摘要
河南、湖北、安徽三省交界的桐柏-大别山,东西长400余公里,南北宽150—180公里。近几年完成了1:20万区调工作,积累了比较丰富的地质资料,但本区研究程度在各省是不相同的,加上地质情况十分复杂,所以对变质岩系的划分、地质构造的认识和岩浆岩的时代,分歧较大。今后,本区仍是地质构造研究中的一个重大课题。
The Tongbai-Dabie Mountains represent an interwoven zone of the platforms in the east and the geosynclines in the west of China,so they are of major importance in studying the tectonic divisions in the eastern part of China.The Tongbai-Dabie mountains consist mainly of five metamorphic formations of different ages and metamorphic grades,i.e.:(1)the upper Archean Dabie Group in the core,(2)the lower Proterozoic Hongan(Susong)Group in the southeastern part of the Dabie Mountains,(3)the Sinian-Silurian Huashan and Yinshan Groups on the southern slope of the Tongbai Mountains,(4)the Tongbai,Xinyang and Fuziling Groups in northern Huaiyang,and(5)the slightly metamorphosed Carboniferous beds in northern Huaiyang where animal and plant fossils have been found.The proto-structure of the Tongbai-Dabie Mountains was a major anticlinorium of nearly east-west trend.It was completed in the late part of the early Proterozoic,i.e.after deposition of the Hongan(Susong)Group,and was assigned to the Huaiyang anticlinorium an anticlinorium in the southern part of the Sino-Korean-Yangtze protoplatform.The disintegration of the anticlinorium began in the Sinian.In Sinianearly Paleozoic times,the Caledonian geosyncline of the South Qinling Range migrated eastwards and changed to the Caledonian Suiying geosyncline under the control of deep faults in the South Tongbai Mountains.In the late Paleozoic,the northern flank of the anticlinorium was cut and depressed,and as the Variscan geosyncline of the North Qinling Range developed and extended eastwards,the Variscan geosyncline of northern Huaiyang was formed under the control of the Tongbai-Mozitan and Hefei-Minggang deep faults.In middle Mesozoic times,a piedmont depression came into existence in the northern part of the Variscan foldbelt,while an intermontane depression developed in the eastern segment of the southern part of the foldbelt.The author considers that the Sino-Korean platform and the Yangtze paraplatform were both the basement of the folds formedat the end of the early Proterozoic(about 1.7 b.y.B.P),which have been known as the Sino-Korean-Yangtze proto-platform.So the tectonic development of the Tongbai-Dabie Mountains was closely related to the geosynelines in the western part of China.Both the Caledonian Suiying geosyncline on the southern slope of the Tongbai Mountains and the Variscan northern-Huaiyang geosyncline on the northern flank of the Tongbai-Dabie Mountains are"appendix-shaped geosynclines"that resulted from extension of the Paleozoic Kunlun-Qinling geosyncline system into the interior of the platform region,whereas the Huaiyang massif is a median massif intervening between geosynclines after disintegration of the anticlinorium.
作者
杨志坚
Yang Zhijian(Nanjing Institute of Geology and Mineral Resources,Chinese Aeademy of Geological Seiences)
出处
《地质学报》
1982年第2期123-135,共13页
Acta Geologica Sinica
