REDUCTION EXPERIMENT OF FeO-BEARING AMORPHOUS SILICATE: APPLICATION TO ORIGIN OF METALLIC IRON IN GEMS
REDUCTION EXPERIMENT OF FeO-BEARING AMORPHOUS SILICATE: APPLICATION TO ORIGIN OF METALLIC IRON IN GEMS
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DOI：
10.1088/0004-637x/792/2/136
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发表时间：
2014-08
期刊：
影响因子：
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通讯作者：
J. Matsuno;A. Tsuchiyama;A. Miyake;R. Noguchi;S. Ichikawa
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文献类型：
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作者：
J. Matsuno;A. Tsuchiyama;A. Miyake;R. Noguchi;S. Ichikawa
嵌入金属和硫化物的玻璃（GEMS）是无水行星际尘埃颗粒（IDP）中的无定形硅酸盐，可以提供有关早期太阳系物质演化的信息。到目前为止，已经提出了几种GEMS的形成过程，但这些理论仍然存在争议。为了研究星际硅酸盐还原可能的GEMS起源，我们合成了具有平均GEMS组成的无定形硅酸盐，并在还原气氛中进行了加热实验。在环境压力下，在还原性气氛中，将含FeO的无定形硅酸盐在923 K和973 K下加热3小时，并在1023 K下加热1-48小时。通过还原在硅酸盐和还原气体之间的界面处形成Fe颗粒。与此相反，TEM观察天然GEMS显示，金属颗粒均匀地嵌入在无定形硅酸盐。因此，本研究表明，GEMS中的金属夹杂物不能形成的还原产物和其他形成过程，如冷凝或辐照更有可能。
Glass with embedded metal and sulfides (GEMS) are amorphous silicates included in anhydrous interplanetary dust particles (IDPs) and can provide information about material evolution in our early solar system. Several formation processes for GEMS have been proposed so far, but these theories are still being debated. To investigate a possible GEMS origin by reduction of interstellar silicates, we synthesized amorphous silicates with a mean GEMS composition and performed heating experiments in a reducing atmosphere. FeO-bearing amorphous silicates were heated at 923 K and 973 K for 3 hr, and at 1023 K for 1–48 hr at ambient pressure in a reducing atmosphere. Fe grains formed at the interface between the silicate and the reducing gas through a reduction. In contrast, TEM observations of natural GEMS show that metallic grains are uniformly embedded in amorphous silicates. Therefore, the present study suggests that metallic inclusions in GEMS could not form as reduction products and that other formation process such as condensation or irradiation are more likely.