Geochemistry and geochronology of Late Jurassic and Early Cretaceous intrusions related to some Au (Sb) deposits in southern Anhui: a case study and review

(整期优先)网络出版时间:2018-03-13
/ 1
SomeAudepositsinsouthernAnhuiProvincehaverecentlybeenfoundtobecloselyassociatedwithLateMesozoicintrusions.TypicalexamplesincludetheHua-shahAu(Sb)depositandAudepositsatZhaojialing,Wuxi,andLiaojia.InordertounderstandthemechanismsthatledtheformationoftheseAudeposits,wemakedetailedreviewsonthegeologicalcharacteristicsoftheseAudeposits.Specifically,wepresentnewLA-ICP-MSzirconU-Pbdating,alongwithelementalandHfisotopicdatafromtheHuashanAu(Sb)deposit.OurdatasuggeststhattheHuashanore-relatedintrusionswereemplacedduringtheLateJurassicandEarlyCretaceousperiods(144-148Ma).Theyarecharacterizedbyarc-magmafea-turesandhighoxygenfugacityandarerichininheritedzircons.ZirconU-PbagesandLu-HfisotopesfromintrusionssuggestthatProterozoicjuvenilelithosphereisthemainsourceoftheseintrusions.TheregionalgeologicalhistoryimpliesthatlithospherebeneathsouthernAnhuiwasproducedduringaProterozoicsubductionandwasfertilizedwithAu(Cu)intheprocess.Integratedwiththeresultsofpreviousstudies,weinferredthatLateMesozoicintrusionsformedbytheremeltingofthelithospherecouldprovidethemetalendowmentfortheAu-richdepositsinsouthernAnhui.