or absorption from C=C and C‐O stretch modes known from infrared spectroscopy at around 0.17 and 0.2 eV energy loss. The observation of multiglobular layered organic aggregates, heterogeneous ¹⁵N‐anomalous compositions, and indication of NH_x‐(amine) functional chemistry lends support to recent ideas that ¹⁵N‐enriched ammonia (NH₃) was a powerful agent to synthesize more complex organics in aqueous asteroidal environments.  相似文献   

Annama H chondrite—Mineralogy,physical properties,cosmic ray exposure,and parent body history          下载免费PDF全文

Tomáš Kohout  Jakub Haloda  Patricie Halodová  Matthias M. M. Meier  Colin Maden  Henner Busemann  Matthias Laubenstein  Marc. W. Caffee  Kees C. Welten  Jens Hopp  Mario Trieloff  Ramakant R. Mahajan  Sekhar Naik  Josep M. Trigo‐Rodriguez  Carles E. Moyano‐Cambero  Michael I. Oshtrakh  Alevtina A. Maksimova  Andrey V. Chukin  Vladimir A. Semionkin  Maksim S. Karabanalov  Israel Felner  Evgeniya V. Petrova  Evgeniia V. Brusnitsyna  Victor I. Grokhovsky  Grigoriy A. Yakovlev  Maria Gritsevich  Esko Lyytinen  Jarmo Moilanen  Nikolai A. Kruglikov  Aleksey V. Ishchenko 《Meteoritics & planetary science》2017,52(8):1525-1541

The fall of the Annama meteorite occurred early morning (local time) on April 19, 2014 on the Kola Peninsula (Russia). Based on mineralogy and physical properties, Annama is a typical H chondrite. It has a high Ar‐Ar age of 4.4 Ga. Its cosmic ray exposure history is atypical as it is not part of the large group of H chondrites with a prominent 7–8 Ma peak in the exposure age histograms. Instead, its exposure age is within uncertainty of a smaller peak at 30 ± 4 Ma. The results from short‐lived radionuclides are compatible with an atmospheric pre‐entry radius of 30–40 cm. However, based on noble gas and cosmogenic radionuclide data, Annama must have been part of a larger body (radius >65 cm) for a large part of its cosmic ray exposure history. The ¹⁰Be concentration indicates a recent (3–5 Ma) breakup which may be responsible for the Annama parent body size reduction to 30–35 cm pre‐entry radius.  相似文献   

Iron oxides in comet 81P/Wild 2     

John C. BRIDGES  Mark J. BURCHELL  Hitesh C. CHANGELA  Nick J. FOSTER  J. Alan CREIGHTON  James D. CARPENTER  Steve J. GURMAN  Ian A. FRANCHI  Henner BUSEMANN 《Meteoritics & planetary science》2010,45(1):55-72

Abstract– We have used synchrotron Fe‐XANES, XRS, microRaman, and SEM‐TEM analyses of Stardust track 41 slice and track 121 terminal area slices to identify Fe oxide (magnetite‐hematite and amorphous oxide), Fe‐Ti oxide, and V‐rich chromite (Fe‐Cr‐V‐Ti‐Mn oxide) grains ranging in size from 200 nm to ～10 μm. They co‐exist with relict FeNi metal. Both Fe‐XANES and microRaman analyses suggest that the FeNi metal and magnetite (Fe₂O₃FeO) also contain some hematite (Fe₂O₃). The FeNi has been partially oxidized (probably during capture), but on the basis of our experimental work with a light‐gas gun and microRaman analyses, we believe that some of the magnetite‐hematite mixtures may have originated on Wild 2. The terminal samples from track 121 also contain traces of sulfide and Mg‐rich silicate minerals. Our results show an unequilibrated mixture of reduced and oxidized Fe‐bearing minerals in the Wild 2 samples in an analogous way to mineral assemblages seen in carbonaceous chondrites and interplanetary dust particles. The samples contain some evidence for terrestrial contamination, for example, occasional Zn‐bearing grains and amorphous Fe oxide in track 121 for which evidence of a cometary origin is lacking.  相似文献   

Effects of aqueous alteration on primordial noble gases and presolar SiC in the carbonaceous chondrite Tagish Lake     

