The source of topography across the Cumberland Peninsula BaffinIsland Arctic Canada differential exhumation of a North Atlanticrift flank

Scott Jess1 Randell Stephenson1 Soslashren B Nielsen2 amp Roderick Brown31 School of Geosciences University of Aberdeen Aberdeen AB24 3UE UK2 Department of Geoscience Aarhus University DK-8000 Aarhus C Denmark3 School of Geographical and Earth Sciences University of Glasgow Glasgow G12 8QQ UK

SJ 0000-0003-1960-2901 RB 0000-0002-0763-3711Correspondence scottjessucalgaryca

Abstract Elevated topography is evident across the continental margins of the Atlantic The Cumberland Peninsula BaffinIsland formed as the result of rifting along the LabradorndashBaffin margins in the late Mesozoic and is dominated by low-reliefhigh-elevation topography Apatite fission-track (AFT) analysis of the landscape previously concluded that the area hasexperienced a differential protracted cooling regime since the Devonian however defined periods of cooling and the directcauses of exhumation were unresolved This work combines the original AFT data with 98 apatite new (UndashTh)He (AHe) agesfrom 16 samples and applies the newly developed lsquobroken crystalsrsquo technique to provide a greater number of thermal constraintsfor thermal history modelling to better constrain the topographic evolution The spatial distribution of AFT and AHe agesimplies that exhumation has been significant toward the SE (Labrador) coastline and results of thermal modelling outline threenotable periods of cooling in the pre-rift stage (460ndash200 Ma) from synrift stage to present (120ndash0 Ma) and within the post-riftstage (30ndash0 Ma) Pre-rift cooling is interpreted as the result of exhumation of Laurentia and synrift cooling as the result of rift-flank uplift to the SE and differential erosion of landscape whereas the final post-rift period is probably an artefact of themodelling process These results suggest that the source of the Cumberland Peninsularsquos modern-day elevated topography isuplift during rifting in the Cretaceous and the isostatic compensation following continuous Mesozoic and Cenozoic differentialerosion This work highlights how interaction of rift tectonics and isostasy can be the principal source for modern elevatedcontinental margins and also provides insight into the pre-rift exhumational history of central Laurentia

Supplementary material Thermal histories are available at httpsdoiorg106084m9figsharec4528409

Received 30 November 2018 revised 23 May 2019 accepted 27 May 2019

The continental margins of the Atlantic exhibit elevated coastaltopography reaching c 3 km in height yet the source and age oftopography remains a contentious issue (Japsen amp Chalmers 2000Nielsen et al 2009 Green et al 2018) The margins of Brazilsouthern Africa Norway and Greenland are all characterized byhigh-elevation low-relief topography and aspects of the offshorestratigraphy have been interpreted in terms of a fluctuating onshoredenudational history (Riis 1996 Evans 1997 Japsen 1998Chalmers 2000 Burke amp Gunnell 2008 Cobbold et al 2010)Various mechanisms have previously been suggested to explainboth the onshore and offshore geology mantle diapirism (Rohrmanamp van der Beek 1996) rift-flank uplift (Redfield et al 2005)tectonic rejuvenation (Ksienzyk et al 2014) far-field stress changes(Japsen et al 2014) and isostasy (Medvedev et al 2008) Howevera clear consensus is yet to be established

Low-temperature thermochronology and thermal history model-ling have become vital tools in establishing the onshore denuda-tional and uplift histories of modern passive margins (eg Gallagheret al 1994 Cockburn et al 2000 Kounov et al 2009 Wildmanet al 2015) in part owing to a lack of direct geological evidence anddifficulties integrating onshore and offshore histories Thermalhistories generated from across several continental margins outlinethe timing and style of cooling or heating to establish periods ofexhumation or burial respectively helping to infer how a landscapehas evolved (Gallagher et al 1998) Across Greenland and Braziltopography is interpreted to have formed from multiple tectonicuplift events following the end of rifting inferred from episodic

rapid cooling in thermal histories (Japsen et al 2006 2012 2014)whereas protracted cooling observed in thermal models fromNorway and southern Africa suggests that topography along thesemargins results from a prolonged denudation across elevated riftflanks (Brown et al 2000 Hendriks amp Andriessen 2002) or ancienttopography (Nielsen et al 2009) These contrasting interpretationsillustrate the contentious debate surrounding the evolution ofAtlantic continental margins and highlight the key role thermalhistory modelling plays in establishing the topographic evolution ofcontinental margins

The Baffin Mountains along the NE coastline of Baffin Island(Fig 1) are an example of low-relief landscape at high elevation(c 2 km) and as in many other instances from margins across theAtlantic the source of this topography remains enigmatic Earlygeomorphological research from Baffin Island suggested that muchof the modern landscape is the result of a peneplain that was upliftedin the late Cenozoic (Cooke 1931 Mercer 1956) However apatitefission-track data and thermal history models from the CumberlandPeninsula SE Baffin Island show no evidence for uplift in theCenozoic and are interpreted as the result of protracted erosion sincethe Devonian (McGregor et al 2013) The present work attempts tobetter constrain the thermal history from across the CumberlandPeninsula with the addition of 98 single grain apatite (UndashTh)Heages from 16 samples of the original fission-track dataset andfurther utilizing the lsquobroken crystalsrsquo approach in one sample toprovide greater temporal and thermal resolution (Brown et al 2013)The resulting spatial data trends and enhanced thermal histories

copy 2019 The Author(s) This is an Open Access article distributed under the terms of the Creative Commons Attribution 40 License (httpcreativecommonsorglicensesby40) Published by The Geological Society of London Publishing disclaimer wwwgeolsocorgukpub_ethics

Research article Journal of the Geological Society

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suggest that uplift of the margin occurred during rifting in the lateMesozoic and has since been preserved by isostatic forces andadditional insight into the pre-rift history is also provided

Geological setting

The geology of the Cumberland Peninsula is dominated by Archeanorthogneisses and amphibolites of the Hoare Bay Group andgranulites of the Cumberland batholith that amalgamated as part ofthe lsquoRae Craton Expansionrsquo (c 20 Ga) (St-Onge et al 2009) Thecollision of five Archean terranes led to the metamorphism of theoriginal continental shelf sediments of the Hoare Bay Group(188 Ga) (St-Onge et al 2009) and generated the granitic melt ofthe Cumberland Batholith now located across the centre of BaffinIsland Subsequent collision with the Superior Craton to the west aspart of the Trans-Hudson Orogeny (c 18 Ga) combined manyearly crustal domains to form the supercontinent of Laurentia(Lewry amp Collerson 1990 St-Onge et al 2009) Evidence of intra-cratonic subsidence and uplift of Laurentia during the Paleozoic and

Mesozoic is apparent in several localities (Flowers et al 2012 Aultet al 2013 Zhang et al 2012) although it is poorly resolved owingto a lack of preserved geology

Extension between eastern Canada and western Greenland isbelieved to have begun in the Late Triassic and continued to thePaleocene (Larsen et al 2009) The geochemistry of igneousintrusions across both margins and observed fault block rotation inthe offshore outline three intense periods of rifting in the lateMesozoic and early Cenozoic Late Jurassic to Early Cretaceous(150ndash130 Ma) Mid-Cretaceous (120ndash100 Ma) and Late Cretaceousto Paleocene (80ndash64 Ma) (Balkwill 1987 Larsen et al 2009) Oceanspreading in the region began in the Labrador Sea during the LateCretaceous and migrated northwards into Baffin Bay in thePaleocene aided by the c 700 km long strike-slip Ungava FaultZone (Funck et al 2007 Suckro et al 2013) (Fig 1) Spreadingwithin Baffin Baywas kinematically reoriented in the Late Paleoceneto Early Eocene (from northndashsouth to NNWndashSSE) (c 57ndash53 Ma)coeval with the Eurekan Orogeny to the north and ceased altogetherin the Late Eocene (c 34 Ma) (Oakey amp Chalmers 2012) (Fig 1)

Fig 1 Geological map highlighting the onshore geology of the study area offshore geology of the surrounding region and sample locations and namesTwo Proterozoic groups make up the majority of the Cumberland Peninsula (Cumberland Batholith and Hoare Bay Group) and underlie all sampling sitesSamples range in elevation from 0 to 840 m stretching across much of the NE coast and reach c 60 km inland This sampling strategy helps establish thedenudational history of the heavily glaciated NE coast Cross-section XndashXrsquo is shown in Figure 3c Offshore the geology is dominated by Mesozoic andCenozoic sediments and Paleogene volcanic rocks Ocean crust overlies both the Labrador Sea and Baffin Bay separated by the transpressional UngavaFault Zone which is thought to be composed of stretched and intruded igneous crust (map adapted from Oakey amp Chalmers 2012) Locations on map QkQikiqtarjuaq Ql Quqalluit P Padloping Island D Durban Island

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Rifting led to significant sedimentary basin development acrossBaffin Bay and the Davis Strait with several kilometres of deltaicand marine sediments offshore (Chalmers 2012) Onshore strati-graphic exposure across the Cumberland Peninsula is limited toCretaceous sands found in half-grabens on Durban Padloping andQuqalluit islands interpreted as the deposits of a major Cretaceousbraided river system (Burden amp Langille 1990) (Fig 1)Subaqueous and subaerial volcanoclastic deposits and lavasoverlie these Cretaceous sands onlapping onto the surroundingbasement and are interpreted as the most westerly extent of theWestGreenland Igneous Province (Clarke amp Upton 1971) (Fig 1)Offshore stratigraphy is not well defined although Cretaceous sandsare found just below the seafloor of the NE coastline of theCumberland Peninsula (MacLean et al 2014) and c 1 km ofNeogene sediments is present off the shelf (Thieacutebault et al 1989Chalmers 2012) The elevated peneplain across Baffin Island hasbeen proposed to result from uplift in the late Cenozoic althoughcontemporary studies have suggested that these features may beformed through differential erosion across the landscape duringglaciation (Egholm et al 2017 Strunk et al 2017)

