秦岭群裂谷岩浆建造地球化学型式及其成因探讨

秦岭群形成于早元古宙华北南缘裂谷化环境中。其下部有一套岩浆岩建造,包括基性和酸性的火山岩或侵入岩。地球化学资料表明,基性岩具有OIB型和CNB型两种地球化学型式,酸性岩具有壳幔混合型地球化学型式。这些变化起因于不同的源区和岩石成因过程,但本质上取决于岩石圈拉张程度和地幔流能量。

DISCUSSION ON GEOCHEMICAL PATTERNS OF THE RIFT IGNEOUS FORMATION AND ORIGIN OF QINLING GROUP

A large number of recent studies have confirmed that Qinling Group was formed in the early proterozoic continental rift in the south margin of North China plate. There is an igneous formation in its lower part, including basic and acidic volcanics and intrusives. The basic rocks show two types of geochemical patterns, o-cean island basalt (OIB) type and continental basalt (CNB) type, and the acidic rocks show the crust - mantle mixed geochemical pattern, according to geochemical data. The changes of geochemical patterns and rock associations of the igneous formation were caused by different sources and different process of partial melting, crystallization and contamination) which were essentially controlled by extensional degree of lithosphere and mantle - flow energy.