南岭花岗岩及矿体中一些云母的研究

On Some Micas from Nanling,S.E.China

一、前言,云母作为造岩矿物广泛分布,对一些成矿和稀少元素起富集作用,这些元素作为云母晶格的组成部分,或形成独立矿物包在云母中,或富集生长于其附近。云母的独立种到目前已超过40个,其中30个已作过结构分析。重要的云母文献已超过300余篇。近几年来,日本发现了几个新的云母种,据报导,日本已使用了高分辨率电子显微镜直接观察云母的多型。

There occurs,in S.E.China,a broad region of granite masses the acidity of whichincreases with ages from prelower Palaezoic to late of Cretaceus.The associated mineral deposits are,W,Sn,Mo,Bi;Cu,Pb,Zn;Li,Be,B;Nb,Ta and rare earths,forming the socalled the Chinese part of the Circum-Pacific polymetallic Zone.The ore bodies appear as vein,greisen or skarn,usually on the tops of cupolas.The granite and the ore-bodies were cut by fine grained porphyritic granite dykes,which were,in turn,cut by basic or ultrabasic dykes.By investigating 200 samples of granites,greisens and skarns of different ages and localities,it appears that micas vary significantly with barren,slightly altered granite and greien-skarn associated with orebodies.Micas play a role of absorber or reservoir of rare or oreforming elements which either enter,as building stones,into the micastructure or as independent minerals enclosed in or enriched around micas.The physical,including colors,and chemical properties of micas depend on the kinds of parent rocks and associated minerals.The micas are,1.Normal biotite and muscovite in barren or unaltered granites,2.Slightly altered micas and 3.Much altered micas associated with ore deposits a)Rubidian zinnwaldite in altered granite and greisen with niobite;grey green;2-3mm;with pinacoidal or prismatic faces;containing Li_(2)O 3.28,Rb2O 1.54,F 7.16%)and with diffused streaks much developed in Laue photograph.b)Zincian siderophyllite in niobite granite;containing Li_(2)O 0.94,MnO0.91,Na2O 1.5,ZnO 0.46 and F 4.6%.c)Be-margarite in the central parts of mica veinlets in stockwork marbles with maximum BeO 1.33%.