U–Pb and Hf isotopic data from Franklinian Basinstrata: insights into the nature of Crockerland andthe timing of accretion, Canadian Arctic Islands

Owen A. Anfinson, Andrew L. Leier, Rich Gaschnig, Ashton F. Embry,and Keith Dewing

Abstract: New detrital zircon uranium–lead (U–Pb) ages and initial epsilon hafnium (εHf(i)) data from the Devonian clasticsuccession of the Canadian Arctic Islands refines the provenance of strata within the Franklinian Basin and providesconstraints on the geologic evolution of the landmass responsible for the Ellesmerian Orogen. This study contributes morethan 500 U–Pb ages and 32 εHf(i) values from the Blackley Formation and the Parry Islands Formation. The MiddleDevonian Blackley Formation represents the onset of clastic sedimentation into the Franklinian Basin during the Devonianperiod. Detrital zircon from two samples yield U–Pb age populations of 380–470, 500–700, 900–2100, and 2550–3000 Ma.The population of 500–700 Ma U–Pb ages indicates a source exotic to the northern Laurentian margin and is attributed toa continental landmass located north of the present Canadian Arctic Islands (often referred to as Crockerland). This is someof the earliest evidence of 500–700 Ma detrital zircon deposition onto the northern Laurentian margin and indicates thisnorthern landmass is at least partially accreted to Laurentia by early-Eifelian time. The Late Devonian Parry IslandsFormation is the uppermost succession of Ellesmerian Orogen foreland basin sedimentation in the Franklinian Basin.Detrital zircon from four samples yield U–Pb age populations of 370–450, 470–750, 930–2100, and 2300–3200 Ma.The U–Pb ages suggest the Parry Islands Formation is derived from the northern source terrane (Crockerland) and indicatethis landmass contains rocks similar to that of the east Greenland Caledonides, Pearya, and northeastern Baltica. Rim andcore U–Pb double dates from the 500–700 Ma detrital zircon population and εHf(i) values from the 380–450, 520–550,and 650–710 Ma detrital zircon populations help constrain magma generation processes within Crockerland and suggestthe zircons are derived from a juvenile lithosphere.

Résumé : De nouveaux âges uranium–plomb (U–Pb) sur zircon détritique et des données epsilon hafnium initial (εHf(i)) de lasuccession clastique (Dévonien) des îles de l’Arctique précisent la provenance de strates dans le bassin franklinien et encadrentl’évolution géologique de la masse terrestre responsable de l’orogenèse a l’Ellesmérien. La présente étude contribue plus de 500âges U–Pb et 32 valeurs εHf(i)) de la Formation de Blackley et de la Formation de Parry Islands. La Formation de Blackley(Dévonien moyen) représente le début de la sédimentation clastique dans le bassin franklinien durant le Dévonien. Des zirconsdétritiques provenant de deux échantillons ont donné des âges U–Pb de 380–470, 500–700, 900–2100 et 2550–3000 Ma. Lespopulations des âges U–Pb de 500–700 Ma indiquent une source exotique a la bordure laurentienne nord et cette source seraitune masse continentale située au nord des îles de l’Arctique actuelles (souvent désignée en tant que Crockerland). Il s’agit d’unedes plus anciennes évidences de déposition de zircon détritique de 500–700 Ma a la bordure laurentienne nord et cela indiqueque cette masse terrestre nordique a été accrétée, du moins en partie, a la Laurentie dès le début de l’Eifélien. La Formationde Parry Islands (Dévonien tardif) constitue la succession au sommet de la sédimentation d’avant-pays de l’orogenèse del’Ellesmérien dans le bassin franklinien. Des zircons détritiques provenant de quatre échantillons ont donné des âges U–Pb de370–450, 470–750, 930–2100 et 2300–3200 Ma. Les âges U–Pb suggèrent que la Formation de Parry Islands soit dérivée duterrane source nord (Crockerland) et cela indique que la masse terrestre contenait des roches semblables a celles des Calédonidesdu Groenland, de Pearya et du nord-est de Baltica. Les dates U–Pb en double de la bordure et du noyau de la population de500–700 Ma de zircon détritique et les valeurs εHf(i) des populations de zircon détritique 380–450, 520–550 et 650–710 Maaident a contenir les processus de génération de magma a l’intérieur de Crockerland et suggèrent que les zircons proviennentd’une lithosphère juvénile.

[Traduit par la Rédaction]

Received 27 March 2012. Accepted 6 July 2012. Published at www.nrcresearchpress.com/cjes on 17 October 2012.

Paper handled by Associate Editor Maurice Colpron.

O.A. Anfinson and A.L. Leier. Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4,Canada.R. Gaschnig. Department of Geology, University of Maryland, College Park, MD 20742, USA.A.F. Embry and K. Dewing. Geological Survey of Canada, 3303-33rd Street NW, Calgary, AB T2L 2A7, Canada.

Corresponding author: Owen A. Anfinson (e-mail: anfinson@jsg.utexas.edu).

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Can. J. Earth Sci. 49: 1316–1328 (2012) Published by NRC Research Pressdoi:10.1139/e2012-067

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IntroductionThe number of detrital zircon uranium–lead (U–Pb) ages

reported from the high Arctic has increased dramatically inrecent years (Kuznetsov 2006; Miller et al. 2006, 2010; Lorenzet al. 2008; Amato et al. 2009; Kirkland et al. 2009; Kuznetsovet al. 2009, 2011; Pease and Scott 2009; Beranek et al. 2010;Pettersson et al. 2010; Røhr et al. 2010; Lemieux et al. 2011;Omma et al. 2011; Orlov et al. 2011; Anfinson et al. 2012;Hadlari et al. 2012). These new data allow for more completeand accurate reconstructions of Arctic paleogeography duringthe Phanerozoic (Kuznetsov 2006; Miller et al. 2006; Colpronand Nelson 2009, 2011). However, significant controversy stillexists regarding the origins, identities, and current locations ofnumerous continental terranes that moved around the Arctic(Colpron and Nelson 2011; Miller et al. 2011). The data setpresented here provides important insights into the paleogeog-raphy of the Canadian Arctic during the Devonian period,refines our understanding of an exotic Paleozoic terrane, andbetter characterizes the detrital zircon U–Pb age populationsin Franklinian Basin strata, which were later recycled intoyounger sedimentary units (Beranek et al. 2010; Røhr et al.2010; Lemieux et al. 2011).

The Franklinian Basin in the Canadian Arctic contains a�10 km thick succession of sedimentary strata depositedbetween late Neoproterozoic and Late Devonian time (Trettin1989; Trettin et al. 1991). Clastic sedimentation occurredduring three intervals (Trettin et al. 1991). The lowermostclastic interval records passive margin shelf deposition fromthe west Greenland – northeast Canadian Shield in the lateNeoproterozoic and Early Cambrian (Dewing et al. 2004). Themiddle clastic interval records sedimentation in a deep-waterbasin, and sediment was derived from the Caledonian Orogen,Svalbard, and Pearya in the Early Silurian and Early Devonian(Trettin 1991; Dewing et al. 2008). The uppermost clasticinterval is often referred to as the Devonian clastic wedge ofthe Canadian Arctic Islands (Tozer and Thorsteinsson 1964).A recent study has shed new light on some of these units(Anfinson et al. 2012); however, fundamental questions re-garding sediment provenance and the nature of the originalsediment source area remain. Understanding these issues iscritical for understanding the tectonic evolution of the northernLaurentian margin at this time.

One formation of particular interest is the Middle Devonian(Eifelian–Givetian) Blackley Formation, which records theonset of clastic sedimentation into the Devonian clastic wedgealong its western margin (Harrison 1995). The Blackley For-mation is only exposed along the western margin of theoutcropping basin, and it is age correlative with the lowermostfluvial and deltaic clastic deposits along the eastern margin ofthe outcropping basin. Unlike nonmarine and shallow-marinestrata to the east, the Blackley Formation is composed of distalturbidite facies (Embry and Klovan 1976). The source regionfor the sediments of the Blackley Formation is not well un-derstood, and few geologic constraints have been placed on theformation (Embry and Klovan 1976; Goodbody 1993; Harri-son 1995; Harrison and Brent 2005). The new U–Pb age datafrom the Blackley Formation provide some of the clearestevidence of the sediment provenance and shed light on thepaleogeography of the Canadian Arctic at the onset of wide-spread clastic deposition in the Middle Devonian.

The Upper Devonian (Frasnian–Famennian) Parry IslandsFormation is the uppermost formation in the Franklinian Basinand represents the youngest preserved succession of proximalEllesmerian Orogen foreland basin sedimentation. Severallines of evidence (e.g., change in paleocurrent directions, εNdvalues, sandstone composition, and detrital zircon U–Pb ages)suggest a change in provenance occurred between depositionof the Parry Islands Formation and the underlying Middle andUpper Devonian clastic deposits (Embry and Klovan 1976;Patchett et al. 1999; Anfinson et al. 2012). This study furtherdefines this provenance shift based on U–Pb ages from thewesternmost extent (Banks Island) to easternmost extent(Grinnell Peninsula, Devon Island) of the Parry Islands For-mation (Figs. 1, 2). The U–Pb detrital zircon age populationsare augmented with εHf(i) isotopic values for populations of370–710 Ma zircons. The εHf(i) data are used to provideinformation on the nature and history of the source terrane andthe geologic nature of its magmatism (Vervoort and Patchett1996; Amelin et al. 1999). In addition, U–Pb ages from the rimand core of detrital zircon grains provide information on theexistence or absence of inherited cores (Miller et al. 2003; Beaet al. 2007).

