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The last interglacial-glacial cycle, Clyde foreland, Baffin Lsland, N. W .T .: stratigraphy, biostratigraphy, and chronology
Institute ofArctic and Alpine Research and Department of Geological Sciences, University of Colorado, Boulder, CO80309, U.S.A.
AND
S. K. SHORT Institute of Arctic and Alpine Research and Department of Anthropology,
University of Colorado, Boulder, CO80309, U.S.A. Received July 20, 1976
Revision accepted for publication July 29, 1977
A study of the stratigraphic sequence (14C and amino acid age control), marine bivalve faunal changes, and palynology of buried soils and organic-rich sediment collected from the Clyde Foreland Formation in the extensive cliff sections of the Clyde foreland, eastern B&n Island, N.W.T., suggests the following last interglacial - Foxe (last glaciation) glacial - present intergla- cial sequence.
( I ) Cape Christian Member (ca. 130000 years BP?) Consists of the Sledgepointer till overlain by the Cape Christian marine sediments. In situ
molluscan fauna, collected from the marine sediments, contain a moderately warm bivalve assemblage. A well-developed soil that formed on the marine sediments (Cape Christian soil) contains an interglacial pollen assemblage dominated by dwarf birch. U-series dates of > 115 000 and ca. 130000 years BP on molluscs from the Cape Christian marine sediments suggestthat they were deposited during the last interglaciation, here termed the Cape Christian Interglacia- tion. The development of a subarctic pollen assemblage in the Cape Christian soil has not been duplicated during the present interglaciation, suggesting higher summer temperatures and perhaps a duration well in excess of 10 000 years for the last interglaciation.
(2) Kuvinilk Member Consists of fossiliferous marine sediments, locally divided by the Clyde till into upper and
lower units. The Clyde till was deposited by the earliest and most extensive advance of the Foxe (last) Glaciation. Kuvinilk marine sediments both under- and overlying the Clyde till contain the pecten Chlamys islandicus, indicating that the outlet glacier advanced into a subarctic marine environment. Amino acid ratios from in situ pelecypod shells above and below the Clyde till are not statistically different, but contrast markedly with ratios obtained from the same species in the Cape Christian Member. Organic horizons within the Kuvinilk marine sediments contain a relatively rich pollen assemblage, although 'absolute' counts are low.
(3) Kogalu Member (>35 000 14C years BP) Sediments of the Kogalu Member unconformably overlie those of the Kuvinilk Member, but
are of a similar character. The dominant sediments are marine in origin, but in places are divided into upper and lower units by the Ayr Lake till. Amino acid ratios from in situ shells above and below the Ayr Lake till are indistinguishable, but substantially less than those in the Kuvinilk Member, suggesting the two members are separated by a considerable time interval. Radiocarbon dates on shells in the Kogalu marine sediments range from 33 000 to 47700 years BP, but these may be only minimum estimates. The sea transgressed to a maximum level 70-80 m as], coincident with the glacial maximum. Subarctic marine fauna of interstadial-interglacial charac- ter occur within the Kogalu marine sediments.
(4 ) Eglinton Member (10000 years BP to present) A major unconformity exists between the Kogalu and Eglinton Members. Ravenscraig marine
sediments were deposited during an early Holocene marine transgression-regression cycle; the oldest dates on these sediments are ca. 10000 years BP. Locally a vegetation mat occurs at the base or within the Ravenscraig unit. Pollen from these beds is sparse, but indicates a terrestrial vegetation assemblage as diverse as that of today. There is no evidence that Laurentide Ice reached the foreland during the last 30 000 years. Eolian sands that overlie a soil developed on the marine sediments record a late Holocene climatic deterioration. Pollen in organic-rich sediments at the base of, and within, the eolian sands record a vegetation shift in response to climatic change.
Can. J . Earth Sci., 14,2824-2857 (1977)
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MILLER ET AL. 2825
Apres une etude de la sequence stratigraphique (dont I'Lge est contr61e au 14C et a l'aide des acides amints), des changements fauniques des bivalves marins et de la palynologie des sols enfouis et des sediments riches en matitre organique preleves dans la formation de Clyde Foreland sur de vastes sections des falaises du promontoire de Clyde, dans I'est de I'ile de B a n , T. N.-O., on suggere la sequence suivante pour le dernier interglaciaire, la periode glaciaire de Foxe (derniere glaciation) et l'interglaciaire actuel.
( I ) Le membre de Cape Christian (environ 130000 ans BP?) Comprend le till de Sledgepointer recouvert par les sediments marins de Cape Christian. La
faune de mollusques in situ recueillie dans les sediments marins contient un assemblage modere- ment chaud de bivalves. Le sol bien developpt qui s'est forme sur les sediments marins (le sol de Cape Christian) contient un assemblage pollinique interglaciaire domine par le bouleau nain. Les dates obtenues par la sene U de plus de 115 000 et d'environ 130 000 ans BP sur des mollusques des sediments marins de Cape Christian indiquent qu'ils se sont dCveloppes durant le dernier interglaciaire, qu'on designe ici sous le nom d'interglaciaire de Cape Christian. Le developpe- ment du sol de Cape Christian et d'un assemblage pollinique subarctique ne s'est pas repet6 durant l'interglaciaire actuel, ce qui laisse supposer des temperatures estivales plus &levees et peut-&tre une duree excedant de beaucoup 10000 ans pour le dernier interglaciaire.
(2) Le membre de Kuvinilk Consiste en sediments marins fossiliferes localement spepares par le till de Clyde en unites
superieure et inferieure. Le till de Clyde s'est depose durant l'avance la plus ancienne et la plus extensive de la (derniere) glaciation. Les sediments marins de Kuvinilk qui apparaissent sous le tillde Clyde et au-dessus cantiennent le pecten Chlamys islandicus, ce qui indique que l'emissaire duglacier aavance dans un milieu subarctique marin. Les rapports d'acides amints provenant de coquilles de pClecypodes in situ au-dessus et en-dessous du till de Clyde ne sont pas differents au point de vue statistique mais contrastent de fagon marquee avec les rapports obtenus pour la m&me espece dans le membre de Cape Christian. Les horizons organiques dans les sedi- ments marins de Kuvinilk contiennent un assemblage relativement riche en pollen quoique les de- comptes "absolus" soient faibles.
(3) Membre de Kogalu (>35 OOOnns BP au 14C) Les sediments du membre de Kogalu reposent en discordance sur ceux du membre de Kuvinilk
mais ont un caractere semblable. Les sediments dominants sont marins d'origine, mais en certains endroits, ils sont divises en unites superieure et inferieure par le till d'Ayr Lake. Les rapports d'acides amines pour les coquillages in situ au-dessus et au-dessous du till d' Ay r Lake ne se distinguent en aucune fagon mais ont des valeurs substantiellement plus basses que celles du membre de Kuvinilk, ce qui suggere que les deux membres sont &pares par un intervalle de temps considerable. Les Lges au radiocarbone sur les coquilles de sediments marins du Kogalu vont de 33 000 a47 700 ans BP, mais ces valeurs pourraient n'ctre que des gges minimum. Lamer a transgresse jusqu'a un niveau maximum de 70 80 m au-dessus du niveau actuel, ce qui coincide avec le maximum de I'avancee glaciaire. Une faune subarctique marine de caractere in- terstadiairelinterglaciaire se retrouve dans les sediments marins du Kogalu.
(4) Membre d'Eglinton (de 10000 ans BP jusqu'c? pre'sent) I1 existe une discordance majeure entre les membres de Kogalu et d'Eglinton. Les sediments
marins de Ravenscraig se sont deposes durant un cycle de transgression/r6gression au debut de I'Holocene; les Lges les plus anciens de ces sediments oscillent autour de 10000 ans BP. Localement, un couvert vegetal est present a la base ou dans I'unite de Ravenscraig. Le pollen dans ces lits est rare mais il indique un assemblage de vegetation terrestre aussi diversifit que celui d'aujourd'hui. I1 n'y a aucune preuve que la glace des Laurentides ait atteint le promontoire au cours des 30 000 dernieres annees. Les sables eoliens qui recouvrent un sol developpt dans les sediments marins enregistrent une deterioration climatique a la fin de 1'Holockne. Le pollen dans les sediments riches en matiere organique a la base et a la interieur ses sables eoliens portent la marque d'un changement de vegetation en reponse a un changement climatique.
[Traduit par le journal)
Introduction The Clyde foreland (Figs. 1, 2) is one of the
major Quaternary exposures in North America. It is the best-exposed outcrop in a series of sedimentary plains that extend along the outer- most coast of eastern Baffin Island (cf. Andrews et al. 1975). Exposed is a complex sequence of glacial, glaciofluvial, and marine sediments inter- bedded with buried soils and organic-matter
accumulations. Research into unravelling the Quaternary history preserved in the sedimentary and fossil record is only beginning. R. P. Goldthwait (personal communication) noted the existence of the sections north of Clyde River in the early 1950's, but the first field study was that of Lsken (1965, 1966a,b) on the stratigraphy, relative sea levels, and glacial chronology. Feyling-Hanssen (1967, 1976b, 1977) studied the
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2826 CAN. J. EARTH SCI. VOL. 14, 1977
*1,2 Siles referenced i n lent
+ Present In Boffin Island
FIG. 1. L cation map of the Canadian Arctic and adjacent areas, showing the outlines of the major continentaha sheets at ca. 10 000 years BP, and the present boundary between Arctic and Subarctic water masses in the Baffin Bay-Davis Strait area (from Lubinsky 1972). Locations discussed in the text are numbered as follows: (1) Port Harrison, Quebec; (2) Fort Chimo, Quebec; (3) Frobisher Bay; (4) Pangnirtung; (5) Broughton Island; (6) Hall Beach; (7) Isortoq beds; (8) Flitaway beds; (9) Clyde River; (10) Ravenscraig Harbour, Eglinton Fiord; (11) Scott Inlet; 'Cape Smith' is the cape at the southeast boundary of outer Scott Inlet; (12) Upernavik, West Greenland; (13) site of the Camp Century ice core, northwest Greenland Ice Sheet; (14) Inglefield Land; (15) Devon Island Ice Cap; (16) Bathurst Island interglacial sites; (17) Banks Island interglacial site; (18) Old Crow Plain sites.
foraminifera contained within the marine facies exposed in the cliffs and developed a broad bio- stratigraphic framework based on microfaunal changes. In conjunction with Feyling-Hanssen's field program, Froese (1967) studied till fabric orientation. Additional information on the glacial and marine histories of Clyde and Inugsuin fiords is reported by Andrews and Ives (1972), whereas information on the submarine bathymetry of the Clyde region is given in Llaken (1973).
