地质通报2023，Vol.42Issue(12)：2142-2155,14.DOI:10.12097/j.issn.1671-2552.2023.12.010
豫西地区汝阳群碎屑岩地球化学特征及其对沉积环境与构造背景的指示
Geochemical characteristics of clastic rocks from Ruyang Group,western He'nan Province,and its indication to depositional environment and tectonic setting
摘要
Abstract
The Mesoproterzoic Ruyang Group along the south margin of North China Craton(NCC)have been attracted much attention,resulting in an increasing number of achievements about chronology and sedimentology.In this paper,we trace the provenance of the clastic sedimentary rock of the Ruyang Group by geochemistry perspective,and reconstruct the palaeogeography and tectonic setting,which provide valuable details to describe the structure of the Meso-Neoproterozoic strata in the southern margin of NCC.The analytical results of major and trace elements contents of the Yunmengshan and Baicaoping Formations suggest that:①Compared with Baicaoping Formation,Yunmengshan Formation shows higher SiO2 contents,lower Fe2O3,MgO,CaO and K2O contents,the obvious depletion of transition trace elements and high field strength elements,indicating relatively higher maturity.All samples show steep descending REE patterns with enriched LREE,flat HREE and obvious fractionation of LREE and HREE,moderately negative Eu anomalies(δEu=0.60～0.85)and weakly negative Ce abnormity(δCe=0.80～0.96),which are similar with those of upper continental crust.②According to trace element content and ratios(V/Cr,Ni/Co,U/Th Sr/Ba,Th/U Sr/Cu,Rb/Sr ratios and Ce,Eu anomaly)of the Yunmengshan and Baicaoping Formations,it is inferred that they are littoral and neritic deposit,and oxidation sedimentary environment,while the palaeoclimate experienced aridity-washy-aridity change.③The tectonic setting discrimination diagrams and the abundance of rare earth elements imply that the clastic rocks of the Yunmengshan and Baicaoping formations developed on passive continental margin.The island arc attribute of some points was inherited from the provenance protolith and influenced by the structure setting when the protolith was deposited.Combined with sedimentary and chronostratigraphic results,this series of passive continental margin littoral and neritic clastic deposits can serve as a record of North China Craton breakup from 1.8 to 1.6 Ga and a geological response to the initial breakup of the Columbia supercontinent.关键词
豫西/汝阳群/地球化学/沉积环境/地质调查工程Key words
Western Henan/Ruyang Group/geochemical/sedimentary environment/geological survey engineering分类
天文与地球科学引用本文复制引用
刘欢,李怀坤,张健,田辉,常青松..豫西地区汝阳群碎屑岩地球化学特征及其对沉积环境与构造背景的指示[J].地质通报,2023,42(12):2142-2155,14.基金项目
中国地质调查局项目《华北地区自然资源动态监测与风险评估》(编号:DD20211388)、国家自然科学青年基金项目《华北燕山地区前寒武纪长龙山组和景儿峪组古生物群及其地层学意义》(批准号:41302007)、中国地质调查局项目《中国大地构造演化和国际亚洲大地构造图编制(天津地质调查中心)》(编号:DD20190359) （编号:DD20211388）
