南祁连志留纪巴龙贡噶尔组火山岩地球化学特征及其地质意义  

Geochemical characteristics and geological significance of the Silurian Balonggunggar Formation volcanic rocks in South Qilian

作　　者：冷晓雷 张雪锋 李宾 王鑫 李晨希 LENG Xiaolei;ZHANG Xuefeng;LI Bin;WANG Xin;LI Chenxi(Mineral Resources Exploration Center of Henan Geological Bureau,Zhengzhou 450053,Henan,China)

机构地区：[1]河南省地质局矿产资源勘查中心,河南郑州450053

出　　处：《资源信息与工程》2024年第3期14-17,23,共5页Resource Information and Engineering

摘　　要：研究区属南祁连早古生代弧后前陆盆地,火山岩类型包括中基性—中酸性岩类。岩相分析表明,火山活动的过程为宁静喷溢—强烈爆发—宁静喷溢—喷溢4个阶段,火山喷发以溢流相为主,伴生微弱的爆发,喷发形式为裂隙式。锆石U⁃Pb加权平均年龄为(417.9±3.9)Ma,表明研究区火山岩成岩时代为志留纪。硅酸盐地球化学特征显示,巴龙贡嘎尔组火山岩大多数属于高钾—钙碱性系列,为岛弧或活动大陆边缘火山岩,具造山带地区火山岩特征;微量稀土地球化学特征暗示巴龙贡嘎尔组火山岩具有相似的岩浆来源和相似的岩浆作用过程。地球化学图解表明,巴龙贡嘎尔组火山岩组形成于造山带(活动大陆边缘)构造环境。The study area belongs to the early Paleozoic back⁃arc foreland basin in South Qilian.The types of volcanic rocks include intermediate⁃basic and intermediate⁃acidic rocks.The volcanic activities are characterized by four stages:quiet eruption,strong eruption,quiet eruption,and eruption.The eruption mode is dominated by overflow phase,accompanied by weak eruption,and the eruption form is fissure type.The weighted average age of zircon U⁃Pb is(417.9±3.9)Ma,indicating that the volcanic rocks in the study area were formed during the Silurian period.The geochemical characteristics of the silicate minerals show that most of the volcanic rocks of the Balonggongar Formation belong to the high potassium⁃calc alkaline series,characterized as volcanic rocks of island arc or active continental margin,with the characteristics of volcanic rocks occurring in orogenic belts.The trace rare earth geochemical characteristics suggest that the volcanic rocks of the Balonggongar formation have similar magmatic sources and processes.The volcanic rocks of the Balonggongar Formation were formed in the tectonic environment of the orogenic belt(active continental margin).

关 键 词：南祁连 火山岩 地球化学 U⁃Pb测年 

分 类 号：P595[天文地球—地球化学]