The purpose of our paper is to present data on the glacial sequence and inferred paleoclimatol- ogy of the Clyde foreland since the last inter- glaciation, derived from the stratigraphy, varia- tions in marine macrofossil faunas, and paly- nology of the organic horizons and soils collected from the Clyde cliffs. Age control is provided by
radiocarbon dates on shells and peats, and amino acid ratios in molluscs. Our paper serves to complement recent papers on the paleoecology of the western and high Canadian Arctic (cf. Rampton 1971 ; Lichti-Federovitch 1973, 1974; Blake 1974), and is a start towards establishing a firm basis of comparison between the glacial record of the eastern Canadian Arctic and other northern polar areas (cf. Kind 1972; Denton 1974).
The Clyde Foreland The low-lying sedimentary plain of the Clyde
foreland lies between Clyde Inlet and Eglinton Fiord (Fig. I), encompassing approximately 700 km2. It is dissected by Kogalu River drain- ing the Ayr Lake trough, and numerous smaller local streams, many of which are now underfit,
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MILLER ET AL. 2827
FIG. 2. A portion of the coastal cliffs eroded into the Clyde foreland looking northwest from ca. 2000 m. The Kuvinilk River is the prominent stream in the upper centre. Profile 8 (Fig. 3), the type locality of the Kuvinilk Member, is exposed in the first high set of cliffs southwest of the Kuvinilk River. About 7 of the 35 km of cliffs are shown in this photo. Photo by R. Weaver, INSTAAR.
occupying relict ice-marginal and melt-water channels. The stratigraphy of the foreland is best exposed in wave-cut cliffs (Fig. 2) that extend in an approximate straight line, starting 5 km northwest of Kogalu River mouth and terminating in the vicinity of Cape Christian, 35 km to the southeast. The cliffs range from < 8 to ca. 35 m high, but are generally 20-30 m high, with the stratigraphy increasing in complexity away from the central cliff region. The tills, glaciofluvial and glaciomarine sediments ex- posed in the cliffs, were derived from continental ice crossing central Baffin Island, draining sea- ward both through Clyde and Inugsuin fiords, and spreading northward as a piedmont lobe onto the Clyde foreland; and from a second major outlet glacier flowing from the central Baffin uplands through the Ayr Lake trough and onto the foreland.
Climate Weather records exist for Clyde River Settle-
ment since the early 1940's. The average summer (June, July, August) temperature is 3.6"C, whereas the January temperature averages -26.9"C. The mean annual temperature is - 11°C. Precipitation is sparse with a summer precipitation of 6.5 cm (Table 1).
Vegetation There has been no comprehensive survey of
the flora of the coastal foreland. Hainault (1966) collected plants from the outer reaches of Inugsuin Fiord, immediately south of Clyde River and compiled a floral list including the preliminary identification of 61 vascular plants. The area lies within the 'Middle Arctic' zone of Polunin (in Barry and Ives 1974) and consists of sedge-moss-lichen tundra. Dwarf, prostrate willow is the major shrub type, but its distribu- tion is patchy. The Clyde foreland lies in Young's (1971) floristic zone 3 or 2, with a summer 'warmth' of 12 (the summed average summer temperature above 0°C).
Stratigraphy and Chronology
Feyling-Hanssen (19763, 1977) referred to the complete lithostratigraphic sequence of the Clyde foreland as the Clyde Foreland Forma- tion, and provided a broad biostratigraphic zonation based on microfaunal assemblage variations. He recognized three drifts (tills) in the upper part of the Clyde cliffs, and noted that drift 3 was prominent along the exposure and could therefore be used as a stratigraphic marker. His analyses of benthic foraminifera assemblages indicated that the formation con- tained sediments of at least upper and middle Quaternary age. Feyling-Hanssen (19766, 1977) did not attempt to develop a lithostratigraphic sequence for the marine sediments in the forma- tion, and the correlation of units was obtained by (i) reference to the main till units; and (ii) the biostratigraphy of the foraminifera in the marine sediments. Our field work was designed to expand on Feyling-Hanssen's biostratigraphic zonation, with specific attention paid to the marine sediments that lie between the tills.
Classical methods of stratigraphic correlation, such as position, field tracing, and provenance studies are of limited utility in the Clyde area. Although the main exposure of the Clyde fore- land stretches over 35 km of coast, slumping and
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2828 CAN. J . EARTH SCI. VOL. 14, 1977
TABLE 1 . Climatic data for selected stations (locations on Fig. 1)
Average temperature "C Summer precipitation Fig. 1 (June, July, August)
Station no. Jan. June July Aug. (cm)
Clyde River (1943-1975) 9 -26.9 Broughton Island (1958-1975) 5 -24.1 Frobisher Bay (1943-1975) 3 -26.2 Fort Chimo (1943-1975) 2 -23.2 Upernavik (1941-1955) 12 -15.3
*Note: the station lies above the local inversion at 580 m as], and this sites on this table are close to sea level.
rapid facies changes prohibit direct tracing of units in the field over distances greater than a few hundred metres (also discussed in Feyling- Hanssen (1967, 1976b), this is typical of most Quaternary exposures). Moreover, initial work on amino acid ratios in the Clyde area (Miller and Hare 1975; Andrews and Miller 1976) suggested that the stratigraphy was not 'layer cake', but contained large-scale cut and fill features not obvious in the field. Hence, criteria such as elevation and position are at best poor guides for lateral correlation of the units along the cliff face. Flowlines for the outlet glaciers reaching the foreland merge inland from the head of Clyde Inlet, and the bedrock between their point of divergence and the foreland is similar in both the Clyde-Inugsuin and Ayr Lake troughs. Hence, provenance studies cannot be used to distinguish between tills. Correlations from the type localities, therefore, need to be based on other criteria. From profiles located in Fig. 3, we have developed a composite lithostratigraphic section (Fig. 4) based on multiple criteria: primarily (i) position with respect to the main till units; (ii) radiocarbon dates; (iii) amino acid ratios as correlation indices; and (iv) mollusc and pollen biostratigraphy. The naming of stratigraphic units of Baffin Island is not easy. There is a dearth of local place names and many of the local Inuit words are too complex for easy use. Thus, in two early abstracts of material covered in this paper (Miller 1976b; Andrews 1977), we have referred to the Upper and Lower Kogalu and Kuvinilk marine sediments. We rename these units in this paper in accord with the International Stratigraphic Guide (Hedberg 1976).
Because of the rapid facies changes in the cliffs and cyclical nature of sedimentation during the Quaternary, strict lithologic variations are not useful criteria for subdivision. Instead, we
i results in temperatures frequently warmer than one at sea level. Other
propose that sedimentation cycles associated with major glacial-glacio-isostatic events are the best criteria for lithostratigraphic subdivision. The major sedimentological changes can be represented as a sequence from marine silt to sand to till to marine sand and silt. A suitable process-response model for such a sequence of sedimentation is based on the interactions be- tween glacial advances and retreats, glacio- isostatic depression and recovery, and global changes of sea level. At the start of a glacial cycle with the sea near its present level, the buildup of ice over the central Baffin Island plateau would initiate isostatic depression of the crust up to 200 km beyond the ice margin (Walcott 1970). During this early phase of a glacial stade, transgressive marine sediments would be deposited along the eastern Baffin Island coast. Through time, the ice sheet would thicken and isostatic depression would be partly offset by global lowering of sea level. Outlet glaciers eventually arriving at the foreland would override the marine deposits of the transgressive phase of the cycle. Till would be laid down beneath the glacier, as basal temperatures would be at the pressure melting point because of the high ice velocities. With a change in the glacier mass balance the ice would retreat, marine deposits would be laid down on top of the till, and glacio-isostatic recovery would result in a marine regressive sequence. Changes in grain- size of the marine sequences would depend on both the depth of water and on the nearness of major sediment sources, especially the ice margin.
Acting on the criteria laid out above, we have subdivided the youngest sediments of the Clyde Foreland Formation into four named members (Fig. 4), each corresponding to a glacial-marine cycle of sedimentation. In addition, we also present informally-named subdivisions of the
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MILLER ET AL.
Eorl~er Foxe (7) moraines
Ice-flow direction Meltwoter channels
..... ..... L ~ r n ~ t of marine submergence
A Raised rnorine delto
FIG. 3. Location map of the Clyde foreland between Clyde Inlet and Eglinton Fiord, showing the locations of the sections discussed in the text and the mid Foxe outlines of the Ayr and Clyde lobes of the northeastern Laurentide Ice Sheet. Ice margins are based on air photo and field mapping of discontinuous end and lateral moraine segments, and ice-marginal meltwater channels.
various members. To indicate that these names are informal, the descriptive terms for the various stratigraphic units are in lower case, e.g. Ayr Lake till, Cape Christian marine sediments, Clyde stade. We use the term Foxe Glaciation (Andrews 1968) for the last glacial stage. The primary dispersal centre for ice reaching the Clyde area was over Foxe Basin, and although undoubtedly contiguous with the main Lauren- tide Ice Sheet to the south, the chronologies of the northern and southern regions are sufficiently different that interregional correlations at even a stadia1 level are not straight forward. The Foxe
Glaciation is locally subdivided into early, mid, and late stades that refer to documented episodes of glacial advance on eastern Bafin Island. Ice recession from the maximum late Foxe stade did not begin until after 9000 years BP (Miller and Dyke 1974), hence the last glaciation in this area continued into the Holocene. In addition, the maximum marine transgression associated with this stade occurred during the early Holo- cene (ca. 8400-10 000 years BP).
