| Fe-Li云母化学成分的解释和分类 |
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| 引用本文： | 孙世华.Fe-Li云母化学成分的解释和分类[J].地质科学,1988,0(3):213-228. |
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| 作者姓名： | 孙世华 |
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| 作者单位： | 中国科学院地质研究所 |
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| 摘 要： | 用置换矢量概念解释了115个天然 Fe-Li 云母化学成分的变化。Fe-Li 云母是三八面体 Li-Fe-Al 云母,其基本置换是四锂云母置换。由于 Al-Li 白云母置换和白云母置换的影响,其化学组成变化的基本趋势呈明显的非线性,因而 Fe-Li 云母不是真正的二元系。作为 Fe-Li 云母,富铁黑云母和铁叶云母都是最富铁的成员,因而建议称 Fe-Li 云母为黑云母-锂云母系列。根据化学成分,晶胞参数和折光率的异常变化还提出了该系列自然分类的方案。
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| 关 键 词： | 云母 Fe-Li 黑云母-锂云母系列 化学成分 置换 置换矢量 分类 |
| 收稿时间： | 1986-06-01 |
| 修稿时间： | 1986-06-01; |
INTERPRETATION OF CHEMICAL COMPOSITION AND SUBDIVISION OF IRON-LITHIUM MICAS |
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| Sun Shihua.INTERPRETATION OF CHEMICAL COMPOSITION AND SUBDIVISION OF IRON-LITHIUM MICAS[J].Chinese Journal of Geology,1988,0(3):213-228. |
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| Authors: | Sun Shihua |
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| Institution: | Institute of Gcology, Academiu Siniica, Beijing |
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| Abstract: | A study of 150 analyses of iron-lithium micas from South China and the other regions indicates that iron-lithium micas are not true binary system minerals but trioctahedral Li-Fe-Al micas, and suggests that iron-lithium micas should be confined as biotite-lepidolite series. Furthermore, the natural subdivision of iron-lithium micas is also made on the basis of the anomalous changes of compositions, refractive indexes and cell parameters.The end-members of iron-lithium micas include K2Li4Al2Si8O20](OH, F)4, K2Fes Si6A12O20](OH, F)4, K2Al,Si6Al2O20](OH, F)4, and K2Fe4Al2Si4Al4O20](OH, F)4. Three basis vectors, polylithionite substitution(Rvi+2-3Li2 Rvi+3(R1v+3)-1Si, Al-Li musco-vite substitution(Rvi+2)-1Li3(□v1)-1 and muscovite substitution(Rvi+2)-3(Rvi+3)2□v1, are uggested to interpretate the essential changes of iron-lithium mica compositions swhose basic trend is nonlinear and coincident with the orientation of the polylithionite substitution vector--the basic substitution.The members of natural iron-lithum micas includeferrobiotite lithian biotite+ + -- protolithionite--siderophyllite lithian siderophylltte generalized ferrobiotite and siderophyllite zinnwaldite--cryophyllue--lepidolite.Generalized ferrobiotite and siderophyllite are separated by value MF = 4.80(MF = 6(Fe+2 + Mn)/(Fe+2 + Mn + Mg)), but there are no essential difference between them when they are both the members of iron-lithium micas. In fact, the members richer in lithium can be derived from both siderophyllites and ferrobiobites.The value FL = 100Li/(1.5Li + R*)(R* = Fe+3 + Mg + Fev1+3 + Tiv)is more reasonable than the value ol Li-content for describing the basic trend. Abnormal changes of chemical composition at near FL = 5.8, 12.5, 33.3, 49.1 and abnormal changes of refractive indexes Nm and Ng and cell parameters b at FL = 57.1 are the grounds for so-called natural subdivision of iron-lithium micas. The natura subdivision is useful for study of the relations between the iron-lithium micas and the petrogenetic sequence of granites. |
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| Keywords: | mica iron-lithium mica biotite-lepidolite series chemicat composition substitution substitution vector subdivision |
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