早第三纪济阳坳陷的性质

A Discussion on Paleogene Jiyang Depression Characteritics and Its Forming Mechanism.

从构造-沉积演化出发,论述了济阳坳陷是一个有着复杂演化历史的复合、叠合盆地,在不同的构造演化阶段有着不同的原型盆地和不同的沉积建造。从8个方面(莫霍面上隆和岩石圈减薄、幔源基性火山岩和超基性岩的发育、高的地温梯度、一系列箕状断陷盆地群的伸展量高达50km以上及沉积速率高达0.1mm/a、张性断裂发育、岩石圈呈“三明治式”流变结构样式、位于中地壳的震源以及幔源气的释放、郯庐大断裂的性质)论证了早第三纪济阳坳陷处于转换-伸展状态,并探讨了转换-伸展盆地的形成机制。

According to the structural and sedimentary evolution,Jiyang depression is a compound and superim-posed basin with complex evolutionary history that there existed different basins of primary types and different sedimen-tary assemblages.It is confirmed that Jiyang depression of Paleogene occurred in trans-extensional behavior in the light of Moho uplifting,lithosphere thinning,development of basic and ultra basic igneous rocks in mantle source rocks,high geothermal gradient,halfgraben-like depression basin groups,extensional amount of more than50km and sedimentary velocity up to0.1mm/a,well-developed tensional fractures,lithosphere appearing sandwich-like rheological structure,seismic source mainly taking place in the middle crust and release of mantle source gases as well as property of Tanlu fault.The mechanism of trans-extensional basin is discussed.