Regional geologic settingThe Devonian clastic wedge in the Canadian Arctic Islands

covers an area of over 200 000 km2 at the surface and in thesubsurface, and is up to 5000 m thick (Thorsteinsson andTozer 1970; Embry and Klovan 1976). The Middle to UpperDevonian strata were deposited in a foreland basin developedin front of the southward advancing Ellesmerian Orogen (Em-bry 1988; De Fritas and Mayr 1998). The Ellesmerian Orogenwas created by the collision of a continental landmass, com-monly referred to as Crockerland, with the northern Laurentianmargin (Embry 1988). For the purposes of this paper, theEllesmerian Orogen includes all orogenic activity in the Ca-nadian Arctic Islands beginning with and immediately follow-ing the deposition of the Devonian clastic wedge (MiddleDevonian – earliest Carboniferous; e.g., Thorsteinsson andTozer 1970; Embry 1988). The age the Ellesmerian Orogenmay extend into the Silurian if events associated with theaccretion of Pearya are included (e.g., Trettin 1987, 1991);however, the connection of Pearya and Crockerland is stillpoorly understood. A brief description of the sedimentarysuccessions and tectonic events associated with the Ellesme-rian Orogen is provided here; for a more complete summarysee Trettin (1989) and Embry (1988).

The clastic sedimentary units associated with the EllesmerianOrogen are composed of three sequences interpreted to reflectmajor tectonic episodes within the adjacent orogen (Embry1988). The sequences are bounded by unconformities and areearly Eifelian to earliest Frasnian (Hecla Bay Sequence), earlyFrasnian to late Frasnian (Beverly Inlet Sequence), and latestFrasnian to middle Famennian (Parry Islands Sequence) in age(Embry 1988). The sequences were initiated by acceleratedsubsidence related to crustal shortening and loading of theorogenic belt (Embry 1988). The Ellesmerian Orogenic frontadvanced southwest with each tectonic episode and promotedprogradation of the fluvial–deltaic plain from northeast tosouthwest across the basin (Embry and Klovan 1976). Likelyassociated with this advancing fluvial–deltaic plain is a distalsubmarine fan (Harrison 1995).

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Final phases (Early Carboniferous) of the Ellesmerian Orog-eny halted deposition of sediment into the Franklinian Basin inthe Canadian Arctic by folding, uplifting, and partially exhumingthe basin (Trettin 1991). Sedimentary units of the Frankliniansuccession have since been deeply eroded and reworked intothe Carboniferous to Tertiary Sverdrup Basin and depositedalong the modern shelf margin (Røhr et al. 2010).

Analytical methodsSamples from the Blackley and Parry Island formations

were jaw crushed, disc milled, and the zircon separated usingconventional water table, magnetic, and heavy liquid tech-niques. The samples were split and dump-mounted ontodouble-sided tape before solidifying in epoxy. The epoxy puckwas then polished to expose the interior of the grains. Thepuck was carbon coated and imaged using cathodolumines-cence (CL) imaging on a scanning electron microscope (SEM)at the University of Idaho.

U–Pb age analysesU–Pb analyses were conducted with a New Wave UP Nd:

YAG 213 nm laser on a ThermoFinnigan Element2 high-resolution – inductively coupled plasma – mass spectrometer(HR–ICP–MS) in the GeoAnalytical Laboratory at Washing-ton State University, Pullman, Washington, following proce-dures described by Chang et al. (2006). All samples were setto a laser spot size of 25 �m and a frequency of 10 Hz. Twoto three runs of two standards (FC-1 and Peixe; Chang et al.2006) were analyzed every 10–15 grains to correct for instru-ment fluctuations and determine fractionation factors. Oncedetrital zircon fractionation factor corrections were made, theU–Pb ages obtained were checked for discordance by plottingthe analyses on Concordia diagrams using Isoplot 3.7 (Ludwig2008). Analysis of the data was carried out after graphicaldepiction of the age populations on probability density plotsusing Microsoft Excel macros developed by G.E. Gehrels atthe University of Arizona, Tucson, Arizona, (Gehrels 2012).The data reported are 206Pb/238U age for grains younger thanTonian (850–1000 Ma) and 207Pb/206Pb ages for Tonian andolder ages (Zeck and Whitehouse 1999). The U–Pb agesreported are those from analyses that range between 90% and110% concordant. The errors reported are 2-sigma errors.

Hf isotopic analysesHafnium analyses were conducted with a New Wave UP

Nd:YAG 213 nm laser on a ThermoFinnigan Neptune multi-collector – inductively coupled plasma – mass spectrometer(MC–ICP–MS) in the GeoAnalytical Laboratory at Washing-ton State University following procedures described by Bahl-burg et al. (2009) and Gaschnig et al. (2011). Lu and Ybinterferences on mass 176 were accounted for by monitoringinterference-free 175Lu and 174Yb and assuming mass biasrelationships of �Lu � �Hf and �Yb � �Hfx, in which the valuefor x was determined by analyzing zircon standards Mud Tank,FC-1, and R-33. Initial 176Hf/177Hf values were calculatedusing a 176Lu decay constant of 1.867e–11 year–1 (Scherer et al.2001), εHf values were calculated using chondrite values of176Hf/177Hf � 0.282 785 and 176Lu/177Hf � 0.0336 (Bouvieret al. 2008), and the depleted mantle curve was constructedusing the parameters of Vervoort and Blichert-Toft (1999).

Formations, samples, and resultsSamples analyzed in this study were gathered from the

collections at the Geological Survey of Canada (GSC) andthe University of Calgary. A brief description of the sam-ples is included in the text; additional information is sum-marized in Table 1. All geographic sample locations aredepicted in Fig. 1, and generalized stratigraphic locations aredepicted in Fig. 2.

The Middle Devonian Blackley FormationThe Eifelian–Givetian Blackley Formation is an interbed-

ded succession of sandstone, siltstone, and shale, with a max-imum exposed thickness of 700 m (Embry and Klovan 1976).It is the basal formation of the Devonian clastic wedge in thefar western margin of the basin (Harrison 1995). The Blackleyformation is only exposed at the surface on northwesternMelville Island (Tozer and Thorsteinsson 1964) and is presentin wells on Banks and Prince Patrick Island (Embry andKlovan 1976; Harrison and Brent 2005). The Blackley For-mation is interpreted to represent a submarine fan comprisedprimarily of turbidites based on the abundance of C–D–E andB–C–D–E Bouma cycles and its similarity in both sorting andthe shape of the gamma ray curve to other reported turbidites

Table 1. Sample information.

Samplename Formation Age

GSCcatalog

Latitude(°N)

Longitude(°) Lithology

Depositionalenvironment

Bl-1 Blackley Eifelian E-73-S1 76.066 –116.166 Poorly sorted, angular, very fine grainedsandstone with a clay matrix

Submarine fan

Bl-2 Blackley Eifelian C-140134 75.922 –115.292 Poorly sorted, angular, very fine grainedsandstone with a clay matrix

Submarine fan

PI-5 Parry Islands Fammenian C-198367 76.701 –93.334 Well sorted, sub-rounded, very finegrained sandstone

Meandering stream

PI-6 Parry Islands Fammenian C-128876 74.854 –109.082 Moderately sorted, moderately rounded,fine-grained sandstone

Meandering stream

PI-7 Parry Islands Fammenian E-73-8 76.320 –119.750 Well sorted, sub-rounded, medium-grained sandstone

Meandering stream

PI-8 Parry Islands Fammenian K-69-16 74.210 –117.320 Well sorted, sub-rounded, very finegrained sandstone

Meandering stream

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(Goodbody 1993). The sandstone–siltstone beds are typically10 cm to 2 m thick and have abrupt basal contacts withabundant sole markings (Goodbody 1993). The age is not wellconstrained and is based on abundant Eifelian microfauna(Harrison 1995) near its base and Givetian spores reportedfrom the Kusrhaak D-16 well on Banks Island (Embry andKlovan 1976 and references therein). The formation doescontain Emsian spores near its base, but these are likelyreworked from underlying strata (Harrison 1995). In the sub-surface on Prince Patrick Island, the formation has a wedge-shaped profile and thins from 2000 m in the northeast to 850 min the southwest, suggesting a northeastern source and south-west transport direction (Harrison and Brent 2005). The for-mation contains significant radiolarian chert content,suggesting it is in part derived from a northern source region,where abundant chert was likely exposed from the upliftingHazen Formation in front of the advancing Ellesmerian Oro-gen (Embry and Klovan 1976; Trettin 1991). A single sampleanalyzed for neodymium showed εNd values (–8.1) compara-

ble with the majority of Middle to Upper Devonian clasticsuccession of the Franklinian Basin (Patchett et al. 1999).

Sample Blackley-1 (BL-1) and Blackley-2 (BL-2) areboth poorly sorted, angular, very fine grained sandstoneswith a clay matrix. Both samples were collected from theCanrobert Hills of Northwestern Melville Island and areEifelian in age (Figs. 1, 2). Sample BL-1 displayed flute castsalong the base.

