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Atlantic Geology Journal of the Atlantic Geoscience Society Revue de la Société Géoscientifique de l'Atlantique

Ediacaran and Cambrian rocks on Scatarie Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada Sandra M. Barr, Chris E. White, Sören Jensen, Teodoro Palacios and Deanne van Rooyen

Volume 56, 2020 Article abstract Scatarie Island and adjacent Hay Island, located 2 km east of the eastern tip of URI: https://id.erudit.org/iderudit/1072994ar the Avalonian Mira terrane of southern Cape Breton Island, Nova Scotia, DOI: https://doi.org/10.4138/atlgeol.2020.011 contain a succession of epiclastic and other sedimentary rocks of inferred Ediacaran to Cambrian age. The age assignment was based previously on See table of contents lithological comparison with the Main-à-Dieu Group and overlying Bengal Road and MacCodrum formations of the Mira River Group. Detrital zircon grains from two sandstone samples from the Bengal Road Formation yielded Publisher(s) typical Avalonian detrital zircon spectra with middle to late Neoproterozoic, Meso- to Paleoproterozoic (1300–2200 Ma) and Neoarchean ages. They indicate Atlantic Geoscience Society maximum depositional ages of 532.4 ± 4.2 Ma and 525.4 ± 2.4 Ma from essentially the same stratigraphic level, consistent with the interpretation that ISSN the rocks are Cambrian. The Bengal Road Formation also yielded scarce organic-walled microfossils including an acanthomorphic acritarch identified 0843-5561 (print) as Polygonium sp., also consistent with Cambrian age. The fine-grained 1718-7885 (digital) siliciclastic succession on Hay Island, tentatively attributed to the MacCodrum Formation, yielded trace fossils, including Teichichnus isp. and Gyrolithes Explore this journal scintillus, that confirm Cambrian age. The Hay Island Gyrolithes scintillus expands the geographical distribution of this ichnospecies, previously known mainly from the Chapel Island Formation of Newfoundland, and represents a Cite this article younger occurrence. Barr, S., White, C., Jensen, S., Palacios, T. & van Rooyen, D. (2020). Ediacaran and Cambrian rocks on Scatarie Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada. Atlantic Geology, 56, 257–279. https://doi.org/10.4138/atlgeol.2020.011

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This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ Ediacaran and Cambrian rocks on Scatarie Island and nearby Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada

Sandra M. Barr1*, Chris E. White2, Sören Jensen3, Teodoro Palacios3, and Deanne van Rooyen4

1. Department of Earth & Environmental Science, Acadia University, Wolfville, Nova Scotia B4P 2R6, Canada 2. Nova Scotia Department of Energy and Mines, Halifax, Nova Scotia B3J 2T9, Canada 2. Área de Paleontologia, Facultad de Ciencias, Universidad de Extremadura, 06006 Badajoz, Spain 4. Department of Mathematics, Physics, & Geology, Cape Breton University, Sydney, Nova Scotia B1P 6L2, Canada

*Corresponding author:

Date received: 30 July 2020 ¶ Date accepted: 13 September 2020

ABSTRACT

Scatarie Island and adjacent Hay Island, located 2 km east of the eastern tip of the Avalonian Mira terrane of southern Cape Breton Island, Nova Scotia, contain a succession of epiclastic and other sedimentary rocks of inferred Ediacaran to Cambrian age. The age assignment was based previously on lithological comparison with the Main-à-Dieu Group and overlying Bengal Road and MacCodrum formations of the Mira River Group. Detrital zircon grains from two sandstone samples from the Bengal Road Formation yielded typical Avalonian detrital zircon spectra with middle to late Neoproterozoic, Meso- to Paleoproterozoic (1300–2200 Ma) and Neoarchean ages. They indicate maximum depositional ages of 532.4 ± 4.2 Ma and 525.4 ± 2.4 Ma from essentially the same stratigraphic level, consistent with the interpretation that the rocks are Cambrian. The Bengal Road Formation also yielded scarce organic-walled microfossils including an acanthomorphic acritarch identified as Polygonium sp., also consistent with Cambrian age. The fine-grained siliciclastic succession on Hay Island, tentatively attributed to the MacCodrum Formation, yielded trace fossils, including Teichichnus isp. and Gyrolithes scintillus, that confirm Cambrian age. The Hay Island Gyrolithes scintillus expands the geographical distribution of this ichnospecies, previously known mainly from the Chapel Island Formation of Newfoundland, and represents a younger occurrence.

RÉSUMÉ

L’île Scatarie et l’île Hay voisine , situées à deux kilomètres à l’est de la pointe du terrane avalonien Mira dans le sud de l’île du Cap-Breton en Nouvelle-Écosse, abritent une succession de roches épiclastiques et d’autres roches sédimentaires remontant présumément à la période de l’Édiacarien au Cambrien. L’âge attribué était antérieurement basé sur une comparaison lithologique avec le groupe Main-à-Dieu et les formations sus-jacentes de Bengal Road et de MacCodrum du groupe de la rivière Mira. Des grains de zircon détritique provenant de deux échantillons de grès de la Formation de Bengal Road ont affiché des spectres de zircon détritique avaloniens typiques des périodes du Néoprotozoïque moyen à tardif, du Mésoprotozoïque au Paléoprotérozoïque (1300 à 2200 Ma) et du Néoarchéen. Ils signalent des âges de sédimentation maximaux de 532,4 ± 4,2 Ma et de 525,4 ± 2,4 Ma d’un niveau stratigraphique essentiellement identique, ce qui correspond à l’interprétation situant les roches au Cambrien. La Formation de Bengal Road a de plus révélé la présence de microfossiles palynomorphes, notamment un acritarche acanthomorphe identifié en tant que l’espèce Polygonium, ce qui correspond également à l’époque du Cambrien. La succession silococlastique à grains fins sur l’île Hay, rattachée à la Formation de MacCodrum, a présenté des ichnofossiles, par exemple, l’ichnoespèce Teichichnus et le Gyrolithes scintillus, qui confirment l’âge du Cambrien. Le Gyrolithes scintillus de l’île Hay élargit la distribution géographique de cette ichnoespèce, antérieurement reconnue comme une espèce principalement présente dans la Formation de Chapel Island de Terre-Neuve, et il représente une occurrence plus récente.

[Traduit par la redaction]

ATLANTIC GEOLOGY 56, 257–279 (2020) doi:10.4138/atlgeol.2020.011 Copyright © Atlantic Geology, 2020 0843-5561|20|0257–0279$4.45|0 ATLANTIC GEOLOGY · VOLUME 56 · 2020 258 INTRODUCTION REGIONAL BACKGROUND

Scatarie Island is a Nova Scotia Wilderness Protected area Southeastern Cape Breton Island, geologically compris- (https://novascotia.ca/nse/protectedareas/wa_scatarie.asp) ing the Mira terrane (Barr and Raeside 1989), is part of located in the Cabot Strait 2 km from the southeastern tip of Avalonia in the northern Appalachian orogen (Fig. 1, inset). Cape Breton Island (Fig. 1). The island has a long history as Like other parts of Avalonia, the Mira terrane is character- a fishing settlement, and archaeological research has provid- ized by Neoproterozoic volcanic, sedimentary, and plutonic ed evidence for 18th century fishing activity on the island; rocks, overlain by lower Paleozoic sedimentary rocks (Fig. tales abound of life there in the Nineteenth and Twentieth 1). Weeks (1954) included all the Precambrian volcanic and centuries. The area is also known for its long history of ship- sedimentary rocks in a single unit called the Fourchu Group; wrecks, most recently the Great Lakes freighter M.V. Miner, but based on mapping, petrological studies, and U–Pb zir- which ran aground when a towing cable broke in Septem- con dating, Barr et al. (1992, 1996) subdivided the rocks into ber 2011 and which was removed from the island in 2015 groups of three different ages, ca. 680 Ma, ca. 620 Ma, and ca. (https://novascotia.ca/news/release/?id=20150622003). 575 Ma (Fig. 1). The name Fourchu Group was retained only Although designated a protected area because of its rare or for the ca. 575 Ma volcanic and minor sedimentary rocks unusual flora, the bedrock geology on Scatarie Island is also in the coastal part of the terrane south of Louisbourg. The remarkable because it includes a rare occurrence of rocks new name Main-à-Dieu Group was assigned to rocks west, that formed during a time interval that spans the boundary north, and east of Louisbourg that were considered equiv- between the Ediacaran and Cambrian periods of geological alent in age to and/or younger than the Fourchu Group on time (Barr et al. 1992, 1996). Although much of the interior the basis of field relations, petrological characteristics, and a of the island consists of dense spruce and fir forest, barrens, poorly constrained U–Pb zircon age of <560 Ma from a rhy- and bogs and hence lacks outcrop, the Ediacaran–Cambrian olite sample (Bevier et al. 1993). Other group names were rocks are well exposed along parts of the shoreline. The pur- assigned to volcanic, volcaniclastic, and sedimentary rocks pose of this paper is to present the first direct paleontologi- farther south and west in the terrane, based mainly on U–Pb cal and U–Pb zircon evidence that rocks formed during the zircon ages from volcanic rocks and associated plutons (Fig. Ediacaran/Cambrian transition are exposed on the eastern 1). Subsequently, formation names were introduced for lith- part of Scatarie Island and adjacent Hay Island (Fig. 2). ological units within each of these groups by Barr and White (2017a, b).

Terranes of the northern Newfoundland CH 270000 Scatarie 0 km 10 Appalachian orogen Island L MacCodrum Fig. 2 Brook Cape G Breton A Main-à-Dieu Island A Fig. 1 Mira River 5090000 PL Ganderia Mira Louisburg M N EBH

Victoria Bridge Atlantic Bras d’Or Lake Ocean PM 5070000 Sgadan Lake area 290000

Carboniferous sedimentary rocks Main-à-Dieu Group ca. 620 Ma plutons

Devonian plutons ca. 575 Ma plutons Coxheath (CH), East Bay Hills (EBH) and Pringle Mountain (PM) groups (ca. 620 Ma) Mira River Group (Cambrian) Fourchu Group (ca. 575 Ma) Stirling Group (ca. 680 Ma)

Figure 1. Simplified geological map of the northern part of the Mira terrane, southeastern Cape Breton Island, modified from Barr et al. (1996), showing the distribution of Neoproterozoic, Cambrian, and Carboniferous rocks and the location of Scatarie Island. Inset map shows the location of the Mira terrane and map area in the context of northern Appalachian terranes, modified from Hibbard et al. (2006). A = Avalonia, G = Ganderia, L = Laurentian margin, M = Meguma, PL = peri-Laurentian arcs.

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 259

290000 291000 292000 Fig. 8

45 5100500 3 Trail Eastern Harbour

60

26 65 Hay qpc 65 Island 54 Fig. 7 5100000 2 25 1 27 qpc CAMBRIAN 45 MIRA RIVER GROUP 40 MacCodrum(?) Formation 50 4 grey laminated siltstone, 3 234 sandstone and shale Bengal Road Formation 49 53 red to grey sandstone and siltstone; 2 4 minor red nodular limey siltstone 1 Red Islet red to maroon sandstone and 3 grey laminated siltstone 30 red to maroon sandstone; minor grey 235 Figs. 5, 6 2 laminated siltstone and conglomerate 1 red to maroon conglomerate (qpc); qpc minor grey laminated siltstone N outcrop ...... EDIACARAN 72 72 bedding ...... MAIN-A-DIEU GROUP 70 syncline axis ...... V Northwest Cove Formation 0 300m fault ...... 232 contacts ...... Scatarie Island Formation

Figure 2. Geological map of the southeastern part of Scatarie Island and nearby Hay Island modified from Barr and White (2017a, b, c). Locations of dated samples SMB17-234 and 235 are shown in member 3 of the Bengal Road Formation, as well as sample SMB17-232 from the underlying Northwest Cove Formation which lacked zircon. Also shown are locations of photographed specimens in Figs. 6–8. Location for sample SMB17-232 = Grid Zone 21T (WGS84) 289998 5099504

The Cambrian sedimentary rocks that locally overlie the mation of Newfoundland; but Barr et al. (1992, 2003, 2012) Neoproterozoic volcanic, sedimentary, and plutonic rocks and Reynolds et al. (2009) considered it to be Cambrian form a broadly synclinal structure in the Mira River area, based mainly on the presence of detrital muscovite and on and Barr and White (2017a, b) referred to them collective- other lithological contrasts with underlying non-micaceous ly as the Mira River Group. Hutchinson (1952) and Weeks red beds. Maximum depositional ages of ca. 544 and 537 Ma (1954) divided Cambrian sedimentary rocks into six forma- were reported by Willner et al. (2013) based on U–Pb dating tions: Morrison River, MacCodrum, Canoe Brook, Trout of detrital zircon from the Mira River area. Brook, MacLean, and McNeil. Barr et al. (1992, 1996) re- The overlying Sgadan Lake Formation is a distinctive tained these formation names except for Morrison River, white, rarely maroon, cross-bedded quartz arenite which which they replaced by the Bengal Road and Sgadan Lake is locally conglomeratic with abundant quartz pebbles. The formations because they considered the latter to be mappa- Sgadan Lake Formation in its type area near Sgadan Lake ble units distinct from the red beds in the underlying Main- was correlated with the Random Formation of Newfound- à-Dieu Group, all of which had been included previously in land by Landing (1991). Landing (1991) also recognized a the Morrison River Formation (Weeks 1954). separate unit of shale between the red bed and quartz aren- As defined by Barr et al. (1992, 1996), the Bengal Road ite units that he correlated with the Chapel Island Forma- Formation is a dominantly red clastic sedimentary unit that tion, which in Newfoundland occurs between the Rencon- overlies volcanic and sedimentary rocks of the Main-à-Dieu tre and Random formations. Barr et al. (1996) also noted the Group. Contacts are mainly faults or are unexposed, but an presence of shale and siltstone but did not consider those originally disconformable relationship is most likely. The rocks to constitute a separate mappable unit and so included Bengal Road Formation differs from sedimentary units of them in their Bengal Road Formation. Barr et al. (2012) re- the underlying Main-à-Dieu Group in that the former con- ported a single concordant detrital zircon age of ca. 529 Ma tains abundant detrital muscovite and lacks volcanic and from the Sgadan Lake Formation in its type area, although volcaniclastic rocks. It also contains a distinctive quartzite- a single analysis cannot be considered to provide a reliable quartz-pebble conglomerate unit at or near its base, and is maximum depositional age. interlayered with, and overlain by, red sandstone and silt- Barr et al. (1992, 1996) also assigned white quartz arenite stone, commonly with well-developed cross-bedding and and conglomerate in MacCodrum Brook to their Sgadan Lake graded bedding. Landing (1991) correlated this red bed unit Formation, although Landing (1991) had placed those rocks of the Mira terrane with the late Ediacaran Rencontre For- in the Rencontre Formation. The Sgadan Lake Formation

