The Baiyinnuo'er deposit in northern China is located in the south section of the Great Xing'an Range,and it is the largest skarn Zn-Pb deposit in the region.Skarn and Zn-Pb orebodies mainly occur between the different units of the Permian Huanggangliang Formation,or within the contact zone between the intrusive rocks and the marble.Although Baiyinnuo'er has been well investi-gated previously,the timing of the Zn-Pb mineralization is still controversial,largely due to the lack of appropriate ore or alteration minerals that could be directly used for iso-topic dating.In this study,we report the results of Rb-Sr isotopic analysis for sphalerite and pyrite samples from the Baiyinnuo'er orebodies,which yielded two isochron ages of 137.4±3.4 and 140.0±7.8 Ma,respectively,con-straining the Zn-Pb mineralization time of the deposit as the Early Cretaceous.The data are also consistent with the age of the granitoids in the mining area,indicating a potential genetic relationship between the Early Cretaceous magmatism and mineralization.Many other intrusion-re-lated hydrothermal deposits(including the two typical skarns,Huanggang and Haobugao)in the southern Great Xing'an Range also share similar mineralization ages(i.e.,140-130 Ma).Together,these data suggest an Early Cre-taceous mineralization event in this region,and this large-scale mineralization could be related to the regional tectonic regime transition from compression to extension as a result of the rollback of the subducted Paleo-Pacific plate.The initial 87Sr/86Sr ratios of the sphalerite and pyrite samples are 0.70569 and 0.70616,respectively,implying that the ore-forming material could have a significant contribution from the mantle components.The current study shows that sulfide Rb-Sr dating could be used in deciphering the timing of skarn deposit formation.

State Key Laboratory of Geological Processes and Mineral Resources,School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Chifeng Hongling Nonferrous Mining Co.Ltd.(Shandong Gold Group),Chifeng 025420,Inner Mongolia,China

[1]Yixin Li;Qihai Shu;Xudong Niu;Fan Yu;Qingwen Zeng;Liangmin Wei;Yang Xiao;Xianglin Dai-.Timing of the formation of the Baiyinnuo'er skarn Zn-Pb deposit,NE China:evidence from sulfide Rb-Sr dating)[J].地球化学学报（英文版）,2022(02):185-196

Baiyinnuo,Skarn,Huanggangliang,skarns,Huanggang,Haobugao,taceous

Timing,formation,Pb,NE,China,evidence,from,sulfide,Rb,dating,northern,located,section,Great,Xing,Range,largest,orebodies,mainly,occur,between,different,units,Permian,Formation,within,contact,zone,intrusive,rocks,marble,Although,has,been,well,investi,gated,previously,timing,mineralization,still,controversial,largely,due,lack,appropriate,alteration,minerals,that,could,directly,used,In,this,study,report,results,isotopic,analysis,sphalerite,pyrite,samples,which,yielded,two,isochron,ages,respectively,straining,Early,Cretaceous,data,also,consistent,granitoids,mining,area,indicating,potential,genetic,relationship,magmatism,Many,intrusion,hydrothermal,deposits,including,typical,southern,share,similar,Together,these,suggest,event,scale,related,regional,tectonic,regime,transition,compression,extension,rollback,subducted,Paleo,Pacific,plate,initial,87Sr,86Sr,ratios,implying,forming,material,have,significant,contribution,mantle,components,current,shows,deciphering

0.464747