U–Pb resultsThe primary detrital zircon age populations for samples

Blackley-1 and Blackley-2 of the Blackley Formation are900–2100 Ma (72% of BL-1 and 84% of BL-2), with asignificant population of 380–470 Ma (11%) and 500–700 Ma(10%) in sample BL-1 (Fig. 3A). The 380–470 Ma populationis slightly less in sample BL-2 (8%), as is the 500–700 Mapopulation (2%). Both samples also contain minor populationsof 2550–3000 Ma detrital zircons. The four ages of approxi-mately 380 Ma (379 Ma � 10.9 to 383.5 � 13.3 Ma) between

Fig. 1. Sample locations and general geographic distribution of Middle to Upper Devonian clastic strata. Black lines in inset map depictthe location of outcrops associated with the Pre-Uralide–Timanide Orogen (Kuznetsov et al. 2010; Gee and Pease 2004). PU, Polar Urals;NZ, Novaya Zemlya; SZ, Severnaya Zemlya; Tr, Taimyr; WI, Wrangel Island; SP, Seward Peninsula; AA, Arctic Alaska; Sv, Svalbard.Basemap is adapted from Trettin (1991).

3000kilometres

W °09110°

W

74° N

76° N

78° N

80° N

80° W

100°

W

120°

W

PI-5PI-1*PI-2*

PI-3*

PI-4*

SamplesLate Devonian PI- Parry Islands Fm.Middle Devonian BL- Blackley Fm.

- Sample Location #- Sample Number * - Sample descriptions

Ellesmerian deformation front

Devonian Clastic Wedge Outcrop -Blackley Fm. to Parry Islands Fm.

PI-6

BL-2

PI-8

PI-7

BL-1

Ellesmere I.

Devon I.Melville I.

Prince Patrick I.

Greenland

Banks I.

Grinnell Pen.

Cornwallis I.

Bathurst I.

75°

45°60°

60° W90° W120° W

North America

Timanides

Baltica

Greenland

Sv

NZSZ

SP

Tr

AA

WI

PU

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the two samples are within error of the depositional age of theformation (Embry 1991).

Interpretation of resultsThe detrital zircon populations from the Blackley Formation

support previous interpretations of a northeastern source region(Embry and Klovan 1976; Harrison 1995). The 900–2100 Mapopulations are similar to grains attributed to the east GreenlandCaledonides and terranes with affinities to the Caledonides such asPearya and Svalbard (Trettin et al. 1987; Pettersson et al. 2010;Anfinson et al. 2012). The 380–470 Ma populations are in-terpreted as being derived from synorogenic volcanic andplutonic rocks of the Caledonian and Ellesmerian orogens.The 500–700 Ma zircon population is exotic to the northernLaurentian margin (Hadlari et al. 2012). The 500–700 Madetrital zircons (and the majority of the 380–470 Ma agerange) are interpreted as having been derived from Crockerland,which is inferred to have been present but was subsequently riftedfrom the northern margin of North America in the Middle Juras-sic to Early Cretaceous (Embry and Dixon 1994).

Sample BL-1 contains a robust 500–700 Ma zircon popu-lation, whereas to the east, age-equivalent fluvial–deltaicstrata contain few zircons from this population (Bird Fiord,Strathcona Fiord, and Hecla Bay formations; Anfinson et al.2012). The exotic detrital zircon population suggests thatCrockerland was accreted to the northern Laurentian marginby the Eifelian. Suggesting that Crockerland is accreted toLaurentia in the Eifelian also implies that the EllesmerianOrogen (according to use of the terminology by Embry 1988)has begun by this time. The scarcity of 500–700 Ma detritalzircons in the samples of the age correlative eastern fluvial–deltaic strata is likely due to their southeastern location, whichreceived little sediment influx from Crockerland and wasoverwhelmed by fluvial systems derived from the east Green-land Caledonides (Fig. 3B).

Upper Devonian Parry Islands FormationThe Frasnian to Famennian Parry Islands Formation is

the youngest of the Franklinian Basin deposits (Embry andKlovan 1976). The Parry Islands Formation has three faciesexposed at multiple intervals, representing a braided stream,meandering stream, and marine shelf environment (Embry1991). The four samples that were analyzed for detritalzircon U–Pb age populations are all collected from the BurnettPoint Member (Fig. 2). The maximum thickness of the BurnettPoint Member is 722 m, and it decreases in thickness to thesouthwest. The lower portion of the member was deposited ina braided stream environment, and the upper portion, a mean-dering stream environment (Embry and Klovan 1976). Thesandstone content and grain size of the Burnett Point Memberdecrease to the southwest. Over 60 paleocurrent measure-ments from the Burnett Point Member indicate a southwesttransport direction of approximately 225° (Embry and Klovan1976).

Sample Parry Islands-5 (PI-5) is the easternmost sample ofthe Parry Island Formation and is a sub-rounded, very finegrained sandstone collected from the Grinnell Peninsula ofnorthwestern Devon Island (Fig. 2). Sample Parry Islands-6(PI-6) was collected from southern Melville Island and is asub-rounded, fine-grained sandstone. Sample Parry Islands-7(PI-7) is the westernmost sample and is a sub-rounded,medium-grained sandstone collected from Prince Patrick Is-land. Sample of Parry Islands-8 (PI-8) is the southernmostsample and is a very fine grained sandstone collected fromeastern Banks Island. The samples described here are rela-tively fine grained (with the exception of sample PI-7) com-pared with samples from previous studies (Samples PI-1, PI-2,PI-3, and PI-4; Anfinson et al. 2012). This is an importantconsideration for the presence of the 500–700 Ma detritalzircon population because these grains commonly exhibit a

Fig. 2. Sample locations and generalized stratigraphy of the Devonian clastic succession. Modified from Embry (1988).

AGEBANKSISLAND

PRINCEPATRICKISLAND

WESTERNMELVILLEISLAND

EASTERNMELVILLEISLAND

CENTRALBATHURST

ISLANDCORNWALLIS

ISLANDEASTERNGRINNELL

PENINSULA

SOUTHERNELLESMERE

ISLAND

CENTRALELLESMERE

ISLANDAGE

DE

VO

NI

AN

ETALEL

DD I

M

EIFE

LIA

NG

IVET

IAN

FRA

SNIA

NFA

MEN

NIA

N

DE

VO

NI

AN

MID

DLE

LATE

EIFE

LIA

NG

IVET

IAN

FRA

SNIA

NFA

MEN

NIA

N

CAPEFORTUNE

MBR

BURNETTPOINTMBR

BURNETTPOINTMBR

BURNETTPOINTMBR

CAPE FORTUNE MBR CAPE FORTUNE MBR

CONSETT HEAD MBR

PARR

YIS

LAN

DS

FM

PARR

YIS

LAN

DS

FMPARR

YIS

LAN

DS

FM

PARR

YIS

LAN

DS

FM

BURNETTPOINTMBR

CAPE FORTUNE MBR

PARRY ISLANDS FM

WEATHERALL FM WEATHERALL FM

WEATHERALL FM

WEATHERALL FM

BEVERLEY INLET FM

BEVERLEY INLET FM

BEVERLEY INLET FM

HECLA BAY FM

HECLA BAY

FM

NORDSTRAND POINT FM

NORDSTRAND POINT FM

HELL GATE FM HELL GATE FMFRAM FM FRAM FM

CAPE DE BRAY FM

CAPE DE BRAY FMCAPE DE BRAY FM

CAPE DE BRAY FMCAPEDE BRAY FM

BLACKLEY FMBLACKLEY FM BLACKLEY FM

EPACMF YAB TTEBBIMF NOSTIKPHILLIPS

FM

BLUEFIORD

FM EIDS FMBLUE

FIORDFM

BLUE FIORD FM BLUE FIORD FM BLUE FIORD FM

BIRD FIORD FM

BIRD FIORD FM BIRD FIORD FM BIRD FIORD FM

STRATHCONA FIORD FM STRATHCONA FIORD FM STRATHCONA FIORD

FMSTRATHCONA FIORD

FM

BEVERLEY INLET FM

WEST EAST- U/Pb Analysis - εHf Analysis - Unconformity

EARL

Y

EARL

Y

EMSI

AN

EMSI

AN KITSON FM

HECLA BAY

FMHECLA BAY

FM

HECLA BAY

FM

HECLA BAY

FM

HECLA BAY

FM

BLUE FIORD FM

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larger grain size (200–350 �m in length) than that found in theother detrital zircon populations described (Anfinson et al.2012). Although it is probable detrital zircons of this age groupcontain smaller grains, or detrital fragments of these grains (asshown with the Blackley Formation), it may be less likely theywill be incorporated into the fine-grained and very fine grainedsandstones.

