Thermal and chemical evolution in the early Solar System as recorded by FUN CAIs: Part II – Laboratory evaporation of potential CMS-1 precursor material
Thermal and chemical evolution in the early Solar System as recorded by FUN CAIs: Part II – Laboratory evaporation of potential CMS-1 precursor material
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FUN CAI 记录的早期太阳系的热和化学演化：第二部分 — 潜在 CMS-1 前体材料的实验室蒸发
DOI：
10.1016/j.gca.2016.08.034
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发表时间：
2017
影响因子：
5
通讯作者：
Wadhwa, Meenakshi
中科院分区：
文献类型：
--
作者：
Mendybaev, Ruslan A.;Williams, Curtis D.;Spicuzza, Michael J.;Richter, Frank M.;Valley, John W.;Fedkin, Alexei V.;Wadhwa, Meenakshi
我们介绍了实验室实验的结果，其中富含镁橄榄石的熔体估计是阿连德CMS-1 FUN CAI的潜在前体，在1900 °C下蒸发到真空中不同的时间长度。该熔体的蒸发导致了在化学以及镁、硅和氧同位素组成空间中定义轨迹的残留物，并且非常接近CMS-1的测量特性。蒸发残渣的同位素组成也被用来确定动力学同位素分馏因子[α 2，1（蒸气-熔融）定义为蒸发气体中给定元素的同位素2和1的比率除以它们在蒸发源中的比率]在1900 °C下，富镁橄榄石熔体中的氧（α18，16 for 18 O/16 O）、硅（α29，28 for 29 Si/28 Si）和（α25，24 for 25 Mg/24 Mg）。α 25，24 = 0.98383 ± 0.00033和α 29，28 = 0.99010 ± 0.00038的值基本上与蒸发过程中熔体组成的变化无关。而当残余熔体成分由镁橄榄石转变为黄长石时，α18，16由0.9815 ± 0.0016变为0.9911。利用CMS-1的α25，24和α29，28的测定值和现今的整体化学成分，估计包裹体的前体成分接近于由太阳成分气体凝聚而成的单斜辉石+尖晶石+镁橄榄石组合。实验蒸发残留物的化学组成和同位素分馏与CMS-1的现今散装化学和同位素组成之间的对应关系证明蒸发在CMS-1的化学演化中发挥了重要作用。
We present the results of laboratory experiments in which a forsterite-rich melt estimated to be a potential precursor of Allende CMS-1 FUN CAI was evaporated into vacuum for different lengths of time at 1900 °C. The evaporation of this melt resulted in residues that define trajectories in chemical as well as magnesium, silicon and oxygen isotopic composition space and come very close to the measured properties of CMS-1. The isotopic composition of the evaporation residues was also used to determine the kinetic isotopic fractionation factors [α2,1(vapor-melt) defined as the ratio of isotopes 2 and 1 of a given element in the evaporating gas divided by their ratio in the evaporating source] for evaporation of magnesium (α25,24for25Mg/24Mg), silicon (α29,28for29Si/28Si) and oxygen (α18,16for18O/16O) from the forsterite-rich melt at 1900 °C. The values ofα25,24= 0.98383 ± 0.00033 andα29,28= 0.99010 ± 0.00038 are essentially independent of change in the melt composition as evaporation proceeds. In contrast,α18,16changes from 0.9815 ± 0.0016 to ∼0.9911 when the residual melt composition changes from forsteritic to melilitic. Using the determined values ofα25,24andα29,28and present-day bulk chemical composition of the CMS-1, the composition of the precursor of the inclusion was estimated to be close to the clinopyroxene + spinel + forsterite assemblage condensed from a solar composition gas. The correspondence between the chemical composition and isotopic fractionation of experimental evaporation residues and the present-day bulk chemical and isotopic compositions of CMS-1 is evidence that evaporation played a major role in the chemical evolution of CMS-1.
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影响因子：
5
作者：
Grossman, L.;Simon, S. B.;Mayeda, T. K.
通讯作者：
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DOI：
--
发表时间：
2010
期刊：
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作者：
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影响因子：
5
作者：
L. Grossman;D. Ebel;S. Simon;A. Davis;F. Richter;N. Parsad
通讯作者：
N. Parsad
DOI：
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发表时间：
2003
期刊：
影响因子：
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影响因子：
64.8
作者：
A. Hashimoto
通讯作者：
A. Hashimoto