沉积与特提斯地质2023，Vol.43Issue(4)：759-769,11.DOI:10.19826/j.cnki.1009-3850.2021.08006
藏南下侏罗统日当组地球化学和碎屑锆石U-Pb年代学特征及构造意义
Geochemistry and detrital zircon U-Pb geochronology of the Jurassic Ridang Formation in the southern Tibet and its tectonic implications
摘要
Abstract
The Mesozoic-Cenozoic strata deposited in the passive continental margin of India in the eastern Himalayas are important carriers for the study of the evolution of the Neo-Tethyan Ocean.In this paper,detrital zircon U-Pb dating and whole-rock geochemical analysis of the Lower Jurassic Ridang Formation siltstone and shale in Quzhuomu Township,Cuona County,Shannan City,Tibet Autonomous Region have been carried out.The detrital zircons have two peak ages,of 496-546 Ma and 853-952 Ma,with the peak ages of 516 Ma and 926 Ma,respectively,and the youngest age of 292.5±5.5 Ma.The content of Al2O3 in the Ridang Formation is high,with an average of 20.8%,while the contents of CaO,Na2O and K2O are low(0.4%-4.0%),indicating that the Ridang Formation is rich in clay minerals.The source area has high compositional maturity and strong weathering,which represents the recycling of sediments and the tectonic quietness or cratonic environment.The Ridang shale is enriched in light rare earth elements(LREEs)and depleted in heavy rare earth elements(HREEs),and the negative Eu anomaly is obvious.Based on the paleogeographic environment,it is considered that the material of Ridang Formation is mainly derived from the Indian plate and the Australian plate on the northern margin of Gondwana continent,and the tectonic background is a stable passive continental margin.关键词
特提斯喜马拉雅/日当组/碎屑锆石U-Pb年代学/砂岩地球化学/大地构造背景Key words
Tethys Himalayas/Ridang Formation/detrital zircon U-Pb geochronology/Sandstone geochemistry/Tectonic settings分类
天文与地球科学引用本文复制引用
喻晓,吕新彪,曹华文..藏南下侏罗统日当组地球化学和碎屑锆石U-Pb年代学特征及构造意义[J].沉积与特提斯地质,2023,43(4):759-769,11.基金项目
中国地质调查局项目(DD20191029,DD20190147) （DD20191029,DD20190147）
国家自然科学基金项目(41802095) （41802095）