U–Pb resultsThe Upper Devonian (Frasnian–Famennian) Parry Islands

Formation contains significant variability from its easternmost(PI-5) to westernmost (PI-7) extent. Sample PI-5 is dominatedby a 950–2100 Ma detrital zircon population (84%), with

secondary detrital zircon populations of 650–750 Ma (4%)and 2350–3250 Ma (11%) (Fig. 4). Sample PI-6 also containsa primary population of 950–2100 Ma detrital zircon (88%),with only minor detrital zircon populations of 400–650 Ma(6%) and 2450–2850 Ma (6%). Sample PI-7 is primarilycomposed of 1000–2100 Ma grains (60%), but has an in-creased number of 390–700 Ma detrital zircons (28%). Sam-ple PI-7 also contains a secondary detrital zircon population of2300–2800 Ma (12%). Sample PI-8 has two primary detritalzircon populations of 370–700 Ma (44%) and 950–2100 Ma(50%), with a secondary detrital zircon population of 2350–2700 Ma (5%).

Fig. 3. (A) Probability density plot depicting the U–Pb ages of the Blackley Formation. Shaded zones highlight similar populations ofdetrital zircons. See text for discussion of 380–470, 500–700, and 900–2150 Ma populations. (B) Interpreted general paleogeographicsetting along the northern Laurentian margin during Eifelian time. The general location of Svalbard along the northeastern corner ofLaurentia is based on interpretations by Gee and Teben’kov (2004). Overlap of Svalbard with part of Crockerland attempts to incorporatethe Timanide connection for part of Svalbard (Majka et al. 2008). See text for discussion of potential island arc development and origin ofdetrital zircons formed in the Eifelian. n, number of concordant detrital zircon U–Pb ages.

300 500 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 2900 3100 3300 3500

Age (Ma)

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Blackley 2 (n=85)

Bla

900 to 2150Proterozoic

500 to 700Cambrian to

Neoproterozoic

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to Mid Ordovician

2550 to 3000Archean

Middle Devonian (Eifelian)

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Hf isotopic resultsHafnium isotopes can provide information about the relative

importance of mantle and crustal components in the generationof the magma from which a zircon grain was crystallized (e.g.,Goodge and Vervoort 2006; Kemp et al. 2007). Thirty-twohafnium isotopic analyses were used to provide furtherinformation on the sources of the 380 – 450, 520 –550, and650 –710 Ma zircon populations in the Parry Islands For-mation. The εHf(i) values for the 380 – 450 Ma populationrange from �8 to –2, the εHf(i) values for the 520 –550 Mapopulation range from �6 to –1, and the εHf(i) values for the650 –700 Ma population range from �16 to 0 (Fig. 5).

Zircon rim versus core U–Pb resultsTwenty-two double spot U–Pb ages from the rim and core

of the 500–700 Ma population of detrital zircon from the ParryIslands Formation were analyzed to investigate the presence ofxenocrystic cores (Fig. 6). The purpose was to provide infor-mation on the basement of Crockerland surrounding themagma chambers that formed the 500–700 Ma zircon popu-lation. Of the 22 analyses undertaken, only a single graincontains a U–Pb age, indicating a significantly older inheritedcore. The single inherited core yielded an age of1809.7 � 12.6 Ma for the core and 656.6 � 12.1 Ma for therim. The other 21 detrital zircon grains demonstrated a differ-

ence in core to rim U–Pb age of no greater than 90 Ma. Onlyfour grains had a U–Pb age difference of �60 Ma between thecore and rim. The final 17 grains have an average difference of15 Ma between the core and rim of the grain (many withinanalytical error).

Interpretation of resultsThe occurrence of 370–450 and 500–700 Ma detrital zircon

populations in the Parry Islands Formation suggests a northernsediment source was contributing a significant volume ofsediment to the western margin of the basin, as source rocks ofthis age were absent from the ancient northern Laurentianmargin (Trettin 1989; Hadlari et al. 2012). Three aspects of thesedimentary record support a shift in provenance in the latestDevonian (from the more easterly derived Middle Devoniansuccessions) and suggest a dominant northern sedimentsource. First, the basal contact of the Parry Islands Formationis a regional basin-wide disconformity overlain by coarse-

Fig. 4. Probability density plot depicting the U–Pb ages of theParry Islands Formation. Shaded zones highlight similarpopulations of detrital zircons. See text for discussion of 370–470,500–700, and 900–2150 Ma populations. *, PI-1, PI-2, PI-3, PI-4from Anfinson et al. (2012). n, number of concordant detritalzircon U–Pb ages.

300 500 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 2900 3100 3300 3500

Age (Ma)

Parry 5 (n=79)

Parry 1* (n=88)

Parry 2* (n=96)

Parry 3* (n=78)

Parry 6 (n=84)

Parry 8 (n=72)

Parry 7 (n=85)

Parry 4* (n=57)

East

West

Farthest South

900 to 2150Proterozoic

370-450 and 500 to 700Paleozoic-

Neoproterozoic

Fig. 5. Initial epsilon hafnium (εHf(i)) isotopic data plotted against theU–Pb age populations of 380–450, 520–550, and 650–710 Ma. Linesdepict the depleted mantle and chondritic uniform reservoir (CHUR)values. Error bars are 2-sigma.

-10

-5

0

5

10

15

20

300 400 500 600 700 800

Zirc

on ε

Hf(i

)

Zircon U-Pb age

Depleted mantle

CHUR

Fig. 6. U–Pb ages of detrital zircon rims plotted against the coreof the same grain. Note only a single significantly olderxenocrystic core (core: 1809.7 � 12.6 Ma, rim: 656.6 � 12.1 Ma).The majority of the slightly older zircon cores indicate they wererecycled from earlier magmatic phases rather than being recycledfrom a much older pre-existing basement. Error bars are 2-sigma.n, number of double dated concordant detrital zircon ages.

500

550

600

650

700

750

800

500 700 900 1100 1300 1500 1700 1900

Rim

Age

Core Age

Zircon Core versus Rim U-Pb Age

U-Pb Age

N=22

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grained pebbly sandstone of fluvial origin, suggesting a reori-entation in basin configuration (Embry and Klovan 1976;Colpron and Nelson 2009). Second, the formation has southand southwest directed paleocurrents and a high detrital chertcontent, thought to be from unroofed lower Paleozoic depositsof the Hazen and Ibbet Bay Formations, which were depositednorth of the Parry Islands sample locations (Embry and Klo-van 1976; Trettin 1991). Last, the εNd values reported byPatchett et al. (1999) show dramatically less negative values(εNd � –5.3, –7.4, –5.3, –5.1 (Parry Islands Formation samplesfrom Prince Patrick and Helena Island)) from the underlyingBeverly Inlet and Hecla Bay Sequences (εNd average approx-imately –10 (samples from Bird Fiord, Hecla Bay, and BeverlyInlet formations of Bathurst, Melville, and Helena Islands)),indicating a juvenile crustal source. The detrital zircon data, abasin-wide unconformity, high northerly derived chert con-tent, south-directed paleocurrents, and εNd values indicatingjuvenile crustal sources all provide evidence for a northernsediment source.

The secondary population of 900–2150 Ma detrital zirconages are attributed primarily to the east Greenland Caledonidesand the uplifting and eroding Middle and Upper Devonianstrata in the foreland of the Ellesmerian Mountains (McNicollet al. 1995; Anfinson et al. 2012). Paleocurrent data indicatethe easternmost sample (PI-5) was likely derived from theGreenland Caledonides (Embry and Klovan 1976). However,the presence of 900–2150 Ma detrital zircons in westernsamples (PI-7 and PI-8; Fig. 4), which are interpreted as beingderived from the north, suggest Crockerland may also containabundant 900–2150 source rocks. Detrital zircon U–Pb agesalone cannot be used to definitively determine the northern oreastern origin of 900–2150 Ma zircons, and further research isneeded to conclusively identify their origin.

The majority of the 500–700 Ma detrital zircons from theParry Island Formation contain a slightly older age for the core ofthe grain compared with the rim, but there is a lack of distinctinherited cores in the detrital zircons. These data suggest themajority of the older zircon cores were recycled from earliermagmatic phases rather than being recycled from a much olderpre-existing basement. The single zircon crystal indicating crustalcontamination (ca. 1800 Ma) is consistent with the age of manylocations. It is untenable to draw any major conclusions from theexistence of a single inherited core.

The εHf(i) value in a zircon crystal can provide informationabout the sources of the magma from which the zircon crys-tallizes. The εHf(i) data from the early Paleozoic and Neopro-terozoic zircons are notable in that nearly all analyses yieldpositive εHf(i) values. The majority of values are greaterthan �4 and some grains from the 650–710 Ma populationoverlap with the depleted mantle curve (Fig. 5). These dataimply there was little if any input from evolved continentalcrust into the magmas from which the zircons crystallized.

Given the lack of continental signature, the zircons were mostlikely derived from magmatic systems built on oceanic crust,such as island arcs (as depicted in Fig. 3B). Such systemsproduce enough intermediate to felsic magmatic products toyield zircons and most modern examples are dominated bymagmas with εHf(i) greater than �4 (e.g., Dhuime et al. 2011).Another possible origin for these zircons is a continental arcsystem built on accreted oceanic terranes, such as the CoastMountains batholith in British Columbia (Cecil et al. 2011).

Both scenarios may be valid if the zircons were derived frommultiple terranes, or if the zircons were derived from a singleterrane that began as an island arc but later (i.e., after 600 Ma)docked with a continent and became the substrate for a con-tinent arc. The decrease in average εHf(i) values after600 Ma could be attributed to the input of continentallyderived sediment into the subduction system or underthrustingof continental crust behind the arc, as has been suggested forsome Cordilleran systems (e.g., Ducea and Barton 2007;DeCelles et al. 2009). One major challenge to these models isthe presence of two 680–710 Ma detrital zircon grains withεHf(i) values with a mean of –0.4. These are the two oldestzircons from the Neoproterozoic age peak, and their morenegative values seem to require some component of eitherancient continental crust or continentally derived sediment intheir magma sources.

