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Tellurium isotopic composition of the early solar system—A search for effects resulting from stellar nucleosynthesis, Sn decay, and mass-independent fractionation |
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| Authors: | Manuela A Fehr Mark Rehkämper Alex N Halliday Uwe Wiechert Detlef Günther Jennifer L Eigenbrode Douglas Rumble III |
| Institution: | 1 ETH Zürich, Institute of Isotope Geology and Mineral Resources, 8092 Zürich, Switzerland 2 Swedish Museum for Natural History, Laboratory for Isotope Geology, 104 05 Stockholm, Sweden 3 Department of Earth Science and Engineering, Imperial College, London SW7 2AZ, United Kingdom 4 Department of Earth Sciences, Oxford OX1 3PR, United Kingdom 5 ETH Zürich, Laboratory of Inorganic Chemistry, 8093 Zürich, Switzerland 6 Carnegie Institution of Washington, Geophysical Laboratory, Washington, DC 20015, USA 7 The Pennsylvania State University, Astrobiology Research Center, University Park, PA 16802, USA |
| Abstract: | New precise Te isotope data acquired by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS) are presented for selected extraterrestrial and terrestrial materials. Bulk samples of carbonaceous, ordinary and enstatite chondrites as well as the metal and sulfide phases of iron meteorites were analyzed to search for nucleosynthetic isotope anomalies and to find evidence of formerly live 126Sn, which decays to 126Te with a half-life of 234,500 yr. None of the meteorites show evidence of mass dependent Te isotope fractionations larger than 2‰ for δ126/128Te. Following internal normalization of the data to 125Te/128Te, the Te isotope ratios of all analyzed meteorites were found to be identical to a terrestrial standard, within uncertainties. This provides evidence that the regions of the solar disk that were sampled during accretion of the meteorite parent bodies were well mixed and homogeneous on a large scale, with respect to Te isotopes. The data acquired for bulk carbonaceous chondrites indicate that the initial 126Sn/118Sn ratio of the solar system was <4 × 10−5, but this is dependent on the assumption that no redistribution of Sn and Te occurred since the start of the solar system. Five Archean sedimentary sulfides that display both mass dependent and mass-independent isotope effects for S yield internally normalized Te isotope data, which indicate that mass-independent Te isotope effects are absent. The mass dependent fractionations in these samples are constrained to be less than ∼1‰ for δ126/128Te. |
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