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

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.