An origin of ultraslow spreading ridges for the Yarlung-Tsangpo ophiolites  

作　　者：Chuan-Zhou Liu Fu-Yuan Wu Tong Liu Chang Zhang Wei-Qi Zhang Zhen-Yu Zhang Zhen Zhang Wu Wei Yin-Zheng Lina 

机构地区：[1]State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [2]CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Fundamental Research》2022年第1期74-83,共10页自然科学基础研究（英文版）

基　　金：the National Science Fund for Distinguished Young Scholars(Grant No.42025201)。

摘　　要：As relics of ancient ocean lithosphere,ophiolites are the most important petrological evidence for marking the sutures and also play a key role in reconstructing plate configuration.They also provide valuable windows for studying crustal accretion and mantle processes occurring at modem ocean ridges.Abundant ophiolites are distributed along the Yarlung-Tsangpo suture and represent the relics of ocean lithosphere of the Neo-Tethys.They are characterized by an incomplete litho-stratigraphy,of which the mantle section is much thicker than the crustal section.Ocean crustal rocks outcropped in the Yarlung-Tsangpo ophiolites are much thinner than normal ocean crusts(~7 km)or even absent.Tectonic settings from which the Yarlung-Tsangpo ophiolites originated remain highly controversial,although an origin of the supra-subduction zone is prevailing.Moreover,their incomplete litho-stratigraphy has been commonly attributed to tectonic dismemberment during the late-stage emplacement after their formation.Nevertheless,such an incompleteness resembles the ocean lithosphere generated at modem ultraslow spreading ridges,such as the Southwest Indian Ridge(SWIR).In this paper,we present several lines of evidence that support the formation of the Yarlung-Tsangpo ophiolites at ultraslow spreading ridges,during which detachment faults were developed.This suggests that the Yarlung-Tsangpo ophiolites might represent the ocean core complexes(OCC)in the Neo-Tethys Ocean.The OCC with high topography in the seafloor were clogged in the trench and preserved as ophiolites through Indo-Eurasia collision.The clogging resulted in the demise of an old subduction and a new subduction was re-initiated beneath the clogged OCC.

关 键 词：Yarlung-Tsangpo ophiolites Tibetan plateau Ultraslow spreading ridges Subduction re-initiation 

分 类 号：P736[天文地球—海洋地质]