The discernible lack of Mesozoic and Cenozoic rocks makes itdifficult to constrain the onshore evolution of the regionFortunately the application of apatite low-temperature thermo-chronology can contribute to our understanding of the regionrsquoshistory

Methods

Low-temperature thermochronology

In this study thermal histories are generated by the joint inversion ofapatite fission-track (AFT) and apatite (UndashTh)He (AHe) data(Gallagher et al 1998) AFT utilizes damage trails produced withinthe crystal lattice of apatite following the fission decay of 238U toestablish the age and rate of cooling through the apatite fission-trackpartial annealing zone (PAZ 120ndash60degC) Central ages utilized inthis study were determined through the external detector method(Gleadow 1981) and the style of cooling is established by thedistribution of horizontal confined fission-track lengths asresidence in the PAZ shortens tracks from their initial size(c 162 microm) producing a length distribution dependent on asamplersquos thermal history AHe utilizes the accumulation of 4He inthe apatite grains derived from the alpha decay of 238U 235U and232Th at temperatures lt70degC (Wolf et al 1998) The concentrationsof both 4He and radioactive isotopes are used to determine the timeat which the grain was within the helium partial retention zone(HePRZ 70ndash40degC) (Wolf et al 1998 Stockli et al 2000)providing temporal and thermal constraints on a geologicaltimescale

From the 20 samples analysed in the initial AFT study (McGregoret al 2013) 16 were used for whole grain (UndashTh)He analysis and20 fragmented grains were analysed from one of the youngest AFTsamples (Ec8) (Brown et al 2013) Selecting appropriate apatitegrains from metamorphic rocks is difficult because of the highlikelihood of 4He-rich inclusions and pitted mineral surfacescaused by grain boundary interactions at depth (Dempster et al2006) Criteria used to ensure that suitable grains were pickedincluded a euhedral or sub-euhedral morphology a lack ofobservable mineral inclusions and good optical clarity to ensurethe internal structure of the grain could be observed Analysis wascompleted at the London Geochronology Centre where each grainwas heated to c 650degC for 120 s using a 25 W 808 nm diode laserand 4He was measured with a Balzers quadrupole mass spectrom-eter Uranium and thorium measurements were completed throughacid digestion and isotope dilution with an Agilent 7700xinductively coupled plasma mass spectrometry system

AHe single-grain age dispersion is common in non-orogenicsettings owing to multiple factors grain size (Reiners amp Farley2001) 4He implantation (Farley et al 1996) U- and Th-richinclusions (Vermeesch et al 2007) implantation (Gautheron et al2012) and radiation damage (Shuster et al 2006 Flowers et al2009 Gautheron et al 2009) In an attempt to improve thermalhistory model precision the use of fragmented grains on sample Ec8was employed Apatite grains commonly break parallel to the c-axisduring mineral separation producing a grain fragment with aspecific portion of the helium diffusion profile and calculated agesare either younger or older than the potential lsquowhole grainrsquo age(Brown et al 2013) The analysis of gt20 fragments of varyinglengths from a single rock sample generates a distribution of ageswith lsquopredictablersquo dispersion that provides a greater number ofthermal and temporal constraints for thermal history modelling(Beucher et al 2013)

Thermal modelling

Integrated inverse modelling of AFT and AHe data was completedusing the transdimensional Bayesian Markov Chain Monte Carlo(MCMC) within QTQt (Gallagher 2012) This approach samplesgt200 000 thermal histories continually assessing the predictions ofAFT central age track distribution and AHe ages against eachiteration to ascertain if the prediction has improved and finallyproducing an lsquoexpected modelrsquo that is bound by 95 credibilityintervals This lsquoexpected modelrsquo outlines a single thermal historyderived from a wide range of possible outcomes and does notforcibly overinterpret the data in the modelling process producing athermal history dependent on the joint inversion of both datasets andthe quality of the data Moreover this approach also permits theapplication of c-axis correction on AFT track length data (Donelicket al 1999) greatly improving modelling accuracy and theresampling of AHe age error which allows for a greater degree offreedom while modelling and objectively discounting single AHeages that are incompatible with the counterpart AFT data

As mentioned above radiation damage within apatite grains caninfluence AHe ages producing le100 dispersion in affectedsamples Continuing recoil of the U and Th decay chain can damagethe surrounding crystal lattice creating vacancies that canaccommodate 4He diffused above c 70degC that is then included inanalysis increasing the overall age (Shuster et al 2006) In anattempt to improve the compatibility of dispersed AHe ages aradiation damage diffusion model and alternative diffusionparameters are incorporated that treat radiation damage defectssimilarly to fission tracks during a calculated thermal history(Gautheron et al 2009) Although this may not account for alldispersion within samples it has been shown to improve AFT andAHe age predictions in comparison with standard apatite diffusionkinetics (eg Cogneacute et al 2012 Guillaume et al 2013 Leprecirctreet al 2015 Wildman et al 2015 Kasanzu 2017)

Results

Low-temperature thermochronology

Fission-track central ages (extracted from McGregor et al 2013)range between 1774 plusmn 68 Ma and 4409 plusmn 222 Ma and display atrend of younger ages toward the SE margin (Figs 2 and 3b)outlining isochrons dipping to the SEndashNW (Fig 3c) Mean tracklengths (MTL) range between 1209ndash1327 microm (uncorrected) and1317ndash1422 microm (c-axis corrected) with the highest values foundacross inland and elevated areas whereas lower MTLs focus aroundhighly glaciated coastal regions Plots of AFT central ages andMTLagainst elevation exhibit no obvious trend (Fig 3a) whereas apositive correlation is apparent between Cl wt and AFT central

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age (Fig 4d) and absent between the kinetic parameter Dpar andAFT central age (Fig 4a) Of the 22 samples five provide χ2 valuesof less than 5 although dispersion of all samples is lt15suggesting that low values are probably determined by fewer than20 grains counted or low track densities

Whole grain AHe ages range between 00 Ma and 34 Ga foruncorrected ages and 00 Ma and 46 Ga for corrected ages(Table 1) Specific removal of ages considered very young(lt1 Ma) and those considered very old (gt1 Ga) from the datasetproduces alternative age ranges 551 and 6102 Ma (uncorrected)and 809 and 6908 Ma (corrected) Mean sample ages from thisaltered dataset range between 1040 and 2794 Ma (uncorrected)and 1237 and 3299 Ma (corrected) and also display a trend ofyounger ages toward the SE similar to that of AFT central ages(Figs 2 and 3b) Effective uranium concentration (eU = [U] + 0235

[Th]) against AHe age shows weak to moderate positive correlationsin 11 of the 16 whole grain samples whereas equivalent sphericalradius and AHe age show weak to moderate positive correlations in14 of the 16 samples (Fig 3d) These trends imply that bothradiation damage and grain geometry are dominant controls onwhole grain ages and suggest that many of the samples have spentconsiderable time within the HePRZ (Reiners amp Farley 2001Flowers et al 2009) Grains with anomalously high ages (gt1 Ga)imply that significant quantities of additional 4He have entered thediffusion domain probably through micro-inclusions or implant-ation Very young ages (lt1 Ma) can be attributed to the potentialaccidental selection of zircon instead of apatite or a failure to reachan optimum temperature during 4He extraction Fragment (lsquobrokengrainrsquo) ages range between 626 and 6101 Ma (uncorrected) and684 and 6901 Ma (corrected) eU against fragment age also

Fig 2 Topographic map of theCumberland Peninsula including AFTand mean AHe ages for given samplesMean AHe ages are displayed in italicssample locations are exhibited with thesame symbols as used in Figure 3c andletters in superscript highlight therespective subsample

Fig 3 Spatial trends of AFT and meanuncorrected AHe ages (a) Age againstelevation exhibits weak positive trendsfrom both AFT and AHe although thereare high levels of scatter suggesting thatthermal histories vary greatly across thestudy area and that elevation is not aprimary control on age (b) Distance fromthe SE margin (Davis Strait) against ageshows a moderate positive correlation forboth AFT and mean AHe ages similar tomany passive margins implying thatcooling is greater toward the SE and thatthe opening of Davis Strait may have hada significant effect on the thermal regimeof the study area 2T whole grain age 1Tfragment age (c) Sample central agesoutline dipping isochrons toward the SEmargin suggesting higher rates of rockexhumation or rift-flank uplift towardsDavis Strait Ec14 (highlighted with ) isidentified as an outlier owing to thesamplersquos young age a result of only fourgrains being counted

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exhibits a weak positive correlation whereas fragment lengthagainst fragment age displays no obvious trend again suggestingthat radiation damage is a principal control on AHe ages

Examination of both the AFT and AHe data reveals anoverlapping of age ranges across several samples reflecting theextent of dispersion in the data although AFT central age againstmean AHe age does exhibit a moderate positive correlationsuggesting some compatibility between the two systems Notablydispersion of AHe ages does display a weak positive correlationagainst AFT central age implying that older AFT central ages mayyield wider dispersion in the (UndashTh)He system conceivably owingto thermal histories with extended periods of time within theHePRZ

