Compound chondrules, i.e. chondrules fused together, make a powerful probe of the density and compositional diversity in chondrule-forming environments, but their abundance among the dominating porphyritic textures may have been drastically underestimated. I report herein microscopic observations and LA-ICP-MS analyses of lobate chondrules in the CO3 chondrites Miller Range 07193 and 07342. Lobes in a given chondrule show correlated volatile and moderately volatile element abundances but refractory element concentrations are essentially independent. This indicates that they formed by the collision of preexisting droplets whose refractory elements behaved in closed system, while their more volatile elements were buffered by the same gaseous medium. The presence of lobes would otherwise be difficult to explain, as surface tension should have rapidly imposed a spherical shape at the temperature peak. In fact, since most chondrules across chondrite groups are nonspherical, a majority are probably compounds variously relaxed toward sphericity. The lack of correlation of refractory elements between conjoined compound chondrule components is inconsistent with derivation of chondrules from the disruption of homogenized melt bodies as in impact scenarios and evokes rather the melting of independent mm-size nebular aggregates. Yet a “nebular” setting for chondrule formation would need to involve not only increased solid concentration, e.g. by

中文翻译：

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球粒形成事件中的碰撞和成分变异

复合球粒，即融合在一起的球粒，对球粒形成环境中的密度和成分多样性进行了强有力的探测，但它们在主要斑状结构中的丰度可能被大大低估了。我在此报告了对 CO3 球粒陨石米勒范围 07193 和 07342 中叶状球粒的显微观察和 LA-ICP-MS 分析。给定球粒中的叶状体显示相关的挥发性和中等挥发性元素丰度，但难熔元素浓度基本上是独立的。这表明它们是由先前存在的液滴碰撞形成的，这些液滴的耐火元素在封闭系统中表现，而它们的挥发性元素则被相同的气态介质缓冲。否则很难解释裂片的存在，因为表面张力应该在温度峰值处迅速形成球形。事实上，由于球粒陨石群中的大多数球粒都是非球形的，因此大多数可能是不同程度地向球形松弛的化合物。连体复合球粒组分之间耐火元素之间缺乏相关性与在撞击情景中从均质熔体的破坏中推导出球粒是不一致的，而是引发了独立的毫米大小的星云聚集体的熔化。然而，球粒形成的“星云”设置不仅需要增加固体浓度，例如通过 连体复合球粒组分之间耐火元素之间缺乏相关性与在撞击情景中从均质熔体的破坏中推导出球粒是不一致的，而是引发了独立的毫米大小的星云聚集体的熔化。然而，球粒形成的“星云”设置不仅需要增加固体浓度，例如通过 连体复合球粒组分之间耐火元素之间缺乏相关性，这与撞击情景中均质熔体破坏导致球粒的推导不一致，而是引发了独立的毫米大小星云聚集体的熔化。然而，球粒形成的“星云”设置不仅需要增加固体浓度，例如通过