^(40)Ar-^(39)Ar geochronology of Cenozoic Linzizong volcanic rocks from Linzhou Basin, Tibet, China, and their geological implications

作     者：ZHOUSu MOXuanxue DONGGuochen ZHAOZhidan QIURuizhao GUOTieying WANGLiangliang 

作者机构：KeyLaboratoryofLithosphericTectonicsDeep-levelProcessandExplorationMinistryofEducationChinaUniversityofGeosciencesBeijing100083China ChinaUniversityofGeosciencesBeijing100083China InstituteofGeologyChineseAcademyofGeologicalSciencesBeijing100037China 

出 版 物：《Chinese Science Bulletin》 (Chin. Sci. Bull.)

年 卷 期：2004年第49卷第18期

页      面：1970-1979页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：Key Laboratory of Lithospheric Tectonics and Exploration National Key Project for Basic Research on Tibetan Plateau, (2002CB412600, GI998040800) National Natural Science Foundation of China, NSFC, (40103003, 49772107, 49802005) Ministry of Education of the People's Republic of China, MOE, (2003009) China University of Geosciences, Wuhan, CUG 

主　　题：^40Ar-^39Ar地球年代学 新生界 火山岩 林州盆地 西藏 地质学 

摘      要：Whole-rock and mineral separate Ar-Ar dating was carried out for the Linzizong volcanic rocks at Linzhou Basin in Tibet to constrain the time span of volcanism and the corresponding stratigraphic sequence. Sampling was based on detailed geologic mapping and stratigraphic se-quence of Dianzhong, Nianbo, Pana Formations, systemati-cally from the bottom to near the top. The results indicate that the Linzizong volcanic rocks erupted from Paleocene to middle of Eocene (64.43—43.93 Ma). Among them, the Pana Formation formed from ca. 48.73 to 43.9 Ma, the Nianbo Formation around 54 Ma and the Dianzhong Formation from 64.4 to 60.6 Ma. In combination with evidence from the geochemical characteristics of the volcanic rocks, and from stratigraphy in southern Tibet, it is postulated that the age of the lowest member in the Dianzhong Formation of the Lin-zizong volcanic rock, which overlies unconformably the Late Cretaceous Shexing Formation, likely corresponds to the inception of the collision between Indian and Asian conti-nents in southern Tibet.