DOI: 10.1016/j.epsl.2018.03.039
Scopus记录号: 2-s2.0-85044926660
论文题名: High-precision Al–Mg isotopic systematics in USNM 3898 – The benchmark “ALL” for initial 87Sr/86Sr in the earliest Solar System
作者: MacPherson G.J. ; Defouilloy C. ; Kita N.T.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 491 起始页码: 238
结束页码: 243
语种: 英语
英文关键词: CAI
; early Solar System chronology
; initial 26Al/27Al
Scopus关键词: Computer aided instruction
; Solar system
; Allende
; Early solar systems
; Error bars
; High-precision
; initial^26Al/^27Al
; Isotopic data
; Isotopic systematics
; Isotopes
; aluminum
; astronomy
; chronology
; isotopic composition
; magnesium
; precision
; solar system
英文摘要: The Allende CAI USNM3898 is the basis for “ALL” the lowest measured initial 87Sr/86Sr value in any solar system material including other CAIs (Gray et al., 1973). If the value ALL is correct (debated), then USNM3898 must be 1–2 million years older than other CAIs (Podosek et al., 1991). This would require in turn that it have a much higher initial 26Al/27Al value than other CAIs, on the order of 4 × 10−4. Podosek et al. (1991) showed that this is not the case, with initial 26Al/27Al = (4.5 ± 0.7) × 10−5, but their Mg-isotopic data had large error bars and there was clear isotopic disturbance in the data having the highest 27Al/24Mg. Without the latter data, the slope of their isochron is higher (5.10 ± 1.19) × 10−5) and within (large) error of being supracanonical. We used high-precision SIMS to re-determine the initial 26Al/27Al in this CAI and obtained a value of (5.013 ± 0.099) × 10−5, with an intercept δ26Mg⁎=−0.008±0.048 and MSWD = 1.3. This value is indistinguishable from that measured in many other CAIs and conclusively shows that USNM3898 is not uniquely ancient. We also confirmed evidence of later isotopic disturbance, similar to what Podosek et al. found, indicating a re-melting and evaporation event some 200,000 years after initial CAI solidification. © 2018 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109929
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Dept. of Mineral Sciences, Museum of Natural History, Smithsonian Institution, Washington, DC 20560, United States; WiscSIMS, Dept. of Geoscience, Univ. of Wisconsin–Madison, Madison, WI 53706, United States
Recommended Citation:
MacPherson G.J.,Defouilloy C.,Kita N.T.. High-precision Al–Mg isotopic systematics in USNM 3898 – The benchmark “ALL” for initial 87Sr/86Sr in the earliest Solar System[J]. Earth and Planetary Science Letters,2018-01-01,491