The Clyde foreland chronology is based on radiocarbon dates and amino acid ratios. Holo- cene deposits are subdivided by 14C dates on
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2830 CAN. J . EARTH SCI. VOL. 14, 1977
---------
n o t s u b d t v i d e d
FIG. 4. Composite stratigraphic section for the Clyde foreland since the last interglaciation, in- cluding litho- and chronological subdivisions as proposed in this paper. (1) Lithostratigraphy is based on recognition of glacial-glacio-marine sedimentation cycles. (2) Biostratigraphic zonations from Feyling-Hanssen (19766 and written communication, 1976). (3) Amino acid stratigraphy is based on the ratios of D-alloisoleucine to L-isoleucine in the Free (F) and combined (C-free plus peptide-bound) fractions. Ratios were determined from in siru (or only moved a short distance) valves of Hiatella arcrica. For samples in which more than five separate valves have been analyzed the standard devia- tions of the analytical results are given.
plant detritus and marine shells. In addition, we have obtained several finite 14C dates on shells in the 35 (700-50 000 year range from deposits predating the late Foxe stade, although M. Stuiver (written communication 1977) suggests that these dates should be treated as minimum estimates only. For these and older deposits, we rely heavily on amino acid ratios in marine bivalves for relative age and correlation pur- poses. The use of various amino acid reactions as geochronological indices has been discussed in some detail previously (Hare and Abelson 1968; Hare and Mitterer 1969; Wehmiller and Hare 1971; Bada and Schroeder 1972; Mitterer 1974; Schroeder and Bada 1976) and, for arctic situations, by Miller and Hare (1975) and Andrews and Miller (1976). These studies have relied almost exclusively on the extent of racemization of a particular protein amino acid (usually aspartic acid or isoleucine) in a sample as determined after acid hydrolysis. Because the
rate of racemization is strongly dependent on thermal history, substantial racemization has occurred in mid-Wisconsin shells from mid lat- itudes where mean annual temperatures are cur- rently + 10 to +20°C, whereas in the Clyde area (mean annual temperature is - 10 to - 12OC), racemization is only just detectable in shells 40 000 14C years old. For Arctic areas we have used a more effective measure of early diagenesis : the extent of isoleucine epimerization in the free amino acid fraction. Free amino acids are derived from the natural breakdown of the protein structure (hydrolysis), and the proportion of free to peptide-bound amino acids shows a steady increase with sample age. The extent of racemization in the free amino acid fraction increases rapidly during the early stages of diagenesis, but then approaches a steady-state value. For Arctic shells of last glaciation age this ratio has proven to be the most reliable age index, whereas in shells older than the last inter-
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MILLER ET AL.
oulder-silt (till)
rosionol unconformity
FIG. 5. Profile 1, Clyde foreland (see Fig. 3 for location). Type section for the Eglinton Member (18.3-20 m). The Scott Inlet eolian sands unconformably overlie oxidized marine sands of the Ravens- craig unit, which at the base is peaty, and dates from ca. 8200 years BP. The Ravenscraig sediments nonconformably overlie undisturbed fossiliferous sands of the upper marine sediments of the Kogalu Member, dated here at 47 700 years BP. The underlying Ayr Lake till unconformably overlies per- Foxe marine silts and glaciogene sediments. The amino acid data are the ratios of D-alloisoleucine to L-isoleucine in the free (F) and combined (free + peptide-bound) (C) fractions. The blackened areas under lithostratigraphy indicate the vertical extent of each stratigraphic unit. A cross-section of the cliffs between profiles 1 and 2 is depicted in the lower diagram. The Ravenscraig sediments pinch-out horizontally and the till in profile 1 rises toward profile 2.
glaciation the free racemization approaches its steady-state value. However, by this time sufficient racemization has occurred that ratios determined after conventional acid hydrolysis are reliable. The extent of isoleucine epimeriza- tion in both the free and combined (i.e. as de- termined after acid hydrolysis) fractions from shells discussed in this section, and from shells in other related deposits, are listed in Table 4. Amino acid ratios in the free and combined fractions, given in Figs. 4-9 and Fig. 15, are indicated by F and C , respectively.
The rate of racemization varies between the different pelecypod genera (Miller and Hare 1975), hence intersection correlations should be based on ratios from the same genus. In this study we have used amino acid ratios from in situ Hiatella arctica valves for all correlations and age assignments. The one assumption that must be satisfied, if amino acid ratios are to be used as correlation indices, is that all deposits of a similar age should have experienced similar thermal histories since shell deposition. The uniform current climate and low relief of the
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2832 CAN. J . EARTH SCl. VOL. 14. 1977
Laminor- bedded si l ly - sands wilh prominent organic bed
Coarse pebbles,
FIG. 6. Profile 2, Clyde foreland (see Fig. 3 for location). The type section for the Kogalu Member (14-25 m). The lower marine sediments of the Kogalu Member unconformably overlie fossiliferous silt of the Kuvinilk Member, which in turn conformably overlies interbedded silty-sand and organic lenses, presumed to be of Kuvinilk age. The contrast in amino acid ratios between the Kogalu and Kuvinilk units indicates that these events were separated by a considerable time interval, whereas the close similarity in ratios between the upper and lower marine sediments within the Kogalu Member suggests that the intervening Ayr Lake till was deposited in a relatively short stade (< 10 000 years?).
Clyde foreland suggests that this assumption is valid for this study.
Cape Christian Member Sledgepointer Till The most prominent and continuously trace-
able unit in the Clyde cliffs is a till deposit in the northwestern portion of the cliffs. Feyling- Hanssen (19766) also recognized this conspicu- ous unit and termed it drift 3. Our informal name for the unit, the Sledgepointer till, is derived from the numerous Inuit-made stone markers used to guide sledge drivers across the foreland in winter. Our type area for the Sledgepointer
till is profile 6 (Fig. 9), where the relationship to the overlying Cape Christian marine sediments is clear.
Even with this most prominent unit, direct field tracing can be difficult, as noted by Feyling- Hanssen (1976b, p. 84): "The till of a later glacial advance may consequently be in contact with drift 3 and not easily distinguishable from that till in the field. What is here called drift 3 may, therefore, in some of the profiles include also a drift 2 or a drift 1 or both."
Cape Christian Marine Sediments and Cape Christian Interglaciation
Fossiliferous marine sands assigned to the
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MILLER ET AL. 2833
FIG. 7. Profile 8, Clyde foreland (see Fig. 3 for location). The type locality of the Kuvinilk Member. This section lies between the outer limits of the Ayr and Clyde lobes at the maximum of the Ayr Lake stade. The lack of substantial differences in amino acid ratios between the upper and lower marine sediments indicate that the Clyde stade also was of a relatively short duration. The Sledge- pointer till is the most prominent unit in this region of the cliffs.
Cape Christian marine sediments (name derived from the cape at the southeast end of the cliffs) are located at profiles 6, 9, and 10 (Figs. 3, 8,9). The type area of the sediments is designated as profile 9. This profile is similar to the section described by Lsken (1966a), and is very close to profile XXVI of Feyling-Hanssen (1967). A 2 m thick sand unit at about 10 m as1 contained abundant mollusc remains, and it was from this unit that Lsken (1966a) reported a '"C age of > 50 000 years. A U-series date ( 2 3 0 ~ h ) on this unit was > 115 000 years (0. H. Lsken, written communication to J. T. Andrews, 1972) and more recently we obtained a new 230Th date of ca. 130 000 years BP (B. J. Szabo, personal communication, 1977). Amino acid ratios in H. arctica valves from this unit are 0.65 (free), and 0.16 (combined) (Table 4). The Cape Christian marine sediments at profile 9 are separated from overlying organic-bearing sands by a unit that Feyling-Hanssen (1967) interpreted as till. This till may have been deposited by the earliest Foxe advance (Clyde till), whereas an upper glaciogene
Sands, current- bedd~ng
hor~zonta l ly bedded, fosslls
Monne (? I sands
B o u l d e r - s ~ l t (1111) limestone er ra t lcs
Coarse sand and gravels 0-8 Poleosol; 4 0 c m thick
Coarse sand and gravels
Slump and beach
FIG. 8. Profiles 9 and 10, Clyde foreland (see Fig. 3 for locations). Profile 9 is the type area for the Cape Christian marine sediments. The stratigraphy of the overlying sediments is complex, and relative age data is not avail- able, but organic-rich littoral sediments (site 0-7) are tentatively assigned to the Kuvinilk Member. Profile 10 is the type locality of the Cape Christian Interglaciation. At this section, the interglacial soil, which has been disturbed and truncated by an over-riding glacial advance, overlies fossiliferous marine sands assigned to the Cape Christian marine sediments on the basis of amino acid ratios.
unit is somewhat younger, possibly of mid Foxe age (Ayr Lake till), but criteria for relative age assignments are lacking. Feyling-Hanssen (1976b, 1977) assigns the faunas in the Cape Christian marine sediments to his Cassidulina teretis sub- zone, which he suggests is of Sangamon age.
