Early-middle Mesoproterozoic tectonic evolutionary history of the southwestern Yangtze Block,China:lithostratigraphic,geochronologic and elemental geochemical constraints  

作　　者：Fu-guang Yin Zhi-ming Sun Guang-ming Ren 

机构地区：[1]Chengdu Institute of Geology and Mineral Resources,China Geological Survey,Chengdu 610081,China

出　　处：《China Geology》2018年第4期540-555,共16页中国地质（英文）

基　　金：grants from a 973 Program (2009CB421003);a National Resources Survey Project (1212010610213);a National Natural Science Foundation of China project (40773001).

摘　　要：During the Early-Middle Proterozoic era,three major lithostratigraphic unit associations,namely Hekou-Dahongshan,Dongchuan,and Kunyang-Huili Groups,were established for the metamorphosed volcanicsedimentary rocks exposed in the southwestern Yangtze Block (SWYB).The integration of petrology, geochemistry and geochronology constrains tectonic framework and evolution of the SWYB,in which four sets of SHRIMP U-Pb zircon ages were obtained from the volcanic rocks interbedded within the Middle Proterozoic successions:1800-1600 Ma,1600-1300 Ma,1300-1100 Ma,and 1100-1000 Ma. Major and trace elemental analysis indicate that four key tectonic evolutionary stages,each coinciding with the above radiometric age set,of the SWYB during the Early-Middle Mesoproterozoic.The SWYB was characterized by an east-westerly trending rift in the Hekou,Dongshan,and Dongchuan areas,and separate basin-forming events during 1800-1600 Ma arid 1600-1300 Ma,respectively.In the SWYB,an intracontinental rift basin and a rift basin occurred in the Caiziyuan-Matang and Laowushan areas, respectively in 1300-1100 Ma ago.During 1100-1000 Ma,the SWYB was characterized by the closure of the Caiziyuan-Matang rift-ocean basin,collision between the Huili Blocks and Kunyang Blocks,and presence of volcanic ares in the Tianbaoshan and Fulingpen areas.Accordingly,the SWYB represents a new basin that records the relatively complete assembly process of the Rodina during the Early-Middle Mesoproterozoic era.

关 键 词：Early-middle MESOPROTEROZOIC SHRIMP U-PB DATING Tectonostratigraphic framework TECTONIC evolution SOUTHWESTERN Yangtze Block Yunnan Province 

分 类 号：P[天文地球]