摘要
右江盆地位于华南板块西南缘与印支板块的结合部位,于中三叠世沉积了一套以细碎屑岩为主的巨厚浊积岩。研究区中三叠统细碎屑岩的主量、微量和稀土元素分析表明,细碎屑岩以杂砂岩和岩屑砂岩为主,其源岩来自大陆上地壳,物源区岩石类型主要为长英质沉积岩和火成岩,岩石风化程度中等偏高,构造背景为大陆岛弧和活动大陆边缘。综合细碎屑岩稀土元素特征及前人对该区中三叠统古流向和碎屑锆石U-Pb年代学研究,认为中三叠统碎屑物来源复杂,云开地区、江南造山带和越北地块是主要的物源区。
The Youjiang basin is located in the junction between the southwestern margin of the South China block and the Indochina block,where a set of thick turbidite dominated by fine-grained clastic rocks deposited in Middle Triassic.Geochemical analyses of the fine-grained clastic rocks in this area,mainly graywackes and lithic sandstones,indicate that their source rocks are mainly felsic sedimentary and igneous rocks from the upper crust and were moderately to highly weathered.The SiO2-K2O/Na2O,SiO2/Al2O3-K2O/(Na2O+CaO),F1′-F2′,La/Sc-Ti/Zr diagrams and the elemental ratios show that the source rocks of the Middle Triassic fine-grained clastic rocks were mainly formed in continental island arc and active continental margin.Based on the characteristics of REE and previous studies on the Middle Triassic paleocurrent and the U-Pb chronology of detrital zircons in this area,it is believed that the provenance of the Middle Triassic detrital materials in the study area is complex,and the Yunkai region,Jiangnan Orogenic Belt and North Vietnam block are likely the main source areas.
作者
赵东杰
王学求
ZHAO Dongjie;and WANG Xueqiu(Key Laboratory of Geochemical Exploration,Ministry of Natural Resources,Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,Hebei,China;UNESCO International Centre on Global-scale Geochemistry,Langfang 065000,Hebei,China;China University of Geosciences,Beijing 100083,China)
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2020年第2期311-324,共14页
Geotectonica et Metallogenia
基金
国家重点研发计划“穿透性地球化学勘查技术”(2016YFC0600600)资助。
关键词
右江盆地
中三叠统细碎屑岩
地球化学特征
物源与构造背景
Youjiang basin
Middle Triassic fine-grained clastic rocks
geochemical characteristics
provenance and tectonic setting
