Deformation induced decoupling between U-Pb and trace elements in titanite revealed through petrochronology and study of localized deformation  

作　　者：Charles Kavanagh-Lepage Félix Gervais Kyle Larson Riccardo Graziani Abdelali Moukhsil 

机构地区：[1]Département des génies civils,géologiques et des mines,Polytechnique Montréal,Montréal H3T 1J4,Québec,Canada [2]Earth and Environmental Sciences,IKBSAS,University of British Columbia Okanagan,3247 University Way,Kelowna,BC V1V 1V7,Canada [3]Natural Resources Canada,Government of Canada,601 Booth St.,Ottawa,ON K1A 0E8,Canada [4]Direction de l’acquisition des connaissances géoscientifiques,Ministère de l’Énergie et des Ressources naturelles du Québec,57004e Avenue Ouest Québec,QC G1H 6R1,Québec,Canada

出　　处：《Geoscience Frontiers》2023年第2期217-240,共24页地学前缘（英文版）

基　　金：funded in part by the Ministère des Ressources naturelles du Québec contribution no.8449–2021-2022–04 under the supervision of A;Moukhsil and partially funded by an NSERC-Discovery grant RGPIN-2014-04593 hosted by F.Gervais.

摘　　要：In this contribution,we analyzed a pair of mafic samples collected from a recently identified shear zone and its proximal footwall from the Manicouagan Imbricate Zone(MIZ)of the central Grenville Province,Québec,Canada.Titanite petrochronology,metamorphic phase equilibria modelling,trace element thermometry,and electron backscattered diffraction data were used to define a Pressure-Temperature-timeDeformation path for the two samples.An interconnected dislocation network within titanite grains,as outlined with Kerneled Average Misorientation maps,are spatially correlated with variation in the U-Pb system but not with that observed for trace element These results suggest that the U-Pb system was decoupled from trace and rare earth elements and that deformation,rather than interface-coupled dissolution-precipitation reactions or re-crystallisation,was the main driver for this decoupling.In addition to highlighting a potential pitfall of titanite petrochronology,our P-T-t-D path reveals that ductile shear zones were active later than previously suggested within the MIZ.

关 键 词：Titanite petrochronology U-Pb Geochronology Phase equilibria modelling Trace elements DEFORMATION DECOUPLING 

分 类 号：P588.3[天文地球—岩石学] P597.3[天文地球—地质学]