Thermal modelling

Thermal histories generated from across the study area exhibit bothlinear protracted cooling and a variety of cooling episodes stretchingfrom the late Paleozoic to Late Cenozoic The study area is dividedinto three segments (NW central and SE) and thermal histories canbe found in Figure 4 and the supplementary material

In the NW segment thermal histories from across Qikiqtarjuaqand the coastline exhibit accelerated cooling from the Cretaceous topresent in Ec1 Ec2 and Ec17 with a rate of cooling that variesbetween 04 and 08degC Maminus1 A Late Cenozoic cooling episode isalso observed in the more elevated Ec13 Ec16 and Ec18 sampleswith rates ranging between 07 and 15degC Maminus1 Late PaleozoicndashearlyMesozoic cooling is exhibited in Ec13 and Ec16 from elevated

positions and Ec17 from a low elevation with cooling ratesspanning 0 4ndash11degCMaminus1 whereas Ec14 and Ec3 the only samplewith just AFT data both exhibit linear protracted cooling with a rateof 02degC Maminus1

In the central segment of the study area accelerated cooling fromthe Cretaceous to present is observed only in Ec22 with a coolingrate of 05degC Maminus1 A Late Cenozoic cooling episode is alsoobserved in thermal histories from low-elevation coastal samplesEc12 and Ec19 both exhibiting a rate of 1degCMaminus1 Accelerated latePaleozoicndashearly Mesozoic cooling is observed in low-elevationsamples Ec19 Ec21 and Ec22 with varying rate of cooling between03 and 11degC Maminus1 whereas linear protracted cooling is observedin the elevated and inland samples Ec20 and Ec23 both exhibiting arate of 02degC Maminus1

In the SE segment accelerated cooling from the Cretaceous topresent is displayed in the low-elevation samples Ec7 and Ec8 witha rate between 06 and 08degC Maminus1 A Late Cenozoic coolingepisode is also observed in only the low-elevation sample Ec5exhibiting a rate of 14degC Maminus1 Additionally late Mesozoiccooling is also observed in the low-elevation Ec7 and Ec8 sampleswith rates varying between 12 and 13degC Maminus1 whereas theelevated Ec10 sample derived from AFT data alone exhibits linearprotracted cooling with a rate of 025degC Maminus1

Predicted AFT central ages and c-axis corrected track distribu-tions from thermal histories are all modelled within error with theexception of Ec14 where the central age is calculated from onlyfour grains suggesting that the age itself is anomalous Predictionsof whole grain AHe ages vary with AHe ages younger than the

Fig 4 Plots of AFT central ages against compositional and kinetic data and AHe whole grain (2T) and fragment (1T) ages against compositional andgeometric data (a) Dpar against AFT central age shows no obvious trend suggesting that it is not a principal control on fission-track annealing (b) [eU]against AHe age in samples Ec2 (NW) Ec7 (SE) and Ec20 (central) displays positive correlations although higher [eU] values do generally produce higherAHe ages implying that additional 4He has accumulated in the grain owing to radiation damage (c) [eU] against AHe fragment age exhibits a weakpositive correlation where higher [eU] values have higher AHe ages with the exception of the two highest [eU] values (gt80 ppm) suggesting that radiationdamage is a principal control on these ages (d) Cl wt against AFT central age shows a weak positive correlation suggesting that the Cl content in theapatite grains may lower the annealing rate producing older ages (e) Equivalent grain radius against AHe ages in samples Ec2 (NW) Ec7 (SE) and Ec20(central) displays positive trends suggesting that diffusion domain size plays a notable role in the final AHe age (f ) Fragment length against AHe fragmentage exhibits no obvious trend implying that the size of diffusion domain is negligible in the final AHe fragment age

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Table 1 Table of apatite (UndashTh)He data from the Cumberland Peninsula

Sample (mean) He (Vol (10minus9 cm3)) U (ppm) Th (ppm) Sm (ppm) eUdagger (ppm) Length (microm) Width (microm) rrsquoDagger (microm) Ftsect Measured age (Ma) Corrected agepara (Ma)

Ec1 (2312) a 000 1471 2580 4168 2077 152 102 573 074 010 plusmn 001 013 plusmn 001b 013 12115 11573 3708 14835 174 75 463 068 551 plusmn 028 809 plusmn 040c 1117 4893 1602 7644 5269 203 110 649 077 46080 plusmn 2304 59786 plusmn 2989d 212 030 100 030 054 253 134 795 081 379037 plusmn 18952 466669 plusmn 23333e 374 5966 1030 134 6208 218 87 544 073 22729 plusmn 1136 31249 plusmn 1562

EC2 (2018) a 875 8758 2309 976 9400 156 88 516 071 26741 plusmn 794 31194 plusmn 923b 308 5970 492 1061 6213 153 66 409 064 18106 plusmn 658 22017 plusmn 797c 255 4607 1097 1219 5013 174 93 549 073 15364 plusmn 507 17867 plusmn 588d 292 4471 1240 800 4859 144 85 490 070 20429 plusmn 740 24222 plusmn 876e 336 7983 469 1020 8217 149 79 468 068 20259 plusmn 667 24287 plusmn 797

Ec5a (1449) a 050 104 466 9200 214 182 95 565 074 23188 plusmn 318 32375 plusmn 450b 090 2611 426 3534 2715 243 101 627 076 9474 plusmn 091 12409 plusmn 119e 162 1795 730 2614 1971 173 110 626 076 10261 plusmn 095 13642 plusmn 126f 146 11 320 1271 100 11 619 376 117 759 080 017 plusmn 000 021 plusmn 000h 449 4118 870 4600 4327 360 132 831 082 15023 plusmn 125 18302 plusmn 151

Ec7 (1040) a 109 2672 386 6405 2771 184 100 590 075 11216 plusmn 405 12908 plusmn 465b 024 1782 298 5461 1859 132 78 453 067 8679 plusmn 518 10448 plusmn 623c 146 3077 455 6982 3192 138 89 506 071 14250 plusmn 503 16979 plusmn 598d 033 2101 287 4632 2174 127 83 468 068 9757 plusmn 561 11679 plusmn 671e 028 1806 410 4611 1908 149 77 459 068 8114 plusmn 460 9857 plusmn 558

Ec8 (2013) b ndash 029 029 055 035 241 118 711 079 ndash plusmn ndash ndash plusmn ndashd 466 2238 465 5300 2354 228 135 781 081 23537 plusmn 188 29222 plusmn 232f 322 2879 1047 101 3137 195 157 840 082 20600 plusmn 1700 25700 plusmn 2200g 047 950 354 4477 1039 193 136 754 080 14653 plusmn 198 18563 plusmn 250i 156 1359 690 5300 1527 138 120 627 076 21714 plusmn 213 29747 plusmn 291

Ec81T (1459) a 064 1312 446 4020 1422 197 151 2404 094 7482 plusmn 059 8043 plusmn 064b 033 1306 541 4672 1439 124 137 1949 092 9227 plusmn 111 10365 plusmn 125c 051 914 457 4662 1027 173 130 2078 093 12744 plusmn 115 13855 plusmn 125d 1101 9240 8265 10861 11196 180 165 2497 094 16458 plusmn 123 17767 plusmn 133e 070 748 462 3992 862 189 135 2193 093 15659 plusmn 125 16931 plusmn 135f 055 1089 277 3377 1158 174 124 2010 093 12459 plusmn 121 13556 plusmn 131h 050 1263 433 7807 1374 175 138 2182 093 7967 plusmn 077 8638 plusmn 084i 079 1198 422 5345 1303 239 145 2453 094 10527 plusmn 093 11256 plusmn 100j 027 918 553 5013 1055 169 119 1936 092 6261 plusmn 075 6844 plusmn 082k 031 1826 525 3338 1953 132 97 1561 090 11352 plusmn 143 12684 plusmn 160l 066 2360 537 7980 2496 178 118 1950 092 11237 plusmn 107 12242 plusmn 117m 021 1168 545 4951 1302 129 109 1687 091 6665 plusmn 103 7431 plusmn 115n 024 1402 428 5909 1510 113 115 1680 091 9191 plusmn 134 10394 plusmn 151o 035 910 619 5346 1062 103 139 1827 092 13176 plusmn 151 16078 plusmn 184p 292 3862 539 7018 3997 176 122 1992 092 19795 plusmn 156 21520 plusmn 169q 138 1450 359 5598 1541 175 201 2818 095 16688 plusmn 128 18136 plusmn 139r 102 8435 1368 7100 8765 134 99 1598 091 9051 plusmn 079 10085 plusmn 088s 025 605 313 1226 680 123 99 1556 090 7743 plusmn 105 8699 plusmn 118t 185 2448 347 6966 2538 127 76 1285 088 61017 plusmn 618 69008 plusmn 694u 174 1752 385 8480 1852 165 120 1943 092 27103 plusmn 201 29559 plusmn 219

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Ec12 (1291) a 351 5600 3066 812 6400 214 105 632 076 10163 plusmn 087 13365 plusmn 114b 171 1045 1977 586 1580 182 106 616 076 15537 plusmn 138 20908 plusmn 185d 583 519 193 309 565 231 80 511 071 083 plusmn 176 116 plusmn 246e 514 1797 5900 440 3227 203 113 663 078 13031 plusmn 103 17228 plusmn 137

