Carbon‐silicate aggregates in the CH chondrite Pecora Escarpment 91467: A carrier of heavy nitrogen of interstellar origin
Carbon‐silicate aggregates in the CH chondrite Pecora Escarpment 91467: A carrier of heavy nitrogen of interstellar origin
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CH 球粒陨石佩科拉悬崖 91467 中的碳硅酸盐聚集体：星际起源的重氮载体
DOI：
10.1111/j.1945-5100.2001.tb01893.x
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
S. Zashu
中科院分区：
文献类型：
--
作者：
N. Sugiura;S. Zashu
非平衡球粒陨石Pecora Escapment(PCa)91467的扫描电子显微镜和二次离子质谱仪揭示了四种同位素重N的载体：(1)碳质物质和硅酸盐的聚集体，(2)含有细小Fe-Cr硫化物包裹体的铁-镍金属颗粒，(3)与Fe-硫化物共生的富硅Fe-Ni金属，以及(4)基质中的水化区域。碳-硅酸盐集合体中的N具有同位素重值(δ15N高达2500%0)，而其他元素的同位素正常，表明该集合体中的碳质物质来自星际。根据同位素和质地证据，我们认为载体(2)和(3)是在太阳星云中短暂加热形成的，而载体(4)是在母体小行星上形成的。碳硅酸盐聚集体很可能与在Murchison发现的星际石墨有关，也可能是本立方石中重氮的来源。
Abstract— Scanning electron microscopy and secondary ion mass spectrometry of the unequilibrated CH chondrite Pecora Escarpment (PCA) 91467 revealed four carriers of isotopically heavy N: (1) aggregates of carbonaceous material and silicates, (2) iron‐nickel metal grains with fine Fe‐Cr sulfide inclusions, (3) Si‐rich Fe‐Ni metal associated with Fe‐sulfide and (4) hydrated areas in the matrix. N in carbon‐silicate aggregates is isotopically heavy (δ15N is as high as 2500%0), whereas the other elements are isotopically normal, suggesting interstellar origin of carbonaceous material in the aggregates. Based on isotopic and textural evidence, we suggest that the carriers (2) and (3) were formed by brief heating in the solar nebula, whereas the carrier (4) was formed in a parent‐body asteroid. The carbon‐silicate aggregates are likely to be related to interstellar graphite found in Murchison and may also be the source of heavy N in bencubbinites.