Discussion

Crockerland: a Timanide connectionThe Timanide Orogen, now exposed in Norway and Russia,

was an accretionary orogen that developed in the Ediacaranand Early Cambrian (Gee and Pease 2004). The Timanidesformed as the result of subduction and accretion of terranes tothe northeastern margin of Baltica (Gee and Pease 2004), ordue to collision of a large continental landmass, sometimesreferred to as Arctida (Zonenshain and Natapov 1987; Kuz-netsov 2006). Granitoids associated with the Timanide Orogenare exposed along the northeastern margin of the east Euro-pean Craton and commonly exhibit U–Pb zircon ages of500–700 Ma (Fig. 7; Orlov et al. 2011; Kuznetsov 2006).Numerous locations throughout the Arctic realm contain abun-dant 500–700 Ma detrital zircons within their Paleozoic andMesozoic sediments and are shown to have probable connec-tions to the Timanide Orogen (see Fig. 1 for locations: PolarUrals (Glodny et al. 2004); Novaya Zemlya (Pease and Scott2009); Severnaya Zemlya (Lorenz et al. 2008); Taimyr (Peaseand Scott 2009); Wrangel Island (Miller et al. 2010); SewardPeninsula (Amato et al. 2009); Arctic Alaska (Miller et al.2010); Svalbard (Pettersson et al. 2010)). Our data, document-

Fig. 7. U–Pb ages for granitoids from Timanide complexes, afterOrlov et al. (2011) and references therein. n, number of U–Pb ages.

0

2

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6

8

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ing an abundance of 500–700 Ma detrital zircons derived fromCrockerland, is consistent with previous suggestions that pro-pose Crockerland has a connection to the Timanide Orogen(Miller et al. 2006; Beranek et al. 2010; Anfinson et al. 2012).Whereas these data add spatial and temporal constraints onCrockerland and provide further insight into its connectionwith the Timanide Orogen, the geologic framework of Crock-erland remains poorly understood.

370–470 Ma populationThe 370–470 Ma detrital zircon population from the De-

vonian clastic deposits is interpreted as a synorogenic popu-lation derived from volcanic island arcs and continental arcsassociated with the Caledonian and Ellesmerian Orogens. Thisinterpretation is based on the juvenile εHf(i) values and thecorrelation of the detrital zircon ages with the timing ofthese regionally extensive orogenic events (Higgins and Leslie2000; Trettin 1989). The 425–470 Ma detrital zircons arepotentially derived from either the East Greenland Cale-donides or Crockerland; however, the 370–420 Ma detritalzircons almost certainly originated from Crockerland due tothe lack of 370–420 Ma plutonic and volcanic rocks in theEast Greenland Caledonides (Kalsbeek et al. 2008). The pos-sibility exists that some detrital zircons of this age originatefrom volcanic and plutonic rocks of the Pearya terrane (MountRawlinson assemblage and Cape Woods Pluton; Trettin et al.1987); however, these are not regionally extensive units anddo not likely fully account for the abundance of this agegrouping in the Middle to Upper Devonian samples. Thepresence of these ages within the Pearya terrane and theirinferred existence within the Crockerland landmass may sug-gest some connection between the two landmasses (or possiblythat Pearya is a fragment of Crockerland), but the connectionbetween these two terrains requires significantly more researchto fully explore this possibility.

The relatively continuous distribution of the 370–470 Mapopulation of detrital zircon from the Devonian clastic wedge(Fig. 3A) may indicate that subduction under the Crockerlandlandmass occurred throughout the majority of this time period.The mean εHf(i) values of �7.3 (380–400 Ma) and �2.1(420–450) Ma indicate the zircons are primarily derived fromeither an island arc (as depicted in Fig. 3B) or continental arcbuilt on accreted oceanic crust.

Although the 370–470 Ma age population does not corre-late to the Timanide Orogen, it does correlate to the timing ofmagmatism expected if a continental landmass were movingwestward across the Arctic, subducting oceanic crust along itsleading (western) edge, during the closure of the IapetusOcean. Paleogeographic reconstructions by Kuznetsov et al.(2010) and Colpron and Nelson (2009, 2011) depict continen-tal fragments moving westward across the Arctic from Ordo-vician to Devonian time, and the 370–470 Ma detrital zirconpopulation is in agreement with this plate motion. The abun-dant 370–420 Ma detrital zircon population, absent in thezircon-bearing source rocks of the East Greenland Cale-donides, suggests Crockerland was the primary source of370–420 Ma detrital zircon in the Franklinian Basin.

500–700 Ma populationThe 500–700 Ma population of detrital zircon is exotic to

the northern Laurentian margin (Hadlari et al. 2012) with the

exception of minor 500 Ma volcanic and plutonic outcropswithin the Pearya terrane (Milne Fiord assemblage; Trettin etal. 1987). The commonly prismatic–pyramidal shape, consid-erable size (some detrital zircons �350 �m), similarity in agefrom the rim and core of the zircon (commonly �15 Ma), andCL images that show faint-thin oscillatory zoning (character-istic for zircons with a magmatic origin; Hanchar and Miller1993) suggest the majority of the 500–700 Ma zircons have amagmatic origin (prismatic–pyramidal shape), with abundantzirconium available (large size), and were able to grow relativelyrapidly (rim/core age similarity and thin zoning) (Hoskin andSchaltegger 2003).

The abundance of 500–700 Ma detrital zircons in the Blackleyand Parry Islands formations and other formations of the Devonianclastic wedge (e.g., samples from Anfinson et al. 2012) suggest thatCrockerland contained a significant volume of 500–700 Mazircon-bearing source rock. The presence of the 500–700 Maage population in the Blackley Formation suggests Crocker-land was accreting to the northern Laurentian margin andcontributing sediment to the Franklinian Basin by Eifeliantime.

The 650–680 Ma detrital zircon population of the ParryIslands Formation has a mean εHf(i) value of �10.6. Althoughthere are only a limited number of εHf(i) values for this agerange, the values do appear similar to the 675–763 Ma detritalzircon grains from late Neoproterozoic Engane–Pe Formationof the Timanide Orogen, which have εHf(i) values that rangefrom �11 to �13 (Kuznetsov et al. 2010).

The abundance of the 500–700 Ma age population withinthe Devonian clastic wedge and the similarity of εHf(i) valueswith those of the Engane–Pe Formation support an associationwith the Timanide Orogen, where zircon-bearing rocks of thisage are abundant (Kuznetsov 2006; Orlov et al. 2011; Kuz-netsov et al. 2010, 2011).

900–2150 Ma populationThe 900–2150 Ma population within the Franklinian Basin

is associated with source regions including the East GreenlandCaledonides, Pearya, Svalbard, and Baltica (Anfinson et al.2012). Our data indicate the continental landmass Crockerlandalso likely contained source rock of this age. This is based onthe abundance of this population within the westernmost ParryIslands Formation samples (PI-7 and PI-8; Figs. 1, 4), whichshow considerable evidence for a northern sediment source(Embry and Klovan 1976). Previous hypotheses suggestedCrockerland was primarily composed of 370–700 Ma crustbased on the dominance of detrital zircons in specific samples(Anfinson et al. 2012). The new data presented here indicatethat the crust composing Crockerland was likely more heter-ogeneous, and indicate the limited detrital zircon populationsfrom previous Parry Island samples (Anfinson et al. 2012)likely reflected a proximity to a sediment source of that par-ticular age.

Within the population of 900–2150 Ma detrital zircons,there is a significant subpopulation of �900–1200 Ma in allParry Islands samples. In particular, within the western sam-ples, interpreted as being derived from the north, the 900–1200 Ma population comprises 18% and 12% of samples PI-7and PI-8, respectively. Recent suggestions by Lorenz et al.(2012) that the Grenville–Sveconorwegian Orogen (and Val-halla Orogen of Cawood et al. 2010) extends into landmasses

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of the Arctic are further supported by our data indicatingCrockerland may be a source of 900–1200 Ma detrital zircongrains. Although the 900–1200 Ma zircons are potentiallysecond- or third-cycle zircons recycled from older Proterozoicsedimentary sequences, it is also considered possible thesezircons are derived directly from Grenville basement similar tothe Grenville age granitoid gneisses of the Pearya terrane(succession I of Trettin et al. 1987). As previously mentioned,until a definitive origin of the 900–2150 Ma population can bepositively identified, this remains tentative.

Present location of CrockerlandEvidence suggests that the Crockerland landmass rifted and

drifted from the northern margin of the Canadian Arctic duringcrustal extension associated with the formation of the Amer-asian Basin in the Middle Jurassic to Early Cretaceous (Embryand Dixon 1994). Crockerland is now likely represented byvarious terranes and (or) submerged continental blocks in theArctic realm (Miller et al. 2006; Colpron and Nelson 2009,2011; Embry 2009). Identifying the present location of Crock-erland relies on the tectonic model associated with the openingof the Amerasian Basin (Embry 1998). The opening of theCanada Basin is poorly constrained, limiting reconstructionsof Arctic terranes associated with the ancient landmass ofCrockerland. The 370–470, 500–700, and 900–2150 Ma de-trital zircon populations discussed in the previous sectionlikely contain sources within the Crockerland landmass. Iden-tification of these ages within modern Arctic terranes may lendsupport to their connection with the Crockerland landmass.