M. E. I. Riebe  H. Busemann  C. M. O'D. Alexander  L. R. Nittler  C. D. K. Herd  C. Maden  J. Wang  R. Wieler 《Meteoritics & planetary science》2020,55(6):1257-1280

Effects of aqueous alteration on primordial noble gas carriers were investigated by analyzing noble gases and determining presolar SiC abundances in insoluble organic matter (IOM) from four Tagish Lake meteorite (C2‐ung.) samples that experienced different degrees of aqueous alteration. The samples contained a mixture of primordial noble gases from phase Q and presolar nanodiamonds (HL, P3), SiC (Ne‐E[H]), and graphite (Ne‐E[L]). The second most altered sample (11i) had a ~2–3 times higher Ne‐E concentration than the other samples. The presolar SiC abundances in the samples were determined from NanoSIMS ion images and 11i had a SiC abundance twice that of the other samples. The heterogeneous distribution of SiC grains could be inherited from heterogeneous accretion or parent body alteration could have redistributed SiC grains. Closed system step etching (CSSE) was used to study noble gases in HNO₃‐susceptible phases in the most and least altered samples. All Ne‐E carried by presolar SiC grains in the most altered sample was released during CSSE, while only a fraction of the Ne‐E was released from the least altered sample. This increased susceptibility to HNO₃ likely represents a step toward degassing. Presolar graphite appears to have been partially degassed during aqueous alteration. Differences in the ⁴He/³⁶Ar and ²⁰Ne/³⁶Ar ratios in gases released during CSSE could be due to gas release from presolar nanodiamonds, with more He and Ne being released in the more aqueously altered sample. Aqueous alteration changes the properties of presolar grains so that they react similar to phase Q in the laboratory, thereby altering the perceived composition of Q.  相似文献   

Orbit and origin of the LL7 chondrite Dishchii'bikoh (Arizona)     

Peter Jenniskens  Nick Moskovitz  Laurence A. J. Garvie  Qing‐Zhu Yin  J. Andreas Howell  Dwayne L. Free  Jim Albers  David Samuels  Marc D. Fries  Prajkta Mane  Daniel R. Dunlap  Karen Ziegler  Matthew E. Sanborn  Qin Zhou  Qiu‐Li Li  Xian‐Hua Li  Yu Liu  Guo‐Qiang Tang  Kees C. Welten  Marc W. Caffee  Henner Busemann  Matthias M. M. Meier  David Nesvorny 《Meteoritics & planetary science》2020,55(3):535-557

The trajectory and orbit of the LL7 ordinary chondrite Dishchii'bikoh are derived from low‐light video observations of a fireball first detected at 10:56:26 UTC on June 2, 2016. Results show a relatively steep ~21° inclined orbit and a short 1.13 AU semimajor axis. Following entry in Earth's atmosphere, the meteor luminosity oscillated corresponding to a meteoroid spin rate of 2.28 ± 0.02 rotations per second. A large fragment broke off at 44 km altitude. Further down, mass was lost to dust during flares at altitudes of 34, 29, and 25 km. Surviving meteorites were detected by Doppler weather radar and several small 0.9–29 g meteorites were recovered under the radar reflection footprint. Based on cosmogenic radionuclides and ground‐based radiometric observations, the Dishchii'bikoh meteoroid was 80 ± 20 cm in diameter assuming the density was 3.5 g/cm³. The meteoroid's collisional history confirms that the unusual petrologic class of LL7 does not require a different parent body than three previously observed LL chondrite falls. Dishchii'bikoh was ejected 11 Ma ago from parent body material that has a 4471 ± 6 Ma U‐Pb age, the same as that of Chelyabinsk (4452 ± 21 Ma). The distribution of the four known pre‐impact LL chondrite orbits is best matched by dynamical modeling if the source of LL chondrites is in the inner asteroid belt in a low inclined orbit, with the highly inclined Dishchii'bikoh being the result of interactions with Earth before impacting.  相似文献   

Ejby—A new H5/6 ordinary chondrite fall in Copenhagen,Denmark     

H. Haack  A. N. Srensen  A. Bischoff  M. Patzek  J.‐A. Barrat  S. Midtskogen  E. Stempels  M. Laubenstein  R. Greenwood  P. Schmitt‐Kopplin  H. Busemann  C. Maden  K. Bauer  P. Morino  M. Schnbchler  P. Voss  T. Dahl‐Jensen 《Meteoritics & planetary science》2019,54(8):1853-1869

