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在金伯利岩人工重砂中发现的“熔离小球”,直径多数<1 mm,除个别出现微晶外,均为非晶质,属于熔体淬火冷却产物。提供了29个小球的主元素分析和3件微量元素分析结果。“熔离小球”按成分可分为3种类型:(1)高铁钛小球;(2)硫铁镍小球;(3)浅色硅铝质小球。其中高铁小球w(FeO)高达99.39%,高钛小球w(TiO2)达45.90%,它们含MnO也偏高,最高达23.75%。Fe、Mn、Ti都属于高负电性元素,在熔体中与氧结合的键强度大,容易发生熔离。硫铁镍小球的w(SO3)变化于38.27%~51.95%,w(FeO)为0.31%~23.10%,w(NiO)为25.24%~61.05%。浅色小球w(SiO2)变化范围为24.01%~52.64%,Al2O3、CaO含量高但变化范围大,总体成分接近基性—超基性硅酸盐熔浆。主元素、微量元素特征以及硫铁镍小球中发现了高镁(Fo=0.95)橄榄石捕虏晶表明,小球形成于金伯利岩岩浆的介质环境。此外高铁及硅铝质两种成分呈交生结构的两相小球的发现,暗示二者为熔离作用成因。小球的熔离作用可以应用SiO2-FeS-FeO的液态不混溶相图做出解释。认为小球形成于岩浆结晶的晚期阶段,相对富含CO2、SO3、FeO、MnO、TiO,在岩浆快速上升、快速降温、降压、熔体中出现了多种局部有序区的条件下发生的。
In the kimberlite artificial heavy sand found in the “molten beads”, most <1 mm in diameter, with the exception of individual crystallites, are amorphous, are part of the melt quenching and cooling products. Provides the master element analysis of 29 pellets and the results of 3 trace elements analysis. “Melt-off pellets” can be divided into three types according to composition: (1) high-iron titanium pellets; (2) sulfur iron nickel pellets; and (3) light silicon aluminum pellets. The high-iron pellets w (FeO) are up to 99.39% and the high titanium pellets w (TiO2) up to 45.90%. They also contain high MnO up to 23.75%. Fe, Mn, and Ti are all highly negatively charged elements, and bond strength to oxygen in the melt is large, and melting easily occurs. The content of w (SO3) varied from 38.27% to 51.95% for FeS, 0.31% to 23.10% for w (FeO) and 25.24% to 61.05% for w (NiO). The light sphere w (SiO2) varied from 24.01% to 52.64%, while the content of Al2O3 and CaO was high but the range of variation was large. The overall composition was close to that of the ultrabasic silicate slurry. The main elements, trace element characteristics and the discovery of high magnesium (Fo = 0.95) olivine xenoliths in the iron-sulfur nickel pellets indicate that the pellets are formed in the kimberlite magma environment. In addition, the high-speed rail and silicon-aluminum two components showed the bi-phase structure of the discovery of two-phase ball, suggesting that the two are due to the role of melting off. Spheroidization can be explained by the liquid-immiscible phase diagram of SiO2-FeS-FeO. It is considered that the pellets are formed in the late phase of magma crystallization and are relatively rich in CO2, SO3, FeO, MnO and TiO, which occur under the condition of rapid increase of magma, rapid cooling, depressurization and various local order zones in the melt of.