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义县火山旋回发育于早白垩世 ,可以划分出 4个亚旋回 ,具有由西向东迁移 ,由基性向中基性、中酸性演化的特点 ,并形成了一系列不同级别的火山构造。区内主要为四至六级火山构造 ,包括火山构造洼地、层状火山、破火山和穹状火山等。不同级别、不同发展阶段的火山构造对化石沉积层的形成、分布和保存起到了不同的作用。三级火山构造控制了义县火山 沉积岩系呈NE向展布 ;四级火山构造形成了两大火山洼地 ,并在两个火山构造洼地中分别形成了相对独立的沉积层 ;五至六级火山构造直接影响了化石沉积层的空间形态和物质组成。
Yixian volcanic cycle developed in the Early Cretaceous, can be divided into four sub-cycles, with the migration from west to east, from the basic to the nature, the evolution of acid in nature, and the formation of a series of different levels of volcanic structure. The area is mainly composed of four to six volcanoes, including volcanic tectonic depressions, stratiform volcanoes, volcanoes and dome volcanoes. Volcanic structures at different levels and stages of development play different roles in the formation, distribution and preservation of fossil deposits. Three volcanic structures control the Yixian volcanic sedimentary series NE distribution; four volcanic tectonic formed two volcanic depressions, and in the two volcanic tectonic depression were formed relatively independent sedimentary layer; five to six volcanoes Structure directly affects the fossil sedimentary layer of the spatial morphology and composition of matter.