摘要
本文用电子探针、X光衍射和激光拉曼探针等方法发现了铁质宇宙尘腔体、中的Si-O玻璃物质;对腔体和外壳基质中的两种不同玻璃物质做了进一步的研究。并据此探讨了本区宇宙尘的演化史,推论在地球形成早期的壳幔演化过程中,于高温条件下,曾发生过一定规模的不混溶作用,各种不混溶相物质冷凝后可形成初始地壳及一定的矿产。
This paper discuss the study of glass material ferri-cosmic dust in Xitieshan Pb-Zn ore beds by electron probe, X-ray and Raman probe etc. methods. Two kinds of different glasses in them have been recongnized. One is a Ca—Mg—Fe—Al—Si—O glass (Tab. 1 and Fig.1, 3) in the matrix (Pho- to.1) of the steel grey spherules, of the coelom spherules and of the outer crust of the steel grey spherules with a core. In the matrix they scatter unevenly irregular among the wüstite crystallites. Another is a Si—O glass in the coelom between the inner core and outer crust of the steel grey spherules with a core (Tab. 1, Fig. 2 and Photo.1, 2, 3). The study shows that in molten state under high temperature con- dition the cosmic dusts themselves or parent meteorite itself had experienced melting separation affected by theirs inner high volatile component and by force of gyration in the atmosphere before they cooled, and had separated into three kinds of unmixing tiny drops of pure Fe-Ni, FeO (Fe_3O_4) and SiO_2. They formed pure Fe-Ni inner core of the spherule or single spherule and the FeO (Fe_3O_4) outer crust or single spherule FeO (Fe_3O4) which consists of magnetite, wüstite and Ca—Mg—Fe—Al—Si—O glass, as well as SiO_2 glass in the coelom between the inner core and the outer crust of the spherule under the rapid cooling condition. They can represent respectivelly each original material composition after taking place melting separation. Based on the above-mentioned view, it can be further deduced that during the evolutional process of the core and mantle of the earth might take place melting separation on a certain scale. All kinds of material of unmixing phase could form the original crust and certain mineral resources.
