中国东部中生代软流层上涌造山作用  

Mesozoic asthenospheric upwelling orogeny in eastern China

作　　者：肖庆辉[1] 邱瑞照[2] 伍光英[3] 邢作云[4] 张昱[4] 童劲松[5] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质调查局发展研究中心,北京100037 [3]宜昌地质矿产研究所,湖北宜昌443003 [4]中国地质大学,湖北武汉430074 [5]安徽省地质调查研究院,安徽合肥230001

出　　处：《中国地质》2006年第4期730-750,共21页Geology in China

基　　金：国土资源部科技计划专项(20001010202;200010103);中国地质调查局重大基础研究项目(200113900018)共同资助。

摘　　要：中国东部中生代造山带不同于陆缘俯冲作用和陆间大陆碰撞造山带,也不是陆缘和陆间碰撞造山带发展演化的某一个特定阶段的产物。它是一种由深部软流层上涌造山作用形成的一个新类型的造山带,又称东亚型造山作用。它的造山作用过程是:(1)早中生代(230～180Ma)的前和初始造山幕,深部软流层物质上涌和底侵作用导致冷、强的大陆岩石圈地幔线状破裂与局部拆沉;(2)中、晚侏罗世(180～140Ma)主造山幕,软流层大规模上涌并沿着岩石圈底部壳-幔边界横向侵入和伸展,使垂向差异运动转变为水平挤压作用,结果地壳表层发生大规模的褶皱构造变形和推覆构造,使陆壳加厚形成山根,岩石圈根发生部分拆沉;(3)白垩纪(140～65Ma)的晚期造山幕,加厚的陆壳山根与岩石圈根的大规模拆沉,岩石圈进入全新的从挤压向伸展转变和巨大减薄阶段,软流层大规模上涌成山。Mesozoic orogens in eastern China are different from continental-margin subductional and continent-continent collisional orogens and are not the product in a particular stage of development and evolution of continental-margin and continent-continent collisional orogens either. They are a new type of orogen resulting from orogeny due to asthenospheric upwelling at depth and may be distinguished from plate-margin and continent-continent collisional orogens by their tectonic setting, tectonic framework, tectonic deformation and metamorphism, magmatism and sedimentation and tectonic evolution. We consider that such orogeny caused by asthenospheric upwelling is another orogenic mechanism that is as important as continent-continent collisional and plate-margin subductional orogenies. Therefore the process of formation of orogens by asthenospheric upwelling is termed by us asthenospheric upwelling orogeny or East Asia-type orogeny. Viewing the Da Hinggan orogen, Yanshan orogen and other orogens in eastern China from the lithospheric-asthenospheric deep process, we think that the formation of these orogens is an orogenic event caused by vertically upward dynamic processes originating by asthenospheric upweUmg at depth as well as a new orogenic mechanism. The evidence is as follows： （1） the lithosphere-asthenosphere dos not show a typical horizontal layered structure but asthenospheric material commonly occurs as mushroom-shaped upwelling plumes penetrating and intruding into the lithospheric mantle, thus causing the older lithospheric mantle to be extensively dismembered and delaminated and forming a steep contact pattern with the relics of the older mantle; （2） the chronological structure of the lithosphere has the nature of uncoupling, i.e.： the mantle is younger, while the crust is older; （3） mafic-ultramafic rocks generated by underplating and ascending of Mesozoic asthenospheric material along lithospheric fractures are found; （4） magmatism of Mesozoic volcanic-plutonic rocks is different from th

关 键 词：造山作用 岩石圈 软流层上涌 中国东部 

分 类 号：P542.2[天文地球—构造地质学]