Study on the Types Distribution and Formation of Buried Hills in Mesozoic in Jiyang Depression

Based on the formation mechanism and structure types of the buried hills, we can divide the buried hills in Mesozoic in Jiyang Depression into five types. They are fault-block type,block-fault type,surge type,drape type and monadnock type. According to the analysis on the cause of formation and the character of traps of the buried hills, the buried hills in Mesozoic in Jiyang Depression can be divided into six buried hill tectonic zones. It is thought that the distribution of the buried hills mainly lies in the structural features of rift basins and activity of basement fault. The formation and evolution process of the buried hills in Mesozoic in Jiyang Depression has experienced four periods: the Triassic draped and uplifted period, the Yanshan Jurassic-Cretaceous block-faulted and uplifted period, the Tertiary extended and block-faulted period and the buried period.