On February 6, 2016 at 21:07:19 UT, a very bright fireball was seen over the eastern part of Denmark. The weather was cloudy over eastern Denmark, but many people saw the sky light up—even in the heavily illuminated Copenhagen. Two hundred and thirty three reports of the associated sound and light phenomena were received by the Danish fireball network. We have formed a consortium to describe the meteorite and the circumstances of the fall and the results are presented in this paper. The first fragment of the meteorite was found the day after the fall, and in the following weeks, a total of 11 fragments with a total weight of 8982 g were found. The meteorite is an unbrecciated, weakly shocked (S2), ordinary H chondrite of petrologic type 5/6 (Bouvier et al. 2017). The concentration of the cosmogenic radionuclides suggests that the preatmospheric radius was rather small ~20 cm. The cosmic ray exposure age of Ejby (83 ± 11 Ma) is the highest of an H chondrite and the second highest age for an ordinary chondrite. Using the preatmospheric orbit of the Ejby meteoroid (Spurny et al. 2017) locations of the recovered fragments, and wind data from the date of the fall, we have modeled the dark flight (below 18 km) of the fragments. The recovery location of the largest fragment can only be explained if aerodynamic effects during the dark flight phase are included. The recovery location of all other fragments are consistent with the dark flight modeling.  相似文献   

Ejection ages from krypton‐81‐krypton‐83 dating and pre‐atmospheric sizes of martian meteorites     

O. Eugster  H. Busemann  S. Lorenzetti  D. Terribilini 《Meteoritics & planetary science》2002,37(10):1345-1360

Abstract— Cosmic‐ray exposure (CRE) ages and Mars ejection times were calculated from the radionuclide ⁸¹Kr and stable Kr isotopes for seven martian meteorites. The following ⁸¹Kr‐Kr CRE ages were obtained: Los Angeles = 3.35 ± 0.70 Ma; Queen Alexandra Range 94201 = 2.22 ± 0.35 Ma; Shergotty = 3.05 ± 0.50 Ma; Zagami = 2.98 ± 0.30 Ma; Nakhla = 10.8 ± 0.8 Ma; Chassigny = 10.6 ± 2.0 Ma; and Allan Hills 84001 = 15.4 ± 5.0 Ma. Comparison of these ages with previously obtained CRE ages from the stable noble gas nuclei ³He, ²¹Ne, and ³⁸Ar shows excellent agreement. This indicates that the method for the production rate calculation for the stable nuclei is reliable. In all martian meteorites we observe effects induced by secondary cosmic‐ray produced epithermal neutrons. Epithermal neutron fluxes, φ_n (30–300 eV), are calculated based on the reaction ⁷⁹Br(n, γβ)⁸⁰Kr. We show that the neutron capture effects were induced in free space during Mars‐Earth transfer of the meteoroids and that they are not due to a pre‐exposure on Mars before ejection of the meteoritic material. Neutron fluxes and slowing down densities experienced by the meteoroids are calculated and pre‐atmospheric sizes are estimated. We obtain minimum radii in the range of 22–25 cm and minimum masses of 150–220 kg. These results are in good agreement with the mean sizes reported for model calculations using current semiempirical data.  相似文献   

The Golden meteorite fall: Fireball trajectory,orbit, and meteorite characterization     

P. G. Brown  P. J. A. McCausland  A. R. Hildebrand  L. T. J. Hanton  L. M. Eckart  H. Busemann  D. Krietsch  C. Maden  K. Welten  M. W. Caffee  M. Laubenstein  D. Vida  F. Ciceri  E. Silber  C. D. K. Herd  P. Hill  H. Devillepoix  Eleanor K. Sansom  Martin Cupák  Seamus Anderson  R. L. Flemming  A. J. Nelson  M. Mazur  D. E. Moser  W. J. Cooke  D. Hladiuk  Barbara Malečić  Maja Telišman Prtenjak  R. Nowell  The Golden Meteorite Consortium 《Meteoritics & planetary science》2023,58(12):1773-1807

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