地球学报2024，Vol.45Issue(4)：439-449,11.DOI:10.3975/cagsb.2024.042802
右江盆地富宁地区石炮组化石及顶部凝灰岩年代学特征及意义
Chronological Characteristics and Significance of Fossils and Tuff at the Top of Shipao Formation in Funing Area,Youjiang Basin
摘要
Abstract
Through field geological investigation,the author collected fossils of Early Triassic bivalves and ammonites about 100 m below the interface between Banna Formation of Middle Triassic and Shipao Formation of Lower Triassic in Funing area of Youjiang Basin,and found a tuff layer with a thickness of about 5 m between T1/T2 interface,which was dated by LA-ICP-MS U-Pb isotope.The isotopic ages of(249.0±1.9)Ma,(247.9±3.4)Ma and(245.5±1.6)Ma were obtained from bottom to top,which were consistent within the error range.The upper boundary age of the Shipao Formation was obtained for the first time in the Lower Triassic.The newly discovered tuff beds and fossils can be used as Early-Middle Triassic isochronous stratigraphic markers for regional comparison,which enriches the distribution range of Early Triassic volcanic rocks in Youjiang Basin.It is considered that it is reasonable to use this set of tuff as a marker for the division of T1/T2 in southeastern Yunnan of Youjiang Basin.Based on the previous data,this set of tuffs and fossils provides important chronological and paleontological evidence for the demarcation of T1/T2 boundary in South China block,and it is considered that the age of the Anniian/Olynikian boundary should be set at 245.5 Ma,which may be more reasonable.关键词
华南陆块/右江盆地/早—中三叠统/凝灰岩/古生物/锆石U-Pb年龄Key words
South China block/Youjiang Basin/Early-Middle Triassic/tuff/paleontology/zircon U-Pb age分类
天文与地球科学引用本文复制引用
李维科,宛胜,刘军平,晏海宝,何世军,赵云江,赵江泰,卢晓萍..右江盆地富宁地区石炮组化石及顶部凝灰岩年代学特征及意义[J].地球学报,2024,45(4):439-449,11.基金项目
本文由云南省科技计划项目(编号:202305AD160031 （）
202401AT070012)、中国地质调查局地质调查项目"云南 1:5 万那佐幅、里往幅、大普弄幅、花甲幅区域地质调查"(编号:DD20160020)和云南省自然资源厅基金项目"云南 1:5 万大庄幅、法裱幅、底土幅、甸中幅区域地质调查"(编号:D202207)联合资助.This study was supported by Science and Technology Plan Project of Yunnan Province (Nos.202305AD160031 and 202401AT070012),China Geological Survey (No. DD20160020),and Department of Natural Resources of Yunnan Province (No.D202207). （编号:DD20160020）
