학술논문
陕南镇巴小洋坝地区南华系物源分析:来自碎屑锆石U-Pb年龄、碎屑成分分析及地球化学的证据 / Provenance analysis of the Nanhua System in the Zhenba Xiaoyangba area,southern Shaanxi:Evidence from detrital zircon U-Pb ages,clastic composition analysis and geochemistry
Document Type
Academic Journal
Author
马圣杰; 裴先治; 裴磊; 刘成军; 李佐臣; 李瑞保; 赵杰; 王潇; 王茂; 林浩; MA Shengjie; PEI Xianzhi; PEI Lei; LIU Chengjun; LI Zuochen; LI Ruibao; ZHAO Jie; WANG Xiao; WANG Mao; LIN Hao
Source
矿产勘查 / Mineral Exploration. 15(2):165-中插15
Subject
Language
Chinese
ISSN
1674-7801
Abstract
扬子板块北缘镇巴小洋坝地区出露了一套完整的南华纪沉积地层,分析其沉积时限、沉积环境及物源示踪对扬子板块北缘新元古代中晚期沉积-构造演化具有重要意义.本文对陕南镇巴小洋坝地区南华系砂岩样品进行碎屑锆石U-Pb测年分析,化学蚀变指数(CIA)、化学风化指数(CIW)、斜长石蚀变指数(PIA)、成分变异指数(ICV)判别及物源分析.结果显示小洋坝地区南华系的沉积时限应为720～635 Ma.长安组、古城组、南沱组沉积于寒冷干燥气候,而大塘坡组沉积于温暖湿润气候.其物源区主要为扬子板块北缘汉南—米仓山微地块.研究区南华系对应了新元古代中晚期扬子板块北缘地区的后碰撞-裂解阶段,是新元古代中晚期Rodinia超大陆裂解在该地区的沉积响应.
A complete set of Nanhuaian sedimentary strata is exposed in the Zhenba Xiaoyangba area at the northern margin of the Yangzi Plate,and the analysis of its depositional timeframe,depositional environments,and source tracing are of great significance for the Middle and Late Neoproterozoic sedimentary-tectonic evolution at the northern margin of the Yangzi Plate.The U-Pb dating analysis of detrital zircon,chemical alteration index(CIA),chemical weathering index(CIW),plagioclase alteration index(PIA),compositional variability index(ICV),and source analysis of the sandstone samples from the Zhenba Xiaoyangba area,southern Shaanxi Province,were car-ried out.The results show that the depositional time of the Nanhua System in the Xiaoyangba area should be 720-635 Ma.The Chang'an Formation,Gucheng Formation,and Nantuo Formation were deposited in a cold and dry climate,while the Datangpo Formation was deposited in a warm and humid climate.The source area is mainly the Hannan-Micangshan micro-massif at the northern margin of the Yangtze Plate.The Nanhua System in the study area corresponds to the post-collisional rifting stage of the northern margin of the Yangtze Plate in the Late Neoproterozoic,and it is the depositional response of the breakup of the Rodinia supercontinent in this area in the Late Neoproterozoic.
A complete set of Nanhuaian sedimentary strata is exposed in the Zhenba Xiaoyangba area at the northern margin of the Yangzi Plate,and the analysis of its depositional timeframe,depositional environments,and source tracing are of great significance for the Middle and Late Neoproterozoic sedimentary-tectonic evolution at the northern margin of the Yangzi Plate.The U-Pb dating analysis of detrital zircon,chemical alteration index(CIA),chemical weathering index(CIW),plagioclase alteration index(PIA),compositional variability index(ICV),and source analysis of the sandstone samples from the Zhenba Xiaoyangba area,southern Shaanxi Province,were car-ried out.The results show that the depositional time of the Nanhua System in the Xiaoyangba area should be 720-635 Ma.The Chang'an Formation,Gucheng Formation,and Nantuo Formation were deposited in a cold and dry climate,while the Datangpo Formation was deposited in a warm and humid climate.The source area is mainly the Hannan-Micangshan micro-massif at the northern margin of the Yangtze Plate.The Nanhua System in the study area corresponds to the post-collisional rifting stage of the northern margin of the Yangtze Plate in the Late Neoproterozoic,and it is the depositional response of the breakup of the Rodinia supercontinent in this area in the Late Neoproterozoic.