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 260 in MacCodrum Brook is overlain by the type section of the inantly dark-grey to rust-brown, well cleaved shale and MacCodrum Formation of Hutchinson (1952). It consists siltstone, overlies the Canoe Brook Formation. Toward the of grey and green siltstone and shale, with minor sandstone stratigraphic top of the Trout Brook Formation, the shale intervals. Carbonate nodules are present close to the base of becomes locally maroon, with thin, graded beds of fine- the formation and also higher in the section. This section is grained sandstone. The Trout Brook Formation contains the only good exposure of this unit, because many outcrops Miaolingian trilobites (Hutchinson 1952) and acritarchs farther south in the Mira River area originally attributed to (Palacios et al. 2009). The MacLean Brook Formation the MacCodrum Formation by Hutchinson (1952) were lat- (Hutchinson 1952) overlies the Trout Brook Formation, and er shown to belong to younger units (Landing 1991; Barr consists of interbedded grey quartz sandstone, siltstone, and et al. 1996). By comparison with Newfoundland, Landing shale with minor light-grey quartz sandstone and maroon (1991) equated the type section of the MacCodrum Forma- shale. It contains Miaolingian trilobites (Hutchinson 1952) tion with the Bonavista Group (Cambrian Stage 2–3) and and Miaolingian and Furongian acritarchs (Palacios et al. suggested that an unconformity is present between it and 2009). The MacLean Brook Formation appears to be con- the underlying quartz arenite. However, Barr et al. (1996) formable with the underlying shales of the Trout Brook For- observed interlayered quartz arenite and shale in some lo- mation and is overlain by grey shale, siltstone, and limestone cations and hence, like Hutchinson (1952), considered that of the Furongian McNeil Formation (Hutchinson 1952). the units are conformable. Later Landing (2004) revised his earlier correlation of the type section of the MacCodrum Formation with Newfoundland units because of the higher GEOLOGY OF SCATARIE ISLAND sandstone content than found in the Bonavista Group, and AND HAY ISLAND instead attributed it to the Chapel Island Formation. The de- tails of rocks in the MacCodrum Brook section are further The geology of Scatarie Island was first described by complicated by the fact that Willner et al. (2013) reported Fletcher (1879), who provided a vivid description of the is- a maximum depositional age of 517 ± 3 Ma for the Sgadan land and recognized various types of “felsites” from coastal Lake quartz arenite there, based on results from an eight- sections. He also reported a conglomerate visible at low tide grain detrital zircon population. Results of work in progress on eastern Scatarie Island that he thought to be of probable to evaluate the implications of this young age and the details Carboniferous age, subsequently assigned to the Cambrian in the still-enigmatic MacCodrum Brook section will be re- Bengal Road Formation (Barr et al. 1996, 2003, this paper). ported in a subsequent paper. Weeks (1954) included all of Scatarie Island in his Fourchu The MacCodrum Formation is the oldest unit on Cape Group, based on mapping by Hayes et al. (1938). Howev- Breton Island that has yielded trace fossils (Landing 2004) er, Barr and White (1989) and Barr et al. (1996) re-assigned and acritarchs (Palacios et al. 2015). Acritarchs from the type most of the Scatarie Island rocks to the Main-à-Dieu Group section on MacCodrum Brook include Granomarginata and and also recognized for the first time the presence of prob- Asteridium (Palacios et al. 2015). Acritarchs and trace fossils able Cambrian rocks overlying the Main-à-Dieu Group on from the type section are consistent with attribution to the the eastern part of the island (Fig. 2). Fortunian or Cambrian Stage 2. The overlying Canoe Brook Barr et al. (1996) divided the Main-à-Dieu Group on Sca- Formation consists of red-brown, carbonate-rich mudstone tarie Island into map units based on rock type, and those and siltstone, maroon siltstone containing grey-green re- units were assigned formation names by Barr and White duction spots, and minor pink to red limestone. According (2017a, b, c). The inferred oldest unit on the island, the Sca- to Landing (1991), the Canoe Brook Formation, as well as tarie Island Formation, forms the northeastern part of the the upper part of the underlying MacCodrum Formation island, in faulted contact to the south with the Northwest (as originally mapped by Hutchinson 1952), are equivalent Cove Formation and Cambrian rocks of the Bengal Cove to the Bonavista Group and Brigus Formation in Newfound- Formation (Fig. 2). The Northwest Cove Formation is the land based on lithological characteristics and skeletal fossils. uppermost formation in a conformable stratigraphic succes- The contact between the MacCodrum and Canoe Brook sion that youngs consistently to the east across Scatarie Is- formations is nowhere exposed. Landing (1991) recovered land (Barr et al. 1996; Barr and White 2017c). The formation skeletal fossils from the Canoe Brook Formation along the consists mainly of amygdaloidal basaltic flows interlayered Louisbourg Highway, which he attributed to the Camenella with red volcanogenic conglomerate, epiclastic sandstone, baltica Zone of Cambrian Stage 3 (Geyer 2019). From the and tuff. upper part of the formation, Landing (1991) reported the The overlying mainly red to maroon sedimentary rocks trace fossil Teichichnus and trilobite hash. Trilobites were were assigned to the Cambrian Bengal Road Formation also discovered by Hutchinson (1952), who reported the based on lithology (Barr et al. 1992, 1996). The distribution Cambrian Stage 3 Callavia Zone-trilobite Strenuella strenua of rock types, structural orientations, and well-preserved from the Victoria Bridge area (Fig. 1) in rocks originally at- younging directions indicate that the Bengal Road Forma- tributed to the MacCodrum Formation but now part of the tion occurs in a faulted synclinal structure (Fig. 2). At the Canoe Brook Formation (Barr et al. 1996). time of a visit in August 1991, a gap of about 10 m separated The Trout Brook Formation (Hutchinson 1952), dom- the uppermost amygdaloidal basalt flow of the Northwest

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 261 Cove Formation from an outcrop of quartzite- and clasts in a muddy matrix that forms about 25% of the rock. quartz-pebble conglomerate, characteristic of the base of the The samples were sent to Overburden Drilling Manage- Bengal Road Formation elsewhere in the Mira terrane (Barr ment (Ottawa, Ontario) for electro-pulse disaggregation et al. 1992). The conglomerate is repeated in three outcrops and zircon separation. Zircon grains in samples in the well-exposed section, although during our most recent SMB17-234 and 235 were then handpicked, mounted on an visit in 2017, the southernmost outcrops observed in 1991 epoxy- covered thin section, polished to expose the centres were not exposed. The rocks are divided into four members. of the zircon grains, and imaged using cold cathodo- The quartzite- and quartz-pebble conglomerate (member 1) luminescence to identify internal zoning and inclusions. grades into red to maroon sandstone with minor interbed- These images were used to select ablation points (30 µm ded grey laminated siltstone and conglomerate of member diameter), avoiding any visible inclusions, cracks, or other 2, and then into a unit of red to maroon sandstone and grey imperfections. Grains were analyzed by laser ablation laminated siltstone which lacks conglomerate (member 3), inductively coupled plasma mass spectrometry (LA-ICP- overlain by red to grey sandstone and siltstone with minor MS) at the Department of Earth Sciences, University of New red nodular limey siltstone (member 4). Younging direction Brunswick (Appendix A: Table A1 and A2 ― two runs for is clear throughout this section, and the first three members each sample are reported and all data from both runs are are repeated north of an east-northeast-trending fault (Fig. analyzed and discussed together). U and Pb isotopic 2). All four members contain abundant detrital muscovite, compositions were measured using a Resonetics S-155-LR absent from the underlying Northwest Cove Formation and 193 nm Excimer laser ablation system connected to an other formations of the Main-à-Dieu Group. Agilent 7700× quadrupole in-ductively coupled plasma– Some control from mainly submerged rocky shoals en- mass spectrometer, following the procedure outlined by ables the synclinal structure to be traced offshore toward McFarlane and Luo (2012) and Archibald et al. (2013). Hay Island, but red beds do not occur on the island. There, Data reduction was done in-house using Iolite software the rocks are grey laminated siltstone, sandstone, and shale (Paton et al. 2011) to process the laser output into data that appear lithologically similar to the MacCodrum Forma- files, and further reduced for U–Pb geochronology using tion in the Mira River area (Barr et al. 1992, 1996). However, VizualAge (Petrus and Kamber 2012). Corrections are applied as follows: for grains with <100 based on some lithological similarities to the Trout Brook 204 Formation, in their more recent compilation maps Barr and counts/s Pb, data are uncorrected; for grains where the percentage error on the 204Pb counts per second was <20%, White (2017c) assigned the Hay Island rocks to the Trout 204 Brook Formation. In either case, no evidence for the white we used a Pb-based correction (Andersen 2002), and for grains where the percentage of radiogenic Pb (Pb* in file) quartz arenite of the Sgadan Lake Formation, or for other is less than 98.5% we used a 208Pb-based correction (Petrus intervening formations, was observed, and if present, it is and Kamber 2012). Data were sorted by % concordance hidden under water. (206Pb/238U versus 207Pb/235U for grains <1000 Ma and 206Pb/238U versus 207Pb/206Pb for grains >1000 Ma), and by the % of radiogenic Pb in the grains as calculated using U–PB GEOCHRONOLOGY VizualAge (Appendix A: Tables A1 and A2). Concordia and weighted mean ages as well as probability distribution his- Sample descriptions and methods tograms were calculated using Isoplot version 4.15 (Ludwig 2012). Three samples (SMB17-232, 234, and 235) were collected Probability distribution histograms are based on for U–Pb dating of detrital zircon but only the latter two 206Pb/238U dates for grains <1000 Ma and 207Pb/206Pb dates contained zircon grains. Sample SMB17-232 is red pebble for >1000 Ma and show all grains that are between 90 and conglomerate from the upper part of the Northwest Cove 102% concordant. To determine the youngest age repre- Formation (Fig. 2). The conglomerate overlies and underlies sented in each sample we used only clusters of more than 3 amygdaloidal basalt flows. It contains abundant plagioclase grains with ages that overlap within error and are 98–101% and epidote clasts and varied lithic fragments (including concordant. Using only near-concordant grains that over- volcanic glass, basalt, dacite, and rhyolite) but minor quartz lap within error is a conservative approach, which serves to and no detrital muscovite or zircon. reduce the possibility of misrepresenting the maximum In contrast, samples SMB17-234 and 235, both from the depositional age as too young by using single grains that red to maroon sandstone and grey laminated siltstone of may have experienced Pb loss (Dickinson and Gehrels member 3, contain abundant detrital muscovite, as well as 2010). Data for reference materials FC-1 and Plesovice are zircon. SMB17-234 is red arkosic sandstone with abundant presented in Appendix A, Table A2, with standards for angular quartz and less abundant plagioclase clasts. Lithic Run 1 and Run 2 shown separately. clasts include both volcanic and clastic sedimentary mate- rial. Sample SMB17-235 is greywacke, finer grained than Results sample 234 and with more abundant muscovite. Many of the muscovite fragments had been deformed and crenulat- Sample SMB17-234 contains zircon grains with a wide ed prior to deposition. They occur with quartz and feldspar range of sizes between 50–300 µm, and grains of all sizes

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 262 were analyzed. Some of the larger grains are subhedral and grains is 525.4 ± 2.4 Ma with a much lower MSWD of 1.11 rectangular and some are rounded and anhedral; the small- (Fig. 3d). In this case the weighted mean age at ~525 Ma is er grains are mostly subhedral to anhedral and rounded. All likely the most robust estimate of the maximum deposition- analyzed grains had very weak fluorescence in CL but some al age for this sample. of the larger grains showed faint oscillatory zoning. Of 132 Zircon grains in sample SMB17-235 range in size from grains analyzed, 80 are between 90 and 102% concordant 50–200 µm and grains of all sizes were analyzed. Some of (Appendix A: Table A1). The major peak in the cumulative the larger grains are subhedral and acicular to rectangular probability distribution is around 520–530 Ma, with minor whereas the smaller grains are mostly subhedral to anhe- peaks at 1.5 Ga, 1.8 Ga and 2.0 Ga and a few grains at 3.0 Ga dral and rounded. All of the grains had weak fluorescence (Figs. 3a, b). The gaps in ages at around 1000 Ma and around in CL but some of the larger grains showed faint oscillatory 2500 Ma are typical of detrital zircon signatures in Avalonia, zoning. Of 128 grains analyzed, 86 are between 90 and 102% as is the scatter of ages between about 1300 and 2100 Ma concordant (Appendix A: Table A1). The major peak in the (e.g., Barr et al. 2012). Among the Neoproterozoic to Cam- cumulative probability distribution is around 530 Ma, with brian grains, it is possible to calculate a concordia age for 12 minor peaks at 1.5 Ga, 1.8 Ga and 2.0 Ga and a few grains grains in the youngest peak at 526.3 ± 2.2 Ma, but the mean around 2.7 Ga and 3.4 Ga (Figs. 4a, b). Like sample SMB17- square of weighted deviation (MSWD) is very high at 7.0 234, this sample also displays the gaps at ca. 1000 and 2500 and has a correspondingly low probability of concordance Ma and a spread of ages between about 1300 and 2200 Ma, at 0.008 (Fig. 3c). The weighted mean age for the same 12 typical of Avalonia. For Neoproterozoic to Cambrian grains,

25 (a) (b) 6 Relative probability Relative Relative probability Relative 20

15 4 Number 10 Number 2 5

0 0 0 500 1000 1500 2000 2500 3000 480 530 580 630 680 730 Age (Ma) Age (Ma)

0.089 data-point error 542 data-point error lines are 2 sigma (c) ellipses are 2 sigma (d)

540 538 0.087 534 530

0.085 526

Pb/ U 522 206 238

520 Age (Ma) 518 0.083 Concordia Age = 526.3 ± 2.2 Ma 514 (2s, decay-const. errs included) Mean = 525.4 ± 2.4 [0.45%] 95% conf. MSWD (of concordance) = 7.0, 510 Wtd by data -pt errs only, 0 of 12 rej. Probability (of concordance) = 0.008 MSWD = 1.11, probability = 0.35 0.081 506 0.61 0.65 0.69 0.73 0.77 207Pb/ 235 U Figure 3. U–Pb zircon diagrams for sample SMB17-234 (data from Table A1). (a) Probability plot for all data between 90 and 102% concordant. (b) Expanded view of probability plot in (a) for ages less than 750 Ma. (c) Concordia diagram for youngest statistically valid age population. (d) Weighted mean diagram for the same 12 grains shown in (c).

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 263 three separate peaks occur on the cumulative probability Island were examined for their fossil contents and docu- distribution (Fig. 4b), but the calculated concordia age for mented by digital photography. More than 100 m of contin- the youngest group of 5 grains is 534.4 ± 3.9 Ma with a high uous outcrop of the Bengal Road Formation is accessible at MSWD of 4.5 and a low probability of concordance at 0.034. low tide. As exposed in July 2017, the section commenced The weighted mean age of the same 5 grains is 532.4 ± 4.2 with about 30 m of laminated and thin-bedded, yellow- and Ma with a much lower MSWD of 0.15 (Fig. 4d). In this case brown-weathering grey siltstone and minor sandstone of the weighted mean age is likely the most robust estimate of member 2. Small-scale truncations and bedding rupture is the maximum depositional age for this sample. The grains commonly seen (Figs. 5a–c). The proportion of sandstone with ages scattered between 550 Ma and 780 Ma could all increases up-section into member 3 and include beds have sources within Avalonia (e.g., van Staal et al. 2020). with large cubes of pyrite (Fig. 5d). Three samples of dark- grey silt-stone were collected for organic-walled microfossils from this section. Member 3 is overlain by red TRACE FOSSILS AND ORGANIC-WALLED sandstone/siltstone of member 4 (Fig. 5e) which contains MICROFOSSILS minor red nodular limey siltstone (Fig. 5f). Outcrops tentatively attributed to the MacCodrum For- Material and methods mation were examined at three coastal sections on Hay Is- land, with a total of five samples collected for organic-walled Coastal sections on eastern Scatarie Island and on Hay microfossils (Fig. 2). Samples collected for organic-walled

6 10 (a) (b) Relative probability Relative 5 probability Relative 8 4 6 3 Number Number 4 2

2 1

0 0 0 1000 2000 3000 4000 500 550 600 650 700 750 800 850 900 950 Age (Ma) Age (Ma)

550 data-point error data-point error lines are 2 sigma (c) 550 ellipses are 2 sigma (d) 0.089 546 542

538 0.087 534 Pb/ U 206 238 530 Age (Ma) 530 0.085 526 Concordia Age = 534.4 ±3.9 Ma Mean = 532.4 ±4.2 [0.79%] 95% conf. (2s, decay-const. errs included) Wtd by data -pt errs only, 0 of 5 rej. MSWD (of concordance) = 4.5, 522 Probability (of concordance) = 0.034 MSWD = 0.15, probability = 0.96 0.083 518 0.64 0.66 0.68 0.70 0.72 0.74 0.76 207Pb/ 235 U

Figure 4. U–Pb zircon diagrams for sample SMB17-235 (data from Table A1). (a) Probability plot for all data between 90 and 102% concordant. (b) Expanded view of probability plot in (a) for ages less than 950 Ma. (c) Concordia diagram for youngest statistically valid age population. (d) Weighted mean diagram for the same 5 grains shown in (c).

