Application of grouped detrital zircon analyses to determine provenance and closely approximate true depositional age:Early Cretaceous McMurray-Clearwater succession,Canada

作     者：L.Rinke-Hardekopf S.E.Dashtgard C.Huang H.D.Gibson L. Rinke-Hardekopf;S.E. Dashtgard;C. Huang;H.D. Gibson

作者机构：Applied Research in Ichnology and Sedimentology(ARISE)GroupDept.of Earth SciencesSimon Fraser University8888 University DriveBurnabyBC V5A 1S6Canada 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2021年第12卷第2期

页      面：877-892页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 081803[工学-地质工程] 07[理学] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：We acknowledge BP plc Cenovus Energy Husky Energy Nexen CNOOC Ltd. and Woodside Energy Ltd.for funding the McMurray Research Consortium and GeoLOGIC for providing the GeoScout software used in this study 

主　　题：Detrital zircon Maximum depositional age Provenance variability Intracontinental foreland basin McMurray-Clearwater succession 

摘      要：In the Lower CretaceousMcMurray-Clearwater succession of the intracontinental Alberta Foreland Basin,Canada,detrital zircon U-Pb geochronology samples(referred to herein as DZ samples)have been used to interpret the strata as representing a paleo-continental-scale drainage ***,the majority of DZ samples are relatively small(n≈90–100),and syndepositional DZ(i.e.,crystallization age5 Ma older than depositional age)are *** has forced a reliance on dinocysts with long stratigraphic ranges to chronostratigraphically subdivide the McMurray-Clearwater succession rather than employing maximum depositional ages(MDAs)derived from DZ ***,43 DZ samples(taken from20 subsurface cores)are assigned to 1 of 5 stratigraphic intervals,and in each stratigraphic interval all associated DZ samples are combined to produce a grouped DZ *** and comparison of individual and grouped DZ samples are used to(1)assess variability in provenance through time and space,and(2)assess the accuracy of chronostratigraphically subdividing the succession using *** the main paleo-drainage axis,a comparison of dissimilarity between DZ samples from the same stratigraphic interval,as well as between stratigraphic intervals,reveals increasing average dissimilarity between individual DZ samples and their respective grouped DZ samplewith increasing spatial separation of *** data indicate that in the McMurray Depocenter some sediment is sourced from local tributaries,leading to geographical provenance *** for all 43 DZ samples and groupedMDAs(gMDAs)for the 5 grouped DZ samples are compared to an ash-derived absolute age and existing *** theMcMurray Formation,comparison of MDAs to gMDAs shows that in basins with rare syndepositional DZ,the gMDA method improved depositional age estimates by transforming low-confidence MDAs(e.g.,youngest single grains)into high-confidence(multi-grain)*** the Clearwater Formationwhere