Ec13 (2203) a 325 1710 325 511 1848 218 113 673 078 21066 plusmn 187 27067 plusmn 239b 524 1930 208 912 2089 224 126 738 080 27820 plusmn 251 34896 plusmn 313c 265 2985 156 989 3141 186 103 605 075 18763 plusmn 174 24891 plusmn 229d 156 5400 980 1433 5800 137 76 446 067 20217 plusmn 204 30151 plusmn 301e 296 2914 451 809 3118 181 86 521 072 22269 plusmn 196 30952 plusmn 271

EC14 (2795) a 088 2334 592 685 2556 177 64 407 064 20800 plusmn 1000 25500 plusmn 1200b 264 2137 131 543 2233 163 86 513 071 41800 plusmn 1900 49500 plusmn 2300c 256 2238 410 667 2415 191 108 631 076 23888 plusmn 887 27200 plusmn 1000d 375 2501 212 563 2619 194 114 660 077 27359 plusmn 998 30900 plusmn 1100e 180 2777 246 587 2905 161 76 460 068 25882 plusmn 968 30900 plusmn 1200

Ec16 (2503) b 4859 4748 160 553 4900 353 166 1008 085 51055 plusmn 399 59645 plusmn 472d 000 006 157 332 043 115 62 366 060 3541 plusmn 5008 6557 plusmn 9274g 221 1852 061 264 1898 189 76 475 069 29060 plusmn 283 41581 plusmn 400h 209 6700 220 615 6800 199 83 515 071 25794 plusmn 265 35814 plusmn 365b 193 4870 365 429 5008 158 102 578 074 15708 plusmn 123 21331 plusmn 166

EC17 (2345) a 140 1381 731 653 1631 169 103 593 075 19485 plusmn 837 22279 plusmn 957b 121 2069 085 749 2180 186 99 584 075 18265 plusmn 697 21108 plusmn 803c 097 1876 178 912 2028 167 67 417 065 27700 plusmn 1800 33600 plusmn 2100d 696 2548 167 746 2677 136 64 387 062 25619 plusmn 822 286 plusmn 009e 061 1265 140 618 1373 179 70 437 066 26200 plusmn 2100 31600 plusmn 2500

Ec18 (2224) c 000 098 415 877 195 119 100 528 072 062 plusmn 341 000 plusmn 000e 000 3104 3006 217 3811 180 140 756 080 052 plusmn 020 065 plusmn 025f 141 4900 2923 813 5700 151 74 446 067 19542 plusmn 199 29223 plusmn 296g ndash 180 157 681 216 197 83 514 071 039 plusmn 014 ndash plusmn ndashi 1465 2130 1473 415 2527 272 200 1097 086 24932 plusmn 209 29282 plusmn 244

Ec19 (2117) a 500 2439 1221 590 2797 198 126 1393 089 19673 plusmn 127 22191 plusmn 143b 906 4385 607 774 4621 216 126 1368 089 23245 plusmn 164 26169 plusmn 184c 983 2325 1165 720 2685 289 169 983 085 21461 plusmn 600 25921 plusmn 723d 160 1941 785 667 2207 216 80 508 071 20447 plusmn 906 23100 plusmn 1000e 821 4656 980 968 5003 230 128 751 080 21032 plusmn 592 23728 plusmn 667

Ec20 (2127) 16 648 4800 3092 1810 5500 211 121 707 079 27718 plusmn 242 35349 plusmn 30727 104 3923 1092 269 4179 137 89 504 071 5271 plusmn 054 7588 plusmn 07832 1798 6700 458 435 175 201 107 633 077 32662 plusmn 291 44030 plusmn 38843 355 2972 321 321 3047 237 112 678 078 24990 plusmn 243 31923 plusmn 30845 252 4117 431 163 4218 182 109 629 076 15692 plusmn 152 20665 plusmn 200

Ec21 (1897) a 1024 2560 016 405 2613 327 137 850 082 14141 plusmn 108 17135 plusmn 131b 2387 2282 197 460 2384 510 179 1141 087 22691 plusmn 172 26083 plusmn 197c 000 1937 864 89 2141 266 129 780 081 030 plusmn 570 040 plusmn 710f 690 2564 216 426 2666 380 222 1287 088 17931 plusmn 137 20367 plusmn 156g 356 4638 677 478 4855 380 222 1287 088 21111 plusmn 170 23977 plusmn 193

(continued)

Uplift

onBaffin

Island

by guest on October 6 2020

httpjgslyellcollectionorgD

ownloaded from

counterpart AFT central ages appropriately replicated whereas agessimilar to or older than AFT central ages are predicted poorlyFragment grain ages within sample Ec8 display a similar trend withyounger ages predicted well alongside AFT and whole grain AHeages although five fragments older than the AFT central age arepoorly replicated (Fig 5)

Discussion

Evolution of the Cumberland Peninsula

The AFT and AHe results and thermal histories from this worksuggest that the modern topography of the Cumberland Peninsulahas been predominantly shaped by surface uplift during rifting in theCretaceous and subsequent differential denudation Additionallyinsight into the pre-rift history of the region is provided by acollection of thermal histories that imply exhumation of centralLaurentia during the late Paleozoicndashearly Mesozoic These resultssupport the conclusions of the original AFT study (McGregor et al2013) although improved resolution of the synrift and post-rifthistory has been gained through the addition of AHe data

Uplift and preservation of the Cumberland Peninsularsquostopography

The principal source of surface uplift across the CumberlandPeninsula is probably flank uplift during active rifting in theCretaceous (Fig 6a) Rift-flank uplift of strong cold lithosphere is along-known and well-understood phenomenon (Buck 1986 Braunamp Beaumont 1989 Weissel amp Karner 1989) and can account forkilometres of rock uplift during the active rifting phase Spatialtrends in the AFT and AHe data exhibit younger ages toward the SEcoastline and outline inclined isochrons oriented NWndashSE implyingthat considerable rock uplift of the SE coastline has occurred(Fig 3) This is corroborated by the onset of cooling in theCretaceous evident in many of the thermal histories from coastaland low-elevation samples (Fig 5) probably the thermal responseto exhumation during and following uplift Exhumation of theregion at the time is evident with an erosional contact betweensynrift fluvial sediments and the underlying basement observableacross Durban Padloping and Quqalluit islands (Fig 1) (Burden ampLangille 1990) Moreover this proposed rift-flank uplift of the SEmargin accounts for the higher modern topography observed towardthe SE of the study area indicative of a major erosional escarpment(Fig 6a) (Mayer 1986 Tucker amp Slingerland 1994) that wouldhave redirected drainage systems in the study area NE into BaffinBay during rifting

After the end of rifting in the Early Paleocene differential erosionof the rift flank probably continued throughout the post-rift stageMany of the thermal histories from across the margin outlinecontinuous cooling throughout the Cenozoic with cooling ratesthemselves varying between high and low elevations implying thatdifferential denudation was evident across the landscape (Fig 5)This last point is implied by the modern fjordal distribution whichmimics the characteristics of dendritic drainage patterns (Fig 6b)suggesting that later glaciers may have overprinted rift-relatedfluvial systems through topographically constrained glacial flowTwo dendritic glacial drainage systems are observable within themodern landscape (Fig 6b) extracted through the application offlow accumulation analysis an analytical approach that determinesoverland fluid flow pathways based on digital elevation models(Jenson amp Domingue 1988) These systems flow SWndashNE intoBaffin Bay at Padloping Island and Qikiqtarjuaq overlapping thelocation of the aforementioned Cretaceous river sediments (Fig 6b)and suggesting that they may outline the redirected fluvial systemsthat formed during surface uplift in the Cretaceous GlacialT

able1

(Contin

ued)

Sam

ple(m

ean)

He(V

ol(10minus

9cm

3))

U(ppm

)Th(ppm

)Sm

(ppm

)eU

dagger(ppm

)Length(microm)

Width

(microm)

rrsquoDagger(microm)

Ftsect

Measuredage(M

a)Corrected

agepara

(Ma)

Ec22(1954)

a812

2411

131

122

2457

305

166

978

085

21438

plusmn147

25349

plusmn173

e236

2218

100

135

2257

238

113

683

078

13004

plusmn118

16622

plusmn150

f469

2840

221

143

2909

263

168

955

084

16332

plusmn128

19495

plusmn152

g278

3751

1444

156

4109

180

79487

070

29736

plusmn227

42386

plusmn321

h405

4055

1573

856

4435

183

146

783

081

17205

plusmn119

21791

plusmn150

Ec23(1944)

a300

4294

250

277

4386

155

106

591

075

21693

plusmn176

29290

plusmn236

b1163

4420

124

352

4491

273

178

1005

085

26191

plusmn186

30935

plusmn219

c251

5399

257

480

5517

182

111

639

077

15646

plusmn125

20514

plusmn163

d000

094

109

041

119

145

99553

073

ndashplusmnndash

ndashplusmnndash

e237

3834

372

240

3950

188

101

596

075

14244

plusmn111

18998

plusmn148

Meanisthearith

metic

meanageforeach

samplecalculated

from

ages

givenin

thetworightm

ostcolumnsexcept

thatthosewith

representgrainages

thathave

been

excluded

forbeingeither

lt1Maor

gt1Ga

daggereU

=[U

]+0235[Th]

Daggerrrsquoisthesphericalequivalent

radius

sectFtisthecalculated

correctio

nfactor

from

Farley

etal(1996)

paraCorrected

ageiscalculated

from

MeasuredAgeFt

S Jess et al

by guest on October 6 2020httpjgslyellcollectionorgDownloaded from

overprinting of these river valleys is likely to have occurred duringthe Neogene and Quaternary inheriting the dendritic drainagepattern through the process of selective linear erosion that over-deepened the pre-glacial network analogous to similar examplesfrom Greenland (Bamber et al 2013 Cooper et al 2016)

