An attempt to separate Q from the Allende meteorite by physical methods |
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| Authors: | Sachiko Amari Shiho Zaizen Jun-Ichi Matsuda |
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| Institution: | 1 Laboratory for Space Sciences and the Physics Department, Washington University, 1 Brookings Drive, St. Louis, MO 63130-4899, USA
2 Department of Earth and Space Sciences, Graduate School of Science, Osaka University, Toyonoka, Osaka 560-0043, Japan |
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| Abstract: | In order to characterize the planetary noble gas carrier Q, we separated a Q-rich floating fraction from the Allende meteorite into ten fractions by a combination of colloidal and density separations. All five noble gases in the separated fractions were analyzed by pyrolysis in 600 and 1600°C temperature steps. Half of Q in the floating fraction is concentrated in the fraction C1-8D with the density of 1.65 ± 0.04 g/cm3. All the separated fractions show similar isotopic ratios except for 40Ar/36Ar ratios. C1-8D has the lowest 38Ar/36Ar and 40Ar/36Ar ratios (0.18784 ± 0.00020 and 4.36 ± 0.15, respectively) in the 1600°C fraction, confirming that the fraction is enriched in Q. Most grains in C1-8D are carbonaceous with small amounts of F and O. These results imply either that the density of Q is 1.65 ± 0.04 g/cm3 or that Q preferentially sticks to matter of that density. All the separates have similar Q to diamond ratios, indicating that Q and diamond are closely associated. |
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