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Figure 5. Field images of coastal exposures of the Bengal Road Formation on eastern Scatarie Island. Scale bars represent 10 mm. (a–c) Characteristic lamination and bedding in lower part of measured section of Bengal Road Formation (mem- bers 2 and 3). Samples SC17-5 and -6 were collected from fine-grained intervals in this type of rock. Deformed bedding give rise to trace fossil-like structures, particularly well seen in (c). (d) Fine-grained sandstone with large pyrite crystals. (e) Red sandstone and siltstone (member 4). (f) Red nodular limey siltstone (member 4). microfossils were prepared and examined at Área de Pale- Results–trace fossils ontologia, University of Extremadura, Badajoz, following palynological procedures outlined in Vidal (1988). See Ap- No definitive trace fossils were observed in the Bengal pendix B for details on locations and samples. Palynolog- Road Formation. Bedding-plane exposures are not well de- ical slides containing figured and representative material veloped, which severely limits the possibility of observing are stored with the collections in Nova Scotia Museum of any delicate bedding-plane parallel trace fossils. Angular or Natural History, Halifax (museum numbers added in the rod-shaped bodies seen in vertical and oblique section (Figs. explanation of the figures). 5b–c) have similarity to trace fossils but their interpretation

Results: organic-walled microfossils

All samples from Hay Island had no or only small amounts of dispersed organic material and no identifiable organic-walled microfossils (see Appendix B). Two samples from the Bengal Road Formation yielded poorly preserved organic-walled microfossils (Fig. 6). This material includes probable cyanobacterial filamentous sheaths (Fig. 6a) and Figure 6. Organic-walled microfossils from Bengal Road organic fragments of uncertain origin. A single poorly pre- Formation, Scatarie Island. Scale bar in c is equivalent served acanthomorphic acritarch (Fig. 6b) is identified as to 20 μm for a–d. Sample number, the Nova Scotia Mu- Polygonium sp. This acritarch does not provide biostrati- seum of Natural History collection number, and England graphic information beyond that of a post-Ediacaran age. Finder coordinates (for position of microfossils on the Sarjeant and Stancliffe (1996) restricted Polygonium to the palynological slide; https://www.graticulesoptics.com/ Cambrian to Devonian interval, but younger occurrences products/stage-micrometers-calibration-scales-grids/co- have been reported. These samples provide the first records ordinate-graticules/s7-england-finder) are provided. (a) of organic-walled microfossils from the Bengal Road Possible cyanobacterial filament, SC17-5, NSM020GF14.1, Formation. V-51-2. (b) Polygonium sp., SC17-6, NSM020GF14.2, J-43- 1 (c) Organic-walled fragment, SC17-6, NSM020GF14.2, M-41-1. (d) Degraded organic-walled fragment, SC17-6, NSM020GF14.2, B-42-4.

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 265 is complicated by frequent small-scale (syndepositional?) have been identified as Conichnus, but both the material disturbance, fracturing and rotation of laminae and beds. described here and that from Newfoundland could alterna- It is probable that structures such as those shown in Fig. 5c tively be the fill of the funnel-shaped top of an otherwise represent rotated pieces of primary sedimentary structures. not preserved, short, vertical trace fossil. Additional nonde- Trace fossils were observed on several coastal sections script trace fossils are also present (Fig. 8e). Trace fossils in on Hay Island (Fig. 2). On the southern part of the island, this outcrop exhibit “floating” and “adhering” preservation, outcrops of mainly grey-green and dark-grey siltstone con- similar to that commonly seen in the Chapel Island Forma- tain examples of starved ripples of fine sandstone (Fig. 7b) tion of Newfoundland (Droser et al. 2002), in which sand- and teichichnid trace fossils with clear evidence for sp- filled burrows are floating in a finer-grained matrix (Fig. 8e) reite (Fig. 7a). The spreiten show at least 5 lamellae, with or secondarily adhered to a later sand bed. A loose sample downward-oriented convexity, which indicates a retrusive along the same stretch of outcrop show Teichichnus isp. and development of the spreite, although no causative burrow more strongly developed sediment mixing (Fig. 8f). The was clearly identified. These trace fossils are assigned to Te- slab is sedimentologically similar and is interpreted as a less ichichnus isp. weathered sample from the same interval of the succession. Trace fossils were observed on weathered outcrop of cleaved grey-green siltstone on the northern tip of the is- land, with the most notable being small, vertically orient- DISCUSSION ed, spiral trace fossils (Figs. 8a–c). These spirals are devel- oped within silty material and filled with fine sand related Both the detrital zircon ages and fossils described here to thin sandstone event beds. The best exposed specimen confirm a Cambrian age for the siliciclastic successions on (Fig. 8a) has two whorls (whorl height approximately 6 eastern Scatarie Island and on Hay Island, a conclusion pre- mm), a burrow diameter of 0.7 mm and a spiral radius of viously based on lithological correlation with the Bengal 1.6 mm. Another less well-exposed specimen with com- Road and MacCodrum formations, respectively, on Cape parable dimensions shows three whorls of the spiral (Fig. Breton Island (Barr et al. 1996). The maximum depositional 8b). Both in dimensions and spiral geometry this material is ages of 532 and 526 Ma and the presence of the acritarch like Gyrolithes scintillus from the Chapel Island Formation, Polygonium sp. from the Bengal Road Formation on east- Burin Peninsula, Newfoundland, as described by Laing et ern Scatarie Island demonstrate that the upper part of this al. (2018). Other trace fossils from the Hay Island outcrop formation is definitely younger than the late Ediacaran Ren- consist of short plug-shaped cones (Fig. 8d). Similar trace contre Formation in Newfoundland, with which the Bengal fossils from the Chapel Island Formation in Newfoundland Road Formation was compared by Landing (1991, 1996). The new data reported here, combined with detrital zircon age constraints from Cape Breton Island (Barr et al. 2012; Willner et al. 2013), indicate that the Bengal Road Forma- tion spans much of the Fortunian and Cambrian Stage 2. The age of the base of the formation is not known, nor is the duration of the inferred break in sedimentation between the Main-à-Dieu and Mira River groups. The stratigraph- ic position of the Bengal Road Formation could in part be equivalent to that of the Ratcliffe Brook Formation in New Brunswick, as previously suggested by Barr et al. (2012); if so, the base of the formation is intra-Fortunian. The geological mapping information (Barr et al. 1992, 1996; this paper) indicates that the eastern coast of Scatarie Island and Hay Island are both part of the same east-plung- ing synclinorium (Fig. 2). Based on lithological character- istics Barr et al. (1996) attributed the Hay Island succession to the MacCodrum Formation, in which case the sandstone facies of the Sgadan Lake Formation either is not exposed above sea level or was never developed in this region. The trace fossils reported here provide ichnostratigraphic evi- dence for a post-Ediacaran age of the Hay Island succession, Figure 7. Field images of trace fossils and sedimenta- especially the presence of Teichichnus. The earliest Teichich- ry structures in the MacCodrum? Formation, southern nus appear in late Fortunian and Stage 2 rocks, and more Hay Island. (a) Siltstone and fine-grained sandstone with generally spreite-burrows have been used as evidence for a transverse sections through Teichichnus spreiten. Scale bar post-Ediacaran age in the absence of other evidence (e.g., represents 10 mm. (b) Current ripple cross-lamination, Bland and Goldring 1995; Jensen et al. 2016). Teichichnus scale bar represents 10 mm. is a common element in lower Cambrian strata of Avalonia

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Figure 8. Field images of trace fossils from MacCodrum? Formation, northern Hay Island. (a–e) Images from vertical surfaces of cleaved siltstone. (a–c) Vertical spiral trace fossil Gyrolithes scintillus. Scale bars represent 5 mm. (d) Small plug-shaped sand-filled structure, which may be a Conichnus or a funnel-shaped top of a vertical tube. Scale bar represents 5 mm. (e) Several short trace fossils in “floating” preservation along a bedding plane marked by gentle change in grain size. A larger burrow is a possible Gyrolithes. Scale bar represents 5 mm. (f) Vertical view of alternation of sandstone and mudstone in loose block. Along mid-line three discrete Teichichnus are seen in, from right to left, transverse (t), oblique (o), and near-longitudinal (n) section. Scale bar represents 5 mm. and Baltica (Loughlin and Hillier 2010). In the Chapel Island on Cape Breton and Scatarie islands. Furthermore, although Formation Teichichnus occurs sparsely in member 2, more attribution of the Hay Island succession to the MacCodrum commonly so in members 3 and 4, where it is the dominant Formation is tentatively maintained here, further studies are trace fossil (Landing et al. 1989; Droser et al. 2002; Gougeon needed to confirm this assignment, and to evaluate the et al. 2018). It is also prominent in the Bonavista Group, in possibility that the Hay Island succession is younger than which Landing et al. (1989) named a Teichichnus Interval. In the MacCodrum Formation, and perhaps consistent with the Mira River area Teichichnus is common in red mudstone the assignment by Barr and White (2017c) to the Miao- of the Canoe Brook Formation (Landing 1991). The earli- lingian Trout Brook Formation. est Gyrolithes straddle the Ediacaran/Cambrian boundary in Newfoundland (Gehling et al. 2001; Laing et al. 2018), and northern Norway (Jensen et al. 2018). Laing et al. (2018) ACKNOWLEDGEMENTS documented Gyrolithes scintillus from close to the basal Cambrian GSSP through 400 m of section of member 2 of We thank Bruce Hatcher and student assistants from the Chapel Island Formation. If the Hay Island succession Cape Breton University for transportation by Zodiac to Sca- overlies that on Scatarie Island, these Gyrolithes scintillus are tarie Island. We are grateful to Brandon Boucher and Chris younger than occurrences in Newfoundland. McFarlane for assisting Deanne van Rooyen with the U–Pb Finally it is noted that the maximum depositional ages dating at the University of New Brunswick and for provid- from zircon in the Bengal Road Formation on Scatarie Is- ing invaluable advice in processing and interpreting the age land are close to the age for the base of the Canoe Brook data. We thank Tim Fedak, Nova Scotia Museum of Natural Formation on Cape Breton Island as inferred from fossils. History, for providing collection numbers. Sören Jensen and This suggests that future work is needed to evaluate possible Teodoro Palacios acknowledge funding from Ministerio de regional differences between the sedimentary successions Economía. Industria y Competitividad grant CGL 2017-

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 267 87631-P. Sandra Barr acknowledges support from Natu- org/10.4095/208235 ral Sciences and Engineering Research Council of Canada Barr, S.M., Davis, D.W., Kamo, S., and White, C.E. 2003. Sig- Discovery Grant RGPIN-2016-04860. We thank journal nificance of U–Pb ages of detrital zircon in quartzite from reviewers Robert MacNaughton and Andrea Mills for their peri-Gondwanan terranes, New Brunswick and Nova helpful comments which improved the clarity and readabil- Scotia, Canada. Precambrian Research, 126, pp. 123–145. ity of the manuscript. https://doi.org/10.1016/S0301-9268(03)00192-X Barr, S.M., Hamilton, M.A., Samson, S.D., Satkoski, A., and White, C.E. 2012. 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Early Cambri- nology, 12, pp. 215–220. https://doi.org/10.1080/019161 an Teichichnus-dominated ichnofabrics and palaeoen- 22.1988.9989345 vironmental analysis of the Caerfai Group, southwest Weeks, F.J. 1954. Southeast Cape Breton Island, Nova Scotia. Wales, UK. Palaeogeography, Palaeoclimatology, Palae- Geological Survey of Canada, Memoir 277, 112 p. https:// oecology, 297, 239–251. https://doi.org/10.1016/j.pa- doi.org/10.4095/101500 laeo.2010.07.030 Willner, A.P., Barr, S.M., Gerdes, A., Massonne, H.-J., and Ludwig, K.R. 2012. Isoplot 4.15: A geochronological toolkit White, C.E. 2013. Origin and evolution of Avalonia: evi- for Microsoft Excel. Berkeley Geochronological Center. dence from U–Pb and Lu–Hf isotopes in zircon from the URL , March 2020. gium. Journal of the Geological Society, London, 170, pp. McFarlane, C.R.M. and Luo, Y. 2012. Modern analytical fa- 769–784. https://doi.org/10.1144/jgs2012–152 cilities: U–Pb geochronology using 193 nm Excimer LA- Editorial responsibility: Robert A. Fensome ICP-MS optimized for in-situ accessory mineral dating in thin sections. Geoscience Canada, 39(3), pp. 158–172. Palacios, T., Jensen, S., Barr, S.M., and White, C.E. 2009. APPENDIX A: U–PB DATA TABLES

