矿物微量元素组成用于火成岩构造背景判别

摘要

火成岩中的矿物，特别是稳定副矿物的微量元素组成可用于火成岩构造–岩浆背景的判别。产于不同构造背景火成岩中单颗粒锆石原位微量元素含量的准确测定，积累了大量资料。本文介绍了用锆石微量元素含量的二维核密度分布投影，构建了U/Yb-Nb/Yb、Sc/Yb-Nb/Yb和 U/Yb-Sc/Yb构造背景判别图解，可以区分洋中脊、地幔柱影响的洋岛及俯冲有关的弧(大陆弧)等不同构造背景形成的火成岩。单斜辉石、尖晶石、黑云母和角闪石的微量元素或主量元素组成同样可用于构造背景识别。%Tectonic settings of igneous rocks can be discriminated based on trace element geochemistry of their constitute minerals, particular the stable accessory minerals. In-situ analyses of trace element contents of minerals in igneous rocks have been compiled and applied to set up a group of discrimination diagrams for tectonic settings. Density distribution plots were created with two-dimensional kernel of trace elements in igneous zircon which present U/Yb-Nb/Yb, Sc/Yb-Nb/Yb and U/Yb-Sc/Yb diagrams. These diagrams are effective for distinguishing the mid-ocean ridge (MOR), magmatic arc (continental arc) and ocean island (and other plume-influenced) settings. Tectonic setting discrimination using clinopyroxene, spinel, biotite and amphibole are also introduced.