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

摘要： 研究区按地壳波速结构划分为8种类型,探讨了不同类型的地壳速度结构与构造单元之间的联系,以及速度结构可能代表的地质含义。指出本区的壳内低速层出现于不同层次,其厚度薄、规模小,不利于在同一造山幕内发育大规模的基底拆离和长距离的推覆。

关键词: 扬子构造区, 地壳, 速度结构, 构造单元, 低波速带