Sedimentary rocks with 500–700 Ma detrital zircon agesare common within Devonian- to Triassic-age successions ofthe Arctic Alaska – Chukotka terrane (Miller et al. 2006, 2010;Amato et al. 2009). It is inferred that many of these zirconswere derived either from local plutonic sources (Patrick andMcClelland 1995; Amato et al. 2009) or sources in the Ti-manide orogenic belt (Miller et al. 2006, 2011). The largepopulation of 500–700 Ma ages in the Arctic Alaska – Chu-kotka terrane indicates a paleogeographic connection betweentheir source regions and that of Crockerland. Supplementaryinvestigations are needed before this issue can be confidentlyresolved.

ConclusionsThe U–Pb age data from the Blackley and Parry Islands

formations of the Franklinian Basin, Canadian Arctic Islands,further constrains the provenance of these two formations andallows for a better resolution of the tectonic events associatedwith the northern Laurentian Margin in the Middle to LateDevonian. εHf(i) isotopic values and rim and core double datesfrom detrital zircon populations of the Parry Islands Formationprovide additional insight into the geologic evolution of thecontinental landmass Crockerland.

The 370–470 Ma detrital zircon population from the De-vonian clastic wedge deposits are synorogenic with the Cale-donian and Ellesmerian orogens and are derived primarilyfrom the landmass Crockerland. The age of this population isconsistent with paleogeographic reconstructions, depictinglarge continental fragments moving westward across the Arc-tic during the Ordovician to Devonian (Colpron and Nelson2009, 2011; Kuznetsov et al. 2010). The mean εHf(i) values of�7.3 (380–400 Ma) and �2.1 (420–450) Ma indicate the

zircons are primarily derived from either an island arc orcontinental arc built on accreted oceanic crust. The lack of a370–420 Ma zircon-bearing source rocks of the East Green-land Caledonides suggests Crockerland is the overwhelmingsource of 370–420 Ma detrital zircon in the Franklinian Basin.

The abundance of 500–700 Ma detrital zircon and εHf(i)values from the Devonian clastic wedge detrital zircons aresimilar to those described from rocks associated with Ti-manide Orogen. The detrital zircon rim and core U–Pb agesfrom the Parry Islands Formation suggest a lack of signifi-cantly older inherited cores in the 500–700 Ma age population(with the exception of one). The lack of inherited cores indi-cate the majority of these grains are first cycle or they wererecycled from earlier magmatic phases rather than being re-cycled from a much older pre-existing basement.

The U–Pb detrital zircon ages, detrital chert content, andsouthwest-tapering wedge-shaped profile of the Blackley For-mation indicate the submarine fan deposits were sourced fromthe northeast. The 500–700 Ma detrital zircon populationanalyzed from the Blackley Formation samples is some of theearliest evidence of 500–700 Ma detrital zircon being depos-ited onto the northern Laurentian margin and indicates thelandmass of Crockerland is accreted to Laurentia by Eifeliantime.

Although the 370–470 and 500–700 Ma detrital zirconages are characteristic of Crockerland, the significant contri-bution of 900–2150 Ma detrital zircons in the western ParryIslands Formation samples (believed to be sourced primarilyfrom Crockerland) suggests the landmass likely containedsignificant 900–2150 Ma zircon-bearing source rock as well.Within the 900–2150 Ma detrital zircon population is a num-ber of 900–1200 Ma ages; if these ages are indeed fromCrockerland, it implies this landmass was likely proximal to,or involved in, the Grenville–Sveconorwegian Orogen.

AcknowledgementsWe would like to thank Jeff Vervoort, Charles Knaack, and

Garret Hart for their constant help with the geochronologicwork at Washington State University. Thank you to TomWilliams at the University of Idaho for help with CL imaging.Thank you to Benoit Beachaump and the Geological Survey ofCanada for providing the opportunity to conduct field researchin the Canadian Arctic. The GSC, Faculty of Graduate Studiesat the University of Calgary, SUNBEAM, and the Dr. AlfredA. Levinson Graduate Scholarship financially supported thisproject. Edits by Luke Beranek, Henning Lorenz, MauriceColpron, and John Greenough greatly improved the text andfigures of this manuscript.

ReferencesAmato, J.M., Toro, J., Miller, E.L., Gehrels, G.E., Farmer, G.L.,

Gottlieb, E.S., and Till, A.B. 2009. Late Proterozoic–Paleozoicevolution of the Arctic Alaska-Chukotka terrane based on U–Pbigneous and detrital zircon ages: Implications for Neoproterozoicpaleogeographic reconstructions. Geological Society of AmericaBulletin, 121(9–10): 1219–1235. doi:10.1130/B26510.1.

Amelin, Y., Der-Chuen, L., Halliday, A.N., and Pidgeon, R.T. 1999.Nature of earths earliest crust from hafnium isotopes in singledetrital zircons. Nature, 399(6733): 252–255. doi:10.1038/20426.

Anfinson, O.A., Leier, A.L., Embry, A.F., and Dewing, K. 2012.Detrital zircon geochronology and provenance of the Neoprotero-

Anfinson et al. 1325

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. J. E

arth

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ded

from

ww

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chpr

ess.

com

by

UN

IVE

RSI

TY

OF

TE

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S A

T A

UST

IN o

n 12

/06/

12Fo

r pe

rson

al u

se o

nly.

zoic to Late Devonian Franklinian Basin, Canadian Arctic Islands.Geological Society of America Bulletin, 124(3–4): 415–430. doi:10.1130/B30503.1.

Bahlburg, H., Vervoort, J.D., Du Frane, S.A., Bock, B., Augustsson,C., and Reimann, C. 2009. Timing of crust formation and recyclingin accretionary orogens: Insights learned from the western marginof South America. Earth-Science Reviews, 97(1–4): 215–241.doi:10.1016/j.earscirev.2009.10.006.

Bea, F., Montero, P., Gonzalez-Lodeiro, F., and Talavera, C. 2007.Zircon inheritance reveals exceptionally fast crustal magma gen-eration processes in central Iberia during the Cambo-Ordovician.Journal of Petrology, 48(12): 2327–2339. doi:10.1093/petrology/egm061.

Beranek, L.P., Mortensen, J.K., Lane, L., Allen, T., Fraser, T., Had-lari, T., and Zantvoort, W. 2010. Detrital zircon geochronology ofthe western Ellesmerian clastic wedge, northwestern Canada: in-sights on Arctic tectonics and the evolution of the northern Cor-dilleran miogeocline. Geological Society of America Bulletin,122(11–12): 1899–1911. doi:10.1130/B30120.1.

Bouvier, A., Vervoort, J.D., and Patchett, P.J. 2008. The Lu-Hf andSm-Nd isotopic composition of CHUR: Constraints from unequili-brated chondrites and implications for the bulk composition ofterrestrial planets. Earth and Planetary Science Letters, 273(1–2):48–57. doi:10.1016/j.epsl.2008.06.010.

Cawood, P.A., Strachan, R., Cutts, K., Kinny, P.D., Hand, M., andPisarevsky, S. 2010. Neoproterozoic orogeny along the margin ofRodinia: Valhalla orogen, North Atlantic. The Journal of Geology,38(2): 99–102. doi:10.1130/G30450.1.

Cecil, M.R., Gehrels, G., Ducea, M.N., and Patchett, P.J. 2011.U–Pb-Hf characterization of the central Coast Mountains batho-lith: implications for petrogenesis and crustal architecture. Litho-sphere, 3(4): 247–260. doi:10.1130/L134.1.

Chang, Z., Vervoort, J.D., McClelland, W.C., and Knaack, C. 2006.U–Pb dating of zircon by LA-ICP-M.S. Geochemistry GeophysicsGeosystems, 7(5): Q05009 doi:10.1029/2005GC001100.

Colpron, M., and Nelson, J.L. 2009. A Palaeozoic northwest passage:Incursion of Caledonian, Baltican and Siberian terranes into east-ern Panthalassa, and the early evolution of the North AmericanCordillera. In Earth accretionary systems through space and time.Edited by P.A. Cawood and A. Kröner. Geological Society ofLondon, Special Publication 318, pp. 273–307.

Colpron, M., and Nelson, J.L. 2011. A Paleozoic NW Passage and theTimanian, Caledonian and Uralian connections of some exoticterranes in the North American Cordillera. In Arctic petroleumgeology. Edited by A.M. Spencer, A.F. Embry, D.L Gautier, A.V.Stoupakova, and K. Sorensen. Geological Society Memoir No. 35,pp. 463–484.

De Fritas, T., and Mayr, U. 1998, Devonian (Emsian to Famennian)foreland clastic succession. In The geology of Devon Island northof 76°, Canadian Arctic Archipelago. Edited by U. Mayr, T. deFritas, B. Beauchamp, and G. Eisbacher. Geological Survey ofCanada, Bulletin 526, pp. 155–194.