Fossiliferous marine sands exposed at profile 10 (Fig. 8) are correlated with the type Cape Christian marine sediments on the basis of similar amino acid ratios (Table 4). Pollen
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2834 C A N . J . EARTH SCI. VOL. 14. 1977
PROFILE 6
Buried 5041 5 0 4 m ! I ~ ~
PO -
15-
-10 -
FIG. 9. Profile 6, Clyde foreland (see Fig. 3 for location). The main feature in this section is the paleosol (site0-5) at 29m asl. The soil, which has been disturbed by subsequent glacial overriding, is overlain by glaciomarine sediments of Kogalu age, and is developed in nonfossili- ferous marine sands tentatively correlated with the Cape Christian marine sediments that in turn overlie the prominent Sledgepointer till. Palynologically, site 0 - 5 is correlative with the type Cape Christian interglacial soil at profile 10. Glacial and marine sediments lower in the section were deposited in pre-Foxe time, and for these sediments the combined allo-iso ratio is more reliable than the ratio in the free fraction.
spectra from a prominent soil developed on the Cape Christian marine sediments at profile 10 indicate interglacial terrestrial conditions. The pollen assemblage from an organic-rich accumu- lation (soil?) at profile 6 (Fig. 9), overlying marine sediments and beneath Ayr Lake till, is similar to that from the soil in profile 10, and the organic portion of the soil at profile 6 gave a 14C age of 50 400 ? l!gz years BP (QL-188), although this may be a minimum date. The marine sands beneath the organic-rich sedi- ment at profile 6 are correlateduwith the Cape Christian marine sediments. The interglacial terrestrial climate inferred from the oollen assemblages in soils (?) developed on the Cape Christian marine sediments has led us to de- signate this warm interval as the Cape Christian Interglaciation, with the type section for the geologic-climatic interval at profile 10. The Cape Christian marine sediments likely were deposited early in the last iifterglaciation, in the same way that marine sediments related to
isostatic readjustment from late Foxe glacial loading are at least in part of Holocene (inter- glacial) age. Several older glacial and marine units (Fig. 4) are exposed lower in the sections in the Clyde cliffs, but these have not yet been studied in any detail.
Kuvinilk Member Kuvinilk Marine Sediments and Clyde Till Profile 8 (location 8, Fig. 3) lay between the
outer margins of the Clyde and Ayr lobes during mid Foxe time, and a glacial-marine sedi- mentary cycle exposed in the upper portion of the cliff at this locality predates deposits of the mid Foxe stade. At profile 8 (Fig. 7) amino acid ratios in H. arctica valves, from marine sands overlying till at 26 m asl, are significantly lower than those in the same species from the Cape Christian marine sediments (0.56 and 0.10 vs. 0.66 and 0.16, free and combined). The till-out- wash unit beneath these marine sediments over- lies a fossiliferous marine sand, which in turn overlies compact, massive fossiliferous silts. Amino acid ratios in the lower marine units are similar to those in shells from the marine sands above the till-outwash unit (Table 4). From these data we conclude that the uppermost glacial- marine sediments at profile 8 represent a distinct glaciation, younger than that of the Cape Christian Member, and we name this unit the Kuvinilk Member (after the nearby Ku- vinilk River). The till unit, named the Clyde till after the major fiord in the area, divides the marine sediments into upper and lower units. The Clyde stade, during which the Clyde till was deposited, is considered to represent the earliest and most extensive advance of the Foxe Glacia- tion and is thus the local early Foxe stade. Moraines tentatively associated with this stade are indicated in Fig. 3. The Clyde till may be cor- relative with Feyling-Hanssen's (1966b) drift 2.
Placement of the Clyde stade within the last glaciation is primarily based on the occurrence of interglacial sediments stratigraphically below the Clyde till, and the absence of diagnostic interglacial terrestrial sediments in younger members. A possible age-range for the Kuvinilk Member, based on the 2 3 0 ~ h date for the Cape Christian Member and amino acid ratios, would be 90 000-1 10 000 years BP.
Feyling-Hanssen (1977 and written communi- cation, 1976) states that the microfauna asso- ciated with the upper marine sediments in the
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MILLER ET AL. 2835
Kuvinilk Member at profile 8 are indicative of an ameliorated marine environment of inter- stadia1 rank, but he does not distinguish between the microfaunal assemblages in Kuvinilk and Kogalu members (both fall in his Islandiella islandica subzone).
Kogalu Member Kogalu Marine Sediments and Ayr Lake Till During the most recent major depositional
episode in the foreland, sediments of the Kogalu Member were deposited. The type section is designated as profile 2 (Fig. 6), only 1.4 km from the Kogalu River, from whence the name is derived. At this locality, a till occurs within the marine sediments, and this is named the Ayr Lake till, after the lake drained by Kogalu River. Where the Ayr Lake till is present, the Kogalu marine sediments are subdivided into upper and lower units. Amino acid ratios in Hiatella arctica valves from the upper and lower marine sedi- ments are not statistically different (Fig. 4, Table 4). The fossiliferous marine sand in profile 1 (Fig. 5) correlates on the basis of amino acid ratios (Table 4) with the upper marine sediments at profile 2. In situ marine shells from the undisturbed Kogalu marine sediments at profile 1 have been radiocarbon dated at 47 700 f 700 years BP (QL-183). The underlying till at profile 1 rises toward profile 2 and is thus correlated with the Ayr Lake till.
The Kogalu Member is comprised of deposits that are assigned to the mid Foxe Glaciation, locally named the Ayr Lake stade. Radiocarbon dates on in situ shells in marine sediments, post- dating deposition of the Ayr Lake till, range between ca. 33 000 and 48 000 years BP, although these are considered only to be minimum dates. The outlines of the Clyde and Ayr Lobes at their mid Foxe maxima are depicted in Fig. 3 ; the age of this margin is > 50 000 years BP. The maxi- mum age of the Kogalu marine sediments is presently unknown; based on the similarities in the amino acid ratios between the upper and lower marine units, we would suggest that the age range is not great (perhaps < 10 000 years). On the basis of amino ratios and ice core oxygen isotope curves, we suggest that the Ayr Lake stade may be as old as 75 000 years.
14C dates on the Kogalu marine sediments include two dates on the uppermost marine unit at Feyling-Hanssen's (1967) Profile IX (Fig. 3). Amino acid ratios (Table 4) indicate that these
marine sands correlate with the Kogalu marine sediments. The original date on a sample collected by Feyling-Hanssen was 40 000 + 1740 years BP (GSC-796), whereas a sample from the same unit collected by Miller gave an age of 41 400 f 500 years BP (QL-186).
Two 14C dates on recessional phases of the mid Foxe Laurentide advance are available. At location 4, Fig. 3, sediment-laden meltwater derived from a mid Foxe recessional stand of the Ayr Lobe formed a glaciomarine delta that is now 42 m as1 and 11 km inland from the present coast. The surface morphology and bedding of the delta are undisturbed. Amino acid ratios from in situ shells (Table 4) indicate that the delta correlates with the upper marine sands at profile 2, and molluscs from the same collection gave a 14C age of 33 600 f 800 years BP (QL- 136). However, due to the small sample size (11 g) and calcareous cementation of the shells, this is only a minimum date. The undisturbed bedding and surface morphology of this reces- sional delta indicate that outlet glaciers have not reached the foreland through the Ayr Lake trough since mid Foxe time.
Shells (possibly ice-transported) collected by J. E. Smith (unpublished data, 1966), within the former margin of the Clyde Lobe (Location 11, Fig. 3), gave a 14C date of 34 900 :+!: years BP (1-1832). Shells recollected from this locality gave a 14C age of 40 000 f 300 years BP (QL- 184) and Kogalu-age amino acid ratios (Table 4).
At 'Cape Smith', outer Scott Inlet (no. 11, Fig. l), an ice-marginal marine delta, deposited during a recessional stand of the Scott Inlet Lobe, lies at 74 m asl. Amino acid ratios from in situ molluscs collected from the delta indicate that it also correlates with the Kogalu marine sediments (Table 4). A 14C date on the molluscs gave an age of 45 200 + 800 years BP (QL-177).
The mode of emplacement of the Ayr Lake till, as well as other till units exposed in the cliffs remains somewhat problematical. During the most extensive glaciations, glacio-isostatic load- ing substantially depressed the land. Although eustatic sea level must also have been lower than at present during recession from the Ayr Lake maximum, relative sea level was ca. 70 m asl. Thus, the Ayr Lake till may have been deposited below sea level, and might be better termed glaciomarine drift. However, Froese (1967) found that most of the units designated as tills by Feyling-Hanssen (1967) had a characteristic till
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2836 CAN. J . EARTH SCI. VOL. 14. 1977
fabric orientation to them, hence we feel that these units are best described as tills, and that outlet glaciers were probably grounded in shallow water on the Clyde foreland.
The Ayr Lake till is tentatively correlated with Feyling-Hanssen's (1 9763) drift 1. However, we strongly disagree with his suggestion that '. ... the glaciation which left drift 1 represents a late Wisconsinian (=Foxe) advance of a Clyde glacier, which reached the coast ..." (Feyling- Hanssen 19766, p. 87). The undisturbed mid- Foxe recessional delta on the Kogalu River (location 4, Fig. 3) clearly indicates that no ice has flowed from the Ayr Lake trough onto the foreland since its deposition. Holocene marine sediments are found only below 30 m on the foreland and are limited in extent compared with those of the Kogalu Member (up to 80 m asl), suggesting no major nearby sediment source (i.e. outlet glacier). There is, to our knowledge, no field evidence to suggest that outlet glaciers from either the Clyde-Inugsuin or Ayr Lake troughs reached the foreland. Indeed, the available field data suggest the foreland has remained ice-free since mid-Foxe time (Andrews and Ives 1972; Miller and Dyke 1974).
Eglinton Member A major depositional hiatus occurs between
deposits of the Eglinton (name derived from Eglinton Fiord) (< 10 000 years BP) and Kogalu (> 35 000, possibly > 50 000 years BP) members. No radiocarbon dates have as yet been obtained for this time period, and we conclude that marine sediment deposited during this interval is below present sea level (Andrews 1975; Miller 1975). Ice was undoubtedly present over central Baffin Island during this interval, but local glaciers remained at about their present extent (Miller 1976a), and much of eastern Baffin Island was ice free. The prevailing climate was probably cold and arid during the latter part of this period (Miller and Williams 1974; cf. Weidick 1975 for West Greenland).
