Also studied in this paper is a zoned structure of retrograde mica, which consists of an inner zone of paragonite, an intermediate zone of muscovite_margarite intergrowths and an outer zone of biotite.

• 退变质云母具环带结构 ,其内带为钠云母 ,中带为白云母和珍珠云母的交生体 ,外带为黑云母