北秦岭火山岩地球化学特征,成因和构造环境

本文研究了北秦岭及华北地台南缘火山岩约500件岩石化学、120件微量元素和135件稀土元素样品数据。熊耳群、大红口组火山岩属B类的地壳混染型,为大陆裂谷环境;宽坪群、秦岭群变拉斑玄武岩建造属A类的幔源型,为海槽环境;二郎坪群、丹凤群细碧角斑岩建造属C+A、C类的壳幔混合型,为海盆环境。

Geochemical Characteristics,Petrogenesis and Tectonic Settings of Volcanic Rocks in the Northern Qinling Mountains

The authors collected and studied about 500 samples of major, 120samples of trace and 135 samples of rare earth elements of the volcanicrocks from the Northern Qinling Mountains and the southern margin of theNorth China platform. The volcanic rocks of the Xiong'er Group and theDahongkou Formation are B-type of volcanics series, being the products ofthe contamination of mantle-derived mafic magma with crust-derived silice-ous magmas in the magma chambers of crust, with continental rift tectonicsettings. The metatholeiite formations of the Kuanping Group and theQinling Group belong to A-type volcanics: series, with mantle-derived magmagenesis and sea trough tectonic settings. The spilite-keratophyre formationsof the Erlangping Group and the Danfeng Group are C+A-type and C-type volcanics series, being the mixing products of the magma from thelower crustal bottom and that from hot mantle diapirs at crust-mantletransitional zones, with sea basin tectonic settings.