造山带混杂岩及相关术语

    The division of mélanges in the orogenic belt and its associated terminologies

    • 摘要: 中国造山带面积约占全国陆域面积的3/5。造山带区由于经历过复杂的多岛洋演化,陆缘增生与陆-陆碰撞等多期次强烈的构造活动,形成了类型多样的混杂岩。混杂岩的识别与分类是造山带地质编图的重点与难点。本文介绍国际国内对混杂岩概念的理解,对与混杂岩紧密相关的名词术语,如蛇绿岩和蛇绿混杂岩、俯冲增生杂岩、杂岩、岩片和超岩片、非史密斯地层、构造地层、洋板块地层、对接缝合带、叠接缝合带等的含义进行了阐述。针对中国造山带地质特征,中国造山带混杂岩可划分出沉积混杂、构造混杂、沉积-构造复合混杂三大类。沉积混杂主要发生在威尔逊旋回的早期阶段(洋拉张阶段),构造混杂和沉积-构造复合混杂主要发生在威尔逊旋回的晚期阶段(洋俯冲消减-碰撞阶段),俯冲增生杂岩是俯冲带由俯冲消减-碰撞作用形成的构造混杂岩。

       

      Abstract: The area of orogenic belts in China covers nearly three-fifths of the land area.Multiple episodes of deformation during the tectonic evolution of orogenic belts, such as archipelagic ocean evolution, continental subduction-accretion and continental collision, caused diverse types of mélanges.Therefore, it is the key point and challenges to differentiate various types of mélanges and recognize the primary block-in-matrix fabric of the mélange on the basis of geological mapping.In this paper, the authors have made a brief introduction and exposition of the current concepts of mélange and mélange nomenclature, such as ophiolite, ophiolite mélange, subduction-accreation complex, complex, slice, superslice, non-Smith strata, tectonostratigraphy, ocean plate stratigraphy, subordinate suture zone and main suture zone.The authors divide the mélanges into three types:olistostrome(sedimentary mélange), tectonic mélange, and sedimentary-tectonic polygenetic mélange, based on the features of orogenic belts in China.Olistostrome(sedimentary mélange)was formed in an extensional environment during the early stage of the Wilson cycle.The other two were formed at the late stage in association with the evolution of oceanic crust subduction or continental collision.Subduction-accretion complex is the product of tectonic mélange as a result of subduction-accretion process in the subduction zone.

       

    /

    返回文章
    返回