CHARACTERISTICS AND MASS-DISTRIBUTION OF EXTRATERRESTRIAL DUST FROM THE GREENLAND ICE CAP
CHARACTERISTICS AND MASS-DISTRIBUTION OF EXTRATERRESTRIAL DUST FROM THE GREENLAND ICE CAP
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DOI：
10.1038/328699a0
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发表时间：
1987-08-20
期刊：
影响因子：
64.8
通讯作者：
HAMMER, C
中科院分区：
文献类型：
--
作者：
MAURETTE, M;JEHANNO, C;HAMMER, C
现在可以从陆地沉积物中大量提取尺寸≥50微米的外星颗粒，但它们的来源仍不确定。这些颗粒中至少 99% 被认为是球粒1,2，是由其母体在大气中融化而形成的，这破坏了它们的矿物成分。在这里，我们对从格陵兰冰盖融化区收集的六个冰石3（黑色尘埃）样本中提取的外星颗粒进行了分析。除了以前从未报道过的谷物家族之外，我们还发现了数量惊人的大量未熔化的球粒陨石碎片，其中母体的非挥发性成分得到了很好的保存。颗粒的质量分布与 1 AU 处的微陨石通量非常相似（参考文献 4），表明大多数颗粒是微陨石，而不是较大陨石的烧蚀产物。这些结果对格陵兰岛微陨石的消融产生了新的限制，并为将它们用作冰川和地质标记提供了指导。
Extraterrestrial grains with sizes ≳50 µm can now be extracted in large numbers from terrestrial sediments but their origins are still uncertain. At least 99% of these grains have been thought to be spherules1,2resulting from the melting of their parent bodies in the atmosphere, which destroyed their mineralogical composition. Here we present analyses of extraterrestrial grains extracted from six samples of cryoconite3(black dust) collected from the melt zone of the Greenland ice cap. In addition to families of grains never reported before, we have found a surprisingly high abundance of unmelted chondritic fragments, in which the nonvolatile component of the parent bodies has been well preserved. The mass distribution of the grains is very similar to that of the micrometeorite flux at 1 AU (ref. 4), indicating that most of the grains are micrometeorites, and not ablation products of larger meteorites. These results yield new constraints on the ablation of such Greenland micrometeorites, as well as guidelines for using them as glaciological and geological markers.