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 269 % 99.6 99.3 96.6 95.5 98.7 97.2 99.3 95.9 conc 101.2 100.0 101.8 100.9 100.2 9 9 9 9 9 9 9 9 9 9 8 8 9 ± 2σ U Pb/ 238 206 ± 2σ U Pb/ 235 207 Calculated ages ± 2σ Pb Pb/ 206 207 ± 2σ Pb Pb/ 206 207 3 EC ± 2σ U Isotopic ratios Pb/ Pb-based correction (98.5 %Pb*). 238 206 208 ± 2σ U Pb/ 3.022 0.085 0.221 0.004 0.569 0.1000 0.0016 1624 30 1412 21 1287 19 79.2 4.020 0.110 0.272 0.004 0.543 0.1076 0.0018 1759 31 1636 23 1552 22 88.2 0.687 0.025 0.086 0.002 0.205 0.0588 0.00183.569 0.092 560 0.2670.683 67 0.004 0.032 0.458 0.086 530 0.0978 0.002 0.0013 0.070 15 0.0583 1583 0.0025 529 25 10 1542 5410.883 99.8 94 21 0.027 1526 0.105 525 0.002 21 0.113 20 0.0614 96.4 0.0014 531 6530.668 49 0.023 0.0840.683 641 0.002 0.028 0.175 15 0.085 0.0583 0.002 0.0017 645 0.2260.674 0.0592 10 0.028 541 0.0020 100.7 0.086 64 0.002 574 0.036 5200.679 73 0.0574 0.025 0.0019 14 0.084 5264.004 0.002 0.120 507 520 0.142 17 0.285 73 0.0591 0.005 0.0018 524 0.4280.662 521 0.1024 0.028 571 0.0019 17 0.0800.690 66 1668 0.002 0.024 531 0.225 34 0.0870.668 0.0605 524 0.002 0.031 0.0022 1634 0.153 15 0.084 0.0580 24 0.002 622 0.0017 520 0.270 16180.856 78 0.0576 0.039 530 24 0.0020 0.102 513 64 97.0 0.002 515 0.135 170.725 532 76 0.0609 0.033 0.0025 496 14 0.0900.639 519 0.002 0.022 636 537 0.080 18 0.0770.686 0.0586 88 0.002 0.032 0.0025 520 0.540 0.085 0.0604 625 0.002 552 0.0014 0.082 210.682 93 0.0589 0.028 618 0.0025 629 0.084 552 50 0.001 11 563 100.6 0.207 19 501 92 0.0591 0.0021 554 13 528 10 571 478 100.4 19 77 523 526 10 17 99.1 519 2.438 0.098 0.193 0.004 0.464 0.0917 0.0028 1461 58 1251 29 11391.636 0.081 22 0.159 78.0 0.005 0.871 0.0753 0.0019 1077 51 981 30 951 27 88.3 1.298 0.049 0.133 0.003 0.694 0.0711 0.0016 960 46 848 19 805 17 83.8 3.282 0.087 0.256 0.004 0.2660.668 0.0934 0.027 0.0013 0.0810.789 1496 0.001 0.033 0.486 26 0.097 0.0599 0.002 1476 0.0020 0.271 20 0.0598 600 0.0021 1470 72 21 5965.738 98.2 518 76 0.160 17 0.350 587 0.006 504 0.480 19 0.1201 0.0022 5940.688 1958 0.032 11 101.2 33 0.0854.435 0.002 0.130 1935 0.238 0.302 0.0595 25 0.005 0.0024 0.393 1931 0.1078 585 29 0.0021 88 98.6 1763 360.710 531 0.035 1717 20 0.090 24 0.002 524 0.159 16980.661 0.0578 10 0.023 26 0.0026 0.083 98.7 96.3 0.001 522 0.198 99 0.0585 0.0016 545 549 20 60 555 516 11 101.8 13 512 0.852 0.025 0.103 0.002 0.399 0.0609 0.0012 634 42 625 140.678 0.030 629 0.081 0.002 10 100.6 0.1281.144 0.0606 0.032 0.0024 0.127 0.002 625 0.627 85 0.0655 0.0010 524 789 18 32 502 774 15 769 12 97.4 1.564 0.043 0.146 0.003 0.777 0.0776 0.0010 1136 26 955 17 881 14 77.5 235 207 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ew Br unswick. Corrections N f 2 % Pb* Pb niversity o 204 cps Pb/ he U 206 41.9 5548 98.89 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 183.3 8210 98.74 106.3 2624 98.38 525.0 22375 99.57 1600.0 101000 98.13 1800.0 60940 99.35 % ± Pb cps 204 204 16 11 14 200.015 256611 99.74 375.0 1100.0 30050 99.74 1056011 99.75 220.014 5146 99.87 10 175.010 346.4 2785 99.74 324311 333.3 99.63 15 1100.0 4803 99.89 12 166.7 11490 99.61 1311 5514 300.0 99.69 260.0 312014 137.5 99.57 3690 99.80 15 1349 350.0 99.85 1519 2445 500.0 99.68 166.7 608012 237.5 99.75 6233 99.51 2071 600.0 99.71 7975 99.62 17 21 13 18 14 233.3 3243 99.69 12 -240.013 3881013 99.72 -1300.0 -260.0 9500 99.53 3158013 99.52 -433.312 9810 -200.0 99.81 19870 99.72 13 1300.0 85700 99.82 1911 633.3 9063 183.3 99.58 13117 99.89 11 -122.2 120050 99.83 amples an alyzed at t Pb cps ± 2σ 204 1 6 7 4 1 5 8 3 3 1 9 4 5 8 4 3 9 8 2 4 1 6 1 3 6 1 -5 -1 -5 -3 -6 -9 Pb ircon s cps 204 de trital z Th/U f Th (ppm) U (ppm) sotopic an alyses o Pb no correction cps); (100 2 = threshold % 204 i -Pb Zr cps 90 2.13E+08 207.71.78E+08 67.7 3.07 459 16 84.2 5.45 2.19E+08 547 34.73 15.75 1.96E+08 168.7 127.3 1.33 1.76E+08 1237 238.8 5.18 31 2.18E+08 446 32.1 13.89 1.86E+081.95E+08 469 210.21.86E+08 266.71.85E+08 1.76 121 2222.01E+08 1.74 206.1 103 427.11.85E+08 1.08 73.6 122.2 101 1.401.77E+08 60.8 4.23 14 111.7 2.01 121.68E+08 70.9 268.21.84E+08 1.58 37.66 109.51.89E+08 85.7 7.12 101.3 119 86.641.78E+08 0.92 714 1.17 99.74 1.76E+08 274 113.11.90E+08 165 108.61.87E+08 54.1 1.66 2.09 164.61.82E+08 60 241.51.85E+08 90.9 1.81 145.1 1.81 134.81.69E+08 1.66 175.4 79.6 91.251.84E+08 1.69 1.92 152.61.90E+08 209.71.75E+08 72.3 182.9 2.11 1.92E+08 134 1.15 1.90E+08 818 114 96.7 13.1 1.18 2.05E+08 103.6 62.44 195.71.62E+08 0.93 1.94E+08 184 7571.94E+08 1.06 188 5901.91E+08 322 87.6 1.28 188.81.83E+08 148.5 2.15 85.6 2.17 620 2.21 32.5 19.08 a a,b a a,b a,b a a a a,b a a a a,b a a a a a,b a a a a a,b a a a a a A-ICP-MS U A1. L Sample Grid Zone 21T (WGS84) 290042 5099656 290042 (WGS84) 21T Zone Grid SMB17-234 R un 1 Table Corrections: 1 = threshold = threshold 1 Corrections: SMB17-234 - 1 SMB17-234 - 2 SMB17-234 - 3 SMB17-234 - 4 SMB17-234 - 5 SMB17-234 - 6 SMB17-234 - 7 SMB17-234 - 8 SMB17-234 - 9 SMB17-234 - 10 SMB17-234 - 11 SMB17-234 - 12 SMB17-234 - 13 SMB17-234 - 14 SMB17-234 - 15 SMB17-234 - 16 SMB17-234 - 17 SMB17-234 - 18 SMB17-234 - 20 SMB17-234 - 21 SMB17-234 - 22 SMB17-234 - 23 SMB17-234 - 24 SMB17-234 - 25 SMB17-234 - 26 SMB17-234 - 27 SMB17-234 - 28 SMB17-234 - 29 SMB17-234 - 30 SMB17-234 - 31 SMB17-234 - 32 SMB17-234 - 33 SMB17-234 - 34 SMB17-234 - 35

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 270 % 97.1 97.5 78.8 89.9 99.8 99.6 91.7 88.9 96.0 76.9 99.3 89.2 93.7 95.2 89.2 94.0 96.7 93.4 92.7 93.1 99.0 79.1 84.7 78.9 98.9 93.9 95.7 81.9 73.0 72.2 81.6 67.4 conc 105.7 102.5 101.8 9 7 8 8 9 7 8 7 7 7 6 7 7 7 45 15 29 24 10 10 13 27 29 20 11 18 ± 17 18 12 20 11 14 26 13 14 2σ U Pb/ 698 554 582 522 656 451 475 830 529 676 663 668 527 963 505 612 486 515 533 497 841 907 543 559 870 1429 2010 1428 1175 1799 238 1159 1692 1983 2057 1184 206 8 8 8 9 19 49 19 17 14 24 23 19 12 16 21 26 25 25 25 ± 13 13 12 14 11 13 13 10 13 15 16 24 11 15 10 14 2σ U 716 555 584 538 738 502 518 902 533 758 Pb/ 708 701 591 537 520 572 502 894 549 595 634 556 996 1390 1985 1593 1190 1785 1265 1839 1017 1049 2033 2482 1283 235 207 Calculated ages 61 77 69 58 30 31 48 40 71 45 61 41 89 ± 28 41 56 59 73 57 73 29 14 41 38 11 88 83 29 37 13 15 16 32 2σ 111 121 Pb 778 571 589 604 994 728 571 705 Pb/ 851 819 838 671 660 728 511 571 732 694 718 1961 1813 1352 1079 1224 1768 1011 1465 1997 1028 1243 1221 2072 2850 1450 1290 206 207 ± 2σ 0.0019 0.0020 0.0019 0.0050 0.0021 0.0019 0.0016 0.0017 0.0012 0.0017 0.0025 0.0024 0.0033 0.0021 0.0032 0.0009 0.0013 0.0014 0.0010 0.0015 0.0016 0.0018 0.0005 0.0017 0.0010 0.0021 0.0017 0.0019 0.0019 0.0008 0.0024 0.0025 0.0009 0.0011 0.0014 Pb Pb/ 206 0.0651 0.1203 0.1108 0.0866 0.0591 0.0596 0.0600 0.0723 0.0636 0.0754 0.0811 0.1081 0.0591 0.0629 0.0729 207 0.0674 0.0664 0.0919 0.1228 0.0735 0.0819 0.0670 0.0810 0.0619 0.1281 0.0616 0.0636 0.0575 0.2030 0.0912 0.0591 0.0637 0.0626 0.0633 0.0839 3 EC 0.378 0.535 0.670 0.352 0.407 0.170 0.328 0.586 0.300 0.674 0.549 0.315 0.156 0.034 0.240 0.247 0.511 0.763 0.573 0.197 0.449 0.306 0.817 0.225 0.660 0.004 0.017 0.109 0.721 0.544 0.025 0.335 0.716 0.100 0.719 ± 2σ 0.003 0.006 0.005 0.009 0.002 0.002 0.002 0.002 0.001 0.004 0.005 0.006 0.002 0.001 0.003 0.001 0.002 0.003 0.004 0.002 0.002 0.001 0.002 0.001 0.004 0.001 0.001 0.001 0.006 0.002 0.001 0.001 0.001 0.001 0.003 U Isotopic ratios Pb/ Pb-based correction (98.5 %Pb*). 238 0.114 0.366 0.248 0.248 0.090 0.094 0.084 0.107 0.072 0.138 0.200 0.322 0.086 0.076 0.111 0.108 0.109 0.197 0.300 0.139 0.151 0.085 0.161 0.082 0.360 0.078 0.086 0.080 0.376 0.202 0.088 0.091 0.100 0.083 0.144 206 208 ± 2σ 0.038 0.170 0.110 0.190 0.033 0.030 0.024 0.037 0.019 0.051 0.086 0.150 0.042 0.026 0.053 0.016 0.025 0.045 0.060 0.030 0.040 0.023 0.023 0.020 0.083 0.023 0.020 0.021 0.170 0.035 0.028 0.041 0.014 0.015 0.036 U Pb/ 1.025 6.076 3.806 2.980 0.733 0.782 0.702 1.069 0.639 1.436 2.235 4.812 0.701 0.668 1.111 235 1.009 0.996 2.479 5.117 1.414 1.727 0.792 1.812 0.699 6.411 0.670 0.757 0.641 2.539 0.720 0.801 0.867 0.730 1.669 207 10.530 3 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Corrections 2 % 99.69 99.99 97.46 99.73 99.66 99.68 99.60 98.64 98.99 98.85 99.67 99.95 99.69 99.12 98.64 Pb* 99.27 99.43 98.33 97.61 99.17 98.36 98.76 98.72 99.28 99.36 99.25 99.21 99.60 91.11 98.56 99.56 97.64 99.58 99.19 98.02 Pb 362 574 9120 8540 3903 3625 6460 2854 3600 1174 204 2820 5845 3323 2929 2820 6182 1017 6543 3570 8760 3533 3222 9945 1047 4100 26900 17300 40100 51500 12708 24280 17090 16657 135000 cps 156700 Pb/ 206 57.7 84.6 42.4 35.7 87.1 54.3 22.4 48.6 66.7 21.4 68.2 18.3 -86.7 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 514.3 200.0 433.3 250.0 173.3 107.7 100.0 170.0 260.0 115.4 533.3 144.4 190.0 340.0 171.4 100.0 -600.0 -800.0 -316.7 1200.0 % ± Pb cps -166.7 204 -2800.0 204 36 10 15 18 13 12 10 26 16 14 19 13 16 11 28 25 27 19 22 17 17 12 15 13 15 16 13 19 17 15 15 39 12 11 28 Pb cps ± 2σ 204 7 5 3 1 4 1 5 3 9 5 7 -3 -2 -6 26 15 13 16 13 66 -9 -1 Pb 70 31 35 98 35 10 18 70 13 10 22 11 -15 213 cps 204 1.09 6.55 1.71 2.96 8.77 4.26 3.54 1.42 1.17 1.74 1.67 0.48 5.41 5.68 4.59 4.65 2.18 2.92 1.62 1.76 9.66 1.96 1.87 1.67 5.50 2.07 4.23 1.39 73.78 31.64 45.67 30.59 11.15 20.47 20.02 Th/U 85 211 155 131 157 763 198 156 185 21.7 5.92 72.7 38.2 50.8 48.1 93.8 29.8 42.4 81.3 73.1 74.4 82.7 17.2 43.5 1020 Th 104.9 118.4 28.19 148.4 129.9 147.8 128.7 48.71 190.5 299.2 (ppm) 460 892 624 335 181 813 462 720 266 543 805 871 416 292 38.8 56.6 1601 1114 U 2230 1361 1912 1297 124.3 216.5 170.2 132.9 227.6 175.6 339.9 162.1 240.9 145.7 352.1 254.1 308.1 (ppm) Pb no correction cps); (100 2 = threshold % 204 Zr cps 90 2.23E+08 1.81E+08 1.57E+08 2.21E+08 1.40E+08 1.55E+08 1.50E+08 1.95E+08 1.50E+08 1.56E+08 1.83E+08 1.78E+08 1.87E+08 1.81E+08 1.80E+08 2.52E+08 2.29E+08 2.13E+08 2.21E+08 2.37E+08 2.38E+08 1.86E+08 2.19E+08 2.05E+08 1.44E+08 2.10E+08 2.44E+08 2.15E+08 2.08E+08 2.15E+08 2.02E+08 2.16E+08 2.21E+08 2.00E+08 2.48E+08 a a a a a a a a a a a a,b a a a a a a ontinued. A1. C Sample Table 1) Run from distinguish to 2 italics (in SMB17-234 Run Corrections: 1 = threshold = threshold 1 Corrections: SMB17-234 - 35a SMB17-234 - 36a SMB17-234 - 36a SMB17-234 - 37 SMB17-234 - 38 SMB17-234 - 39 SMB17-234 - 40 SMB17-234 - 41 SMB17-234 - 42 SMB17-234 - 43 SMB17-234 - 44 SMB17-234 - 45 SMB17-234 - 46 SMB17-234 - 47 SMB17-234 - 48 1 - SMB17-234 2 - SMB17-234 3 - SMB17-234 4 - SMB17-234 5 - SMB17-234 6 - SMB17-234 7 - SMB17-234 8 - SMB17-234 9 - SMB17-234 10 - SMB17-234 11 - SMB17-234 12 - SMB17-234 13 - SMB17-234 14 - SMB17-234 15 - SMB17-234 16 - SMB17-234 17 - SMB17-234 18 - SMB17-234 19 - SMB17-234 20 - SMB17-234

