摘要
大别山地区的“大别群”,在湖北和安徽境内呈近东西—北西西向出露。这套变质杂岩为一套蓝闪片岩相、铁铝榴石角闪岩相、麻粒岩相和榴辉岩相所组成。它们不整合伏于浅变质岩系之下。“大别群”的时代,经湖北区测队用铁石铀-钍-铅定年法获得四组年龄数值,其变化在1952—2424万年之间,采用韦瑟里尔谐和图法,对数据进行的回归分析,获得上交点年龄值为29亿年。“大别群”的上限及代表的年龄值为20亿年左右。安徽区测队获上覆宿松群大兴组下部同位素年龄值为18.5亿年(图1)。
The tectonic environmints of Dabieshan have long been discussed among geologists. In 1976, We raised the opinion that there perhaps may be a "fossil subduation" trending E. W. Recently we have system a tically studied the minerals from this metamorphic terrain of Dabie group in Hubei and Anhui, and their P-T Conditions. The lower proterozoic Wuhe group in Anhui is also considered.Phanerozoic formation discordantly overlies on these metamorphosed terrains. The radioactive age of zircon in Machao group are 1328, 1578 my., the age of biotite in Wuhe group are 1650, 1767, 1810 my. High P-Low T minerals, such as omphacite, garnet, crossite, barroisite, phengite, of barroisite-ecologite, amphobole-schist and granulite facies are the main subjects of this study. According to the study of minerals in Dabieshan metamorphic terrain we suggest that the Dabieshan was a plate boundary of paleoceanic plate in jinning cycle Low T-High P metamorphic belt was found in the southern side of the mountain, i. e., the oceanic side. Pressure decreased northward.
作者
谢窦克
马承安
史鸿歧
蒋永材
冯锦江
Xie Douke;Ma chengan;Shi Hongqi;Liang Yongchai;Fong Jingjiang
出处
《岩矿测试》
CAS
1983年第2期87-97,I0001,共12页
Rock and Mineral Analysis
