论文标题
53MN-53CR年代学和ε54CR-Δ17OERG CHECH 002的家谱：太阳系中最古老的安山岩
53Mn-53Cr chronology and ε54Cr-Δ17O genealogy of Erg Chech 002: the oldest andesite in the Solar System
论文作者
论文摘要
陨石样品ERG CHECH（EC）002是迄今为止分析的太阳系中最古老的长毛岩石岩石，并提供了一个独特的机会，可以在金属硅酸盐平衡或核心形成后立即研究在分化的原始球星上的长毛皮形成。灭绝的53MN-53CR计时仪表通过使用铬铁矿，金属硅酸盐硫化物和全摇滚级分和通过散装样品的顺序消化获得的“渗滤液”以及“渗滤液”，通过应用等速线方法来对EC 002的形成。假设其母体的软骨进化，也从铬铁矿馏分中获得了53CR/52CR模型年龄。 The 53Mn-53Cr isochron age of 1.73 (+/-) 0.96 Ma (anchored to D'Orbigny angirte) and the chromite model age constrained between 1.46 (-0.68/+0.78) and 2.18 (-1.06/+1.32) Ma after the formation of calcium-aluminium-rich inclusions (CAIs) agree with the 26Al-26Mg ages (anchored to CAIS）在先前的研究中报道。这表明EC 002的快速冷却允许多个同位素系统的近距离闭合。此外，中子富含中子的54CR（核合成异常）与质量非依赖性同位素变化17O的过量相结合，对EC 002母体的增生区域提供了家谱约束。 EC 002的54CR和17O同位素组成证实了其起源于“非碳质”储层，并与vestoid Material NWA 12217和异常的EETEET EET 92023重叠。这表明在Protoplanetary disk源源源源源源源源和eC 002和Vestoids之间。铁陨石的神秘来源仍然无法解决为EC 002，它更像是一种差异化的外壳，具有与曾经是行星岩心的已知熨斗陨石基团相匹配的同位素组成。
The meteorite sample Erg Chech (EC) 002 is the oldest felsic igneous rock from the Solar System analysed to date and provides a unique opportunity to study the formation of felsic crusts on differentiated protoplanets immediately after metal-silicate equilibration or core formation. The extinct 53Mn-53Cr chronometer provides chronological constraints on the formation of EC 002 by applying the isochron approach using chromite, metal-silicate-sulphide and whole-rock fractions as well as "leachates" obtained by sequential digestion of a bulk sample. Assuming a chondritic evolution of its parent body, a 53Cr/52Cr model age is also obtained from the chromite fraction. The 53Mn-53Cr isochron age of 1.73 (+/-) 0.96 Ma (anchored to D'Orbigny angirte) and the chromite model age constrained between 1.46 (-0.68/+0.78) and 2.18 (-1.06/+1.32) Ma after the formation of calcium-aluminium-rich inclusions (CAIs) agree with the 26Al-26Mg ages (anchored to CAIs) reported in previous studies. This indicates rapid cooling of EC 002 that allowed near-contemporaneous closure of multiple isotope systems. Additionally, excess in the neutron-rich 54Cr (nucleosynthetic anomalies) combined with mass-independent isotope variations of 17O provide genealogical constraints on the accretion region of the EC 002 parent body. The 54Cr and 17O isotope compositions of EC 002 confirm its origin in the "non-carbonaceous" reservoir and overlap with the vestoid material NWA 12217 and anomalous eucrite EET 92023. This indicates a common feeding zone during accretion in the protoplanetary disk between the source of EC 002 and vestoids. The enigmatic origin of iron meteorites remains still unresolved as EC 002, which is more like a differentiated crust, has an isotope composition that does not match known irons meteorite groups that were once planetesimal cores.