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 271 % 98.3 89.4 91.0 95.5 99.3 93.2 91.0 99.9 98.9 97.1 89.7 85.8 79.6 83.7 84.8 83.5 87.9 78.7 82.2 98.6 98.3 94.0 92.8 91.9 96.0 90.0 99.7 92.1 80.0 66.0 86.1 84.9 80.4 79.8 80.6 87.9 conc 7 6 7 6 7 8 8 7 7 7 8 7 ± 11 14 16 17 23 16 18 18 16 12 17 19 23 14 21 16 12 17 27 15 19 18 15 11 2σ U Pb/ 601 511 487 780 505 533 520 507 531 720 506 545 880 508 819 531 521 722 238 1229 1436 1533 1615 1383 1729 1347 1239 1307 1874 1928 1236 2047 1502 1175 1665 1587 1436 206 6 8 9 ± 10 14 14 11 13 15 11 18 28 11 10 12 11 15 10 11 21 15 11 10 36 12 11 13 10 16 12 12 12 12 14 12 15 2σ U Pb/ 572 535 787 528 611 558 557 537 532 766 511 681 567 853 538 530 821 1311 1598 1670 1750 1499 1843 1015 1493 1338 1350 1956 1965 1283 2050 1555 1256 1854 1774 1581 235 207 Calculated ages ± 47 70 51 57 21 67 61 41 56 53 19 13 33 19 23 18 16 32 26 20 41 64 63 59 24 12 26 29 17 18 17 18 16 12 42 2σ 132 Pb Pb/ 832 530 738 803 629 653 718 778 560 545 922 800 952 567 574 1433 1804 1147 1831 1905 1656 1967 1334 1711 1508 1408 2040 2007 1374 2054 1631 1384 2072 1989 1782 1116 206 207 ± 2σ 0.0015 0.0035 0.0021 0.0016 0.0016 0.0006 0.0009 0.0008 0.0013 0.0012 0.0015 0.0010 0.0011 0.0014 0.0015 0.0010 0.0011 0.0009 0.0018 0.0020 0.0019 0.0013 0.0012 0.0011 0.0015 0.0018 0.0010 0.0013 0.0008 0.0013 0.0022 0.0011 0.0007 0.0016 0.0017 0.0016 Pb Pb/ 206 207 0.0668 0.0580 0.0639 0.0659 0.0607 0.0614 0.0904 0.1103 0.0780 0.1119 0.1166 0.1017 0.1207 0.0858 0.1048 0.0940 0.0892 0.1258 0.1235 0.0633 0.0651 0.0876 0.1268 0.0588 0.0584 0.0698 0.1004 0.0658 0.0881 0.1281 0.0708 0.1222 0.1089 0.0768 0.0590 0.0592 3 EC 0.129 0.443 0.325 0.252 0.047 0.427 0.236 0.709 0.673 0.449 0.638 0.545 0.413 0.907 0.561 0.589 0.606 0.564 0.487 0.094 0.442 0.398 0.544 0.223 0.279 0.598 0.601 0.417 0.770 0.670 0.957 0.633 0.550 0.588 0.212 0.005 ± 2σ 0.001 0.001 0.001 0.002 0.001 0.001 0.003 0.003 0.002 0.003 0.005 0.003 0.004 0.003 0.004 0.003 0.003 0.004 0.005 0.001 0.001 0.003 0.005 0.001 0.001 0.002 0.003 0.001 0.003 0.004 0.005 0.004 0.003 0.002 0.001 0.001 U Isotopic ratios Pb/ Pb-based correction (98.5 %Pb*). 238 0.083 0.082 0.078 0.129 0.081 0.098 0.210 0.250 0.088 0.269 0.285 0.239 0.308 0.146 0.232 0.212 0.225 0.337 0.349 0.084 0.082 0.211 0.374 0.086 0.086 0.118 0.262 0.082 0.200 0.295 0.136 0.279 0.250 0.119 0.086 0.084 206 208 ± 2σ 0.018 0.045 0.024 0.031 0.019 0.011 0.038 0.046 0.024 0.058 0.084 0.045 0.065 0.056 0.065 0.040 0.049 0.067 0.110 0.022 0.025 0.040 0.090 0.014 0.019 0.037 0.053 0.017 0.039 0.087 0.085 0.069 0.043 0.034 0.020 0.018 U Pb/ 235 0.758 0.660 0.696 1.174 0.684 0.826 2.638 3.829 0.957 4.180 4.612 3.381 5.144 1.721 3.358 2.737 2.784 5.867 5.950 0.731 0.734 2.543 6.540 0.697 0.690 1.128 3.629 0.749 2.447 5.209 1.325 4.740 3.747 1.245 0.700 0.687 207 3 3 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE - - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Corrections 2 % Pb* 98.78 97.79 98.97 99.54 99.38 99.75 98.82 97.52 97.46 97.89 97.87 98.28 98.20 97.91 97.76 98.52 99.37 98.77 99.21 99.18 98.89 99.24 99.78 99.72 99.64 99.26 99.26 98.89 98.83 96.17 99.46 97.04 97.79 98.40 99.65 99.63 Pb 815 897 204 1344 3768 6342 3580 3246 9373 3304 1429 1566 8850 4967 3050 2381 3124 1774 2146 7423 3645 26700 24200 19070 10580 11743 14571 66100 42733 12722 15570 20008 23500 27270 36090 cps 175600 115300 Pb/ 206 62.4 66.7 21.6 35.1 71.4 48.0 19.2 59.5 14.4 26.8 59.1 75.8 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 107.1 141.7 500.0 300.0 100.0 166.7 118.2 137.5 108.3 130.0 366.7 137.5 185.7 157.1 125.0 122.2 700.0 466.7 % ± Pb cps -350.0 -650.0 1500.0 1500.0 1200.0 204 -2000.0 204 10 15 14 21 33 17 10 18 25 12 12 15 29 15 13 15 11 13 13 11 11 12 13 11 22 15 11 14 31 28 19 13 25 14 20 13 Pb cps ± 2σ 204 1 2 6 9 1 8 3 8 1 7 7 1 9 2 6 -4 -1 -2 Pb 16 14 21 97 94 12 35 12 25 11 12 10 37 12 71 22 33 151 215 cps 204 1.40 3.56 8.50 4.56 2.70 2.30 1.80 1.16 2.53 1.74 1.71 1.68 4.58 1.47 1.57 3.14 1.11 1.65 1.46 1.90 1.41 1.85 2.10 1.82 7.00 1.63 6.25 3.88 3.88 6.50 11.60 41.29 21.93 23.72 14.32 14.62 Th/U 31 44 168 116 248 476 225 555 127 94.9 32.8 48.2 53.6 79.3 98.3 97.8 90.7 98.3 47.6 98.1 Th 1321 109.1 243.6 160.9 167.8 201.7 13.15 53.88 105.9 149.8 107.6 155.9 147.9 109.1 126.4 118.9 (ppm) 254 986 925 406 965 778 423 491 773 399 696 59.9 U 1130 1284 1856 1280 598.1 218.4 644.6 690.4 135.7 189.9 415.8 270.4 362.8 246.6 316.9 152.5 161.8 142.6 172.3 149.2 182.2 314.1 196.2 687.1 (ppm) Pb no correction cps); (100 2 = threshold % 204 Zr cps 90 2.17E+08 2.03E+08 1.97E+08 2.19E+08 1.97E+08 1.56E+08 1.88E+08 2.15E+08 2.47E+08 2.48E+08 2.00E+08 2.02E+08 2.22E+08 2.31E+08 1.99E+08 2.18E+08 2.45E+08 2.08E+08 1.35E+08 1.94E+08 2.00E+08 2.23E+08 2.41E+08 1.99E+08 2.25E+08 2.13E+08 2.03E+08 2.13E+08 2.13E+08 2.11E+08 2.14E+08 2.17E+08 2.23E+08 2.14E+08 2.05E+08 2.13E+08 a a a a,b a,b a a a a a a a a a a a,b a a ontinued. A1. C Sample Table Corrections: 1 = threshold = threshold 1 Corrections: 21 - SMB17-234 22 - SMB17-234 23 - SMB17-234 24 - SMB17-234 25 - SMB17-234 26 - SMB17-234 27 - SMB17-234 28 - SMB17-234 29 - SMB17-234 30 - SMB17-234 31 - SMB17-234 32 - SMB17-234 33 - SMB17-234 34 - SMB17-234 35 - SMB17-234 36 - SMB17-234 37 - SMB17-234 38 - SMB17-234 39 - SMB17-234 40 - SMB17-234 41 - SMB17-234 42 - SMB17-234 43 - SMB17-234 44 - SMB17-234 45 - SMB17-234 46 - SMB17-234 47 - SMB17-234 48 - SMB17-234 49 - SMB17-234 50 - SMB17-234 51 - SMB17-234 52 - SMB17-234 53 - SMB17-234 54 - SMB17-234 55 - SMB17-234 56 - SMB17-234

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 272 % 99.4 94.8 93.8 92.4 63.4 92.6 95.5 91.2 97.9 93.6 88.4 98.5 conc 100.7 9 9 7 6 7 9 7 8 9 7 9 9 6 ± 2σ U Pb/ 511 470 751 762 10 69.1 238 1145 13 82.8 1004 11 76.4 206 9 7 9 9 8 8 ± 2σ U Pb/ 235 207 Calculated ages ± 2σ Pb Pb/ 206 207 ± 2σ Pb Pb/ 206 207 3 EC ± 2σ U Isotopic ratios Pb/ Pb-based correction (98.5 %Pb*). 238 206 208 ± 2σ U Pb/ 1.995 0.072 0.166 0.003 0.604 0.0873 0.0021 1367 46 1113 25 992 19 72.6 0.864 0.025 0.104 0.002 0.3844.969 0.0604 0.130 0.0011 0.318 0.005 618 0.5396.674 39 0.1132 0.180 0.0017 0.372 632 1851 0.007 0.744 14 27 0.1305 1813 0.0017 636 23 2105 1780 23 25 2068 96.1 23 2037 31 96.8 0.725 0.034 0.090 0.002 0.2490.762 0.0592 0.031 0.0026 0.093 0.002 574 0.217 95 0.0599 0.0020 555 600 22 72 554 574 10 19 99.9 571 1.418 0.050 0.125 0.003 0.798 0.0830 0.0016 1269 38 896 21 757 16 59.6 235 6.923 0.110 0.336 0.005 0.690 0.1508 0.0015 2355 17 2101 14 1868 24 79.3 0.834 0.021 0.092 0.001 0.2120.702 0.0660 0.014 0.0015 0.082 0.001 806 0.377 48 0.0621 0.0011 615 678 11 38 568 539 5.233 0.084 0.306 0.004 0.811 0.1248 0.00114.831 2026 0.100 16 0.256 0.005 1859 0.819 0.1373 15 0.0016 17207.760 2193 0.160 22 20 0.356 84.9 0.005 1788 0.764 0.1595 19 0.0020 1467 2450 27 211.348 66.9 0.021 2201 0.1232.223 0.002 19 0.035 0.455 0.169 19622.343 0.0795 0.002 0.028 0.0010 22 0.736 0.194 0.0961 0.002 1184 80.1 0.0008 0.525 241.188 0.0881 1549 0.029 0.0007 0.115 16 866 1384 0.002 1188 0.480 151.379 0.0749 0.035 11 0.0014 1225 0.1221.315 1006 0.002 1066 0.018 0.300 13 0.126 38 0.0824 0.002 64.9 0.0019 0.412 794 0.0763 1255 0.0008 13 45 1103 702 22 879 15 853 744 10 84.6 1.963 0.023 0.169 0.002 0.569 0.0849 0.0006 1314 14 1103 0.681 0.019 0.0780.638 0.001 0.011 0.156 0.076 0.0629 0.001 0.0017 0.4080.632 0.0616 0.029 705 0.0008 0.0780.917 58 0.002 0.021 659 0.022 0.103 0.0587 526 28 0.001 0.0028 0.227 11 0.0653 501 556 0.0016 487 104 784 4961.020 51 0.036 18 0.109 663 0.002 486 0.148 12 0.0675 10 0.0022 97.9 633 8531.126 68 0.026 0.114 0.002 711 0.445 18 0.0717 0.0014 668 977 10 40 93.9 5.158 765 0.082 0.3130.703 13 0.005 0.021 0.735 0.085 698 0.735 0.1195 0.001 0.024 0.0011 0.385 0.084 0.0599 1949 0.001 0.0016 0.194 16 0.0633 1845 600 0.0020 58 14 718 1756 538 67 24 12 90.1 558 527 144.249 0.065 522 0.286 0.004 0.762 0.1078 0.0013 1763 22 1683 13 1620 21 91.9 2.905 0.049 0.242 0.003 0.329 0.0868 0.0013 1356 29 1382 13 1397 17 103.0 4.174 0.049 0.279 0.003 0.700 0.1087 0.0007 1777 11 1669 10 1586 17 89.2 3.110 0.044 0.243 0.003 0.756 0.0932 0.0007 1492 14 1434 11 1402 17 94.0 0.695 0.016 0.085 0.001 0.044 0.0595 0.0014 585 51 535 10 526 207 16.580 0.220 0.553 0.008 0.753 0.2188 0.0020 2972 15 2910 13 2838 33 95.5 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Corrections 2 % Pb* Pb 204 cps Pb/ 206 68.9 2111 97.75 28.6 2825 97.69 41.7 3575 94.59 57.6 7045 95.52 32.3 5858 97.19 78.925.0 2253 97.79 1630 98.57 57.1 9925 98.56 41.7 9000 98.77 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 164.9 4198 99.07 166.7 13583433.3 98.14 89100240.0 98.87 8940 98.51 -213.3 106330 98.19 % ± Pb cps -250.0 55100 99.85 2300.0 390300 95.86 204 204 1014 152.3 777113 466.7 99.90 31200 260.0 99.70 17156 99.39 31 32 14 -466.7 13800 99.71 16 15 19 23 10 21 13 12 15 16 16 12 200.017 3578 99.15 212.5 2066 99.48 14 233.3 3527 99.16 1310 216.717 333.3 20533 283.3 98.62 5850 99.47 2963 99.22 1311 433.3 1100.0 31933 99.03 28610 99.38 10 15 10 -1000.0 163200 99.51 10 -176.4 24200 99.57 Pb cps ± 2σ 204 7 3 5 1 1 6 3 5 6 8 6 6 3 6 63 9 1 -3 -4 -1 -6 Pb cps 204 Th/U Th (ppm) U (ppm) Pb no correction cps); (100 2 = threshold % 204 Zr cps 90 32E+08 721 92.4 7.80 45 Grid Zone 21T (WGS84) 289998 5099504 2. 2.34E+08 595 83.4 7.13 -15 1.95E+08 468.32.10E+08 10.98 149.41.85E+08 42.65 101.8 287.21.92E+08 1.47 138.61.94E+08 133 18 223.3 2.16 117 18 312.1 1.18 0.72 100.0 781 99.68 2.17E+08 382.7 137.8 2.782.10E+08 56 388.8 150.9 2.582.46E+08 36 2.59E+08 477.9 439.7 843.4 1.09 87.4 33 9.65 2.11E+082.44E+08 5252.18E+08 1631 80.5 1136 765 6.52 109.32.12E+08 2.13 10.39 1.94E+08 299.6 65 2.30E+08 944 821.84E+08 270.1 200.3 3.65 70.8 4.71 751 3.81 36 31.3 19 23.99 64 1.93E+08 186.2 152.32.29E+08 1.22 1251 405.6 3.08 28 2.04E+08 209.72.20E+08 118.4 625 1.77 1.96E+08 596 162.82.46E+08 1.05 94.5 814 21 1.72 20.9 122.21E+08 38.951.96E+08 18 510 57.1 156 20 219 97.6 2.33 2919 1.60 111.1 99.36 2.20E+08 602 6350 99.49 32.3 18.64 292.04E+08 162.13E+08 300 163.41.52E+08 91.4 102.1 223.9 55.22.13E+08 3.28 1.60 190.8 224.1 1.17 131.7 30522.34E+08 98.90 1.70 1352.10E+08 208.72.06E+08 88 1.532.08E+08 218 261 11 276.8 0.96 209 198.8 13 1.25 1.39 118.2 9018 98.56 a a a a a a a a a a a,b a a a a

a a a a a ontinued. A1. C Sample SMB17-235 R un 1 Table SMB17-235 - 7 Corrections: 1 = threshold = threshold 1 Corrections: 57 - SMB17-234 58 - SMB17-234 59 - SMB17-234 60 - SMB17-234 61 - SMB17-234 62 - SMB17-234 63 - SMB17-234 64 - SMB17-234 65 - SMB17-234 66 - SMB17-234 67 - SMB17-234 69 - SMB17-234 70 - SMB17-234 71 - SMB17-234 72 - SMB17-234 73 - SMB17-234 74 - SMB17-234 75 - SMB17-234 76 - SMB17-234 77 - SMB17-234 78 - SMB17-234 79 - SMB17-234 80 - SMB17-234 81 - SMB17-234 82 - SMB17-234 83 - SMB17-234 84 - SMB17-234 85 - SMB17-234 SMB17-235 - 1 SMB17-235 - 2 SMB17-235 - 3 SMB17-235 - 4 SMB17-235 - 5 SMB17-235 - 6

