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满洲里-额尔古纳地区岩浆作用及其大地构造意义
MAGMATISM AND ITS TECTONIC SIGNIFICANCE IN THE MANZHOULI-E’ERGONA REGION
【摘要】 对满洲里 -额尔古纳地区不同时代岩浆岩的地质、地球化学特征进行了初步研究。研究表明晚元古代花岗岩具 S型花岗岩或地壳改造型花岗岩特征 ,形成于同碰撞造山环境。加里东早期花岗岩具 I型、科迪勒拉 I型或 ACG特征 ,代表活动大陆边缘构造属性 ,加里东晚期花岗岩具 S型或地壳改造型特征 ,代表陆 -陆碰撞造山环境 ,加里东期花岗岩记录了多宝山 -牙克石 -伊尔施陆间洋壳消减和闭合的过程。海西晚期花岗岩属富碱低钙钙碱性岩石 ,具 S型花岗岩或 CPG,KCG花岗岩特征 ,形成于碰撞后构造环境。中生代早期岩浆岩形成于蒙古 -鄂霍茨克残余洋“剪刀式”闭合所造成的张性似裂谷环境 ,中生代晚期岩浆岩形成于挤压环境。
【Abstract】 Based on the geological and geochemical studies of magmatite in the different period from the Manzhouli-E’erguna region, it is suggested that the Later Proterozoic granitoids, which is characterized by S-type granitoids or crust-reconstructed granite type in south of China,were associated with a collision geodynamic environment. The Early Caledonian granitoids, showing characteristics of I-type granitoids, Cordilleran I-type granitoids or low-K, high-Ca amphibole-bearing calc-alkaline granitoids (ACG),were associated with an active continental margin and reflected the subduction of oceanic crust during the Caledonian period. The Later Caledonian granitoids, which is characterized by S-type granitoids or crust-reconstructed granite type in south of China,were associated with a collision between two continents. The magmatism of the Caledonian recorded the history of subduction of Duobaosan-Yakeshi-Yiershi intercontinental ocean. The Later Hercynian granitoids, which are similar to S-type, cordierite bearing-peraluminous granitoids (CPG) or K-rich calc-alkaline granitods (KCG), revealed a post-collision geodynamic environment. The Early Mesozoic magmatite developed on the tensional background caused by closing of Mongolia-Ehucike Residual Ocean in scissors form. The Later Mesozoic magmatite formed in compression background.
【Key words】 granitoids; geochemistry; tectonic environment; Manzhouli-E’erguna region;
- 【文献出处】 矿物岩石 ,Journal of Mineralogy and Petrology , 编辑部邮箱 ,2001年01期
- 【分类号】P588.1;P542
- 【被引频次】75
- 【下载频次】585