Ravenscraig Marine Sediments Marine sediments deposited during the late
Foxe marine transgression-regression cycle are included within the Ravenscraig marine sedi- ments. At the type locality for the Eglinton Member (profile 1, Fig. 5), Ravenscraig marine sediments occur between 18.3 and 19.8 m asl. The lower-most 20 cm of the unit consists of thin organic layers separated by clastic sediments.
The organic matter gave a 14C age of 8210 + 50 years BP (QL-187, Table 2). The overlying marine sands were oxidized during the early Holocene, prior to eolian deposition. The name for this marine unit is derived from a similar marine deposit in Ravenscraig Harbour (no. 10, Fig. 1) from which an organic lense within the marine sediments gave a 14C age of 8610 + 1885 years BP (DIC-375, Table 2).
Ravenscraig marine sediments are also found in a gully incised into the main Clyde cliff section, 3.7 km southeast of Kogalu River mouth, and 200 m inland from the coast (location 7, Fig. 3). The gully has been back- filled by well-sorted, horizontally bedded marine sands to an elevation of ca. 27 m, 5 m below the surrounding land surface. Four metres below the surface of the marine sands, an organic-rich horizon was encountered, consisting primarily of in situ moss (Scorpidium turgescence (th. Jens.) Loeske; identified by W. Weber, University of Colorado), and 14C dated at 9880 + 200 years BP (GSC-2201). Mandibles of the tadpole shrimp (Lepiduris sp.) and ephippia of Daphnia (identified by J. V. Matthews, Geological Survey of Canada (GSC), Ottawa, Ont.; unpublished plant macrofossil report 75-2) found within the moss indicate a terrestrial -fresh water en- vironment and suggest that the overlying marine sediments represent an early Holocene trans- gression. This date is one of the oldest Holocene dates from eastern Baffin Island. Other dates on the highest ~aienscraig marine sediments from nearby localities range from 9480 + 165 years BP (DIC-374) on peaty organic matter to ca. 7800 years BP on marine shells (Andrews 1976) (Table 3). Shells from a delta 9 m as1 (location 3, Fig. 3) that formed as the sea regressed from the foreland yielded a 14C age of 6110 + 170 years BP (SI-2613).
Throughout the late Foxe stade (ca. 28 000 - ca. 8500 years BP), the main Laurentide ice margin lay 50-90 km inland from the present coast (Miller and Dyke 1974). The ice margin did not undergo significant recession until ca. 8500 ~ years BP, and only after that time were uplift i rates appreciable (cf. Andrews 1975). Ravens- I
craig marine sediments represent the marine transgression caused by the eustatic sea level rise I
before significant isostatic readjustment oc- curred. By 8000 years BP local uplift rates 1 exceeded the rate of sea-level rise, and the sea regressed from the forelands. During the last one
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TABLE
2. R
adio
carb
on d
ates
on
buri
ed p
eats
and
soi
ls, C
lyde
are
a, B
affin
Isl
and.
Mor
e de
taile
d lo
catio
ns a
nd d
escr
iptio
ns i
n A
ndre
ws
(197
6)
Dat
e Sa
mpl
e Sa
mpl
e ID
M
ater
ial
(yea
rs B
P)
Lab
ID
L
ocat
ion
elev
atio
n C
omm
ent
GR
L-2
50-0
Pe
at
GR
L-2
79-0
Pe
at
GR
L-2
03-0
Pe
at
GR
L-2
51-0
O
rgan
ic
detr
itus
GR
L-2
49-0
O
rgan
ic
detr
itus
GR
L-2
87-0
In
situ
mos
s
4260
? 4
75
DIC
-378
O
uter
Sco
tt In
let
16 m
D
ates
ons
et o
f de
posi
tion
of S
cott
Inle
t eol
ian sands.
Bas
al d
ate
on 1
3 cm
pea
t se
ctio
n ov
erla
in b
y 4.
5 m
eo
lian
sand
. 53
70k
130
GIF
-386
6 C
lyde
clif
fs (
no.
5. F
ig.
3)
28 m
B
ase
of p
eat
sect
ion
over
lain
by
1 m
eol
ian
sand
s.
Max
imum
dat
e fo
r on
set
of e
olia
n ac
tivity
. Z
82
10k
50
QL
-187
C
lyde
clif
fs, P
rofi
le I
18 m
A
t th
e ba
se o
f tr
ansg
ress
ive
Rav
ensc
raig
marine
sedi
- m
ents
(si
te 0
-1, F
ig.
5).
m
8610
+ 1
885
DIC
-375
R
aven
scra
ig H
arbo
r O
rgan
ic l
ense
with
in R
aven
scra
ig m
arin
e se
dim
ents
. L
arge
err
or te
rm d
ue to
sm
all s
ampl
e si
ze a
fter
aci
d an
d $
base
pre
trea
tmen
t. >
94
80k
165
DIC
-374
C
ape
Ada
ir
Org
anic
hor
izon
in
fore
st b
eds
with
in R
aven
scra
ig
r m
arin
e se
dim
ents
. 98
80+
200
G
SC-2
201
Cly
de c
liffs
, Pro
file
7
ca. 2
5 m
A
t the
bas
e of
Rav
ensc
raig
mar
ine
sedi
men
ts (s
iteO
-6).
+ 100
0 G
RL
-204
-0
Hum
ic
50 4
00-
900
QL
-188
C
lyde
clif
fs, P
rofi
le 6
28
m
< 1
25
~
frac
tion
of C
ape
Chr
istia
n in
terg
laci
al s
oil.
soil
Dat
e m
ay b
e m
inim
um.
(sit
e0-5
, F
ig. 9
).
Isor
toq
Riv
er
Peat
>
40
000
G
SC-4
27
Cen
tral
Ba
n Is
land
(T
eras
mae
et
a/.
196
6).
Flita
way
L.
Peat
z
30 0
00
1-12
41
Cen
tral
Baf
fin I
slan
d (T
eras
mae
et
01.
1966
).
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TA
BL
E
3. R
adio
carb
on d
ates
on
mar
ine
shel
ls, C
lyde
are
a, B
affi
n Is
land
. M
ore
deta
iled
loc
atio
ns a
nd d
escr
ipti
ons
in A
ndre
ws
(197
6)
Spec
ies
Sam
ple
Sam
ple
ID
date
d D
ate
Lab
ID
L
ocat
ion
elev
atio
n C
omm
ent
m
GR
L-2
56
3
-
6110
+17
0 SI
-261
3 K
ogal
u R
iver
, 3
km
< 9
D
ates
regr
essi
on o
f th
e se
a af
ter t
he m
axim
um H
oloc
ene
(s-5
) fr
om m
outh
, Pr
ofile
3
tran
sgre
ssio
n. T
hin
shel
ls, p
erio
stra
cum
int
act
GR
L-2
55-S
H
.a.
10 0
95 + 9
5 SI
-261
2 O
uter
Sco
tt I
nlei
37
O
ldes
t da
te y
et o
btai
ned
for
late
Fox
e (R
aven
scra
ig)
sedi
men
ts. A
lmos
t ex
clus
ivel
y H
. arr
rico
G
RL
-156
-S
P.a
. 33
600
+80
0 Q
L-1
36
Kog
alu
Riv
er,
I I k
rn
42
Del
ta r
elat
es t
o a
rece
ssio
nal p
hase
of
Ayr
Lak
e st
ade;
(s
-6)
from
mou
th,
Prof
ile 4
se
a le
vel
had
falle
n fr
om it
s m
axim
um o
f z 7
0 m
to
42
m.
Not
sub
sequ
entl
y ov
er-r
un.
Dat
e is
pro
babl
y a
min
i-
mum
(se
e te
xt)
GR
L-1
48-S
M
.t.
40
00
0k
30
0
QL
-184
C
lyde
Inl
et,
Pro
file
I I
54
You
ng d
ate
from
J.
E. S
mit
h (u
npub
lish
ed d
ata,
196
6),
34 9
00: ;;;;
olde
r da
te o
n re
coll
atio
n. S
trat
igra
phic
sign
ific
ance
un-
cl
ear,
but
pro
babl
y as
soci
ated
with
rec
essi
on f
rom
Ayr
L
ake
stad
e R
FH
-121
5 -
40 0
00
k 1
740
GSC
-796
C
lyde
clif
fs, P
rofi
le I
X
27-2
9 F
eyli
ng-H
anss
en (
1967
1, e
nclo
sing
sed
imen
t ov
erlie
s up
perm
ost
till
in C
lyde
clif
fs
GR
L-1
52-S
-
41 4
00f
500
QL
-186
C
lyde
clif
fs, P
rofi
le 1
X 27
-33
Rec
olle
ctio
n co
nfir
ms
appa
rent
age
of
GS
C-7
96, S
ub
ar
ctic
mac
rofa
una
GR
L-1
60-S
H
.a.
45 2
00k
800
QL
-177
C
ap
Sm
ith,
Out
er S
cott
74
Ic
e-co
ntac
t del
ta f
orm
ed c
lose
to t
he g
laci
al m
axim
um
Inle
t du
ring
Ayr
Lak
e st
ade
GR
L-1
72-S
H
.a.
47 7
00f
700
QL
-183
C
lyde
clif
fs, P
rofi
le I
15
Und
istu
rbed
in
sirtr
mol
lusc
s ov
erly
ing
till
of A
yr
Lak
e (s
-1)
stad
e. N
onco
nfom
ably
ove
rlai
n by
R
aven
scra
ig s
edi-
m
ents
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. J. E
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MILLE iR ET AL. 2839
to two millennia, there has been a slight relative sea level rise of 1 to 2 m.
