Evolution of continental crust and upper mantle during the formation of Gondwana supercontinent: deduced from magma processes

本文研究了东南极洲索朗丹山脉冈瓦纳超大陆形成过程中下地壳和上地幔的演化。根据野外关系和部分侵入岩的锆石U-Pb测年，岩浆活动可划分为3个阶段：第1阶段；1000~950 Ma，第2级；~800 Ma和阶段3；600 ~ 500 Ma。第1、2阶段为碰撞前岩浆活动，第3阶段为碰撞后岩浆活动。结合岩石学和地球化学，碰撞后火成岩活动以高钾玄武岩岩浆为特征。相对衰竭的地幔与大陆碰撞后的上地壳相互作用导致了交代地幔的部分熔融，从而形成了明显的岩浆活动。

We studied here on the evolution of lower crust and upper mantle during the formation of Gondwana supercontinent from the Sor Rondane Mountains, East Antarctica. Based on field relationships and zircon U-Pb dating for some intrusive rocks, the magma activities can be classified into the following three stages, Stage 1; 1000~950 Ma, Stage 2; ~800 Ma and Stage 3; 600~500 Ma. Stages 1, 2 are regarded as pre-collisional magmatism, while Stage 3 represents the post-collisional magma activity. Taking petrography and geochemistry into account, the post-collisional igneous activity is characterized by high-K basaltic magma. The significant magmatism can be resulted from the partial melting of metasomatized mantle that has been interaction between relatively depleted mantle and upper continental crust deduced from continental collision.