This interpretation of the post-rift evolution of the CumberlandPeninsula does fail to account for the final period of coolingobserved in a number of thermal histories This cooling (c 30ndash0 Ma) occurs outside the temperature sensitivity ranges of both theAFT and AHe systems implying that it may be an artefact ofthe modelling process owing to a drop in surface temperatures in theLate Cenozoic (c 10ndash20degC) Climatic cooling at high latitudes isthought to have occurred at the EocenendashOligocene boundary(c 33 Ma) (Eldrett et al 2009 Bernard et al 2016) and the onset ofglaciation across NE Canada is believed to have occurred in theMiocene (Ehlers amp Gibbard 2007) A significant drop in surfacetemperature following a samplersquos exit from the PAZ and HePRZwould result in a significant cooling event being present inthermal models owing to the enforced present-day thermalconstraint of 0degC

In addition to defining the regionrsquos uplift history results fromthermal modelling also provide insight into the exhumation of theCumberland Peninsula prior to rifting supporting the conclusions

of McGregor et al (2013) A record of the geology during this timeis absent in the study area although cooling during the latePaleozoicndashearly Mesozoic in a collection of thermal models (Fig 5)reiterates the conclusions of numerous studies that infer widespreadexhumation of Laurentia during the same period (Pysklywec ampMitrovica 2000 Flowers et al 2012 Ault et al 2013 McGregoret al 2013) Stratigraphic evidence of exhumation from this time islimited in the immediate surroundings although much larger basinsacross the cratonrsquos periphery such as the Sverdrup Basin do showevidence of terrestrial systems originating from across Laurentia(Patchett et al 2004 Midwinter et al 2016) This could suggest thatlarge-scale fluvial systems flowed across Laurentia toward theSverdrup Basin during the late Paleozoic and early Mesozoic(Fig 6c) providing a viable mechanism for cooling across theCumberland Peninsula prior to later rifting

Preservation of the Cumberland Peninsularsquos topography

The results presented above suggest that the origin of hightopography across SE Baffin Island occurred during rifting in theCretaceous followed by continuous fluvial and glacial erosion in theCenozoic This interpretation provides an explanation for much ofthe thermochronology geomorphology and stratigraphy although it

Fig 5 Thermal histories from across the Cumberland Peninsula Expected thermal histories are shown as black lines and the grey shaded area representsthe 95 confidence interval on either side of the expected history Data predictions are shown as graphs of observed age against predicted age ( AFT AHe) and the fit of predicted track distribution against a histogram of track lengths Moreover the timing of active rifting in the region (150ndash64 Ma) isindicated by grey boxes in each thermal history Ec7 thermal history shows two periods of cooling pre-rift between 230 and 160 Ma (12degC Maminus1) andsynrift to present between 95 and 0 Ma (06degC Maminus1) Ec10 thermal history outlines a protracted cooling history from 400 to 0 Ma (025degC Maminus1) Ec20thermal history displays protracted cooling from 400 to 0 Ma (015degC Maminus1) Ec2 thermal history exhibits cooling from synrift to present between 66 and0 Ma (08degC Maminus1) Ec8 thermal history shows two significant cooling periods pre-rift between 250 and 190 Ma (13degC Maminus1) and synrift to presentbetween 95 and 0 Ma (07degC Maminus1) Ec22 thermal history shows two periods of cooling pre-rift between 400 and 160 Ma (03degC Maminus1) and synrift topresent cooling from 90 to 0 Ma (05degC Maminus1) Ec12 thermal history exhibits protracted cooling to 20 Ma (02 Ma) followed by a post-rift cooling episodeto present (1degC Maminus1) Ec16 thermal history shows two periods of cooling pre-rift between 360 and 240 Ma (04degC Maminus1) and post-rift from 35 to 0 Ma(07degC Maminus1)

Uplift on Baffin Island

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does not explain how the modern topography itself remains elevatedat present (le2 km)

A mechanism that can explain elevated topography in regions ofcontinuous exhumation is isostatic feedback from the lithospherefollowing differential denudation (Stephenson amp Lambeck 1985Gilchrist amp Summerfield 1990 Tucker amp Slingerland 1994 Roubyet al 2013) Surface uplift across Greenland and Norway inresponse to erosional unloading of the lithosphere during glaciationhas been shown to reach c 1000 m (Medvedev et al 2008 2013Medvedev amp Hartz 2015) implying that a similar effect may haveoccurred across the Cumberland Peninsula The extent of glacialerosion across the margin is evident in the modern geomorphologysuggesting that significant volumes of rock have been removed inturn driving a considerable isostatic response To test the degree towhich erosion has driven surface uplift in the region a simple 2Dflexural model of the isostatic responsewas considered in which themodern fjords are refilled with eroded material (Fig 7) (see alsosupplementary material) analogous to the work of Medvedev et al(2013) Results show an increase in maximum elevation of 91 m anda drop in average elevation of 209 m outlining how differentialdenudation of the lithosphere will produce rock column uplift andeffectively preserve the highest topography (Fig 7) This model

provides a simple demonstration of the first-order role isostasy playswithin the exhumation of passive margins and how it preserves theelevated rift-flank topography of the Cumberland Peninsula

Implications for Atlantic continental margins

The origin and age of topography across continental passivemargins has been a widely debated topic within the geologicalcommunity for over a century (eg Geikie 1901 Reusch 1901Steers 1948 Holtedahl 1958 Moumlrner 1979 Japsen amp Chalmers2000 Anell et al 2009 Nielsen et al 2009 Green et al 2013 2018Japsen et al 2018) Both post-rift tectonism and isostaticcompensation driven by differential erosion are cited as possiblesources of elevated topography across Greenland Norway Braziland South Africa (Brown et al 2000 Hendriks amp Andriessen 2002Japsen et al 2006 2012 2014 Nielsen et al 2009) Thecontentious interpretation of inferred peneplains as direct indicatorsof surface uplift and the lack of an obvious cause of uplift followingthe end of rifting make it difficult to support the former theory ofpassive margin topographic generation Instead the conclusions ofthis work support the latter of the two theories as the rift-relatedtopography of the Cumberland Peninsula is interpreted to have has

Fig 6 Interpretation of the three cooling periods observed in thermal histories (a) Conceptual model illustrating the rift-flank uplift and erosion of theCumberland Peninsula (line of section is shown in Fig 1) Rift-flank uplift of the SE margin instigates an erosional scarp retreat and behind the escarpmentfluvial systems and later glaciers erode valleys and fjords into the landscape producing the modern geomorphology (b) Flow accumulation analysis of themodern topography and bathymetry outlines two separate erosional systems one converging at Qukiavuk Island and another at Padloping Island Thiswould suggest that the glacial systems have overprinted the Mesozoic fluvial systems and that the modern topography is simply a reflection of the ancientlandscape Offshore Cretaceous sands are found at the seafloor c 15 km NE of these onshore outcrops further supporting the concept of major Cretaceousfluvial systems (MacLean et al 2014) (c) Paleogeography of Laurentia suggests uplift of the Hudson Bay Basin in the Devonian and elevated Caledonidesto the SE may have directed fluvial systems north over the Canadian Shield across the Cumberland Peninsula (red) with deposition into the SverdrupBasin resulting in cooling from the Carboniferous to Triassic Palaeomap taken from Blakey (2007)

S Jess et al

by guest on October 6 2020httpjgslyellcollectionorgDownloaded from

been preserved by differential exhumation of the rift flank andisostatic compensation Moreover the trend in AFT central agessuggesting the flexure of the lithosphere is comparable with thoseobserved across southern Norway (Redfield et al 2005) WestGreenland (Redfield 2010) and Brazil (Gallagher et al 1995)highlighting the probable first-order control rifting has on passivemargin topography The similarity in these results would suggest thattopography along many Atlantic passive margins may be explainedthrough the interaction of rift tectonics differential exhumation andisostatic compensation rather than post-rift tectonism

Previous thermochronological studies from passive margins inthe Baffin Bay region display similar trends in cooling providingregional consistency to this studyrsquos interpretation Across thecontinental margins of Baffin Bay and the Labrador Sea AFT andAHe ages appear similar to those reported here (Hendriks et al1993 Japsen et al 2006 Jess et al 2019 McDannell et al 2019)and the interpretation of rift-related uplift and differential erosionshaping the landscape is comparable (Hendriks et al 1993 Jesset al 2019) AFT data from both Newfoundland and WestGreenland are interpreted to suggest that the modern topographyis the result of rift-related uplift (Hendriks et al 1993 Jess et al2019) whereas low rates of exhumation during the Cenozoic areinferred from thermal modelling of both AFT and AHe data (Jesset al 2018) Collectively this suggests that much of the topographyobserved across the wider region is probably the result of preservedrift-related uplift such that both margins have evolved according toa single unifying conceptual model that does not require theintervention of post-rift uplift

