(Table 1) Chemical composition of Middle Cenozoic magmatic rocks from the Schmidt Peninsula, North Sakhalin

Middle Cenozoic evolution of magmatism in the Schmidt Peninsula between 37 and 25 Ma began with eruptions of subalkaline and moderately alkaline andesite, latite, trachyandesite, and trachyrhyolite lavas and ended with subvolcanic intrusions of highly alkaline strongly undersaturated essexites. According to trace element data magmatism evolved from melting of a mantle source in the zone of ocean-continent plate convergence to small degree partial melting in the lithospheric mantle at the final stage. This succession is generally typical for Late Cenozoic continental-margin magmatism in the Southeast Russia. Similarity in the Middle and Late Cenozoic stages of magmatism is an evidence for their individual significance.

施密特半岛（Schmidt Peninsula）在37 Ma至25 Ma时段的中新生代岩浆作用演化序列，以亚碱性（subalkaline）与弱碱性安山岩（andesite）、安粗岩（latite）、粗安岩（trachyandesite）及粗面流纹岩（trachyrhyolite）熔岩的喷溢为开端，最终以强碱性强不饱和正霞正长岩（essexites）的次火山侵入体（subvolcanic intrusions）就位作为演化终点。依据微量元素（trace element）数据，该岩浆作用的演化过程从洋陆板块汇聚带的地幔源区熔融，逐步转变为末期岩石圈地幔的低程度部分熔融。这一演化序列整体上契合俄罗斯东南部晚新生代陆缘岩浆作用的典型特征。中新生代中期与晚期岩浆作用阶段的相似性，证实了二者各自具备独立的地质意义。