Scott Inlet Eolian Sands The youngest widespread unit in the Clyde
cliffs, and along much of the eastern Baffin Island coast, is a generally thin (< 1 m) eolian sand unit, although locally it occurs up to 6 m thick. At the type section (profile 1) the eolian sands are <0.5 m thick. A thicker section exists in outer Scott Inlet (no. 11, Fig. I), from which its name is derived. At this locality the lower- most 3 cm of a 13 cm thick peat at the base of a 4.5 m section of eolian sands have been dated at 4260 + 475 years BP (DIC-378). Interbedded organic-rich horizons are present throughout the overlying eolian section, which was deposited in gullies incised into a late Foxe raised marine delta. The date on the basal peat member pro- vides a close estimate for the onset of eolian deposition. A corroborative date has been obtained from the Clyde cliffs (location 5, Fig. 3). At this locality the cliff top is composed of eolian sand, extending to a depth of ca. 1 m where it overlies 30 m of peaty sand, resting unconformably on older marine sediments. The lowermost portion of the peaty sand has a 14C age of 5370 f 130 years BP (GIF-3866). At a somewhat later date, peat accumulation ceased and was followed by a period of eolian de- position.
Basal 14C dates from similar eolian units on Cumberland Peninsula, Baffin Island (in An- drews 1976), suggest that eolian deposition in this region began 2000 to 4500 years BP postdating the local thermal maximum (suggested to date between 7000 and 5000 years BP (Miller 1973, 1975)).
Molluscan Biostratigraphy Considerable work has been carried out in
Alaska, northern Russia, Greenland, and Arctic Europe on the marine molluscan biostratigraphy of Quaternary deposits (Laursen 1950; Feyling- Hanssen 1955; Petrov 1967; Hopkins 1967; Hopkins et al. 1972; Troitskiy 1974). 1n Arctic Canada only a few sections have been reported and described that are older than the Holocene. Exceptions are the reports of Blake (1973, 1975) on molluscs from Coburg Island in northwest Baffin Bay and the work of Feyling-Hanssen (1976a,b, 1977) on foraminifera from eastern Baffin Island.
The basis for the present discussion of the
molluscan faunas of the marine units in the Clyde cliffs are the works of Ellis (1960), Lubinsky (1972), and Clarke (1974) on the present faunas of the eastern Canadian Arctic, and the work of Andrews (1972) on Holocene molluscan assemblages from the eastern coast of Baffin Island.
Molluscs of the Baffin Bay region are classified into Arctic and Subarctic faunas with the boundary fixed ecologically by the West Green- land Current (Fig. 1).
The Subarctic province extends to 77" N on the coast of West Greenland but only to about 66'30' N on eastern Baffin Island. The difference in climate (Table 1) and vegetation between the coasts of West Greenland and Baffin Island is striking; the eastern coast of Baffin Island is primarily unglaciated except at high elevations, but relative to West Greenland the terrestrial flora and marine faunas are impoverished.
Molluscs that are considered indicative of Subarctic conditions include: Mytilus edulis LinnC, Chlamys islandicus Muller, Macoma balthica LinnC; whereas possible Subarctic types include : Mya pseudoarenaria' Schlesch, Astarte borealis var. withami Wood, Astarte subaequila- tera S o ~ e r b y ' ~ ~ (subspecies of Astarte crenata Gray), and Astarte montagui Dillwyn. These designations are based primarily on the distribu- tion maps in Lubinsky (1972) and partly on their occurrence at specific times within the Holocene (Andrews 1972).
Collection and ZdentiJication Fossils were collected from raised marine
sediments that were deposited during either glacio-isostatic depression or recovery of the crust by successive glacial advances and retreats. Shells were collected for dating purposes, hence the results reported here no doubt underrepre- sent small shells. However, over 1000 g of shells were often collected; thus, we feel that the data are worth evaluating in a qualitative presence- absence mode (Table 5).
Cape Christian Member The Cape Christian marine sediments contain
large, robust valves of Mya pseudoarenaria with maximum dimensions of 70 x 45 mm. These dimensions are larger than specimens from
'There are arguments as to whether these are distinct species.
'This species may be indicative of deep water (e.g. Ockelmann 1958).
Can
. J. E
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For
pers
onal
use
onl
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TA
BL
E
4. A
min
o ac
id r
atio
s de
term
ined
fro
m f
ossi
l mol
lusc
s co
llect
ed i
n th
e C
lyde
for
elan
d re
gion
Sam
ple
Rel
ativ
e A
llo-I
so r
atio
* IN
ST
A A
R
elev
. se
a le
vel
Spec
ies
Loc
alit
y la
b. n
o.
(m)
(m)
anal
yzed
F
ree
Com
bine
d R
elat
ive
age?
14
C ag
e an
d co
mm
ents
S-1
, pro
file
1
GR
L-1
72-S
15
>
18
H.a
. 0.
292r
f-0.
026 (
12)
0.04
1 f 0.
006
(17)
K
ogal
u S-
2, p
rofi
le 1
G
RL
-228
-S
7-10
>
12
H.a
. 0.
90 (
2)
0.33
(4)
E
arly
pre
- H
ighe
st r
atio
s ye
t ob
tain
ed f
rom
Cly
de
Fox
e G
laci
atio
n ar
ea f
ossi
ls
S-3,
pro
file
2
GR
L-2
303
23
2 2
5 H
.a.
0.27
(2)
0.
038
(2)
Kog
alu
S-4,
pro
file
2
GR
L-2
29-S
13
>
14
H.a
. 0
.58
& 0
.047
(1
1)
0.07
5 K
uvin
ilk
Cly
de ti
ll is
not
pre
sent
S-
5, p
rofi
le 3
G
RL
-256
-S
2-4
9 M
.t.
ND
0.
02
Rav
ensc
raig
61
10f
17W
Sl-2
613)
. No
dete
ctab
le a
!- lo
isol
euci
ne in
the
free
fra
ctio
n S-
6, p
rofi
le 4
G
RL
-156
-S
30-4
0 42
H
.a.
0.32
0.
06f
Kog
alu
33 M
X)?
800
(QL
-136
) S-
7, p
rofi
le 6
G
RL
-213
-S
34-3
7 2 3
7 M
A.?
0.
36
0.3
4k
K
ogal
u F
ragm
ente
d sh
ells
ass
ocia
ted
wit
h A
yr
Lak
e til
l. S
peci
es i
dent
ific
atio
n un
re-
liab
le
S-8,
pro
file
6
GR
L-2
07-S
25
un
know
n H
.a. ?
0.
86
0.20
-0.0
9 -
Sm
all,
unid
enti
fiab
le, f
ragm
ente
d d
vm
fr
om
che
Sled
gepo
inte
l. til
l. Trans-
port
ed s
hell
s may
be o
f se
vera
l age
s S-
9, p
rofi
le 6
G
RL
-181
-S
11
> 1
1 H
.a.
0.79
(2)
0.20
P
re-F
oxe
S-10
, pro
file
6
GR
L-1
59-S
4
24
H
.a.
0.73
0.
21
Pre
-Fox
e N
ote
diff
eren
ce in
com
bine
d ra
tios
for
C
.C.
0.64
0.
10
spec
ies
wit
hin
the
sam
e de
posi
t S-
11, p
rofi
le 8
G
RL
-250
-S
27
>2
7
H.a
. 0
.5
(4)
0.09
5 K
uvin
ilk
S-12
, pro
file
8
GR
L-1
96-S
23
>
25
H.a
. 0.
55 (
2)
0.09
5 (8
) K
uvin
ilk
S-13
, pro
file
8
GR
L-1
97-S
20
>
25
H.a
. 0.
58 (
2)
0.09
(8)
Kuv
inil
k C
omm
ent o
n S-
1 1 to
S-1
4 se
ries
: Rat
ios
M.t.
0.
51 (
3)
0.07
(3)
in
the
Free
F
ract
ion
do
not
sho
w a
sy
stem
atic
incr
ease
. Thi
s m
ay b
e du
e to
sm
all
num
ber
of a
naly
ses/
sam
ple
Ess
enli
ally
no
sub
stan
tial
dif
fere
n=
with
in a
ny o
f th
e K
uvin
ilk
unit
s.
S-14
, pro
file
8
GR
L-1
98-S
20
>
25
H
.a.
0.55
0.
010
Kuv
inil
k S-
15, p
rofi
le 9
G
RL
-168
-S
10
2 1
0 H
.a.
0.6
6+
0.0
31(1
1)
0.1
6k
0.0
25(3
7)
Cap
e C
hris
tian
L
arge
err
or t
erm
in
Com
bine
d ra
tios
C
.C.
0.67
(3)
0.07
(2)
poss
ibly
a r
esul
t o
f lo
ng s
urfa
ce e
x-
posu
re
of
som
e va
lves
. N
ore
spec
ies
effe
ct
on
rati
os.
Sin
gle
valv
e fr
om
Lok
ens
(196
61 c
olle
ctio
n an
alyz
ed b
y P.
E.
Har
e. C
onfi
rms
that
CR
L-1
68-S
is
pro
babl
y fr
om s
ame
loca
lity
. U-s
erie
s da
te c
a. 1
30 0
00 years B
P
Can
. J. E
arth
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For
pers
onal
use
onl
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TA
BL
E
4 (C
oncl
uded
)
INS
TA
AR
L
ocal
ity
lab.
no.
Adj
acen
t to
or
sam
e as
pro
file
9
GB
L-3
-65
S-16
, pro
file
10
GR
L-2
31-S
S-
17, p
rofi
le 1
1 G
RL
-173
4
Cap
e S
mit
h,
GR
L-1
603
Out
er S
cott
Inl
et
Sam
ple
Rel
ativ
e A
llo-I
so r
atio
* el
ev.
sea
leve
l Sp
ecie
s (m
) (m
) an
alyz
ed
Fre
e C
ombi
ned
Rel
ativ
e ag
e?
I4C
age
and
com
men
ts
10
21
0
H.a
. -
0.12
C
ape
Chr
isti
an
> 5
0 00
0 (Y
-170
2) U
-ser
ies
2 1
15 0
00
year
s B
P 3
13
0
.73
(2)
0.17
(3)
Cap
e C
hris
tian
56
un
know
n M
.t.
0.31
(2)
0.
05
Kog
alu
40 0
00
2 3
00 (
QL
-184
) A
ssoc
iate
d w
ith
rece
ssio
n of
th
e C
lyde
Lob
e fr
om i
ts
Ayr
Lak
e st
adia
1 m
axim
um
65-7
0 74
H
.a.
