浙西地区新元古代骆家门组SHRIMP锆石U-Pb年龄及其地质意义  

SHRIMP zircon U-Pb dating of the Luojiamen Formation in western Zhejiang Province and its geological implications

作　　者：张恒[1] 高林志[1] 李廷栋[1] 耿树方[1] 刘燕学[1] 丁孝忠[1] 史志刚[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《地质通报》2015年第2期447-455,共9页Geological Bulletin of China

基　　金：中国地质调查局项目(编号:121201011120131);全国油气基础地质研究与编图项目(编号:2011ZX05043-005)

摘　　要：对河上镇群底部骆家门组2个凝灰岩样品进行锆石测年,得到的2组SHRIMP锆石U-Pb年龄分别为824±5Ma和832±6Ma、791±15Ma。同时,对骆家门组底部花岗岩砾石中的锆石进行了测试,获得的SHRIMP锆石U-Pb年龄为901±9Ma。由此进一步约束了骆家门组的形成时代。骆家门组年龄的标定对于浙江地区神功运动界面上、下地层双溪坞群和河上镇群年龄的完善,进而确定江南造山带的地层格架和地层对比具有重要意义。这些地层年龄和已经获得的角度不整合于骆家门组之下双溪坞群的年龄数据,为神功运动时限的约束和对比提供了重要依据。Zircon dating of tuff bedding is reported for the first time from the Luojiamen Formation in the Heshangzheng Group. Two groups of tuff SHRIMP zircon U-Pb ages of the Luojiamen Formation were obtained, i.e., 824±5Ma and 832±6Ma together with 791±15Ma. In addition, the zircons of granite conglomerate from the bottom of the Luojiamen Formation were also measured, with the SHRIMP zircon U-Pb age being 901 ± 9Ma, which further constraints the stratigraphic age of the Luojiamen Formation. Zircon dating of the Luojiamen Formation has completed the stratigraphic age of the Heshangzhen and Shuangxiwu groups which lie over and below the interface of the Shengong Movement, which is of great importance for stratigraphic correlation and determina-tion of the stratigraphic framework of the Jiangnan Orogenic Belt. Combined with the age of the Shuangxiwu Group which under-lies the Luojiamen Formation in angle unconformity, these stratigraphic ages provide the basis for time constraints and contrast of the Shengong Movement.

关 键 词：浙江 骆家门组 凝灰岩 新元古代 SHRIMP锆石U-PB年龄 

分 类 号：P534.3[天文地球—古生物学与地层学] P597.3[天文地球—地质学]