Abstract:

Huanghua Depression is rift of Bozhong Triple Rifts that have the features of mantle uplift，high—heat flow and strong volcanic activity. Four tectono—stratigraphic units in this depression exist in each of the three tectonic levels. The evolution of the rift basin underwent three periods of tectonic movement patterns with different orientations:①During the pre— rift period，the compressive orientations with S—N direction. NW—SE direction and NWW —SEE direction were produced by the Indo— China Movement，the Early Yanshan Movement and the Late Yanshan Movement respectively;②During the rift period，two phases of rifting with the extensions of NW—SE and S—N direstion were produced in the depression;③During the post—rift period，the tectonic movement changed from horizontal movement to vertical subsidence because of the shrinkage of the rift.

Key words: Rift zone, Depression, Uplift, Tectonic system