We have conducted an extensive towed-magnetic-sled survey during the period of June 14–28, 2023, over the seafloor about 85 km north of Manus Island, Papua New Guinea, centered around the calculated path of the bolide CNEOS 2014-01-08 (IM1). We found about 850 spherules of diameter 0.1–1.3 mm in our samples. The samples were analyzed by micro-XRF, Electron Probe Microanalyzer and ICP Mass spectrometry. Here we report major and trace element compositions of the samples and classify spherules based on that analysis. We identified 78 % of the spherules as primitive, in that their compositions have not been affected by planetary differentiation. We divided these into four groups, three of which correspond to previously described cosmic spherule types. Spherules in the fourth group, comprising 22 % of the collection, appear to all reflect planetary igneous differentiation and are all different from previously described spherules. We call them D-type spherules. At least five of the D-type spherules are suggested to be terrestrial in origin, although many spherules exhibit elemental ratios that are distinct from known planetary bodies and their origins are undetermined. A subset of the D-spherules show an excess of Be, La and U, by up to three orders of magnitude relative to the solar system standard of CI chondrites. Detailed mass spectrometry of 12 of these “BeLaU”-type spherules, the population of which may constitute up to ∼10 % of our entire collected sample, suggests that they are derived from material formed by planetary igneous fractionation. Their chemical composition is unlike any known solar system material. We compare these compositions to known differentiated bodies in the solar system and find them similar to those of evolved planetary materials–with lunar KREEP the closest in terms of its trace element enrichment pattern, but unusual in terms of their elevated CI-normalized incompatible elements. The “BeLaU”-type spherules reflect a highly differentiated, extremely evolved composition of an unknown source.

中文翻译：

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从 CNEOS 2014-01-08 （IM1） bolide 太平洋现场回收的球体的化学分类


2023 年 6 月 14 日至 28 日期间，我们在巴布亚新几内亚马努斯岛以北约 85 公里的海底进行了广泛的牵引磁滑调查，以流星 CNEOS 2014-01-08 （IM1） 的计算路径为中心。我们在样本中发现了大约 850 个直径为 0.1-1.3 mm 的球体。通过微区 XRF、电子探针显微分析仪和 ICP 质谱法对样品进行分析。在这里，我们报告了样品的主量和痕量元素组成，并根据该分析对小球进行分类。我们确定了 78% 的球体是原始的，因为它们的成分没有受到行星分化的影响。我们将这些分为四组，其中三组对应于前面描述的宇宙球体类型。第四组中的球形结构占集合的 22%，似乎都反映了行星火成岩的分化，并且都与前面描述的球状结构不同。我们称它们为 D 型小球。至少有 5 个 D 型球体被认为起源于地球，尽管许多球体表现出与已知行星体不同的元素比例，并且它们的起源尚未确定。D 球体的一个子集显示 Be、La 和 U 的过量，相对于太阳系 CI 球粒陨石的标准，高出多达三个数量级。对 12 个这样的“BeLaU”型球体的详细质谱分析表明，它们来自行星火成岩分馏形成的材料，其种群可能占我们整个收集样本的 10% 左右。它们的化学成分不同于任何已知的太阳系材料。 我们将这些成分与太阳系中已知的分化天体进行比较，发现它们与进化的行星物质相似——月球 KREEP 在其微量元素富集模式方面最接近，但在它们升高的 CI 归一化不相容元素方面不寻常。“BeLaU”型小球反映了未知来源的高度分化、极其进化的成分。