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应用近代微束矿物学分析测试技术,对在中国陨落的随州、寺巷口和岩庄等三块球粒陨石中矿物的冲击熔融和分离结晶作用进行了较系统的研究。查明存在有硅酸盐单矿物熔体、硅酸盐矿物混合熔体和全岩熔体三种组成不同的冲击熔体。研究结果显示:(1)三种熔融相与未熔相之间在主成分和微量元素组成上没有明显差别,说明它们是原地熔融的产物,但在较大的冲击熔块中,也发现冲击熔融作用引发了一部分元素,如亲铁元素、硒元素和轻重稀土元素的分异现象;(2)查明Al2O3、Cr2O3、Na2O和CaO等优先进入从冲击熔体结晶的辉石常压相或辉石的高压相——镁铁榴石(属地幔过渡带矿物)中;(3)Al元素能进入阿基莫石(即辉石的钛铁矿结构相,属下地幔矿物)中,以固熔体形式稳定下来。ELNES的测定查明,其氧化铁组分中Fe3+/∑Fe的比值高达0.67(3);(4)陨石全岩熔体中硅酸盐相与金属-硫化物相之间为完全不混熔,后者以孤立的共结体团块产于硅酸盐熔体之中,除Zn、Na、Cr、Co和Cu在硫化物相中和Na在金属相中有明显富集外,其他元素的浓度则无明显变化;(5)在寺巷口陨石熔脉的金属-硫化物共结团块内发现了FeNi金属-硫化铁-磁铁矿组合,进一步证实了S和O等轻元素可以加入到以Fe-Ni金属为主要组成的地核成分中去;(6)在岩庄陨石的FeNi金属-硫化铁共结体团块的硫化铁内发现了Na、Mn和Fe的磷酸盐矿物小球体,说明P和Na、Mn等元素也能成为地核的组成元素。以上研究在行星演化、地幔矿物学和地球化学,以及陨石学研究上均有着重要的科学意义。
The application of modern microbeam mineralogy analysis and testing technology to systematically study the impact melting and separation and crystallization of minerals in three chondrules in Suizhou, Sihekou and Yanzhuang which fell in China. It is found that there exist three kinds of impact melts with different compositions of silicate mono-mineral melt, silicate mineral mixed melt and whole rock melt. The results show that: (1) There is no significant difference between the three main phases and the unmelted phases on the main and minor elements, indicating that they are the products of in-situ melting, but also found in the larger impact frit Impact melting caused a number of elements, such as pro-iron elements, selenium and light and heavy rare earth elements of the phenomenon; (2) to identify Al2O3, Cr2O3, Na2O and CaO preferentially into the crystallization from the impact melt pyroxene Or pyroxene-magnesia (belonging to mantle transitional zone minerals); (3) Al element can enter the amikromite (ie, ilmenite structural phase of pyroxene, subordinate mantle minerals) Stable as a solid melt. The ELNES measurement showed that the ratio of Fe3 + / ΣFe in the iron oxide fraction was as high as 0.67 (3). (4) There was no fusion between the silicate phase and the metal-sulfide phase in the whole rock melt , With the isolated co-agglomerate mass produced in the silicate melt, with the exception that Zn, Na, Cr, Co and Cu are significantly enriched in the sulfide phase and Na in the metallic phase, and the other elements (5) FeNi metal-iron sulphide-magnetite assemblage was found in the metal-sulphide co-agglomerate of the meteorite vein in Sihekou, further confirming that light elements such as S and O can (6) Phosphate minerals of Na, Mn and Fe are found in the iron sulfide of the FeNi metal-iron sulfide co-agglomerate of the Iwizumi meteorite Small spheres, indicating P and Na, Mn and other elements can also become the core elements. The above studies have important scientific significance in the study of planetary evolution, mantle mineralogy and geochemistry, and meteorology.