内蒙古大青山太古宙麻粒岩带的板块构造演化模式  

A PLATE-TECTONIC MODEL FOR THE EVOLUTION OF THE DAQINGSHAN GRANULITE BELT IN INNER MONGOLIA, CHINA

作　　者：甘盛飞[1] 钱祥麟[2] 

机构地区：[1]沈阳黄金学院 [2]北京大学

出　　处：《地质学报》1996年第4期298-308,共11页Acta Geologica Sinica

基　　金：国家自然科学基金(编号 8400007)

摘　　要：太古宙末期在全球范围内出现的麻粒岩带是地壳早期地质演化历史中的一个重大事件,可能意味着地壳构造演化机制的重大转变。越来越多的地质事实表明,太古宙晚期大陆地壳已具有足够的刚性和稳定性。太古宙时期地幔存在强烈的热对流,具备发生板块运动的条件。太古宙麻粒岩带就是太古亩地壳发生刚性板块运动的直接产物。内蒙古大青山太古宙麻粒岩带呈东西向连续出露于大青山地区达230余公里,由中晚太古代乌拉山群麻粒岩相组成,其变质原岩形成于活动大陆边缘环境。晚太古代时期乌拉山群岩石发生了麻粒岩相变质作用和韧性构造变形。太古宙末,在南北向挤压力作用下,华北克拉通与古蒙古陆块发生板块碰撞,深部的乌拉山群麻粒岩相岩石沿着一系列高温韧性剪切带被逆掩推覆至地表,形成了呈东西向的大青山太古宙麻粒岩带。One of the most important events in the early geological evolutionary history of the Earth was the wide occurrence of granulite belts at the end of the Archaean in the world, which means a possible transformation of evolution mechanism of the crust. More and more geological evidence shows that the Archaean continental crust was rigid and stable enough to start plate-tectonic movement. Archaean granulite belts are just the product of plate-tectonic movement of rigid Archaean crust. The Daqingshan granulite belt, which extends continuously for 230 km in an E-W direction in the Daqing Mountains of Inner Mongolia, is composed of granulite facies metasedi-mentary and metavolcanic rocks of the Late Archaean Wulashan Group which were formed under conditions of active continental margins. During the Late Archaean, Wulashan Group rocks underwent granulite facies metamorphism and ductile deformation at temperatures of 750 -850℃ and pressures of 0. 7 -0. 9GPa, resulting in the formation of a series of folds (F, and F2) and schistosity (S1 and S2) as well as mineral lineations. At the end of the Archaean, the North China Craton collided with the ancient Mongolian continental block under N-S pressure. The granulite facies rocks of the Wulashan Group were thrust onto the surface of the earth from the depth through a series of high-temperature ductile shear zones, i. e. , the augen gneissic mylonite zone in the Daqing Mountains area. As a result, the Daqingshan granulite belt appeared along the northern margin of the North China Craton.

关 键 词：太古宙 板块构造 麻粒岩带 乌拉山群 内蒙古 

分 类 号：P542.4[天文地球—构造地质学] P588.346[天文地球—地质学]