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为了定量给出华北克拉通燕山期岩浆活动的规模,在合理构建华北燕山期地质-物理模型的基础上,利用有限元方法,在忽略玄武岩浆内对流只考虑热传导的假定下,反演了该区燕山期形成花岗岩所需要的侵入玄武岩浆的量.通过计算表明:(1)在压力1GPa、地幔的玄武岩浆底侵作用于下地壳英云闪长岩围岩的情况下,英云闪长岩围岩的纯熔融量与底侵玄武岩纯结晶总量的比值约为0.161;假设仅有25%的熔浆可分离出来,则分离出的熔浆与玄武岩结晶总量比约为0.04025.(2)数值模拟得到最后发生相变的整体区域为-50.285～-36.867km.与前人研究得到的现今下地壳下部和壳幔过渡带33～40m和40～50km接近,表明此数值模拟方法具有可行性.
In order to quantitatively give the scale of the Yanshanian magmatic activity in the North China Craton, based on the reasonable geologic-physical model of the Yanshanian period in North China, the finite element method was used to ignore the convection in the basalt magma only considering the heat conduction. The results show that: (1) Under the pressure of 1 GPa, basaltic magma underplating of the mantle is applied to the surrounding rock of the lower crust dioritic diorites, The ratio of the pure melting amount of rock mass to the total volume of pure basalt underbased basalts is about 0.161. If only 25% of the melt is separable, the total volume ratio of the melt to basalt isolated is about 0.04025. 2) The total area of the last phase transformation obtained by numerical simulation is -50.285 ~ -36.867km, which is close to the current lower crustal crust-mantle transitional zone of 33 ~ 40m and 40 ~ 50km obtained from previous studies, indicating that this numerical simulation method has feasibility.