| 陨石熔壳研究 |
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| 引用本文： | 王奎仁,洪吉安.陨石熔壳研究[J].高校地质学报,1995,1(2):22-28. |
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| 作者姓名： | 王奎仁 洪吉安 |
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| 作者单位： | 中国科学技术大学地球与空间科学系 |
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| 摘 要： | 本文通过对毫县陨石熔壳的化学成分分析，Ｘ射线物相分析和红外光谱分析，并与一岩相互对照，讨论了熔壳中Ｆｅ的氧化状态的变化、击变玻璃及主要矿物结构参数的变化；研究了熔壳的氧化作用、击变作用、击变作用下矿物的变形机制，同时，熔壳的ＳＥＭ显微 貌像给出了熔壳的一套完整剖面，从而讨论了熔壳的烧蚀作用主要有破碎作用，熔融作用和抽蚀作用三种方式。此外，透射电观察敢证实了陨石熔壳中石英玻璃的存在。
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| 关 键 词： | 熔壳 氧化作用 击变作用 烧蚀作用 陨石 |
| 收稿时间： | 1995-06-20 |
A STUDY ON THE FUSION CRUST OF METEORITE |
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| Wang Kui-ren, Hong Ji-an.A STUDY ON THE FUSION CRUST OF METEORITE[J].Geological Journal of China Universities,1995,1(2):22-28. |
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| Authors: | Wang Kui-ren Hong Ji-an |
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| Institution: | Department of Earth and Space Sciences, Advanced Center for Earth Sciences ＆ Astronomy, University of Science＆Technology of China. Third World Academy of Science; Hefei, 230026 |
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| Abstract: | In the present paper, the fusion crust of Boxian meteorite is analysed by several methods. Based on the chemical composition and compared with the whole meteorite, it can be found that the redox state of Fe in the fusion crust has changed: the amount of metal iron and FeS decreases, while that of Fe increases, and new phases wustite and magnetite are formed.
The phase analysis by X-ray powder diffraction shows that all the olivine in the fusion crust is forsterite compared to chrysolite in the internal meteorite because of phase transformation and phase rebuilding at high tempratures. In the meantime. the cell volume of the three dominant minerals in the fusion crust is larger than that inside the meteorite. The crystallographic parameters of all these three minerals decrease in one direction, and increase or keep constant in the other two directions. All these are concordant with one-direction stress. Due to the shock pressure, the minerals suffered one-dimensional crystal compression.
The infrared spectrum pattern of the fusion crust reveals the occurrence of diaplectic glass, which indicates that the sh0ck pressure is higher than 53.0 GPa.
The SEM micro-images of the fusion crust give a perfect section, which shows that the crust can he divided into three layers from the surface inwards: glassy layer, proous layer and transitional layer. The outer layer-s made up entirely of glass, about 50m thick, and it is a real fusion crust. The mid-layer is porous, about 210~m thick. The internal layer, about 250μm thick, is similar to that inside the meteorite except the grain sizes of the minerals.
In these three layers, the grain size is of micrometer scale, unlike that in the internal meteorite. The absence of chondrules indicates that the fusion crust suffered breaking action under high shock pressure. The occurrence of the real fusion glass indicates that melting did take place in the fusion crust due to high temperature. The pores are formed due to extracting action.
In summary the fusion crust has been modified by the following processes: oxidation, shock, breaking, melting and extraction. All these results can give guides to the research of some aerospace materials. |
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| Keywords: | fusion crust oxidation shock metamorphism calcine erosion |
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