Petrogenesis and tectonic significance of the early Paleozoic Delenuoer ophiolite in the Central Qilian Shan, northeastern Tibetan Plateau

作者：Zhen Ma,Jinrong Wang,Liangliang Zhang,Yixin Liu,Yunyun Gao,Xiang Zhang,Sheng Yu,Cheng Zhang

摘要：The newly discovered early Paleozoic Delenuoer ophiolite,in the western margin of the Central Qilian Shan,is composed of serpentinized peridotite,cumulate gabbro,diabase,massive basalt,and pillow basalt.This study presents geochronological and geochemical data for the cumulate gabbro and basalt.LA-ICP-MS U-Pb dating of zircons from the cumulate gabbro yielded a magmatic crystallization age of 472±4 Ma.The basalts have normal mid-ocean ridge basalt(N-MORB)compositions and a narrow range ofεNd(t)values(+4.5 to+5.3),which indicates they were derived from a depleted mantle source.On the basis of regional geological constraints,it is proposed that the Delenuoer ophiolite is a westward extension of the South Ophiolite Belt(Yushigou-Youhulugou-Donggou-Dongcaohe Ophiolite Belt)in the North Qilian Shan.The Delenuoer ophiolite,along with the Gulangxia-Delenuoer fault,defines the westernmost part of the tectonic boundary between the North and Central Qilian Shan.This ophiolite may have formed during southward subduction of the Qilian Ocean slab during the early Paleozoic.

发文机构：Key Laboratory of Mineral Resources in Western China State Key Laboratory of Geological Processes and Mineral Resources Changqing Branch Geological Survey of Gansu Province No.2 Geology and Mineral Exploration Team

关键词：OPHIOLITEDelenuoerCentralQilianShanEarlyPaleozoicTectonicboundary

分类号： P58[天文地球—岩石学]