关键词: 扬子构造区, 地壳, 速度结构, 构造单元, 低波速带

Abstract: Studied in this paper are eight types of velocity structures of the crust in the studied region that can be distinguished,the relationship between the velocity structures and tectonic units of the crust as well as the geological implication for the different velocity structure types. Mean-while,the authors indicate that the low-velocity layers existing in the studied region occur at dif-ferent levels and have their small thickness and extension. Hence, they are unfavourable for de-velopment of large-scale basement detachment and lohg-distance overthrusting in an orogenic episode.

Key words: Yangtze tectonic region, Crust, Velocity structure, Tectonic element, Low-velocity zone