地质论评2026，Vol.72Issue(2)：441-460,20.DOI:10.16509/j.georeview.2025.08.012
北秦岭柿树园组变质沉积岩碎屑锆石年代学及构造意义
Geochronology of detrital zircons from metaclastic of Shishuyuan Formation in Northern Qinling Mountains and its tectonic implication
摘要
Abstract
The Shishuyuan Formation,located in the North Qinling Orogenic Belt,is a set of terrigenous clastic deep-water flysch deposits,composed mainly of slightly metamorphosed sandstone and mudstone.Its age assignment has historically relied on regional stratigraphic correlation and paleontological fossils collected from carbonate lenses within the sequence.However,chronological studies specifically targeting the terrigenous clastic rocks remain unstudied.LA-MC-ICPMS zircon U-Pb dating results show that the detrital zircon ages of the Shishuyuan Formation range from 438 to 3562 Ma,with a primary peak at ca.949 Ma and five secondary peaks at ca.2482 Ma,ca.1707 Ma,ca.1140 Ma,ca.839 Ma and ca.514 Ma.The youngest population of detrital zircon ages range from 438 to 543 Ma.Combined with the Devonian greenschist-facies metamorphism observed in the formation and the absence of ca.414 Ma depositional records from the adjacent Kuanping Group to the north,the main depositional age of the Shishuyuan Formation is inferred to be the Middle-Late Silurian(438～415 Ma).Integrated regional studies suggest that the Shishuyuan Formation represents a tectonostratigraphic unit composed of sedimentary subunits of varying ages,which requires further subdivision into distinct units.Provenance analysis indicates that the sediments were primarily derived from the North Qinling Belt,with secondary contributions from the southern margin of the North China Block and the South Qinling Belt,characterized by a dual provenance.The tectonic setting of the Shishuyuan Formation and the Kuanping Group(Xiewan Formation)is inferred to represent a shared marine basin.However,unlike the late back-arc basin of the Erlangping Group,this basin is interpreted as a continental margin basin formed during Middle Silurian to Devonian post-collisional extension in the North Qinling Orogenic Belt.关键词
北秦岭/柿树园组/碎屑锆石/LA-ICP-MS锆石U-Pb定年Key words
northern Qinling Mountains/Shishuyuan Formation/detrital zircon/LA-ICP-MS zicon U-Pb dating引用本文复制引用
翟文建,赵焕,姚帅,彭翼,翟文芳..北秦岭柿树园组变质沉积岩碎屑锆石年代学及构造意义[J].地质论评,2026,72(2):441-460,20.基金项目
本文为河南省地质研究院科研项目(编号:2024-909-XM05、2024-901-XM04、2025-902-XM07)和中国地质调查局项目(编号:DD20160043-03)的成果. This study was financially supported by the research project of Henan Institute of Geology(Nos.2024-909-XM05,2024-901-XM04,2025-902-XM07)and the China Geological Survey Project(No.DD20160043-03) （编号:2024-909-XM05、2024-901-XM04、2025-902-XM07）