DeCelles, P.G., Ducea, M.N., Kapp, P., and Zandt, G. 2009. Cyclicityin Cordilleran orogenic systems. Nature Geoscience, 2(4): 251–257. doi:10.1038/ngeo469.

Dewing, K., Harrison, J.C., Pratt, B.R., and Mayr, U. 2004. Aprobable late Neoproterozoic age for the Kennedy Channel andElla Bay formations, northeastern Ellesmere Island and its impli-cations for a passive margin history of the Canadian Arctic. Ca-nadian Journal of Earth Sciences, 41(9): 1013–1025. doi:10.1139/e04-044.

Dewing, K., Mayr, U., Harrison, J.C., and de Freitas, T. 2008. UpperNeoproterozoic to Lower Devonian stratigraphy of northeast Elles-mere Island. In Geology of northeast Ellesemere Island adjacent toKane Basin and Kennedy Channel, Nunavut. Edited by U. Mayr.Geological Survey of Canada, Bulletin 592, pp. 31–108.

Dhuime, B., Hawkesworth, C., and Cawood, P. 2011. When conti-nents formed. Science: Geochemistry, 331(6014): 154–155. doi:10.1126/science.1201245. PMID:21233372.

Ducea, M.N., and Barton, M.D. 2007. Igniting flare-up events inCordilleran arcs. Geology, 35(11): 1047–1050. doi:10.1130/G23898A.1.

Embry, A.F. 1988. Middle-Upper Devonian sedimentation in theCanadian Arctic Islands and the Ellesmerian orogeny. In Devonianof the World. Edited by N.J. MacMillan, A.F. Embry, and D.J.Glass. Canadian Society of Petroleum Geologists, Memoir 14, 2,pp. 15–28.

Embry, A.F. 1991. Middle-Upper Devonian clastic wedge of theArctic Islands, In Geology of the Innuitian orogen and ArcticPlatform of Canada and Greenland. Edited by H.P. Trettin. Geo-logical Survey of Canada, Geology of Canada, No. 3, pp. 263–279.

Embry, A.F. 1998. Counterclockwise rotation of the Arctic Alaskaplate: best available model or untenable hypothesis for the openingof the Amerasia Basin. Polarforschung, 68: 247–255.

Embry, A.F. 2009. Crockerland—the source area for the Triassic toMiddle Jurassic strata of Northern Axel Heiberg Island, CanadianArctic Islands. Bulletin of Canadian Petroleum Geology, 57(2):129–140. doi:10.2113/gscpgbull.57.2.129.

Embry, A.F., and Dixon, J. 1994. The age of the Amerasia Basin. InProceedings, International Conference on Arctic Margins. Editedby D. Thurston and K. Fujita. United States Mineral ManagementService, Report No. 94-0040, pp. 289–295.

Embry, A.F., and Klovan, J.E. 1976. The Middle-Upper Devonianclastic wedge of the Franklinian Geosyncline. Bulletin of CanadianPetroleum Geology, 24: 485–639.

Gaschnig, R.M., Vervoort, J.D., Lewis, R.S., and Tikoff, B. 2011.Isotopic evolution of the Idaho batholith and Challis intrusiveprovince, northern US Cordillera. Journal of Petrology, 52(12):2397–2429. doi:10.1093/petrology/egr050.

Gee, D.G., and Pease, V. (Editors). 2004. The Neoproterozoic Ti-manide orogen of Eastern Baltica. Geological Society of London,Memoir 30, 248 p.

Gee, D.G., and Teben’kov, A.M. 2004. Svalbard: a fragment of theLaurentian margin. In The Neoproterozoic Timanide orogen ofEastern Baltica. Edited by D.G. Gee and V. Pease. GeologicalSociety of London, Memoir 30, 248 p.

Gehrels, G. 2012. Detrital zircon U–Pb geochronology: current meth-ods and new opportunities, In Recent advances in tectonics ofsedimentary basins. Edited by C. Busby and A. Azor. BlackwellPublishing, 33 pp. [Published Online: 30 Jan. 2012.]

Glodny, J., Pease, V.L., Montero, P., Austrheim, H., and Rusin, A.I.2004. Protolith ages of eclogites, Marun-Keu complex, PolarUrals, Russia: implications for the pre- and early Uralian evolutionof the northeastern European continental margin. In The Neopro-terozoic Timanide orogen of Eastern Baltica. Edited by D.G. Geeand V. Pease. Geological Society of London, Memoir 30,pp. 87–105.

Goodbody, Q.H. 1993. Lower and Middle Paleozoic stratigraphy ofMellville Island. In The geology of Mellville Island, Arctic Can-ada. Edited by R.L. Christie and N.J. McMillan. Geological Surveyof Canada, Bulletin 450, pp. 23–103.

Goodge, J.W., and Vervoort, J.D. 2006. Origin of Mesoproterozoic

1326 Can. J. Earth Sci., Vol. 49, 2012

Published by NRC Research Press

Can

. J. E

arth

Sci

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

UN

IVE

RSI

TY

OF

TE

XA

S A

T A

UST

IN o

n 12

/06/

12Fo

r pe

rson

al u

se o

nly.

A-type granites in Laurentia: Hf isotope evidence. Earth andPlanetary Science Letters, 243(3–4): 711–731. doi:10.1016/j.epsl.2006.01.040.

Hadlari, T., Davis, W.J., Dewing, K., Heaman, L.M., Lemieux, Y.,Ootes, L., Pratt, B.R., and Pyle, L.J. 2012. Two detrital zirconsignatures for the Cambrian passive margin of northern Laurentiahighlighted by new U–Pb results from northern Canada. Geolog-ical Society of America Bulletin. [Published online March 9, 2012,14 pp.]

Hanchar, J.M., and Miller, C.F. 1993. Zircon zonation patterns asrevealed by cathodoluminescence and backscattered electron im-ages: implications for interpretation of complex crustal histories.Chemical Geology, 110(1–3): 1–13. doi:10.1016/0009-2541(93)90244-D.

Harrison, J.C. 1995. Melville Island’s salt-based fold belt, ArcticCanada. Geological Survey of Canada, Bulletin 472, 331 p.

Harrison, J.C., and Brent, T.A. 2005. Basins and fold belts of PrincePatrick Island and adjacent areas. Canadian Arctic Islands, Geo-logical Survey of Canada, Bulletin 560, 197 p.

Higgins, A.K., and Leslie, A.G. 2000. Restoring thrusting in theEast Greenland Caledonides. Geology, 28(11): 1019–1022. doi:10.1130/0091-7613(2000)28�1019:RTITEG�2.0.CO;2.

Hoskin, P.W.O., and Schaltegger, U. 2003. The composition ofzircon and igneous and metamorphic petrogenesis, In Zircon.Edited by J.M. Hanchar, and P.W.O. Hoskin. Mineralogical Soci-ety of America, Rev. Mineral. Geochem. 53: 27–62.

Kalsbeek, F., Higgins, A.K., Jepsen, H.P., Frei, R., and Nutman, A.P.2008. Granites and granites in the East Greenland Caledonides. InThe Greenland Caledonides: Evolution of the northeast margin ofLaurentia. Edited by A.K. Higgins, J.A. Gilotti, and M.P. Smith.Geological Society of America, Memoir 202, pp. 227–250.

Kemp, A.I.S., Hawkesworth, C.J., Foster, G.L., Paterson, B.A.,Woodhead, J.D., Hergt, J.M., Gray, C.M., and Whitehouse, M.J.2007. Magmatic and crustal differentiation history of graniticrocks from Hf-O isotopes in zircon. Science, 315(5814): 980–983.doi:10.1126/science.1136154. PMID:17303751.

Kirkland, C.L., Pease, V., Whitehouse, M.J., and Ineson, J.R. 2009.Provenance record from Mesoproterozoic-Cambrian sediments ofPeary Land, North Greenland: Implications for the ice-coveredGreenland Shield and Laurentian paleogeography. PrecambrianResearch, 170(1–2): 43–60. doi:10.1016/j.precamres.2008.11.006.

Kuznetsov, N.B. 2006. The Cambrian Baltica-Arctida collision, pre-Uralide-Timanide orogen, and its erosion products in the Arctic.Doklady Earth Sciences, 411A(9): 1375–1380. doi:10.1134/S1028334X06090091.

Kuznetsov, N.B., Natapov, L.M., Belousova, E.A., Griffin, W.L.,O’Reilly, S.Y., Soboleva, A.A., et al. 2009. The first resultsof isotopic dating of detrital zircons from clastic rocks ofPre-Uralide-Timanide complexes: contribution in the LatePrecambrian stratigraphy of the Enganepe uplift, Western PolarUrals. Doklady Earth Sciences, 424(1): 41–46. doi:10.1134/S1028334X09010097.

Kuznetsov, N.B., Natapov, L.M., Belousova, E.A., O’Reilly, S.Y.,and Griffin, W.L. 2010. Geochronological, geochemical and iso-topic study of detrital zircon suites from late Neoproterozoicclastic strata along the NE margin of the East European Craton:Implications for plate tectonic models. Gondwana Research, 17(2–3):583–601. doi:10.1016/j.gr.2009.08.005.