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 273 % 96.3 97.9 99.8 95.4 83.9 98.8 98.2 96.9 99.5 99.9 98.1 99.6 98.2 98.0 98.6 94.6 96.9 99.0 99.5 98.9 99.5 95.7 69.9 94.5 76.4 84.0 91.2 91.2 94.1 72.2 66.4 conc 100.2 104.5 100.0 100.0 8 8 9 8 9 9 9 9 9 9 11 12 11 22 26 22 21 10 12 10 25 10 12 21 19 13 16 16 11 11 14 24 33 16 17 ± 2σ U Pb/ 554 820 534 549 528 684 527 664 707 566 530 533 558 548 531 567 604 935 680 836 495 535 787 521 904 841 1575 1798 1532 1497 1713 1265 1114 1675 1449 238 206 20 19 14 16 14 16 18 14 18 19 15 14 17 17 20 24 23 26 23 14 22 31 18 23 22 24 23 23 22 20 17 18 47 24 69 ± 2σ U 555 862 555 548 539 685 552 702 730 572 537 543 576 550 537 575 607 720 830 543 535 784 620 971 Pb/ 1591 1808 1548 1518 1067 1714 1287 1233 1014 1756 1495 235 207 Calculated ages 89 45 56 68 51 51 74 41 54 86 62 59 67 71 26 33 33 34 54 97 72 52 64 23 74 41 31 59 31 97 35 69 ± 2σ 123 111 111 Pb 552 977 643 534 574 695 552 646 822 806 618 765 574 578 629 541 556 593 611 853 800 787 Pb/ 1606 1804 1559 1528 1338 1721 1322 1459 1008 1252 1267 1837 1540 206 207 ± 2σ 0.0024 0.0016 0.0016 0.0014 0.0018 0.0014 0.0020 0.0015 0.0017 0.0033 0.0017 0.0021 0.0032 0.0013 0.0017 0.0024 0.0013 0.0034 0.0017 0.0016 0.0019 0.0019 0.0030 0.0018 0.0015 0.0027 0.0015 0.0017 0.0021 0.0013 0.0041 0.0020 0.0023 0.0022 0.0035 Pb Pb/ 206 0.0586 0.0717 0.0611 0.0990 0.0581 0.0592 0.1103 0.0626 0.0966 0.0586 0.0950 0.0612 0.0860 0.0665 0.0660 0.0604 0.1054 0.0647 0.0592 0.0593 0.0607 0.0583 0.0587 0.0853 0.0597 0.0602 0.0916 0.0675 0.0728 0.0823 0.0829 0.0658 0.0654 0.1123 0.0956 207 3 EC 0.117 0.325 0.173 0.536 0.209 0.442 0.365 0.307 0.386 0.309 0.378 0.317 0.437 0.197 0.295 0.080 0.819 0.135 0.154 0.005 0.400 0.521 0.045 0.541 0.152 0.008 0.330 0.521 0.194 0.396 0.500 0.149 0.170 0.334 0.741 ± 2σ 0.002 0.002 0.001 0.004 0.001 0.002 0.005 0.002 0.004 0.002 0.004 0.001 0.004 0.002 0.002 0.002 0.005 0.002 0.001 0.001 0.002 0.002 0.002 0.004 0.002 0.002 0.003 0.002 0.002 0.003 0.003 0.003 0.003 0.005 0.006 U Isotopic ratios Pb/ Pb-based correction (98.5 %Pb*). 238 0.090 0.136 0.086 0.277 0.089 0.085 0.322 0.112 0.268 0.086 0.262 0.085 0.156 0.108 0.116 0.092 0.305 0.080 0.086 0.086 0.090 0.089 0.087 0.217 0.092 0.098 0.189 0.111 0.084 0.151 0.139 0.139 0.130 0.297 0.252 206 208 ± 2σ 0.034 0.042 0.024 0.098 0.027 0.024 0.140 0.032 0.100 0.044 0.097 0.030 0.085 0.028 0.037 0.034 0.110 0.040 0.024 0.023 0.029 0.029 0.037 0.078 0.025 0.039 0.065 0.037 0.029 0.047 0.120 0.051 0.045 0.130 0.310 U Pb/ 0.733 1.336 0.728 3.787 0.719 0.702 4.946 0.967 3.605 0.705 3.459 0.725 1.867 0.997 1.056 0.762 4.416 0.711 0.700 0.709 0.764 0.722 0.702 2.558 0.764 0.822 2.372 1.033 0.842 1.715 1.608 1.269 1.163 4.647 3.350 235 207 2 2 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE - - 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Corrections 2 % 99.69 99.39 99.55 99.79 99.76 99.71 99.87 99.72 99.61 99.69 99.60 99.52 97.98 99.39 99.93 99.58 99.57 98.92 99.67 99.66 99.56 99.71 99.50 99.56 99.71 99.70 98.22 99.36 98.37 96.28 99.86 98.09 99.68 98.84 97.36 Pb* Pb 479 679 978 969 969 790 1214 4776 3418 8970 3100 5438 7466 3611 9717 4896 6853 3143 7743 1071 1098 2462 1789 1028 1140 1185 2702 204 34400 14540 21470 20680 16950 19600 100120 158800 cps Pb/ 206 63.0 28.2 71.4 48.9 33.0 56.0 54.5 87.5 78.9 63.6 91.7 76.5 65.0 20.8 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 185.7 185.7 133.3 600.0 122.2 300.0 220.0 750.0 233.3 107.1 466.7 150.0 -225.0 -650.0 -260.0 -240.0 -650.0 1000.0 1200.0 1400.0 % ± Pb cps -1100.0 204 204 13 13 17 12 12 11 10 12 11 15 14 12 14 22 30 22 18 37 14 12 13 14 15 15 11 13 14 12 14 11 13 21 13 13 45 Pb cps ± 2σ 204 7 7 6 9 2 9 1 4 5 2 1 1 3 1 -8 -2 -1 -5 -5 -2 27 42 78 45 25 22 16 19 14 22 12 17 14 20 Pb 112 216 cps 204 1.19 2.89 3.81 5.60 7.12 4.99 1.26 2.55 1.79 6.69 1.74 1.81 1.59 2.04 1.00 2.32 2.98 1.68 0.96 2.59 1.24 2.46 1.91 0.84 1.37 1.33 1.71 1.88 1.00 2.81 na 11.85 14.22 22.80 Th/U 131.13 73 145 108 196 134 8.93 82.8 64.3 41.5 40.1 87.9 86.3 7.38 94.6 89.8 67.1 Th 23.56 198.9 21.54 113.2 122.1 180.1 226.4 43.92 154.5 57.39 41.79 191.9 59.22 132.1 131.8 274.2 246.7 251.8

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 274 % 96.6 95.9 93.2 90.0 82.9 93.3 conc 7 7 8 9 8 8 ± 2σ U Pb/ 546 647 238 1794 18 100.0 1472 15 99.0 206 9 9 9 9 ± 2σ U 790 540 549 49 69.5 Pb/ 3340 10 3272 30 97.0 235 207 Calculated ages 8 ± 2σ 2841 Pb Pb/ 567 206 207 ± 2σ Pb Pb/ 206 207 3 EC ± 2σ U Isotopic ratios Pb/ Pb-based correction (98.5 %Pb*). 238 206 208 ± 2σ U Pb/ 0.707 0.037 0.086 0.002 0.174 0.0598 0.0029 596 105 538 22 534 11 99.2 4.526 0.140 0.2932.435 0.006 0.082 0.688 0.213 0.1113 0.004 0.0021 0.296 0.0824 1821 0.0021 34 1255 1734 500.842 27 0.034 1250 1657 0.0996.023 0.002 24 0.170 31 0.397 1247 0.358 0.0618 91.0 0.006 0.0020 20 0.4660.734 0.1219 99.4 0.032 667 0.0022 0.084 69 1984 0.002 0.028 32 620 0.0639 1977 0.0026 18 25 738 606 1977 86 10 30 97.7 99.6 558 18 519 10 93.1 1.151 0.082 0.089 0.004 0.385 0.0957 0.0068 1542 134 780 43 549 21 70.4 2.332 0.110 0.185 0.005 0.536 0.0913 0.0031 1453 65 1221 33 1094 25 75.3 0.832 0.047 0.087 0.002 0.037 0.0700 0.0040 928 117 612 26 537 12 87.7 5.831 0.160 0.345 0.005 0.497 0.1224 0.0020 1992 29 1950 24 1909 26 95.9 1.020 1.100 0.089 0.008 0.933 0.0590 0.0770 235 4.864 0.056 0.321 0.004 0.579 0.1097 0.0007 1794 12 1798 4.890 0.071 0.3040.857 0.004 0.026 0.711 0.084 0.1169 0.001 0.0010 0.205 0.0752 1909 0.0023 15 1074 1800 616.023 12 0.090 627 1710 0.294 0.005 14 20 0.737 0.1481 89.6 520 0.0013 2324 15 1978 13 1661 22 71.5 1.398 0.110 0.1335.000 0.003 0.130 0.606 0.2743.390 0.0741 0.004 0.180 0.0047 0.416 0.246 0.1320 0.005 1044 0.0024 128 0.669 0.0985 2125 0.0036 878 32 1596 47 1821 68 807 21 1493 1559 15 41 19 77.3 1416 73.4 28 88.7 0.745 0.016 0.088 0.001 0.220 0.0614 0.00121.007 0.023 653 0.111 42 0.002 0.1290.719 0.0656 565 0.021 0.0017 0.083 0.001 794 0.069 54 0.0631 0.0019 707 712 120.885 64 0.038 680 0.094 549 0.002 10 0.206 13 96.2 0.0683 0.0028 512 878 854.707 640 0.059 0.311 20 0.004 0.560 576 0.944 0.1094 0.016 0.0009 0.106 1790 0.001 0.140 146.244 0.0643 0.082 0.0010 1768 0.361 11 0.004 752 0.514 1744 32 0.1254 18 0.0012 674 97.4 2034 17 2010 12 1986 21 97.6 3.094 0.092 0.211 0.004 0.766 0.1062 0.0016 1735 28 1430 23 1233 20 71.1 0.893 0.025 0.099 0.001 0.253 0.0659 0.0018 803 57 649 143.302 0.037 606 0.256 0.003 0.549 0.0929 0.0007 1486 13 1481 3.387 0.047 0.256 0.003 0.786 0.0951 0.0005 1531 10 1501 11 1468 17 95.9 5.999 0.080 0.343 0.005 0.806 0.1262 0.0009 2046 12 1975 12 1899 22 92.8 207 23.300 0.590 0.651 0.010 0.756 0.2583 0.0031 3236 19 3239 24 3232 39 99.9 25.840 0.270 0.661 0.008 0.679 0.2821 0.0014 3375 12.880 0.190 0.497 0.007 0.361 0.1875 0.0022 2720 1924.670 0.370 2670 0.631 14 0.009 0.808 2600 0.2820 31 0.0021 95.6 3374 12 3295 15 3152 36 93.4 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE - 3 1 1 1 1 1 1 1 1 1 1 1 -- 3 - 3 3 - 3 -- 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Corrections 2 % Pb* Pb 204 cps Pb/ 206 5.8 369 91.85 14.057.7 44 58.00 169 95.30 25.8 3258 94.46 11.412.8 359 94.08 526 95.81 11.0 1060 95.46 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 400.0 8986 98.12 106.3 604 98.51 593.3 89933 99.86 113.3115.4 12593 98.65 1248 97.82 % ± Pb cps 204 204 12 200.0 1165 99.70 12 300.012 29125 100.00 1200.0 2100012 99.64 12 300.017 240.0 3118 99.64 6226 566.7 99.78 5260 99.20 28 45 15 17 14 -350.0 59770 99.43 17 15 17 18 450.0 757513 99.20 1300.0 9940 98.71 43 54 26 37 12 -1200.0 24730 99.18 12 -1200.0 184700 99.82 Pb cps ± 2σ 204 6 4 1 4 5 3 7 1 4 1 2 9 -4 -1 -1 Pb cps 204 Th/U Th (ppm) U (ppm) Pb no correction cps); (100 2 = threshold % 204 Zr cps 90 2.26E+08 333.1 6.78 49.13 1.50E+08 136.3 170.97.39E+07 0.80 113.2 321 72.4 1.56 26 1.53E+08 122.1 48.5 2.52 16 1.89E+08 176.2 120.341.80E+08 1.46 257.41.77E+08 98.3 221.82E+08 27.43 11.70 169.9 3.58 14 103.331.89E+08 19 1.64 125.91.85E+08 87.461.71E+08 72.8 135.7 41.54 1.73 1.99E+08 89.2 2.11 176.2 5439 76.9 98.91 92.2 1.16 1.91 2.19E+082.49E+08 457.8 134.9 58.9 144.4 7.77 0.93 15 13 2.04E+08 563.3 389 1.451.94E+08 66 2.44E+08 7702.12E+08 905 528 313.7 1.46 246.8 254 378 1.27 3.562.68E+08 203 937 1164 312.6 3.72 337 2.30E+08 326.8 235.1 1.392.01E+08 28 428.42.27E+08 103.8 136.6 142.21E+08 4.13 264.4 61.3 54 118.5 2.232.17E+08 50.0 2.23 25 189.3 301.95E+08 122.6 332.62.24E+08 16 1429 1.54 134.8 99.53 46.3 2.47 79 53.3 16 46.2 1133 99.45 1.71 2.16E+08 20 31532.27E+08 98.77 539 125.0 349 2432.18E+08 2.22 375 165002.24E+08 96.30 445 0.932.43E+08 12.33 465 26 36.09 245.22.24E+08 241.6 19 132.31E+08 93.2 1.92 2099 501.1 2.63 255.8 132.25E+08 46 23.37 4.19 16 313.1 50.0 16 10.95 121 166.9 13 68.4 17 1.88 27 5496 99.69 14 34.8 3284 81.3 99.51 22.3 4787 82.4 98.80 7713 99.60 6149 99.43 13476 98.67 a a a a a a a a a a a a a a a a a a,b a a a a a ontinued. A1. C Sample Table 1) Run from distinguish to 2 italics (in SMB17-235 Run Corrections: 1 = threshold = threshold 1 Corrections: SMB17-235 - 41 SMB17-235 - 42 SMB17-235 - 42a SMB17-235 - 43 SMB17-235 - 44 SMB17-235 - 45 SMB17-235 - 46 SMB17-235 - 47 SMB17-235 - 48 SMB17-235 - 49 SMB17-235 - 50 SMB17-235 - 51 1 - SMB17-235 2 - SMB17-235 3 - SMB17-235 4 - SMB17-235 5 - SMB17-235 7 - SMB17-235 9 - SMB17-235 10 - SMB17-235 12 - SMB17-235 13 - SMB17-235 14 - SMB17-235 15 - SMB17-235 16 - SMB17-235 17 - SMB17-235 18 - SMB17-235 19 - SMB17-235 20 - SMB17-235 21 - SMB17-235 22 - SMB17-235 23 - SMB17-235 25 - SMB17-235 26 - SMB17-235

