中国造山带蛇绿岩的时空分布及构造类型

    TEMPORAL-SPATIAL DISTRIBUTION AND TECTONIC TYPES OF OPHIOLITES IN OROGENIC BELTS OFCHINA

    • 摘要: 中国造山带蛇绿岩及其解体的超镁铁岩体大部沿着缝合带和深大断裂出露,形成21条不同时代与规模的岩带。时间上,古生代蛇绿岩占优势,中、新生代次之,元古宙极少。一些较大的蛇绿岩带往往是由两个或两个以上不同时代和构造类型的蛇绿岩块组成的复合岩带。中国西部造山带蛇绿岩以塔里木-中朝地台南缘为界,其时空分布由北向南有由老变新之趋势,可能暗示中国西部和西南大陆具有由北向南依次增生的演化机制。根据蛇绿岩剖面类型和洋盆发育阶段,可将中国蛇绿岩分为四种构造类型:(1)初始洋盆型;(2)成熟洋盆型;(3)岛弧型;(4)残余海盆(非蛇绿岩)型镁铁一超镁铁岩。中国造山带蛇绿岩以(1)类为主,其余类型较少。

       

      Abstract: Ophiolites in orogenic belts of China and ultramafic rocks resulting from their disintegrationare mostly exposed along suture zones and deep faults,forming 2 rock belts of differing ages andsizes。In terms of time,ancient ophioites predominate ,Meso- Cenozoic ones come next and Protero-zoic ones are rare. Some major ophiolite belts are usually composite rock belts composed of two ormore ophiolite blocks of different ages and tectonic types. With the southern margin of the Tarim-Sino-Korean platform as the boundary,ophiolites in orogenic belts of western China have a ten-dency to become young from north to south,which might imply that there is an evolution mecha-nism of successive south-directed accretion in the western and southwestern parts of the Chinesemainland.According to the section types of ophiolites and development stages of oceanic basics,ophiolites of China may be divided into four tectonic types:initial oceanic basin type,mature o-ceanic basin type,island are type and relict oceanic basin(non- ophiolite)type of mafic-ultramaficrocks,with the first type prdominating and the others being less important.

       

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