0.27
(2)
0.
04
Kog
alu
F 45
200f
800 (QL-177) Ic
econ
tact
gla
- r
ciom
arin
e de
lta
near
max
imum
ext
ent
of S
cott
Inl
et L
obe
Pro
file
IX,
GR
L-1
77-S
27
-33
ca. 3
5 H
.a.
0.2
4
0.0
4
Kog
alu
41 400&500 (
QL
-186
) C
lyde
clif
fs
M.t
. 0.
27
0.0
4
RF
H-1
215
27-2
9 ca
. 35
H.a
. 0
.30
0.
05
40 0
00 f 17
40 (
GSC
-796
) O
rigi
nal
col-
'
lect
ion
by
R.
W.
Fey
ling
-Han
ssen
0.
5 km
N o
f G
RL
-253
4 15
-17
> 20
H
.a.
0.28
0.
046
Kog
alu
Sam
ple
unde
rlie
s A
yr L
ake
till
. R
atio
s pr
ofile
1
are
not s
tatis
ticra
lly d
iffe
rent
from
tho
se
in s
hell
s abo
ve th
e til
l M
oder
n -
0 0
H.a
. 0.
0 ca
. 0.0
18
Mod
ern
No
free
am
ino
acid
s; a
lloi
sole
ucin
e in
co
mbi
ned
frac
tion
is th
e am
ount
form
ed
duri
ng l
abor
ator
y ac
id h
ydro
lysi
s -
'Rat
io
of D
-sllo
isol
euci
ne
to L
-iso
leuc
ine
in t
he f
ree
amin
o ac
id a
ssem
blag
e (F
ree)
and
aft
er c
onvc
nlio
nal
acid
hyd
roly
sis
(Com
bine
d).
Fig
urcs
in p
are
nth
am
ere
the
num
ber
of a
naly
ses
per
sam
ple.
ND
-no1
de
tect
able
. ?U
nit
nam
es d
evel
ornd
in t
his
pape
r, s
ee t
ext
for
disc
ussi
on. S
peci
es a
bbre
viat
ions
are
as
foll
ows:
H.a
. = H
iote
lla a
rcti
ca, M
.t. =
,Uyd
rru
ncat
a, C
.C. =
Clin
ocar
dium
cili
atur
n.
Can
. J. E
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onal
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2842 CAN. J. EARTH SCI. VOL. 14, 1977 I TABLE 5. Marine molluscs from deposits formed between the last interglaciation and present, eastern Baffin Island* I
Early Water- Holocene Kogalu Kogalu Kuvinilk Kuvinilk Cape mass Holocene (Ravens- (upper) (lower) (upper) (lower) Christian
Species affinity Modern optimum craig) (7 sites) (1 site) (1 site) (3 sites) (2 sites) --
Portlandia arctica A X X X X Astarte warhami A X X Astarte borealis placenta A X X X Mya truncata P X X X X X X X Hiatella arctica P X X X X X X X X Serripes groenlandicus P X X X X Clinocardium ciliatum P X X X Macoma calcarea P X X X X Astarte elligtica P X Chlamys islandicus S X X X X Mytilus edulis S X Mya pseudoarenaria S X X Macoma balthica S X X ? Astarte borealis withhami S X X Astarte striala S X X Astarte montagui S X X Astarte subaeauilatera S X X
*A = Arctic. S = Subarctic, P = Panarctic-boreal, X = Species is present.
Holocene deposits of Home Bay, some 150 km to the south (J. T. Andrews, unpublished data, 1967). The growth rate of a broken valve of Serripes graeniandicus was ca. 5 mmlyear, slightly higher than the same species from the , Holocene sequences of Home Bay (Andrews 1972). Our tentative conclusion from these limited data is that the marine environment was similar to the Holocene marine optimum.
Kuvinilk Member Chlamys islandicus occurs in Kuvinilk marine
sediments both over- and underlying the Clyde till, suggesting that the early Foxe glaciers advanced into Subarctic waters. Astarte sub- aequilatera was identified from the marine sedi- ments above the Clyde till.
Kogalu Member The one site where the Kogalu marine sedi-
ments underlying the Ayr Lake till are fossili- ferous has a sparse fauna consisting primarily of the ubiquitous Hiatellu arctica. However, the Kogalu sediments postdating the Ayr Lake till are extensively exposed and contain a faunal assemblage nearly identical with that of the Holocene marine optimum of eastern Baffin Island (cf. L ~ k e n 1965; Andrews 1972). The exception is the absence of Mytilus edulis and Mya pseudoarenaria. In certain sites Chlamys islandicus is abundant and it has been found in most sections. The presence of C. islandicus
during Kogalu times indicates that Subarctic I
water was present against eastern Baffin Island; ! a similar conclusion based on foraminifera is I
given by Feyling-Hanssen (19766, 1977). I
Eglinton Member Early Holocene (10 000 to ca. 8400 years BP) ,
faunas are restricted to a few Arctic and Pan- arctic species, notably Hiatella arctim and Mya truncata. However, radiocarbon dates document a flood of Subarctic molluscs into the eastern Canadian Arctic close to 8400 years BP. This event is isochronous with a similar event in East Greenland (Hjort and Funder 1974) and coincides with the introduction of floating drift- wood into the High Arctic islands of Canada (Blake 1972).
Palynology
Information on Holocene pollen and vegeta- tion changes is virtually nonexistent for the eastern Canadian Arctic. This general absence of data on the Holocene pollen-vegetation- climate relationship is matched by the paucity of data on the character of the last interglacial climate in the eastern Canadian Arctic. Terasmae et al. (1966) have, however, reported on the pollen and macrofossils of two interglacial deposits located in central Baffin Island (Fig. 1) that have been assigned to the Flitaway Inter- glacial (Andrews 1968).
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MILLER ET AL.
TABLE 6. Data on peat and detrital organic collections, Clyde region
Site no. . Relative age Location Profile and figure
0-1 Ravenscraig Clyde cliffs Profile 1 ; Figs. 3, 5 0 - 2 Kuvinilk Clyde cliffs Profile 2; Figs. 3, 6 0 - 3 Postglacial Delta on Lower Kogalu River Location 3; Fig. 3 0-4 Base of Scott Inlet Clyde cliffs Location 5 ; Fig. 3
eolian sands 0 -5 Cape Christian
Interglaciation Clyde cliffs Profile 6; Figs. 3, 9 0 -6 Ravenscraig Back-filled delta, Clyde cliffs Location 7; Fig. 3 0-7 Kuvinilk Clyde cliffs Profile 9; Figs. 3, 8 0-8 Cape Christian
Interglaciation Clyde cliffs Profile 10; Figs. 3, 8 0 -9 Base of Scott Inlet Scott Inlet Location 11 ; Fig. 1
eolian sands
In an attempt to better define the terrestrial (or of a second slide) is undertaken, however, to vegetation fluctuations associated with the increase the low values of Picea (spruce), Pinus glacial stades and marine environmental changes, (pine), and other exotic taxa to statistically buried soils and organic-rich horizons were reliable totals related to 'absolute' values, and to collected for I4C dating and pollen analysis from identify rare local taxa not located in the count. several units in the Clyde cliffs. The INSTAAR Date reduction is largely handled by computer (Institute of Arctic and Alpine Research) programs (Nichols 1975). ~ a l ~ n o l o ~ ~ Laboratory has been-set up to handlk Arctic and Subarctic samples (cf. Nichols 1975). In preparing peat samples, each sample is weighed and a Eucalyptus tablet is added; at present, ' ab~olu te '~ values are calculated using both dry weight (cf. Jsrgensen 1967) and Stockmarr (1971) exotic additive methods. Values are reported as grains per gram dry weight (glgdw) of sediment. Samples are treated with caustic soda, acetolysis, and hydrofluoric acid for prolonged boiling times, then weighed again and mounted on weighed slides. Trap and polster samples receive the same treatment.
For Baffin Island pollen samples, a standard count of 100 grains, excluding local over- representative peat-forming taxa (Cyperaceae (sedges); Ericaceae (heaths); and Sphagnum), is as meaningful statistically as substantially larger totals (cf. Nichols 1975, p. 54). This total is smaller than the usual standard count for this laboratory (300 grains), because of the sparseness of the pollen in the intractable sediment (i.e. the slides are difficult to count). and because local
A - Descriptive Palynology
Pollen diagrams were constructed for seven collections from the Clyde region. These are site 0-94 (base of the Holocene Scott Inlet eolian sand); sites 0-1 and 0-6 (base of the Ravens- craig marine sediments, Fig. 5 and location 7, Fig. 3); sites 0-2 and 0-7 (within the Kuvinilk marine sediments, Figs. 6 and 8); and sites 0-5 and 0 -8 (Cape Christian marine sediments, Figs. 8 and 9). In addition, a new pollen count was performed for the Isortoq interglacial sample (Terasmae et al. 1966), and pollen diagrams were constructed for modern pollen rain collected in moss polsters and Tuffy and Tauber traps in the Clyde area (collected by H. Nichols in 1973 and 1974). The relative pollen diagrams for these collections are shown in Fig. 10. Pollen taxa have been grouped into a growth-form classification and by moisture requirements (Table 9; P. J. Webber, personal communication, 1975). Abso- lute pollen counts for both polster and fossil collections are listed in Table 8.
, ,
pollen production is generally derived from a ( A ) Cape Christian Interglaciation very few plant taxa of low productivity. Com- Two sites are assigned to the Cape Christian monly, a count of a whole slide will total less Interglaciation on stratigraphic grounds (Figs. than 100 grains. Additional scanning of a slide 8 and 9). The pollen spectra on Fig. 10 and
Table 8 are dominated by high percentages of 3The quotes around 'absolute' are a reminder that
present pollen counting methods described as absolute 4Site 0-9 (etc.) = organic sample 9; locations in are not truly so (Nichols 1975). Table 6.
