摘要
基于大量的1:5万区调资料,通过对北淮阳东部"小溪河组"的岩石组成、各种界面关系和岩石化学等特征的研究认为"小溪河组"变质岩原岩主要由一套产于大陆裂谷环境且具有完整演化特征的A型花岗岩组成,不具有地层意义;另一部分为构成其围岩的火山-沉积的表壳岩。建议废除"小溪河组"一词,将变形变质侵入岩改称小溪河片麻岩套;表壳岩部分单独建组。同位素年龄资料表明该套片麻岩形成于晚元古代。大别山地块于晚元古代因北淮阳裂谷作用从华北地块分出。可能的裂谷南北边界分别为桐柏-磨子潭断裂和金寨-韩摆渡断裂。
A series of characteristic metamorphic rocks so called the Xiaoxihe Formation' are out- cropped in the eastern Beihuaiyang area on the noth side of the Dabie Mountain in East of China. The study on the rock association,primary rock formation and the formation and evolvement of the Dabie Mountion. Considerable metamorphic A-type granite and partially metamorphic alkaline basalt, etc. Known as the upper crustal rocks are recognixed in 'the Xiaoxihe Formation'. For this, the author di- vides it into two parts of the Xiaoxihe gneiss suite dominated by the metamorphic A-type gramite, and the metamorphic upper crustal rocks. The A-type granite and alkaline basalt from the upper mantle are thonght to be formed in a continental rift dated at the late Proterozoic. Possible for the south and north of the rift are the Tongbo-Mozitan Fanlt and the Jinzhai-Hanbaidu Fault, respectively.
出处
《安徽地质》
1992年第3期11-19,共9页
Geology of Anhui
关键词
小溪河组
片麻岩套
构造环境
北淮阳裂谷
Xiaoxihe Formation
gneiss suite
ectonic environment
Beihuaiyang Rift.