Dispersion in AHe ages

The application of the lsquobroken crystalrsquo technique within Ec8improves modelling results through the inclusion of additionalthermal information although robust joint inverse thermal historymodelling of other samples is made difficult by high levels of wholegrain age dispersion (Fig 5 Ec12 and Ec16) The radiation damagemodel and diffusion parameters applied to thermal histories(Gautheron et al 2009) improves AHe age predictions relative tostandard apatite diffusion parameters (Farley 2000) although it doesnot produce suitable predictions for a collection of the AHe agesThis implies other underlying factors which are not accounted forin the modelling method (eg mineral inclusions zonationimplantation) and the developing understanding of the AHesystem may hinder effective prediction of highly dispersed AHeages in the passive margin settings Moreover data used to validateand justify radiation damage models commonly differ from those

found along passive margin settings (1) sedimentary samples arecommonly used (2) AFT ages rarely exceed 200 Ma (3) there is alack of well-documented stratigraphy commonly in place to improvemodelling constraints (Flowers et al 2009 Gautheron et al 20092012) Accordingly the geological setting of the CumberlandPeninsula and lengthy periods spent within the HePRZ (gt100 myr)hinder the application of current radiation damage models implyingthat further work on the topic in passive margin settings is essential

Summary and conclusions

Low-temperature thermochronology and thermal history modellinghelp to outline how the landscape of the Cumberland PeninsulaBaffin Island has evolved through the Mesozoic and CenozoicResults from this work imply that the modern topography of themargin is derived from rift-flank uplift in the Mesozoic and isostaticflexure in response to erosion thereafter

Rift-flank uplift of the margin is implied by the spatialdistribution of AFT and AHe ages the onset of acceleratedcooling in the Cretaceous and the modern geomorphology It issuggested that during rifting uplift of the SE coastline of BaffinIsland formed a considerable elevated landscape and escarpmentthat forced erosive fluvial systems NE into Baffin Bay These fluvialdrainage patterns may still be observable in the modern geomorph-ology as selective linear erosion during glaciation probably over-deepened many of the pre-glacial valleys to form the modern fjordsTwo outcomes of this differential erosion include the preservationof elevated topography and the removal of vast quantities of rockfrom the upper crust prompting a positive isostatic response acrossthe peninsula In addition to constraining the timing uplift insightinto the pre-rift history of the region is provided with widespreadcooling in the late Paleozoic and early Mesozoic linked toexhumation of Laurentia in accordance with similar interpretationsfrom across the Cumberland Peninsula and northern Canada Theseresults and interpretations provide a suitable account of theCumberland Peninsula regionrsquos uplift history and determine thatits modern elevated topography is a remnant rift flank augmentedby differential erosion and isostasy

Acknowledgements E McGregor is sincerely thanked for the collectionof samples and A Carter and J Schwanethal are also thanked for their assistancein sample preparation and analysis Thanks are also given to Y Gunnell J Spotilaand L Currie for their constructive comments and reviews

Funding The work reported here was conducted during a PhD studyundertaken as part of the Natural Environment Research Council (NERC) Centre

Fig 7 Results of 2D flexural model with Flex2D (Allmendinger et al 2011) with initial model assumptions as given in the text Filling of the fjordsdeemed as a simple estimation of the erosion pushes down the lithosphere and gives the pre-erosion topography (grey) which appears 907 m lower thanthe modern-day topography These results suggest that differential unloading of the lithosphere does promote growth of the topography and that thetopography of Cumberland Peninsula today is maintained by this isostatic response

Uplift on Baffin Island

by guest on October 6 2020httpjgslyellcollectionorgDownloaded from

for Doctoral Training (CDT) in Oil amp Gas (grant number NEM00578X1) andwas sponsored by the University of Aberdeen

ReferencesAllmendinger RW Cardozo N amp Fisher DM 2011 Structural Geology

Algorithms Vectors and Tensors Cambridge University Press CambridgeAnell I Thybo H amp Artemieva IM 2009 Cenozoic uplift and subsidence in

the North Atlantic region Geological evidence revisited Tectonophysics 47478ndash105 httpsdoiorg101016jtecto200904006

Ault AK Flowers RM amp Bowring SA 2013 Phanerozoic surface history ofthe Slave craton Tectonics 32 1066ndash1083 httpsdoiorg101002tect20069

Balkwill H R 1987 Labrador basin structural and stratigraphic style InSedimentary Basins and Basin-Forming Mechanisms Canadian Society ofPetroleum Geology Memoir 12 17ndash43

Bamber JL Siegert MJ Griggs JA Marshall SJ amp Spada G 2013Paleofluvial mega-canyon beneath the central Greenland ice sheet Science341 997ndash999 httpsdoiorg101126science1239794

Bernard T Steer P Gallagher K Szulc A Whitham A amp Johnson C 2016Evidence for EocenendashOligocene glaciation in the landscape of the EastGreenland margin Geology 44 895ndash898 httpsdoiorg101130G382481

Beucher R Brown RW Roper S Stuart F amp Persano C 2013 Natural agedispersion arising from the analysis of broken crystals Part II Practicalapplication to apatite (UndashTh)He thermochronometry Geochimica etCosmochimica Acta 120 395ndash416 httpsdoiorg101016jgca201305042

Blakey RC 2007 Carboniferous-Permian paleogeography of the assembly ofPangaea In Wong TE (ed) Proceedings of the XVth InternationalCongress on Carboniferous and Permian Stratigraphy Utrecht 10ndash16August 2003 Amsterdam Royal Dutch Academy of Arts and Sciences356ndash443

Braun J amp Beaumont C 1989 A physical explanation of the relation betweenflank uplifts and the breakup unconformity at rifted continental marginsGeology 17 760ndash764 httpsdoiorg1011300091-7613(1989)017lt0760APEOTRgt23CO2

Brown RW Gallagher K Gleadow AJ amp Summerfield MA 2000Morphotectonic evolution of the South Atlantic margins of Africa and SouthAmerica In Summerfield MA (ed)Geomorphology and Global TectonicsWiley Chichester 255ndash284

Brown RW Beucher R Roper S Persano C Stuart F amp Fitzgerald P2013 Natural age dispersion arising from the analysis of broken crystalsPart I Theoretical basis and implications for the apatite (UndashTh)Hethermochronometer Geochimica et Cosmochimica Acta 122 478ndash497httpsdoiorg101016jgca201305041

Buck W R 1986 Small-scale convection induced by passive rifting the causefor uplift of rift shoulders Earth and Planetary Science Letters 77 362ndash372httpsdoiorg1010160012-821X(86)90146-9

Burden ET amp Langille AB 1990 Stratigraphy and sedimentology ofCretaceous and Paleocene strata in half-grabens on the southeast coast ofBaffin Island Northwest Territories Bulletin of Canadian PetroleumGeology 38 185ndash196

Burke K amp Gunnell Y 2008 The African erosion surface a continental-scalesynthesis of geomorphology tectonics and environmental change over thepast 180 million years In Burke K amp Gunnell Y (eds) Continental-ScaleSynthesis of Geomorphology Tectonics and Environmental Change over thePast 180 Million Years Geological Society of America Memoirs 201 1ndash66httpsdoiorg10113020081201

Chalmers JA 2000 Offshore evidence for Neogene uplift in central WestGreenland Global and Planetary Change 24 311ndash318 httpsdoiorg101016S0921-8181(00)00015-1

Chalmers JA 2012 Labrador Sea Davis Strait and Baffin Bay In RobertsDG amp Bally AW (eds) Regional Geology and Tectonics PhanerozoicPassive Margins Cratonic Basins and Global Tectonic Maps ElsevierBoston 384ndash435

Clarke DB amp Upton BGJ 1971 Tertiary basalts of Baffin Island fieldrelations and tectonic setting Canadian Journal of Earth Sciences 8248ndash258 httpsdoiorg101139e71-025

Cobbold PR Chiossi D Green PF Jaspen P amp Bonow J 2010Compressional reactivation of the Atlantic Margin of Brazil Structuralstyles and consequences for hydrocarbon exploration AAPG InternationalConference and Exibition American Association of Petroleum GeologistsRio de Janeiro Brazil 30114

Cockburn HAP Brown RW Summerfield MA amp Seidl MA 2000Quantifying passive margin denudation and landscape development using acombined fission-track thermochronology and cosmogenic isotope analysisapproach Earth and Planetary Science Letters 179 429ndash435 httpsdoiorg101016S0012-821X(00)00144-8

Cogneacute N Gallagher K Cobbold PR Riccomini C amp Gautheron C 2012Post-breakup tectonics in southeast Brazil from thermochronological data andcombined inversendashforward thermal history modeling Journal of GeophysicalResearch Solid Earth 117 httpsdoiorg1010292012JB009340

Cooke H C 1931 Studies of the physiography of the Canadian Shield III Thepre-Pliocene physiographies as inferred from the geologic recordTransactions of the Royal Society of Canada 25 sec IV 127ndash180

Cooper MA Michaelides K Siegert MJ amp Bamber JL 2016 Paleofluviallandscape inheritance for Jakobshavn Isbraelig catchment GreenlandGeophysical Research Letters 43 6350ndash6357 httpsdoiorg1010022016GL069458

Dempster TJ Campanile D amp Holness MB 2006 Imprinted textures onapatite A guide to paleoporosity and metamorphic recrystallization Geology34 897ndash900 httpsdoiorg101130G22299A1

Donelick RA Ketcham RA amp Carlson WD 1999 Variability of apatitefission-track annealing kinetics II Crystallographic orientation effectsAmerican Mineralogist 84 1224ndash1234 httpsdoiorg102138am-1999-0902

Egholm D L Jansen J D et al 2017 Formation of plateau landscapes onglaciated continental margins Nature Geoscience 10 592ndash597 httpsdoiorg101038ngeo2980

Ehlers J amp Gibbard PL 2007 The extent and chronology of Cenozoic globalglaciation Quaternary International 164 6ndash20 httpsdoiorg101016jquaint200610008

