Jesenice—A new meteorite fall from Slovenia |
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Authors: | Addi BISCHOFF Miha JERSEK Thomas GRAU Breda MIRTIC Ulrich OTT Jan KU?ERA Marian HORSTMANN Matthias LAUBENSTEIN Siegfried HERRMANN Zdeněk ?ANDA Marc WEBER Gerd HEUSSER |
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Institution: | 1. Institut für Planetologie, Wilhelm‐Klemm‐Str. 10, 48149 Münster, Germany;2. Slovenian Museum of Natural History, Presernova 20, SI‐1000 Ljubljana, Slovenia;3. European Research Center for Fireballs and Meteorites (ERFM), Puschkinstra?e 23, 16321 Bernau bei Berlin, Germany;4. Department of Geology, Faculty of Natural Sciences and Engineering, University of Ljubljana, SI‐1000 Ljubljana, Slovenia;5. Abteilung Biogeochemie, Max‐Planck‐Institut für Chemie, Joh.‐J.‐Becher‐Weg 27, 55128 Mainz, Germany;6. Nuclear Physics Institute, Academy of Sciences of the Czech Republic, CZ‐250 7. 68 ?e? near Prague, Czech Republic;8. Research Center ?e?, Ltd., CZ‐250 9. 68 ?e?, Czech Republic;10. Laboratori Nazionali del Gran Sasso – I.N.F.N., S.S.17/bis, km 18+910, I‐67010 Assergi (AQ), Italy;11. Max‐Planck‐Institut für Kernphysik, Postfach 103980, 69029 Heidelberg, Germany |
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Abstract: | Abstract– On April 9, 2009, at 3:00 CEST, a very bright fireball appeared over Carinthia and the Karavanke Mountains. The meteoroid entered the atmosphere at a very steep angle and disintegrated into a large number of objects. Two main objects were seen as separate fireballs up to an altitude of approximately 5 km, and witnesses reported loud explosions. Three stones were found with a total weight of approximately 3.611 kg. The measured activity of short‐lived cosmogenic radionuclides clearly indicates that two specimens result from a very recent meteorite fall. All cosmogenic radionuclide concentrations suggest a rather small preatmospheric radius of <20 cm; a nominal cosmic‐ray exposure age based on 21Ne is approximately 4 Ma, but the noble gas and radionuclide results in combination indicate a complex irradiation. Jesenice is a highly recrystallized rock with only a few relic chondrules visible in hand specimen and thin section. The texture, the large grain size of plagioclase, and the homogeneous compositions of olivines and pyroxenes clearly indicate that Jesenice is a L6 chondrite. The bulk composition of Jesenice is very close to the published average element concentration for L ordinary chondrites. The chondrite is weakly shocked (S3) as indicated by the undulatory extinction in olivine and plagioclase and the presence of planar fractures in olivine. Being weakly shocked and with gas retention ages of >1.7 Ga (4He) and approximately 4.3 Ga (40Ar), Jesenice seems not to have been strongly affected by the catastrophic disruption of the L‐chondrite parent body approximately 500 Ma ago. |
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