DOI: 10.1016/j.epsl.2020.116088
论文题名: Episodic formation of refractory inclusions in the Solar System and their presolar heritage
作者: Larsen K.K. ; Wielandt D. ; Schiller M. ; Krot A.N. ; Bizzarro M.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 535 语种: 英语
中文关键词: 26Al
; episodic outburst
; Mg isotope
; presolar dust
; refractory inclusion
; Solar System formation
英文关键词: Dust
; Heat treatment
; Isotopes
; Meteorites
; Orbits
; Silicate minerals
; Solar system
; Ca-al-rich inclusions
; Carbonaceous chondrites
; episodic outburst
; Isotope compositions
; Mg isotopes
; Mutual exclusivities
; Solar system formation
; ^26Al
; Refractory materials
; carbonaceous chondrite
; episodic event
; isotopic composition
; Jupiter
; magnesium
; planetary atmosphere
; refraction
; solar activity
; solar system
英文摘要: Refractory inclusions [Ca-Al-rich Inclusions (CAIs) and Amoeboid Olivine Aggregates (AOAs)] in primitive meteorites are the oldest Solar System solids. They formed in the hot inner protoplanetary disk and, as such, provide insights into the earliest disk dynamics and physicochemical processing of the dust and gas that accreted to form the Sun and its planetary system. Using the short-lived 26Al to 26Mg decay system, we show that bulk refractory inclusions in CV (Vigarano-type) and CR (Renazzo-type) carbonaceous chondrites captured at least two distinct 26Al-rich (26Al/27Al ratios of ∼5 × 10−5) populations of refractory inclusions characterized by different initial 26Mg/24Mg isotope compositions (μ26Mg*0). Another 26Al-poor CAI records an even larger μ26Mg*0 deficit. This suggests that formation of refractory inclusions was punctuated and recurrent, possibly associated with episodic outbursts from the accreting proto-Sun lasting as short as <8000 yr. Our results support a model in which refractory inclusions formed close to the hot proto-Sun and were subsequently redistributed to the outer disk, beyond the orbit of Jupiter, plausibly via stellar outflows with progressively decreasing transport efficiency. We show that the magnesium isotope signatures in refractory inclusions mirrors the presolar grain record, demonstrating a mutual exclusivity between 26Al enrichments and large nucleosynthetic Mg isotope effects. This suggests that refractory inclusions formed by incomplete thermal processing of presolar dust, thereby inheriting a diluted signature of their isotope systematics. As such, they record snapshots in the progressive sublimation of isotopically anomalous presolar carriers through selective thermal processing of young dust components from the proto-Solar molecular cloud. We infer that 26Al-rich refractory inclusions incorporated 26Al-rich dust which formed <5 Myr prior to our Sun, whereas 26Al-poor inclusions (such as FUN- and PLAC-type CAIs) incorporated >10 Myr old dust. © 2020 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165096
Appears in Collections: 气候变化与战略
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作者单位: Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, DK-1350, Denmark; Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at ManoaHI 96822, United States
Recommended Citation:
Larsen K.K.,Wielandt D.,Schiller M.,et al. Episodic formation of refractory inclusions in the Solar System and their presolar heritage[J]. Earth and Planetary Science Letters,2020-01-01,535