Eldrett JS Greenwood DR Harding IC amp Huber M 2009 Increasedseasonality through the Eocene to Oligocene transition in northern highlatitudes Nature 459 969 httpsdoiorg101038nature08069

Evans DJ 1997 Estimates of the eroded overburden and the PermianndashQuaternary subsidence history of the area west of Orkney Scottish Journal ofGeology 33 169ndash181 httpsdoiorg101144sjg33020169

Farley KA 2000 Helium diffusion from apatite General behavior as illustratedby Durango fluorapatite Journal of Geophysical Research Solid Earth 1052903ndash2914 httpsdoiorg1010291999JB900348

Farley KA Wolf RA amp Silver LT 1996 The effects of long alpha-stoppingdistances on (UndashTh)He ages Geochimica et Cosmochimica Acta 604223ndash4229 httpsdoiorg101016S0016-7037(96)00193-7

Flowers RM Ketcham RA Shuster DL amp Farley KA 2009 Apatite(UndashTh)He thermochronometry using a radiation damage accumulation andannealing model Geochimica et Cosmochimica Acta 73 2347ndash2365 httpsdoiorg101016jgca200901015

Flowers RM Ault AK Kelley SA Zhang N amp Zhong S 2012Epeirogeny or eustasy PaleozoicndashMesozoic vertical motion of the NorthAmerican continental interior from thermochronometry and implications formantle dynamics Earth and Planetary Science Letters 317 436ndash445 httpsdoiorg101016jepsl201111015

Funck T Jackson HR Louden KE ampKlingelhoumlfer F 2007 Seismic study ofthe transform-rifted margin in Davis Strait between Baffin Island (Canada) andGreenland What happens when a plume meets a transform Journal ofGeophysical Research Solid Earth 112 httpsdoiorg1010292006JB004308

Gallagher K 2012 Transdimensional inverse thermal history modeling forquantitative thermochronology Journal of Geophysical Research SolidEarth 117 httpsdoiorg1010292011JB008825

Gallagher K Hawkesworth CJ amp Mantovani MSM 1994 The denudationhistory of the onshore continental margin of SE Brazil inferred from apatitefission track data Journal of Geophysical Research Solid Earth 9918117ndash18145 httpsdoiorg10102994JB00661

Gallagher K Hawkesworth CJ amp Mantovani MSM 1995 Denudationfission track analysis and the long-term evolution of passive margintopography application to the southeast Brazilian margin Journal of SouthAmerican Earth Sciences 8 65ndash77 httpsdoiorg1010160895-9811(94)00042-Z

Gallagher K Brown R amp Johnson C 1998 Fission track analysis and itsapplications to geological problems Annual Review of Earth and PlanetarySciences 26 519ndash572 httpsdoiorg101146annurevearth261519

Gautheron C Tassan-Got L Barbarand J amp Pagel M 2009 Effect of alpha-damage annealing on apatite (UndashTh)He thermochronology ChemicalGeology 266 157ndash170 httpsdoiorg101016jchemgeo200906001

Gautheron C Tassan-Got L Ketcham RA amp Dobson KJ 2012 Accountingfor long alpha-particle stopping distances in (UndashThndashSm)He geochronology3D modeling of diffusion zoning implantation and abrasion Geochimica etCosmochimica Acta 96 44ndash56 httpsdoiorg101016jgca201208016

Geikie A 1901 The Scenery of Scotland Viewed in Connection with its PhysicalGeology Macmillan London

Gilchrist A amp Summerfield M 1990 Differential denudation and flexuralisostasy in formation of rifted-margin upwarps Nature 346 739ndash742 httpsdoiorg101038346739a0

Gleadow A J 1981 Fission-track dating methods what are the real alternativesNuclear Tracks 5 3ndash14

Green PF Lidmar-Bergstroumlm K Japsen P Bonow JM amp Chalmers JA2013 Stratigraphic landscape analysis thermochronology and the episodicdevelopment of elevated passive continental margins Geological Survey ofDenmark and Greenland Bulletin 30

Green PF Japsen P Chalmers JA Bonow JM amp Duddy IR 2018Post-breakup burial and exhumation of passive continental margins Sevenpropositions to inform geodynamic models Gondwana Research 53 58ndash81httpsdoiorg101016jgr201703007

Guillaume B Gautheron C Simon-Labric T Martinod J Roddaz M ampDouville E 2013 Dynamic topography control on Patagonian relief evolutionas inferred from low temperature thermochronology Earth and PlanetaryScience Letters 364 157ndash167 httpsdoiorg101016jepsl201212036

Hendriks BW amp Andriessen PA 2002 Pattern and timing of the post-Caledonian denudation of northern Scandinavia constrained by apatite fission-

S Jess et al

by guest on October 6 2020httpjgslyellcollectionorgDownloaded from

track thermochronology In Doreacute AG Cartwright AJ Stoker MSTurner JP amp White N (eds) Exhumation of the North Atlantic MarginTiming Mechanisms and Implications for Petroleum Exploration GeologicalSociety London Special Publications 196 117ndash137 httpsdoiorg101144GSLSP20021960108

Hendriks M Jamieson RA Willett SD amp Zentilli M 1993 Burial andexhumation of the Long Range Inlier and its surroundings westernNewfoundland results of an apatite fission-track study Canadian Journalof Earth Sciences 30 594ndash1606 httpsdoiorg101139e93-137

Holtedahl H 1958 Some remarks on geomorphology of continental shelves offNorway Labrador and southeast Alaska Journal of Geology 66 461ndash471httpsdoiorg101086626528

Japsen P 1998 Regional velocityndashdepth anomalies North Sea Chalk a record ofoverpressure and Neogene uplift and erosion AAPG Bulletin 82 2031ndash2074

Japsen P amp Chalmers JA 2000 Neogene uplift and tectonics around the NorthAtlantic overview Global and Planetary Change 24 165ndash173 httpsdoiorg101016S0921-8181(00)00006-0

Japsen P Bonow JM Green PF Chalmers JA amp Lidmar-Bergstroumlm K2006 Elevated passive continental margins Long-term highs or Neogeneuplifts New evidence from West Greenland Earth and Planetary ScienceLetters 248 330ndash339 httpsdoiorg101016jepsl200605036

Japsen P Bonow JM et al 2012 Episodic burial and exhumation in NE Brazilafter opening of the South Atlantic Geological Society of America Bulletin124 800ndash816 httpsdoiorg101130B305151

Japsen P Green PF Bonow JM Nielsen TF amp Chalmers JA 2014 Fromvolcanic plains to glaciated peaks Burial uplift and exhumation history ofsouthern East Greenland after opening of the NE Atlantic Global andPlanetary Change 116 91ndash114 httpsdoiorg101016jgloplacha201401012

Japsen P Green PF Chalmers JA amp Bonow JM 2018 Mountains ofsouthernmost Norway uplifted Miocene peneplains and re-exposed Mesozoicsurfaces Journal of the Geological Society London 175 721ndash741 httpsdoiorg101144jgs2017-157

Jenson SK amp Domingue JO 1988 Extracting topographic structure fromdigital elevation data for geographic information system analysisPhotogrammetric Engineering and Remote Sensing 54 1593ndash1600

Jess S Stephenson R amp Brown R 2018 Evolution of the central WestGreenland margin and the Nuussuaq Basin Localised basin uplift along astable continental margin proposed from thermochronological data BasinResearch 30 1230ndash1246 httpsdoiorg101111bre12301

Jess S Stephenson R Roberts DH amp Brown R 2019 Differential erosion ofa Mesozoic rift flank Establishing the source of topography across Karratcentral West Greenland Geomorphology 334 httpsdoiorg101016jgeomorph201902026

Kasanzu CH 2017 Apatite fission track and (UndashTh)He thermochronologyfrom the Archean Tanzania Craton Contributions to cooling histories ofTanzanian basement rocks Geoscience Frontiers 8 999ndash1007 httpsdoiorg101016jgsf201609007

Kounov A Viola G De Wit M amp Andreoli MAG 2009 Denudation alongthe Atlantic passive margin new insights from apatite fission-track analysis onthe western coast of South Africa In Lisker F Ventura B amp GlasmacherUA (eds) Thermochronological Methods From PalaeotemperatureConstraints to Landscape Evolution Models Geological Society LondonSpecial Publications 324 287ndash306 httpsdoiorg101144SP32419

Ksienzyk AK Dunkl I Jacobs J Fossen H amp Kohlmann F 2014 Fromorogen to passive margin constraints from fission track and (UndashTh)Heanalyses on Mesozoic uplift and fault reactivation in SW Norway In CorfuF Gasser D amp Chew DM (eds) New Perspectives on the Caledonides ofScandinavia and Related Areas Geological Society London SpecialPublications 390 679ndash702 httpsdoiorg101144SP39027

Larsen LM Heaman LM Creaser RA Duncan RA Frei R ampHutchisonM 2009 Tectonomagmatic events during stretching and basin formation inthe Labrador Sea and the Davis Strait evidence from age and composition ofMesozoic to Palaeogene dyke swarms in West Greenland Journal of theGeological Society London 166 999ndash1012 httpsdoiorg1011440016-76492009-038

Leprecirctre R Missenard Y Barbarand J Gautheron C Saddiqi O amp Pinna-Jamme R 2015 Postrift history of the eastern central Atlantic passivemarginInsights from the Saharan region of South Morocco Journal of GeophysicalResearch Solid Earth 120 4645ndash4666 httpsdoiorg1010022014JB011549