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 275 % 90.7 68.9 86.1 84.5 87.0 88.3 76.5 89.8 82.4 88.8 96.0 93.3 95.6 94.1 95.4 95.5 92.0 93.6 99.6 92.2 93.4 96.0 90.7 86.0 71.0 77.4 83.7 95.1 99.3 95.0 79.3 77.0 conc 100.2 100.1 100.3 100.2 9 9 9 8 ± 16 22 26 26 19 81 30 10 11 30 23 31 28 25 22 29 22 16 23 15 18 20 18 22 23 20 29 11 13 31 12 10 2σ U Pb/ 619 773 627 756 684 726 721 748 702 238 1396 1913 2417 1482 1558 2256 1812 2706 2139 2574 2759 2066 2010 1786 2028 1159 1905 1452 1716 1653 1140 1889 1768 1711 1682 1053 2046 206 9 8 ± 17 10 19 20 12 14 11 43 34 11 49 25 13 12 16 11 13 16 42 13 13 12 38 11 19 40 15 20 36 11 20 33 21 22 2σ U Pb/ 683 728 765 733 866 860 759 745 701 1393 2058 2596 1680 1630 2508 1913 2780 2136 2667 2833 2113 2095 1838 2029 1193 1974 1482 1799 1775 1309 2168 1932 1751 1686 1145 2366 235 207 Calculated ages 9 ± 66 43 64 74 26 23 12 26 68 60 29 24 35 13 17 18 18 24 66 17 33 12 13 15 29 70 16 29 15 27 45 17 2σ 122 107 119 Pb Pb/ 896 787 908 862 728 701 1050 1393 2200 2739 1121 1938 1735 1226 2737 2040 2831 2137 2734 2892 2164 2186 1908 2036 1257 2039 1513 1891 1922 1605 2442 2113 1800 1693 1327 2657 206 207 ± 2σ 0.0016 0.0022 0.0012 0.0018 0.0014 0.0010 0.0045 0.0035 0.0012 0.0028 0.0025 0.0016 0.0013 0.0021 0.0012 0.0014 0.0019 0.0020 0.0043 0.0012 0.0025 0.0014 0.0009 0.0040 0.0006 0.0010 0.0019 0.0037 0.0015 0.0022 0.0032 0.0009 0.0015 0.0035 0.0020 0.0018 Pb Pb/ 206 207 0.0743 0.0689 0.0885 0.1378 0.1896 0.0770 0.1188 0.1062 0.0812 0.1894 0.1258 0.2006 0.1329 0.1891 0.2083 0.1350 0.1367 0.0654 0.1168 0.1255 0.0693 0.0825 0.1257 0.0678 0.0943 0.1157 0.1177 0.0990 0.1587 0.1311 0.0636 0.1100 0.1038 0.0628 0.0855 0.1805 3 EC 0.181 0.275 0.373 0.540 0.647 0.144 0.685 0.438 0.241 0.945 0.667 0.756 0.487 0.659 0.544 0.597 0.601 0.379 0.692 0.613 0.392 0.308 0.788 0.479 0.562 0.456 0.541 0.642 0.698 0.546 0.534 0.687 0.710 0.456 0.407 0.884 ± 2σ 0.002 0.002 0.003 0.005 0.006 0.002 0.005 0.004 0.001 0.017 0.006 0.007 0.005 0.007 0.007 0.005 0.005 0.002 0.006 0.005 0.002 0.003 0.005 0.002 0.003 0.004 0.004 0.003 0.005 0.005 0.002 0.004 0.006 0.002 0.002 0.007 U Isotopic ratios Pb/ Pb-based correction (98.5 %Pb*). 238 0.102 0.101 0.242 0.346 0.455 0.127 0.259 0.274 0.119 0.420 0.325 0.521 0.393 0.491 0.534 0.378 0.366 0.124 0.319 0.370 0.112 0.197 0.344 0.118 0.253 0.305 0.292 0.194 0.341 0.316 0.123 0.304 0.297 0.115 0.177 0.374 206 208 ± 2σ 0.019 0.032 0.048 0.100 0.140 0.021 0.220 0.160 0.024 0.500 0.160 0.200 0.097 0.220 0.170 0.100 0.120 0.043 0.250 0.093 0.041 0.042 0.081 0.079 0.037 0.064 0.110 0.140 0.120 0.130 0.073 0.059 0.100 0.064 0.062 0.220 U Pb/ 235 1.049 0.963 2.949 6.600 1.348 4.280 4.010 1.334 5.620 7.195 7.024 6.870 1.119 5.170 6.381 1.059 2.243 5.990 1.119 3.300 4.887 4.751 2.660 7.466 5.720 1.092 4.611 4.273 1.007 2.094 9.300 207 11.890 10.980 14.480 12.840 15.290 - 3 3 3 3 3 3 3 3 3 3 3 2 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE ------1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Corrections 2 % Pb* 98.23 98.83 99.73 97.51 96.19 98.56 93.44 96.37 97.77 94.83 98.05 98.47 99.70 98.29 98.99 99.14 98.61 98.93 94.67 99.83 99.20 99.30 99.01 96.07 99.66 98.75 97.04 92.91 94.21 95.89 94.69 99.50 99.72 97.53 97.41 92.85 Pb 955 815 896 441 623 320 536 353 327 747 204 4344 1056 1557 1240 7914 3339 6318 4514 1625 1769 4035 5200 2623 6026 1682 1417 1928 1011 1343 1484 40700 12271 20173 20255 47314 85600 cps Pb/ 206 7.6 82.4 55.6 24.7 32.7 78.9 56.7 54.8 47.7 71.4 26.2 21.9 60.9 76.9 42.9 24.3 27.3 14.9 15.1 16.0 12.0 14.1 10.2 13.4 17.9 10.1 22.4 17.8 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 121.4 275.0 157.1 180.0 100.0 228.6 % ± Pb cps -280.0 1100.0 204 204 14 15 18 17 18 15 17 11 11 11 17 42 10 16 23 14 27 10 18 11 18 18 26 24 28 23 22 39 16 14 41 31 40 39 40 21 Pb cps ± 2σ 204 1 4 7 1 7 -5 Pb 17 27 73 14 55 19 30 31 88 14 61 23 15 13 42 11 74 66 105 174 159 175 192 156 384 307 173 395 174 524 118 cps 204 4.69 7.20 2.20 1.14 1.36 6.20 7.07 0.75 1.61 1.47 1.14 1.23 1.47 2.06 1.54 2.61 3.75 1.89 2.40 1.50 3.09 1.75 4.47 7.45 1.88 0.62 6.10 3.16 9.68 6.02 4.48 12.87 16.88 14.89 16.62 37.91 Th/U 53 317 230 260 290 81.5 49.2 40.7 57.4 67.2 53.3 91.1 71.8 62.4 34.8 49.7 73.8 75.4 14.8 Th 120.6 227.3 37.86 155.4 105.9 33.37 105.1 115.1 121.2 242.9 87.76 174.1 207.7 159.5 154.9 158.1 121.2 (ppm) 40 128 973 490 687 698 356 419 513 951 757 518 826 543 132 561 U 1049 1085 566.1 354.1 258.6 312.3 475.3 55.69 177.3 112.3 105.2 128.8 163.2 125.3 198.2 276.3 181.4 228.3 653.9 327.6 (ppm) Pb no correction cps); (100 2 = threshold % 204 Zr cps 90 2.15E+08 2.50E+08 2.17E+08 2.29E+08 2.01E+08 2.35E+08 1.98E+08 1.72E+08 2.12E+08 2.18E+08 2.11E+08 2.19E+08 1.91E+08 2.07E+08 2.45E+08 2.24E+08 2.25E+08 2.24E+08 2.32E+08 2.19E+08 2.02E+08 2.53E+08 2.19E+08 2.26E+08 2.46E+08 2.16E+08 2.26E+08 2.61E+08 2.10E+08 1.93E+08 2.13E+08 2.14E+08 2.05E+08 1.86E+08 2.16E+08 2.02E+08 a a a a a a a a a a a a a a a a a a a a a ontinued. Sample Table A1. C Corrections: 1 = threshold = threshold 1 Corrections: 27 - SMB17-235 28 - SMB17-235 29 - SMB17-235 32 - SMB17-235 34 - SMB17-235 35 - SMB17-235 37 - SMB17-235 38 - SMB17-235 39 - SMB17-235 41 - SMB17-235 42 - SMB17-235 43 - SMB17-235 44 - SMB17-235 45 - SMB17-235 46 - SMB17-235 47 - SMB17-235 48 - SMB17-235 49 - SMB17-235 50 - SMB17-235 51 - SMB17-235 54 - SMB17-235 55 - SMB17-235 56 - SMB17-235 57 - SMB17-235 58 - SMB17-235 59 - SMB17-235 60 - SMB17-235 62 - SMB17-235 63 - SMB17-235 64 - SMB17-235 65 - SMB17-235 67 - SMB17-235 68 - SMB17-235 69 - SMB17-235 70 - SMB17-235 71 - SMB17-235

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 276 % 93.3 95.5 97.3 63.5 73.8 79.3 80.3 94.5 94.3 96.9 92.3 93.7 86.8 89.9 96.3 conc 7 7 7 7 ± 19 19 22 28 23 25 20 24 21 28 33 2σ U Pb/ 619 658 533 502 238 1914 1513 1247 1621 1505 2608 1802 1886 1623 2412 2133 206 7 ± 10 10 19 15 34 30 12 12 10 14 15 22 16 21 2σ U Pb/ 663 689 564 532 1943 1915 1420 1813 1671 2656 1877 1950 1738 2567 2171 235 207 Calculated ages 8 ± 38 13 21 19 20 43 49 58 59 22 23 39 20 30 2σ Pb Pb/ 800 786 688 664 1967 2383 1690 2043 1874 2691 1952 2013 1869 2682 2215 206 207 ± 2σ 0.0009 0.0012 0.0017 0.0011 0.0031 0.0031 0.0009 0.0007 0.0015 0.0016 0.0025 0.0022 0.0017 0.0024 0.0017 error correction. Abbreviations: cps = counts per per = counts cps Abbreviations: correction. error Pb 3 Pb/ 206 207 0.1207 0.0658 0.1533 0.1036 0.1260 0.1146 0.1842 0.0654 0.1197 0.1239 0.1143 0.1832 0.0624 0.1390 0.0617 3 EC 0.548 0.792 0.841 0.823 0.688 0.598 0.668 0.858 0.486 0.558 0.481 0.475 0.067 0.489 0.139 radiogenic Pb; 2 ± 2σ 0.004 0.001 0.004 0.004 0.006 0.005 0.006 0.001 0.004 0.005 0.004 0.006 0.001 0.007 0.001 U Isotopic ratios Pb/ Pb-based correction (98.5 %Pb*). 238 0.346 0.101 0.265 0.214 0.286 0.263 0.499 0.107 0.323 0.340 0.286 0.454 0.086 0.392 0.081 206 208 ± 2σ 0.069 0.019 0.120 0.061 0.200 0.150 0.130 0.013 0.088 0.100 0.130 0.200 0.020 0.170 0.020 U after Hg correction; Pb/ 1 235 5.781 0.923 5.600 3.053 4.990 4.200 0.971 5.358 5.838 4.530 0.746 7.520 0.690 207 12.681 11.540 3 3 3 3 2 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE - - - - - 1 1 1 1 1 1 1 1 1 1 Corrections 2 % Pb* 99.69 99.22 92.13 97.38 93.67 93.93 99.42 99.50 98.91 98.91 96.97 96.08 99.30 98.81 99.24 Pb 452 435 204 4911 1937 2038 6800 6970 1450 1138 1886 38563 27690 20420 20310 cps 203100 Pb/ 206 15.7 31.7 76.2 46.4 18.1 11.5 10.4 21.2 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 113.3 125.0 120.0 % ± Pb cps -144.4 -220.0 -208.7 -233.3 204 204 17 36 19 10 16 12 13 13 29 43 48 22 11 10 14 Pb cps ± 2σ 204 1 8 -9 -5 -5 -6 Pb 15 60 21 10 28 229 160 374 462 104 cps 204 grains used in weighted mean calculations for youngest clusters; clusters; youngest for calculations mean weighted in used grains b 3.81 5.12 2.25 1.26 1.18 2.34 2.00 4.76 1.92 1.38 1.44 10.80 10.98 39.48 68.06 Th/U 189 465 83.2 95.7 95.7 13.9 Th 119.5 110.6 264.9 109.3 19.34 121.9 62.95 39.41 13.56 (ppm) 426 426 456 946 38.6 90.7 U 1195 455.5 586.2 312.7 255.3 183.6 168.1 432.8 535.4 (ppm) Pb no correction cps); (100 2 = threshold % 204 Zr cps 90 2.35E+08 2.50E+08 2.41E+08 2.40E+08 1.90E+08 2.20E+08 1.98E+08 2.26E+08 2.32E+08 2.19E+08 2.36E+08 2.02E+08 2.11E+08 2.27E+08 2.09E+08 a a a a a a a a a ontinued. grains 102% 90 and concordant; between a A1. C Sample Table Corrections: 1 = threshold = threshold 1 Corrections: 72 - SMB17-235 73 - SMB17-235 74 - SMB17-235 76 - SMB17-235 77 - SMB17-235 78 - SMB17-235 79 - SMB17-235 80 - SMB17-235 81 - SMB17-235 82 - SMB17-235 83 - SMB17-235 84 - SMB17-235 85 - SMB17-235 86 - SMB17-235 87 - SMB17-235 NOTES: second.

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 277 % 99.1 98.8 99.0 98.7 98.5 98.6 98.9 98.4 99.4 98.8 99.6 99.0 99.9 99.1 97.8 97.2 99.4 98.7 98.9 100.0 100.2 100.2 100.1 101.2 101.1 101.5 100.6 100.8 100.2 101.4 101.9 101.0 101.5 102.7 100.1 101.1 100.5 conc 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 15 16 15 15 15 16 15 16 18 15 15 17 15 16 16 15 16 15 ± 2σ U Pb/ 333 326 333 333 335 334 329 325 326 334 330 329 331 336 335 335 336 334 328 1101 1097 1102 1093 1103 1092 1096 1102 1090 1106 1102 1095 1094 1105 1088 1102 1102 1101 238 206 9 8 9 9 9 9 9 8 9 8 9 8 9 9 9 10 10 10 10 18 19 18 18 18 20 19 20 24 18 18 23 19 19 20 18 20 19 ± 2σ U 336 330 337 337 328 325 340 338 329 329 326 333 335 332 332 339 332 337 329 Pb/ 1097 1099 1101 1092 1104 1089 1096 1105 1090 1101 1097 1090 1101 1100 1088 1103 1099 1095 235 207 Calculated ages 54 46 55 50 59 64 50 47 59 55 60 43 50 47 52 42 57 51 56 34 37 34 34 31 43 32 36 62 31 32 53 34 40 42 34 40 37 ± 2σ Pb 371 373 350 363 358 325 379 342 354 354 316 322 358 339 294 352 299 354 307 Pb/ 1092 1108 1103 1090 1113 1077 1075 1126 1121 1112 1091 1079 1108 1077 1087 1113 1090 1095 206 207 ± 2σ 0.0013 0.0011 0.0013 0.0012 0.0014 0.0015 0.0012 0.0011 0.0014 0.0013 0.0013 0.0014 0.0013 0.0013 0.0012 0.0016 0.0012 0.0014 0.0024 0.0012 0.0012 0.0020 0.0013 0.0015 0.0016 0.0013 0.0014 0.0010 0.0012 0.0011 0.0012 0.0010 0.0013 0.0012 0.0013 0.0015 0.0014 Pb Pb/ 206 0.0540 0.0541 0.0535 0.0538 0.0537 0.0529 0.0542 0.0533 0.0536 0.0536 0.0759 0.0765 0.0763 0.0758 0.0767 0.0753 0.0753 0.0772 0.0770 0.0767 0.0759 0.0754 0.0765 0.0753 0.0757 0.0767 0.0527 0.0529 0.0537 0.0533 0.0522 0.0536 0.0523 0.0536 0.0525 0.0758 0.0760 207 3 EC 0.011 0.294 0.122 0.218 0.111 0.266 0.286 0.193 0.057 0.041 0.301 0.343 0.302 0.105 0.305 0.284 0.246 0.439 0.057 0.290 0.312 0.221 0.331 0.248 0.265 0.134 0.486 0.286 0.043 0.113 0.184 0.162 0.287 0.289 0.287 0.284 0.378 ± 2σ 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.003 0.003 Pb-based correction (98.5 %Pb*). U Isotopic ratios 208 Pb/ 238 0.053 0.052 0.053 0.053 0.052 0.053 0.053 0.052 0.052 0.052 0.186 0.186 0.186 0.185 0.187 0.185 0.185 0.186 0.184 0.187 0.186 0.185 0.185 0.187 0.184 0.186 0.052 0.053 0.053 0.053 0.054 0.053 0.053 0.054 0.053 0.187 0.186 206 ± 2σ 0.012 0.011 0.013 0.012 0.013 0.012 0.012 0.013 0.012 0.013 0.053 0.055 0.054 0.051 0.052 0.058 0.052 0.057 0.068 0.051 0.052 0.066 0.053 0.057 0.059 0.052 0.013 0.011 0.012 0.011 0.012 0.011 0.013 0.012 0.012 0.058 0.055 U Pb/ 0.392 0.385 0.394 0.394 0.381 0.398 0.396 0.384 0.383 0.379 1.950 1.955 1.961 1.933 1.969 1.930 1.941 1.974 1.933 1.960 1.948 1.936 1.958 1.953 1.925 1.965 0.380 0.389 0.392 0.388 0.388 0.396 0.387 0.394 0.384 1.957 1.946 235 207 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Corrections 2 % 99.80 99.79 99.80 99.86 99.76 99.77 99.83 99.81 99.87 99.83 99.91 99.79 99.93 99.86 99.94 99.82 99.91 99.82 99.73 99.92 99.94 99.84 99.88 99.99 99.85 99.88 99.87 99.84 99.76 99.84 99.89 99.84 99.93 99.90 99.83 99.92 Pb* 100.00 204 6380 6035 4385 3600 4988 6950 4061 4722 5843 6613 3429 3376 1358 3171 2781 8222 3352 8040 32270 29650 34640 28220 27390 20550 73640 27770 16860 35900 82400 82600 17300 49110 13747 41960 43570 21775 47040 Pb/ Pb cps 206 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 85.7 81.3 68.8 -52.4 200.0 350.0 150.0 122.2 100.0 185.7 100.0 400.0 325.0 157.1 133.3 400.0 100.0 120.0 700.0 250.0 136.4 300.0 204 -122.2 -366.7 -550.0 -333.3 -275.0 -650.0 -433.3 -366.7 -550.0 1200.0 1300.0 1100.0 1200.0 % ± Pb cps -1200.0 -1300.0 204 12 14 12 11 12 10 11 11 13 12 13 12 13 11 12 12 10 13 11 13 11 13 12 13 11 12 11 11 12 13 14 15 15 11 12 12 11 Pb ± 2σ 204 6 4 8 1 9 1 7 3 4 7 9 3 2 6 1 4 1 1 -9 -3 -2 -1 -3 -4 -2 -3 -3 -1 -2 12 14 13 16 16 11 10 11 -21 Pb cps 204 1.66 1.59 1.67 2.11 1.57 2.51 1.68 1.80 2.42 1.61 1.62 1.80 1.76 2.33 1.71 9.14 9.78 7.52 9.35 8.80 2.29 2.66 2.20 10.72 12.46 11.61 11.05 11.45 11.07 11.44 10.95 11.22 10.81 11.46 10.38 11.65 11.27 Th/U 164 69.8 53.3 35.1 90.5 Th 191.6 183.6 260.8 62.75 169.9 294.2 292.6 151.4 164.1 77.98 187.6 65.47 32.58 40.14 60.13 47.84 74.99 56.86 47.07 58.45 53.39 84.84 62.81 49.19 114.8 69.89 77.75 38.29 128.8 159.83 111.56 109.37 (ppm) 178 283 813 U 317.2 260.3 307.3 336.7 408.4 157.4 284.9 201.3 128.8 473.6 473.7 273.1 288.7 181.5 321.5 702.1 406.1 466.2 395.7 664.6 547.8 685.6 629.2 538.7 640.3 598.8 829.5 678.9 563.9 863.1 846.2 962.4 725.5 101.69 (ppm) Pb no correction cps); (100 2 = threshold % 204 Zr cps 90 1.85E+08 1.83E+08 1.84E+08 1.84E+08 1.81E+08 1.82E+08 1.81E+08 1.80E+08 1.79E+08 1.93E+08 1.70E+08 1.71E+08 1.70E+08 1.70E+08 1.64E+08 1.75E+08 1.67E+08 1.65E+08 1.87E+08 1.87E+08 1.84E+08 1.86E+08 1.86E+08 1.81E+08 1.83E+08 1.81E+08 1.80E+08 1.79E+08 1.79E+08 1.75E+08 1.77E+08 1.84E+08 1.70E+08 1.77E+08 1.88E+08 1.89E+08 1.83E+08 LA-ICP-MS U-Pb isotopic analyses of zircon reference materials analyzed the at University of New Brunswick. Sample Table A2. Run 1 for both samples Corrections: 1 = threshold = threshold 1 Corrections: - 1 FC-1 - 2 FC-1 - 3 FC-1 - 4 FC-1 - 5 FC-1 - 6 FC-1 - 7 FC-1 - 8 FC-1 - 9 FC-1 FC-1 - 10 FC-1 - 11 FC-1 - 12 FC-1 - 14 FC-1 - 15 FC-1 - 16 FC-1 - 17 FC-1 - 18 FC-1 - 19 Plesovice - 1 Plesovice - 2 Plesovice - 3 Plesovice - 4 Plesovice - 5 Plesovice - 6 Plesovice - 7 Plesovice - 8 Plesovice - 9 Plesovice - 10 Plesovice - 11 Plesovice - 12 Plesovice - 13 Plesovice - 14 Plesovice - 15 Plesovice - 16 Plesovice - 17 Plesovice - 18 Plesovice - 19

