摘要
通过对额尔古纳地区中生代火山岩新的岩石化学、微量元素、构造等方面的分析, 表明该地区中生代火山岩(主要指塔木兰沟组(J_3t)火山岩、上库力组(K_1s)火山岩是形成在的明 显的挤压环境中;再结合区域构造、区域岩浆作用、古地磁特征和稳定同位素分析,笔者得出以 下认识;1、该区中生代火山岩岩浆来源较深(幔源);岩浆是挤压背景下,“减压-剪切”作用的产 物,而不是裂谷环境中的产物,从而使得岩浆在演化过程中混入了大量的壳源物质;2、中生代火 山活动大致分两个亚族回,其中塔木兰沟组(J_3t)火山岩和上库力组(K_1S)火山岩是同一岩浆亚 族回的产物,并构成一个完整的亚族回。
The Mesozoic volcanic rocks in Ergun region, which were formed mainly in the period of late Jurassic to early Cretaceous (150-100Ma), were formed in compressional surroundings apparently according to the analyses in petrochemistry, trace element and tectonics. Further studying in regional tectonics and magma activity, palaeo-magnetism as well as stable isotope etc., we concluded: 1 .The Mesozoic volcanic rocks were from the mantle, and were formed in compressional surroundings with'reduced pressure'-'shearing'process. That is why there are many materials of crust-source added in the Mesozoic volcanic rocks. 2. The Mesozoic volcanic activities can be divided into two subcircles. Among them, the volcanic rocks of Tamulangou formation(J_3t)and Shangkuli formation(K_1s)were formed in the same subcircle.
出处
《火山地质与矿产》
1999年第1期35-47,共13页
Volcanology & Mineral Resources
基金
地矿部攻关项目!95-02-008-01
关键词
中生代
火山岩
动力学环境
额尔古纳地区
Ergun region mesozoic volcanic activity dynamic background Daxing' anling Mts