On line etching of bulk EH5 St. Mark’s – Radiogenic and subsolar noble gases
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چکیده
Introduction: On line etching is very useful to analyse noble gas components such as “Q” or the solar wind [1, 2]. A bulk meteorite sample, however, has never been analysed by on line etching in order to characterise its complete noble gas inventory. Experiment: The aim of this ongoing study is to analyse noble gases in a bulk sample of the EH5 chondrite St. Mark’s by on line etching (conc. HF) and to compare the results with data for an acidresistant residue of this meteorite [3]. The surprising discovery that phase Q contains besides Q-gas significant amounts of the subsolar component (5-7% of the total [4]) allows us to determine the subsolar isotopic (He-Ar) and elemental (He-Xe) composition. The subsolar Kr and Xe isotopic composition, however, is not well defined [5]. This experiment should provide such data. Furthermore, if the subsolar gas in the silicates should turn out to be identical to that in phase Q, this would suggest that both carriers trapped subsolar gas from a common fractionated reservoir (e.g. the early active Sun) rather than an originally solar composition [e.g. 6].
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تاریخ انتشار 2002