宿松杂岩中白云母的矿物学特征及地质意义

大别山为印支期扬子陆块和华北陆块之间的碰撞造山带。太湖—宿松地区位于大别山东段部位，主要由扬子陆块北缘不同变质程度的变质基底和少量浅变质盖层组成。本文选择了宿松杂岩中的白云母进行探针分析以及X射线粉末衍射分析，研究结果表明宿松杂岩中的白云母都是2M₁型且均为多硅白云母。其中，多硅白云母的晶胞参数b₀平均值为9.039，显示宿松杂岩的变质压力为中压—高压。根据宿松杂岩中白云母的显微变形特征可以知道白云母至少存在着两期变形，一期是导致石榴子石压力影形成和白云母右旋的构造作用，应该对应着燕山期大别造山带中-下地壳物质发生平行造山带向东流动的地质事件。另一期是导致白云母形成涡流构造形成的构造作用，这一期构造应该对应扬子板块和华北板块碰撞事件。根据白云母中的Ti温度计和多硅白云母压力计可以得出宿松杂岩的变质条件为T=480 ℃～579 ℃，P=0.7～1.2 GPa，属于绿片岩相到角闪岩相。

The mineralogical characteristics of muscovite in the Susong complex and its geological significance

Dabie Mountain is a collision orogen between the Yangtze block and the North China block，Taihu-Susong area is located in the eastern segment of Dabie Mountain，and it is mainly composed of the metamorphic basement suffered different-grade metamorphism and a few low-grade metamorphic cover of the north edge of the Yangtze block. In this study， we selected muscovite of Susong metamorphic complex to make EPMA and X-ray powder diffraction analysis. The results showed that the multi-type of muscovite in Susong complex is 2M₁ and is phengite. Among them，the average of lattice parameters b₀ of phengite is 9.039，showing the metamorphic pressure of Susong metamorphic complex is medium-voltage to high-voltage. According to the microscopic deformation features of muscovite in Susong complex，we can know there are at least two period deformations，one leading to the pressure shadow of garnet and the right-handed structure of muscovite，which should correspond to the geological event which the middle and lower crustal material of Dabie orogen belt flowing to east parallel to the orogen belt in the Yanshanian. The other one results in the formation of muscovite's eddies structures，which should correspond to the collision events of the Yangtze plate and North China plate. According to the Ti-in-muscovite thermometers and phengite manometers，we can know that the conditions of Susong metamorphic complex are T=480 ℃～579 ℃，P=0.7～1.2 GPa，belongs to the greenschist facies to amphibolite facies.