摘要
内蒙古固阳一带广泛出露了一套太古宙乌拉山 (岩 )群的高角闪岩相—麻粒岩相的岩石。通过区域地质调查及重点地段的研究 ,确定其在区域变质作用中总体处于高角闪岩相 ,但也存在局部高温高压 (麻粒岩相 )的地段。根据脉体特征及相互关系 ,划分出第一期以富钠 (脉体为英云闪长岩、奥长花岗岩 )为特征和第二期以富钾 (脉体为钾长花岗岩 )为主的两期混合岩化作用。确定第一期为前构造期的混合岩化作用 ,是区域变质作用的延续与发展 ;第二期为同构造期的混合岩化作用 ,随着乌拉山旋回构造运动的加强而加强。
A series of Archean high grade amphibolites and granulites are extensively distributed in Guyang area,Inner Mongolia.On the basis of the intensive regional mapping and studies focusing on some key geological exposures,it is found that most of the rocks in this area underwent metamorphism of amphibolite facies,but the others are occupied by high-pressure and high-temperature metamorphism (i.e.granulite facies).Two phases of migmatization can be determined based on the features of veins and the relations among them.That is,the first phase is characterized by Na-enriched vein rocks such as tonalite and trondhjemite and the second by K-enriched vein rocks such as K-feldspar granite.Moreover it is concluded that the first phase belongs to pretectonic migmatization,which is the continuation and development of the regional metamorphism, and the second phase belongs to the syntectonic migmatization,which was strengthened with the strengthening of the Wulashan tectonic cycle and diminished with the ending of the Wulashan tectonic cycle.
出处
《现代地质》
CAS
CSCD
2002年第1期31-36,共6页
Geoscience
基金
国土资源部区域地质调查项目"内蒙古固阳地区三幅 1:5万联测"