Kuznetsov, N.B., Orlov, S.Yu., Miller, E.L., Shazillo, A.V., Dronov,A.V., Soboleva, A.A., Udoratina, O.V., and Gehrels, G. 2011. Firstresults of U/Pb dating of detrital zircons from Early Paleozoic and

Devonian sandstones of the Baltica-Lagoda region (south LagodaArea). Doklady Earth Sciences, 438(2): 759–765. doi:10.1134/S1028334X11060316.

Lemieux, Y., Hadlari, T., and Simonetti, A. 2011. Detrital zircongeochronology and provenance of Devono-Mississippian strata inthe northern Canadian Cordilleran miogeocline. Canadian Journalof Earth Sciences, 48(2): 515–541. doi:10.1139/E10-056.

Lorenz, H., Gee, D.G., and Simonetti, A. 2008. Detrital zircon agesand provenance of the late Neoproterozoic and Paleozoic succes-sions on Severnaya Zemlya, Kara Shelf: a tie to Baltica. Norwe-gian Journal of Geology, 88: 235–258.

Lorenz, H., Gee, D.G., Larionov, A.N., and Majka, J. 2012. TheGrenville-Sveconorwegian orogen in the high Arctic, GeologicalMagazine, Firstview, pp. 1–17.

Ludwig, K.R. 2008. Isoplot 3.7 – A geochronological tookit forMicrosoft Excel, Berkeley Geochronology Center, Special Publi-cation No. 4, pp. 1–77.

Majka, J., Mazur, S., Manecki, M., Czerny, J., and Holm, D.K.2008. Late Neoproterozoic amphibolite-facies metamorphism of aPre-Caledonian basement block in southwest Wedel JarlsbergLand, Spitsbergen: new evidence from U–Th–Pb dating of mon-azite. Geological Magazine, 145(06): 822–830. doi:10.1017/S001675680800530X.

McNicoll, V.J., Harrison, J.C., Trettin, H.P., and Thorsteinsson, R.1995. Provenance of the Devonian clastic wedge of Arctic Canada:evidence provided by detrital zircon ages. In Stratigraphic evolu-tion of Foreland Basins. Edited by P.A. Scholle. SEPM SpecialPublication, No. 52, pp. 77–93.

Miller, C.F., McDowell, S.M., and Mapes, R.W. 2003. Hot and coldgranites? Implications of zircon saturation temperatures and pres-ervation of inheritance. Geology, 31(6): 529–532. doi:10.1130/0091-7613(2003)031�0529:HACGIO�2.0.CO;2.

Miller, E.L., Toro, J., Gehrels, G.E., Amato, J.M., Prokopiev, A.,Tuchkova, M.I., et al. 2006. New insights into Arctic paleogeog-raphy and tectonics from U–Pb detrital zircon geochronology.Tectonics, 25, TC3013, 19 p.

Miller, E.L., Gehrels, G.E., Pease, V., and Sokolov, S. 2010. Stra-tigraphy and U–Pb detrital zircon geochronology of Wrangel Is-land, Russia, implications for Arctic Paleogeography. AAPGBulletin, 94(5): 665–692. doi:10.1306/10200909036.

Miller, E., Kuznetsov, N., Soboleva, A., Udoratina, O., Grove, M.,and Gehrels, G. 2011. Baltica in the Cordillera? Geology, 39(8):791–794. doi:10.1130/G31910.1.

Omma, J.E., Pease, V., and Scott, R. 2011. U–Pb SIMS zircongeochronology of Triassic and Jurassic sandstones on northwest-ern Axel Heiberg Island, northern Sverdrup Basin, Arctic Canada.In Arctic petroleum geology. Edited by A.M. Spencer, A.F. Em-bry, D.L Gautier, A.V. Stoupakova, and K. Sorensen. GeologicalSociety Memoir No. 35, pp. 559–566.

Orlov, S.Yu., Kuznetsov, N.B., Miller, E.L., Soboleva, A.A., andUdoratina, O.V. 2011. Age constraints for the pre-Uralide-Timanide orogenic event infrerred from the study of detrital zir-cons. Doklady Earth Sciences, 440(1): 1216–1221. doi:10.1134/S1028334X11090078.

Patchett, P.J., Roth, M.A., Canale, B.S., de Freitas, T.A., Harrison,J.C., Embry, A.F., and Ross, G.M. 1999. Nd Isotopes, geochem-istry, and constraints on sources of sediments in the FranklinianMobile Belt, Arctic Canada. Geological Society of America Bul-letin, 111(4): 578–589. doi:10.1130/0016-7606(1999)111�0578:NIGACO�2.3.CO;2.

Patrick, B.E., and McClelland, W.C. 1995. Late Proterozoic granitic

Anfinson et al. 1327

Published by NRC Research Press

Can

. J. E

arth

Sci

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

UN

IVE

RSI

TY

OF

TE

XA

S A

T A

UST

IN o

n 12

/06/

12Fo

r pe

rson

al u

se o

nly.

magmatism on Seward Peninsula and a Barentsian origin forArctic Alaska-Chukotka. Geology, 23(1): 81–84. doi:10.1130/0091-7613(1995)023�0081:LPGMOS�2.3.CO;2.

Pease, V., and Scott, R.A. 2009. Crustal affinities in the ArcticUralides, northern Russia: Significance of 11 detrital zircon agesfrom Neoproterozoic and Paleozoic sediments in Novaya Zemlyaand Taimyr. Journal of the Geological Society, 166(3): 517–527.doi:10.1144/0016-76492008-093.

Pettersson, C.H., Pease, V., and Frei, D. 2010. Detrital zircon U–Pbages of Silurian-Devonian sediments from NW Svalbard: a frag-ment of Avalonia and Laurentia? Journal of the Geological Soci-ety, 167(5): 1019–1032. doi:10.1144/0016-76492010-062.

Røhr, T.S., Andersen, T., Dypvik, H., and Embry, A.F. 2010. Detritalzircon characteristics of the Lower Cretaceous Isachsen Forma-tion, Sverdrup Basin: source constraints from age and Hf isotopedata. Canadian Journal of Earth Sciences, 47(3): 255–271. doi:10.1139/E10-006.

Scherer, E., Munker, C., and Mezger, K. 2001. Calibration of theLutetium-Hafnium Clock. Science, 293(5530): 683–687. doi:10.1126/science.1061372. PMID:11474108.

Thorsteinsson, R., and Tozer, E.T. 1970, Geology of the ArcticArchipelago, In Geology and Economic Minerals of Canada. Ed-ited by R.J.W. Douglas. Geological Survey of Canada, EconomicGeology Report, 5th ed. pp. 547–590.

Tozer, E.T., and Thorsteinsson, R. 1964. Western Queen Elizabeth Islands,Arctic Archipelago. Geological Survey of Canada, Memoir 332.

Trettin, H.P. 1987. Pearya: a composite terrane with Caledonianaffinities in northern Ellesmere Island. Canadian Journal of EarthSciences, 24(2): 224–245. doi:10.1139/e87-025.

Trettin, H.P. 1989. The Arctic Islands. In The geology of NorthAmerica: an overview. Edited by A.W. Bally and A.R. Palmer.Geological Society of America, A, pp. 349–370.

Trettin, H.P. (Editor). 1991. Silurian-Early Carboniferous deforma-tional phases and associated metamorphism and plutonism, ArcticIslands. In Geology of the Innuitian orogen and Arctic Platform ofCanada and Greenland. Geological Survey of Canada, Geology ofCanada, No. 3, pp. 295–344.

Trettin, H.P., Parrish, R., and Loveridge, W.D. 1987. U–Pb agedeterminations on Proterozoic to Devonian rocks from northernEllesmere Island, Arctic Canada. Canadian Journal of Earth Sci-ences, 24(2): 246–256. doi:10.1139/e87-026.

Trettin, H.P., Mayr, U., Long, G.D.F., and Packard, J.J. 1991. Cam-brian to Early Devonian Basin Development, Sedimentation, andVolcanism, Arctic Islands. In Geology of the Innuitian orogen andArctic Platform of Canada and Greenland. Geological Survey ofCanada, Geology of Canada, No. 3, pp. 165–238.

Vervoort, J.D., and Blichert-Toft, J. 1999. Evolution of the depletedmantle: Hf isotope evidence from juvenile rocks through time.Geochimica et Cosmochimica Acta, 63(3–4): 533–556. doi:10.1016/S0016-7037(98)00274-9.

Vervoort, J.D., and Patchett, P.J. 1996. Behavior of hafnium andneodymium isotopes in the crust: constraints from Precambriancrustally derived granites. Geochimica et Cosmochimica Acta,60(19): 3717–3733. doi:10.1016/0016-7037(96)00201-3.

Zeck, H.P., and Whitehouse, M.J. 1999. Hercynian, Pan African,Proterozoic and Archaean ion-microprobe zircon ages for a Betic-Rif core complex, Alpine belt, W Mediterranean—consequencesfor its P-T-t path. Contributions to Mineralogy and Petrology,134(2–3): 134–149. doi:10.1007/s004100050474.

Zonenshain, L.P., and Natapov, L.M. 1987. Tectonic history of theArctic. In Timely problems of continent and ocean tectonics,Moscow. Nauka Press, pp. 31–57. [In Russian.]

1328 Can. J. Earth Sci., Vol. 49, 2012

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. J. E

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UN

IVE

RSI

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/06/

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r pe

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