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 278 % 98.7 99.9 99.7 98.7 99.1 98.0 97.7 98.9 98.8 99.5 98.2 99.3 99.3 99.9 99.3 99.6 101.4 101.0 100.6 100.3 101.3 100.7 100.2 100.6 100.3 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 conc 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 12 12 12 12 12 12 11 12 12 13 12 12 12 13 12 12 14 13 ± 2σ U Pb/ 341 338 336 340 340 339 337 335 341 342 333 335 336 341 342 342 339 335 336 1103 1101 1098 1100 1097 1099 1103 1098 1097 1099 1097 1102 1094 1102 1102 1091 1098 1096 238 206 6 5 5 5 6 5 6 5 5 6 6 6 5 7 5 6 6 5 6 9 9 9 11 11 11 12 10 10 10 12 12 11 12 10 12 18 13 ± 2σ U 345 339 332 337 338 340 336 340 337 340 336 334 343 349 340 341 343 339 338 Pb/ 1102 1100 1096 1096 1097 1102 1098 1099 1099 1095 1102 1098 1095 1101 1100 1089 1098 1095 235 207 Calculated ages 43 35 39 35 43 37 43 28 38 46 45 44 33 51 30 38 43 33 38 27 24 26 34 25 19 20 25 24 34 30 24 30 33 22 31 53 38 ± 2σ Pb 364 323 315 297 321 329 330 371 313 310 339 317 384 398 318 337 347 348 352 Pb/ 1101 1111 1088 1075 1098 1115 1083 1094 1095 1074 1100 1076 1092 1100 1101 1095 1102 1080 206 207 ± 2σ 0.0010 0.0008 0.0011 0.0009 0.0008 0.0010 0.0009 0.0010 0.0007 0.0009 0.0011 0.0011 0.0010 0.0009 0.0010 0.0013 0.0010 0.0007 0.0008 0.0009 0.0010 0.0012 0.0012 0.0009 0.0011 0.0013 0.0009 0.0012 0.0019 0.0008 0.0012 0.0007 0.0009 0.0010 0.0008 0.0009 0.0015 Pb Pb/ 206 0.0540 0.0531 0.0765 0.0529 0.0524 0.0531 0.0532 0.0534 0.0542 0.0529 0.0529 0.0536 0.0529 0.0768 0.0760 0.0756 0.0763 0.0767 0.0757 0.0762 0.0760 0.0756 0.0763 0.0755 0.0762 0.0765 0.0764 0.0762 0.0763 0.0545 0.0549 0.0529 0.0534 0.0538 0.0537 0.0538 0.0757 207 3 EC 0.207 0.274 0.209 0.175 0.211 0.330 0.221 0.225 0.408 0.045 0.027 0.025 0.171 0.438 0.353 0.174 0.119 0.436 0.253 0.203 0.123 0.244 0.362 0.288 0.107 0.205 0.384 0.103 0.149 0.595 0.069 0.077 0.256 0.168 0.336 0.245 0.100 ± 2σ 0.001 0.001 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.003 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.002 Pb-based correction (98.5 %Pb*). U Isotopic ratios 208 Pb/ 238 0.054 0.054 0.187 0.054 0.054 0.054 0.054 0.054 0.053 0.054 0.055 0.053 0.053 0.186 0.186 0.186 0.186 0.186 0.187 0.186 0.186 0.186 0.186 0.187 0.185 0.187 0.186 0.184 0.186 0.054 0.054 0.055 0.055 0.054 0.053 0.054 0.185 206 ± 2σ 0.008 0.007 0.031 0.007 0.007 0.009 0.007 0.008 0.006 0.007 0.009 0.008 0.009 0.031 0.031 0.036 0.029 0.026 0.025 0.029 0.030 0.036 0.034 0.027 0.032 0.036 0.028 0.033 0.053 0.007 0.010 0.006 0.008 0.008 0.007 0.008 0.038 U Pb/ 0.405 0.396 1.963 0.387 0.394 0.396 0.398 0.393 0.397 0.394 0.398 0.392 0.390 1.959 1.947 1.947 1.948 1.962 1.949 1.951 1.954 1.945 1.956 1.952 1.944 1.963 1.958 1.927 1.953 0.403 0.409 0.398 0.400 0.403 0.397 0.395 1.945 235 207 FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Corrections 2 % 99.72 99.81 99.76 99.91 99.84 99.87 99.79 99.80 99.80 99.90 99.82 99.75 99.87 99.79 99.77 99.70 99.80 99.82 99.87 99.79 99.75 99.72 99.69 99.81 99.71 99.67 99.82 99.69 99.67 99.69 99.64 99.88 99.83 99.72 99.76 99.80 99.71 Pb* 204 6663 3452 9037 6623 5851 3925 8615 9325 3926 3448 9155 3977 3923 4013 8243 3482 31750 50840 57110 45880 48120 47770 76540 12805 19850 55880 43165 58040 35790 75500 26030 48580 15828 48000 56260 14340 27460 Pb/ Pb cps 206 Pb-based correction(20% error) ; 3 = threshold % for % for = threshold 3 ; error) correction(20% Pb-based 86.7 75.0 78.3 92.9 -76.9 185.7 122.2 216.7 200.0 550.0 200.0 150.0 550.0 460.0 100.0 137.5 157.1 122.2 275.0 250.0 108.3 333.3 204 -100.0 -157.1 -400.0 -132.4 -500.0 -466.7 -125.0 -183.3 -300.0 1100.0 1000.0 1100.0 % ± Pb cps -1100.0 -1000.0 -1000.0 204 9 9 9 9 10 13 11 11 11 12 10 13 12 11 13 12 11 11 10 12 10 11 13 11 10 11 14 10 11 10 11 10 10 13 11 10 12 Pb ± 2σ 204 7 9 1 1 6 6 2 5 8 2 2 8 7 9 1 4 4 3 1 -7 -3 -1 -1 -7 -2 -3 -8 -1 -6 -4 15 10 16 12 14 12 -10 -13 Pb cps 204 2.74 1.66 2.20 2.14 1.66 1.53 1.83 1.85 2.48 2.23 1.68 1.61 2.39 1.59 1.81 1.66 2.58 9.90 9.94 9.00 9.48 9.45 2.98 10.69 10.77 12.34 11.54 10.23 12.31 11.98 11.41 12.83 10.97 12.33 11.19 10.94 10.79 error correction. Abbreviations: cps = counts per second. per = counts cps Abbreviations: correction. error Th/U 3 72 225 47.1 73.3 51.7 90.1 67.7 Th 86.18 174.8 76.28 265.3 147.6 136.4 193.2 213.1 153.8 43.68 64.95 65.23 38.94 75.86 42.89 75.02 65.93 78.12 64.58 52.83 30.72 58.64 94.83 36.21 71.72 39.87 111.62 154.21 114.67 103.59 (ppm) 527 U 236.3 289.9 167.8 238.9 373.1 405.1 270.1 252.2 181.6 160.7 324.3 248.4 339.7 162.8 255.6 112.8 694.4 702.5 480.4 751.2 495.1 767.3 811.4 776.4 773.7 932.8 602.9 730.5 394.1 643.1 899.1 446.3 677.9 radiogenic Pb; 2 118.82 123.71 1254.1 (ppm) Pb no correction cps); (100 2 = threshold % 204 Zr cps 90 2.34E+08 2.19E+08 2.14E+08 2.09E+08 2.12E+08 2.08E+08 2.06E+08 2.09E+08 2.06E+08 2.04E+08 2.01E+08 2.02E+08 2.02E+08 1.99E+08 1.99E+08 2.02E+08 2.01E+08 2.23E+08 2.19E+08 2.03E+08 2.01E+08 2.01E+08 1.97E+08 1.95E+08 1.94E+08 1.92E+08 1.91E+08 1.93E+08 2.25E+08 2.13E+08 2.04E+08 2.02E+08 2.04E+08 2.00E+08 1.96E+08 1.93E+08 1.97E+08 after Hg correction; Continued. 1

Sample Table A2. Run 2 for both samples Corrections: 1 = threshold = threshold 1 Corrections: - 1 FC-1 - 2 FC-1 - 3 FC-1 - 4 FC-1 - 5 FC-1 - 6 FC-1 - 7 FC-1 - 8 FC-1 - 9 FC-1 FC-1 - 10 FC-1 - 12 FC-1 - 13 FC-1 - 14 FC-1 - 15 FC-1 - 17 FC-1 - 18 FC-1 - 19 FC-1 - 20 Plesovice1 - 1 Plesovice1 - 2 Plesovice1 - 3 Plesovice1 - 4 Plesovice1 - 5 Plesovice1 - 6 Plesovice1 - 7 Plesovice1 - 8 Plesovice1 - 9 Plesovice1 - 10 Plesovice2 - 1 Plesovice2 - 2 Plesovice2 - 3 Plesovice2 - 4 Plesovice2 - 5 Plesovice2 - 6 Plesovice2 - 7 Plesovice2 - 8 Plesovice2 - 9 NOTES:

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada ATLANTIC GEOLOGY · VOLUME 56 · 2020 279 APPENDIX B Scatarie Island, Bengal Road Fm. Coastal section of upper part of Bengal Road Formation Location and sample information, organic-walled micro- fossils and trace fossils. Sample coordinates are in Grid Zone SC17-5. 0289970, 5099472. Abundant dispersed organic 21T (WGS84). Locations are indicated also on Figure 2 and matter and very scarce organic-walled microfossils that are shown in a stratigraphic column (Fig. B1). limited to fragments without recognizable forms, except for a small filament of possible cyanobacteria (Fig. 6a). SC17-6. 0289994, 5099484. Small amount of dispersed organic matter and very scarce organic-walled microfossils Fig.5f without recognizable forms, except for an acritarch assigned Red sandstone and to Polygonium sp. (Fig. 6b). siltstone, minor limey SC17-7. 0289995, 5099517. Small amount of dispersed Fig.5e siltstone with nodules.

Mbr 4 organic matter. Possible black carbonaceous fragments without recognizable forms. SC17-7 SMB17-235 Fig.5d Hay Island, MacCodrum? Formation Laminated and thin- 1. Section on southern Hay Island at 0291878, 5099931. bedded grey siltstone with upsection increase Teichichnid trace fossils (Fig. 7). Sample SC17-2, with small SC17-6 in sandstone. At top, amount of dispersed organic matter, possible black carbo- sandstone with large naceous fragments without recognizable morphologies. pyrite cubes. From same area at 0291885, 5099911, sample SC17-3, with Mbr 3 Fig.5a-c small amount of dispersed organic matter, possible black carbonaceous fragments without recognizable morphol- SC17-5 ogies. Among the maceration-resistant minerals are some 10 m idiomorphic zircon crystals. Also sample SC17-4, with no dispersed organic matter. Possible black carbonaceous frag- Not exposed. ments without recognizable shapes.

Red and maroon 2. Section on northeastern Hay Island at 0292071, Bengal Road Formation Bengal Road sandstone; minor 5100170, cleaved dark grey siltstone with carbonate nod- siltstone and ules. Sample SC17-8, with small amounts of organic matter. Mbr 2 congomerate Possible black carbonaceous fragments without recogniz- able forms. Not exposed. 3. Section on northern Hay Island at 0292230, 5100309. Gyrolithes, Teichichnus and other trace fossils (Fig. 8). Sam- Red quartzite- and ple SC17-9, with no dispersed organic material. Possible quartz-pebble Mbr 1 conglomerate; minor black carbon fragments without recognizable forms. interbedded sandstone

inferred Not exposed. disconformity NW VV VV Amygdaloidal basalt; Cove VV VV epiclastic sandstone Fm. and conglomerate

Figure B1. Stratigraphic interpretation of the southern limb of the southernmost syncline on the eastern shore of Scatarie Island (Fig. 2). Members 3 and 4 were logged in August 2017. Members 1 and 2 are schematic and based on notes made in 1991 when they were partially exposed. Abbreviation: NW Cove Fm = Northwest Cove Formation.

Barr et al. – Ediacaran and Cambrian Rocks on Scatarie Island and nearby Copyright © Atlantic Geology, 2020 Hay Island, Avalonian Mira terrane, Cape Breton Island, Nova Scotia, Canada