关键词: 古构造环境, 变质构造地层, 北淮阳构造带

Abstract:

There are different opinions on regarding to the paleotectonic settings of the previous so-called Foziling Lithogroup in the eastern Beihuaiyang belt, north foothills of the Dabie Mountains. This difference is derived from the mixing of tectonostratigraphic units with different tectonic settings and geologic history under the name of Foziling Lithogroup and the study of paleotectonic settings based on the Foziling Lithogroup as a whole. Recent work in structural and tectonic deformation, petrography and geochemistry on the so-called Foziling Lithogroup indicates that it is composed of two distinct tectonostratigraphic units separated by a nearly horizontal ductile shear detachment system. The newly defined tectonostratigraphic units above and below the detachment zone are named as Zhufoan Lithogroup and Luzhenguan Melange respectively. Sedimentary characteristics together with the petrographic and geochemical analysis results revealed from the newly defined units in this study imply that the Luzhenguan Melange was formed in a passive continental margin, the Zhufoan Lithogroup, however, was formed in the southern active continental margin of the North China Plate. These research results indicate that the collision between the North China and Yangtze plates in the Palaeozoic is supposed to be located in the north of Zhufoan Lithogroup, and the Yangtze Plate served as a subducted plate beneath the North China Plate.

Key words: paleotectonic setting, metamorphic tectonostratigraphy, Beihuaiyang tectonic belt