Lewry JF amp Collerson KD 1990 The Trans-Hudson Orogen extentsubdivision and problems In Lewry JF amp Stauffer MR (eds) The EarlyProterozoic Trans-Hudson Orogen of North America Geological Associationof Canada Special Paper f 1ndash14

MacLean B Williams G Zhang S amp Haggart JW 2014 New insights intothe stratigraphy and petroleum potential of the Baffin Shelfrsquos Cretaceousrocks Bulletin of Canadian Petroleum Geology 62 289ndash310 httpsdoiorg102113gscpgbull624289

Mayer L 1986 Tectonic geomorphology of escarpments and mountain frontsIn Geophysics Study Commitee (eds) Active Tectonics National AcademyPress Washington DC 125ndash135

McDannell KT Schneider DA Zeitler PK OrsquoSullivan PB amp Issler DR2019 Reconstructing deep-time histories from integrated thermochronologyAn example from southern Baffin Island Canada Terra Nova 31 189ndash204httpsdoiorg101111ter12386

McGregor ED Nielsen SB Stephenson RA Petersen KD ampMacDonaldDIM 2013 Long-term exhumation of a Palaeoproterozoic orogen and therole of pre-existing heterogeneous thermal crustal properties a fission-trackstudy of SE Baffin Island Journal of the Geological Society London 170877ndash891 httpsdoiorg101144jgs2012-146

Medvedev S amp Hartz EH 2015 Evolution of topography of post-DevonianScandinavia Effects and rates of erosion Geomorphology 231 229ndash245httpsdoiorg101016jgeomorph201412010

Medvedev S Hartz EH amp Podladchikov YY 2008 Vertical motions of thefjord regions of central East Greenland impact of glacial erosion depositionand isostasy Geology 36 539ndash542 httpsdoiorg101130G24638A1

Medvedev S Souche A amp Hartz EH 2013 Influence of ice sheet and glacialerosion on passive margins of Greenland Geomorphology 193 36ndash46httpsdoiorg101016jgeomorph201303029

Mercer JH 1956 Geomorphology and Glacial History of SouthernMost BaffinIsland Geological Society of America Bulletin 67 553ndash570 httpsdoiorg1011300016-7606(1956)67[553GAGHOS]20CO2

Midwinter D Hadlari T Davis WJ Dewing K amp Arnott RWC 2016Dual provenance signatures of the Triassic northern Laurentian margin fromdetrital-zircon U-Pb and Hf-isotope analysis of Triassic -Jurassic strata in theSverdrup Basin Lithosphere 8 668ndash683 httpsdoiorg101130L5171

Moumlrner NA 1979 The Fennoscandian uplift and Late Cenozoic geodynamicsgeological evidence GeoJournal 3 287ndash318 httpsdoiorg101007BF00177634

Nielsen SB Gallagher K et al 2009 The evolution of western Scandinaviantopography a review of Neogene uplift versus the ICE (isostasyndashclimatendasherosion) hypothesis Journal of Geodynamics 47 72ndash95 httpsdoiorg101016jjog200809001

Oakey GN amp Chalmers JA 2012 A new model for the Paleogene motion ofGreenland relative to North America plate reconstructions of the Davis Straitand Nares Strait regions between Canada andGreenland Journal of GeophysicalResearch Solid Earth 117 httpsdoiorg1010292011JB008942

Patchett PJ Embry AF et al 2004 Sedimentary cover of the Canadian Shieldthrough Mesozoic time reflected by Nd isotopic and geochemical results forthe Sverdrup Basin Arctic Canada Journal of Geology 112 39ndash57 httpsdoiorg101086379691

Pysklywec RN ampMitrovica JX 2000 Mantle flowmechanisms of epeirogenyand their possible role in the evolution of the Western Canada SedimentaryBasin Canadian Journal of Earth Sciences 37 1535ndash1548 httpsdoiorg101139e00-057

Redfield T 2010 On apatite fission track dating and the tertiary evolution of westGreenland topography Journal of the Geological Society London 167261ndash271 httpsdoiorg1011440016-76492009-036

Redfield TF Braathen A Gabrielsen RH Osmundsen PT Torsvik TH ampAndriessen PAM 2005 Late Mesozoic to early Cenozoic components ofvertical separation across the MoslashrendashTroslashndelag Fault Complex NorwayTectonophysics 395 233ndash249 httpsdoiorg101016jtecto200409012

Reiners PW amp Farley KA 2001 Influence of crystal size on apatite (UndashTh)Hethermochronology an example from the Bighorn Mountains WyomingEarth and Planetary Science Letters 188 413ndash420 httpsdoiorg101016S0012-821X(01)00341-7

Reusch H 1901 Some contributions towards an understanding of the manner inwhich the valleys and mountains of Norway were formed NGU Yearbook1900 124ndash263

Riis F 1996 Quantification of Cenozoic vertical movements of Scandinavia bycorrelation of morphological surfaces with offshore data Global andPlanetaryChange 12 331ndash357 httpsdoiorg1010160921-8181(95)00027-5

Rohrman M amp van der Beek P 1996 Cenozoic postrift domal uplift of NorthAtlantic margins an asthenospheric diapirism model Geology 24 901ndash904httpsdoiorg1011300091-7613(1996)024lt0901CPDUONgt23CO2

Rouby D Braun J Robin C Dauteuil O amp Deschamps F 2013 Long-termstratigraphic evolution of Atlantic-type passive margins A numericalapproach of interactions between surface processes flexural isostasy and 3Dthermal subsidence Tectonophysics 604 83ndash103 httpsdoiorg101016jtecto201302003

Shuster DL Flowers RM amp Farley KA 2006 The influence of naturalradiation damage on helium diffusion kinetics in apatite Earth and PlanetaryScience Letters 249 148ndash161 httpsdoiorg101016jepsl200607028

Steers JA 1948 Twelve yearsrsquo measurement of accretion on Norfolk saltmarshes Geological Magazine 85 163ndash166 httpsdoiorg101017S0016756800073003

Stephenson R amp Lambeck K 1985 Erosionndashisostatic rebound models foruplift an application to south-eastern Australia Geophysical Journal of theRoyal Astronomical Society 82 31ndash55 httpsdoiorg101111j1365-246X1985tb05127x

Stockli DF Farley KA amp Dumitru TA 2000 Calibration of the apatite(UndashTh)He thermochronometer on an exhumed fault block White MountainsCalifornia Geology 28 983ndash986 httpsdoiorg1011300091-7613(2000)28lt983COTAHTgt20CO2

St-Onge MR van Gool JA Garde AA amp Scott DJ 2009 Correlation ofArchaean and Palaeoproterozoic units between northeastern Canada andwestern Greenland constraining the pre-collisional upper plate accretionaryhistory of the Trans-Hudson orogen In Cawood PA amp Kroumlner A (eds)Earth Accretionary Systems in Space and Time Geological Society LondonSpecial Publications 318 193ndash235 httpsdoiorg101144SP3187

Uplift on Baffin Island

by guest on October 6 2020httpjgslyellcollectionorgDownloaded from

Strunk A Knudsen M F Egholm D L Jansen J D Levy L B JacobsenB H amp Larsen N K 2017 One million years of glaciation and denudationhistory in west Greenland Nature Communications 8 14199 httpsdoiorg101038ncomms14199

Suckro SK Gohl K Funck T Heyde I Schreckenberger B Gerlings J ampDamm V 2013 The Davis Strait crustmdasha transform margin between twooceanic basins Geophysical Journal International 193 78ndash97 httpsdoiorg101093gjiggs126

Thieacutebault F Cremer M Debrabant P Foulon J Nielsen OB ampZimmerman H 1989 Analysis of sedimentary facies clay mineralogy andgeochemistry of the NeogenendashQuaternary sediments in Site 645 Baffin BayIn Srivastava SP Arthur MA et al (eds) Proceedings of the OceanDrilling Program Scientific Results 105 Ocean Drilling Program CollegeStation TX 83ndash100

Tucker GE amp Slingerland RL 1994 Erosional dynamics flexural isostasyand long-lived escarpments A numerical modeling study Journal ofGeophysical Research Solid Earth 99 12229ndash12243 httpsdoiorg10102994JB00320

Vermeesch P Seward D Latkoczy C Wipf M Guumlnther D amp Baur H2007 α-Emitting mineral inclusions in apatite their effect on (UndashTh)He agesand how to reduce it Geochimica et Cosmochimica Acta 71 1737ndash1746httpsdoiorg101016jgca200609020

Weissel JK amp Karner GD 1989 Flexural uplift of rift flanks due tomechanical unloading of the lithosphere during extension Journal ofGeophysical Research Solid Earth 94 13919ndash13950 httpsdoiorg101029JB094iB10p13919

WildmanM Brown RWatkins R Carter A Gleadow A amp SummerfieldM2015 Post break-up tectonic inversion across the southwestern cape of SouthAfrica New insights from apatite and zircon fission track thermochronometryTectonophysics 654 30ndash55 httpsdoiorg101016jtecto201504012

Wolf RA Farley KA amp Kass DM 1998 Modeling of the temperaturesensitivity of the apatite (UndashTh)He thermochronometer Chemical Geology148 105ndash114 httpsdoiorg101016S0009-2541(98)00024-2

Zhang N Zhong S amp Flowers R M 2012 Predicting and testing continentalvertical motion histories since the paleozoic Earth and Planetary ScienceLetters 317 426ndash435

S Jess et al

by guest on October 6 2020httpjgslyellcollectionorgDownloaded from