The reconstruction of oceanic plate stratigraphy and its implications: A case study of Zhongba area, southern Tibet

Mélange generally consists of such chaotic blocks as pillow lava, limestones, radiolarian cherts, siliceous shales and sandstones, which tectonically contact with each other. Mélange serves as a piece of evidence of the accretionary prism (AP) related to the subduction zones. Recently, by using radiolarian biostratigraphy, the theory of ocean plate stratigraphy (OPS) is referred to as an approach to the accretionary process of these blocks. In order to reconstruct the process of subduction and successive accretion of ocean floor material of Neo-tethys, the authors used the theory to mapping the accretionary prism related to the Yalung Zangbo suture zone in Zhongba area, southern Tibet. The OPS of AP in Zhongba area consists of Jurassic basalt of sea mountain, Jurassic-Cretaceous reefs on the sea mountain, the pelagic sediments such as siliceous shales and radiolarian cherts and the Cretaceous terrigenous clasts close to the trough. This study provides new information on the direction, duration and the tectonic settings of the subduction of the Neo-tethys Ocean.