Formation of refractory metal nuggets and their link to the history of CAIs
Formation of refractory metal nuggets and their link to the history of CAIs
复制标题
难熔金属块的形成及其与 CAI 历史的联系
DOI：
10.1016/j.gca.2015.07.014
复制
发表时间：
2015
影响因子：
5
通讯作者：
Schönhense
中科院分区：
文献类型：
--
作者：
Schwander;Kööp;Schönhense
富钙铝夹杂物(CaI)通常含有大量的难熔金属块(RMN)，由Os、Ir、Mo、Pt和Ru等元素组成。金块通常被认为是由太阳能气体的平衡冷凝形成的，与氧化物和硅酸盐矿物同时或先于氧化物和硅酸盐矿物形成。然而，导致其组成极不稳定、尺寸较小以及与CaI矿物共生的确切机制仍然令人费解。在前人关于化学分离的RMN工作的基础上，我们研究了来自三种不同陨石类型的RMN，即高度原始的球粒陨石Acfer094(C2-未组合)、Allende(CV3ox)和Murchison(CM2)。我们的结果表明，观测到的特征与直接冷凝来源之间存在几个不一致之处，包括冷凝温度变化预期的难熔金属中缺乏相关的丰度变化。相反，我们表明，大多数RMN特征与从富含难熔金属的CaI液体中沉淀形成的RMN是一致的。此外，在具有明显熔融结晶织构的CAI中普遍出现RMN，以及在Schwander等人的RUN产品中出现成分高度可变的合成RMN，还支持这一情况。(2015)。在某些情况下，陨石RMN的大小与它们在CAI中的宿主矿物的大小相关，这表明了共同的冷却速度。
Ca, Al-rich inclusions (CAIs) often contain numerous refractory metal nuggets (RMNs), consisting of elements like Os, Ir, Mo, Pt and Ru. The nuggets are usually thought to have formed by equilibrium condensation from a gas of solar composition, simultaneously with or prior to oxide and silicate minerals. However, the exact mechanisms responsible for their extremely variable compositions, small sizes and associations with CAI minerals remain puzzling. Expanding on previous work on chemically separated RMNs, we have studied a large number of RMNs within their host CAIs from three different meteorite types, i.e., the highly primitive chondrite Acfer 094 (C2-ungrouped), Allende (CV3ox) and Murchison (CM2). Our results show several inconsistencies between the observed features and a direct condensation origin, including a lack of correlated abundance variations in the refractory metals that are expected from variations in condensation temperature. Instead, we show that most RMN features are consistent with RMN formation by precipitation from a CAI liquid enriched in refractory metals. This scenario is additionally supported by the common occurrence of RMNs in CAIs with clear melt crystallization textures as well as the occurrence of synthetic RMNs with highly variable compositions in run products from Schwander et al. (2015). In some cases, the sizes of meteoritic RMNs correlate with the sizes of their host minerals in CAIs, which indicates common cooling rates.
登录
查看更多内容
富钙、铝阿连德包裹体中富难熔金属组合的组成和起源
影响因子：
5
作者：
H. Palme;I. Hutcheon;B. Spettel
通讯作者：
B. Spettel
DOI：
--
发表时间：
2003
期刊：
影响因子：
--
作者：
G. MacPherson
通讯作者：
G. MacPherson
陨石中难熔包裹体中不透明组合的“国内”起源
影响因子：
64.8
作者：
J. Blum;G. Wasserburg;I. Hutcheon;J. Beckett;E. Stolper
通讯作者：
E. Stolper
影响因子：
1
作者：
W. Kleber
通讯作者：
W. Kleber
微流星体与地球大气相互作用的模拟
影响因子：
6.5
作者：
G. Briani;E. Pace;S. Shore;G. Pupillo;A. Passaro;S. Aiello
通讯作者：
S. Aiello