The relative fertile lithospheric characters of Yanshan area, unique plate tectonic situation and developed deep faults can explain reasons of the volcanism and tectonic events in Yanshan area throughout the Mesozoic.

• 4 燕山地区特有的相对“易熔”的岩石圈性质，所处的特殊的构造位置及发育的深大断裂，可以较好的解释该地区发生贯穿整个中生代的火山活动和构造变形的可能性。