摘要
蠕英石常见于中酸性侵入岩和片麻岩中。蠕英石石英含量与蠕英石斜长石An值或岩石中Ca含量呈正比关系。条纹钠长石、甚至钾长石的残余体出现在蠕英石中,说明蠕英石是含钙的销质气液对钾长石发生交代作用的产物。尽管有多种形态和产状的蠕英石,其成因却都是相同的。岩石受变动后形成的蠕英石应晚于未变动时形成的蠕英石。
Myrmekite, an intergrowth between vermicular quartz and sodic plagioclase,often occurs in minor amounts in felsic intermediate-acidic intrusive and gneissicrocks. Several hypotheses for myrmekite genesis are briefly reviewed. Theproportionality relationship between the amount of vermicular quartz and thecomposition of plagioclase in myrmekite or the Ca content of the rocks isconsistent with hypotheses of replacement, solid-state exsolution, and recrystalli-zation of primary plagioclase. The presence of perthitic albite and even K-felds-par relicts in the myrmekite obviously indicates that the myrmekite is formedby replacement of Ca-bearting sodic solution or emanation after K-feldspar.Therefore, myrmekites of different morphology and spatial distribution are ofthe same metasomatic origin. The myrmekite formed during the deformationperiod should be later than that formed during the pre-deformation period.
出处
《岩石矿物学杂志》
CAS
CSCD
1992年第4期324-331,T001,共9页
Acta Petrologica et Mineralogica
关键词
蠕英石
钠长石
成因
myrmekite
metasomatism
solid-state exsolution
perthitic albite
