The volcanic rocks of Yanshan Period have features of the mantle source. 燕山期火山岩具备幔源特征。
Hence peridotite modes can be used to reflect efficiently mantle melting and melt extraction processes beneath ocean ridges only if the excess olivine is removed appropriately. 为此，只要把深海橄榄岩中过量的橄榄石剔除后，其实际矿物组分就能有效地反映洋脊下地幔熔融作用和熔融萃取过程。
