摘要
东营凹陷早白垩纪火山岩 ,沿青城断裂分布 ,是一套弱碱性—钙碱性、富钠的大陆玄武岩、玄武安山岩。其87Sr/86Sr=0 .70 51 97,K Ar同位素年龄为 1 1 6.8± 2 .4～ 1 2 1 .6± 2 .5Ma,稀土含量在 84 .93× 1 0 -6～ 90 .60× 1 0 -6,ΣLREE/ΣHREE =6.99～ 7.2 4。岩浆主要来自上地幔 ,并受地壳物质混染。研究表明 ,该套火山岩产出的大地构造背景是活动大陆边缘火山弧后 ,左旋压扭应力场中的NWW向展布的次级张性盆地。
Early Cretaceous volcanic rocks in the Dongying depression, distributed along the Qingcheng fault, are a suite of alkaline\|calc\|alkaline, Na\|rich continental basalt\| basaltic andesite series. Their \{\}\+\{87\}Sr/\{\{\}\+\{86\}Sr\} is 0.705 19, isotopic age is 116.8±121.6 Ma, REE abundance is (84.93-90.60)×10\+\{-6\}, and ΣLREE/ΣHREE varies between 6.99 and 7.24. The magma came from the mantle and then was contaminated by crustal sources. Studies have shown that their tectonic setting is a secondary tensional basin, developed in the NWW direction, in the sinistral compressive stress field in the back\|volcanic arc on the tectonically active continental margin.
出处
《矿物学报》
CAS
CSCD
北大核心
2000年第3期293-297,共5页
Acta Mineralogica Sinica
关键词
东营凹陷
早白垩纪
火山岩
稀土元素
地球化学
Dongying depression
Early Cretaceous
volcanic rock
geochemistry
tectonic setting