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CL
YD
E
CU
FF
E;E
L;
i 0-2
FA
CE
2 I
CLY
DE
C
UF
F
FAC
E
4 0
-7
E,?F
L: 7 3
1504
TO
P
R.
. 1
'40
OM
1
I*
. -
FL
LT
hW
aI
L.
-
1'3
00?
01
8 -
FIG
. 10.
Rel
ativ
e po
llen
diag
ram
s of
the
mod
em p
olle
n ra
in in
the
Cly
de a
rea
and
in b
urie
d or
gani
c-ri
ch s
edim
ents
from
the
Cly
de fo
rela
nd s
ecti
ons
as w
ell
as p
olle
n co
unts
from
the
lso
rto
q a
nd F
litaw
ay in
terg
laci
al b
eds
on n
orth
-cm
tral
Baffin I
slan
d (T
cm
ae
et
al. 1
966)
. Ex~
ept fo
r th
e Sc
ott
inle
t se
ctio
n, n
one
of t
he d
iagr
ams r
elat
e to
diff
eren
t str
atig
raph
ic le
vels
in th
e sa
mpl
cs. L
ocat
ions
of
site
s are
giv
en i
n T
able
6.
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MILLER ET AL. 2845
TABLE 7. Contemporary pollen influx at Clyde (+ = pollen located during scanning of a slide) in grains/cm2/
year
Tauber Trap
Species 1 2 3 TuffyTra~
Betula (birch) and members of the Ericaceae, indicating that the area was dominated by mesic to dry conditions. A significant contrast between
Alnus Betula Juglans Picea Pinus Salix Ambrosia Artemisia Campanula Caryophyllaceae Chenopod Compositae-Tub Cruciferae Epilobium Gramineae Leguminosae Potentilla Ranunculaceae Rosaceae Rubus Sarcobatus Saxifraga Typha latifolia Cyperaceae Ericaceae Filicales Lyc. cl. Lyc. selago Sphagnum
'
exotic pollen accumulation during Kuvinilk time. During this early stade of the last glacia- tion, exotic pollen accounted for between l and 17% of the total pollen rain.
The growth form analysis highlights the dramatic difference between the Cape Christian Interglaciation and Holocene pollen assemblages (Table 9). The tundra changes from a shrub tundra to a grass-sedge tundra with the inter- stadia1 pollen indicating a mixed shrub-grass- sedge environment. In addition, the Cape Christian Interglacial pollen is dominated by taxa with a dry to mesic moisture preference, rather than the mesic-wet preference of Holocene samples (Table 9).
(B) Kuvinilk Marine Sediments (sites 0-2 and 0-7) ( > 47 700 years BP)
Organic-rich layers are included within shal- low-water littoral facies of the Kuvinilk marine sediments (Figs. 6, 8). Pollen accumulation is low (Table 9) and there is an order of magnitude
the last interglaciation and the Holocene (Fig. 10) is the near absence of Gramineae (grass) pollen during Cape Christian time. 'Absolute' pollen counts indicate that Betula varied from 3 156 to 16 013 glgdw (Table 7) and Alnus (alder) varied between 54 and 1373 glgdw; these are peak values for Alnus in the Clyde area. Pinus and Picea are present, but not in large numbers. The high amounts of Betula pollen indicate that dwarf birch (probably Betula nana and (or) Betula glandulosa) was present at the site. The outer Clyde coast now lies some 450 km north of the limit of isolated stands of Betula nana on Cumberland Peninsula (Fig. 1).
The pollen assemblages of the Cape Christian interglacial sediments have many details in common with interglacial peats and organic-rich sediments north and west of the Barnes Ice Cap (Terasmae et al. 1966). Figure 10 shows two individual pollen counts; one from the Isortoq beds of the Flitaway Interglacial and the other
1 from sediments at Flitaway Lake (in Terasmae et al. 1966). Both are dominated by Betula, with Salix (willow) being a much smaller con- tributor. The 'absolute' count by Short indicates 27 622 g/gdw of Betula. Macrofossils of both species of dwarf birch were recovered from the Isortoq beds, and M. Kuc (personal com- munication, 1976) has identified more than 61 mosses and vascular plants from the same unit. Terasmae et al. (1966) suggested that alder may have grown very close to the Isortoq Valley, because at other levels (see their Fig. 8) the Alnus pollen was present in clumps, indicating limited travel. The indications are that northern Baffin Island, at least to 71" N, had a Low Arctic shrub tundra cover during the last interglaciation.
We consider Betula as exotic pollen in the Holocene sediments, but the high amounts (both percentage and 'absolute') within the Cape Christian Interglaciation indicate the presence
1 of indigenous dwarf birch. 'Absolute' amounts of exotic pollen were twice as high during the last interglaciation as they were during the mid Holocene (Table 9), and support a two-fold increase in total pollen accumulation in the earlier interglaciation. Values of exotic pollen are virtually zero during the early Holocene when ice lay to the west and southwest (Fig. I), although this contrasts with a low but consistent
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TA
BL
E 8. "
Abs
olut
e"
polle
n da
ta f
rom
mod
em a
nd f
ossi
l po
llen
colle
ctio
ns in
the
Cly
de a
rea.
Tau
ber
and
Tuf
fy t
rap
data
are
exp
ress
ed a
s gr
ains
cm
-2 y
ear-
' w
here
as p
olst
er a
nd f
ossi
l si
tes
are
grai
nslg
ram
dry
wei
ght
(glg
dw).
Tra
nsec
t 2
pols
ters
col
lect
ed in
197
2; tr
anse
ct 3
pol
ster
s co
llect
ed in
197
3. F
or r
elat
ive-
age
assi
gnm
ents
of
the
site
s (0
-2,
0-6
etc.
) an
d sp
ecif
ic lo
catio
ns s
ee T
able
6.
+ =
pol
len
loca
ted
duri
ng s
lide
scan
-
-
-
-
- -
Tau
ber
Tra
p Po
lste
rs-T
rans
ect
2 T
rans
ect
3 T
uffy
1
2 3
Tra
p I
2 4
5 6
7 8
9
10
I 2
Alnus
24
+ 83
B
etul
a 49
+
80
+ +
Jugl
ans
Pice
a +
f
+ 36
P
inus
+
+ 49
25
9 36
10
3 80
4
42
42
7 0
Salix
26
71
39
0 25
9 81
9 67
7 56
9 39
9 77
10
06
20
121
208
11
>
Am
bros
ia
+ z
Art
emis
ia
+ 25
9 40
7
x C
ampa
nula
8 1
>
C
aryo
phyl
face
ae
34
142
146
8015
16
4 +
103
239
31
1508
16
20
8 5F
l
Che
nopo
d 24
+
11
2 C
ompo
sita
e-T
ub.
(/i
Cru
cife
rae
71
103
g E
pilo
biur
n 1
G
ram
inea
e 78
2 21
10
4002
17
065
6964
24
21
3310
71
79
1410
47
769
300
5503
11
700
947
619
Leg
urni
nosa
e +
+ +
- P M
yric
a 49
-
Pote
ntill
a -I-
10 .I
Ran
uncu
lace
ae
4
Ros
acca
e +
246
107
517
+ 8
20
83
32
21
Rub
us
Sar
coba
tus
Saxi
frag
acea
e 9
195
107
414
+ 3 1
57
30
3 16
7 T
ypha
latif
olia
C
yper
acea
e 9
95
146
164
178
414
1 8
101
42
32
14
Eri
cace
ae
71
98
+ 71
10
3 +
15
20
21
Filic
ales
10
7 +
Lyc
opod
ium
cfa
v.
Lyc
opod
iurn
sela
go
+ 52
Sp
hagn
um
9 71
f
+ +
f
+ I-
4
f
11
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TABLE
8 (C
ontin
ued)
Sco
tt In
let
Sit
e 0
-1
Site
0-7
Si
te
OC
~
2.5c
m
5c
m
7cm
ge
m
llc
m
13
~~
0-
6 I
n III
I IE
II
I
Ain
us
+ 93
32
8 10
1 +
199
29
3 B
etul
a 30
5 +
246
302
144
113
112
32
96
23
15
7 Ju
glan
s Pi
oea
93
+ +
+ +
3 Pi
nus
+ +
82
+ +
73
199
14
7 7
Sal
ix
2337
25
10
1148
80
5 14
44
145
597
140
77
96
47
8 1
34
Am
bros
ia
3 A
rtem
isia
82
73
7
Cam
panu
la
14
Car
yoph
ylIa
ceae
18
6 49
2 10
1 +
199
19
42
45
68
Che
nopo
d 14
14
5 r
Com
posi
tae-
Tub
. 3
r
m
Cru
cifc
rae
5~
l E
pilo
biur
n m
Gm
min
eae
6910
62
28
5823
84
51
1242
1 68
35
1850
5 13
2 14
0 83
16
4 19
6 14
7 i
126
+
Legu
min
osae
!-
Myr
ica
7 Po
tent
ifla
+ R
anun
cula
ceae
R
osac
eae
203
144
6 3
Rub
us
Sar
coba
tus
Sax
ifra
gam
e T
ypha
lati
folia
C
y pe
race
ae
3048
13
94
2214
12
07
1300
29
1 15
92
168
35
82
17
22
20
Eri
cace
ae
406
93
1968
50
3 60
66
291
132
56
38
109
7 15
17
Fi
lical
es
203
186
+ 20
1 14
4 73
94
16
3
Lyc
opod
ium
cla
v.
102
+ +
Lyc
opod
iwn
*lag
o 10
2 10
1 14
4 73
19
9 19
22
7
37
14
Suh
amur
n 3
3 3
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TA
BL
E
8 (C
oncl
uded
)
Site
0-2
Si
te 0
-8
Site
0-5
Fl
it-
Isor
toq
away
I
I1
111
I I1
111
IV
V
VI
I 11
I1
1 R
iver
L
ake
A~
US
14
10
54
47
1
870
400
1002
84
9 12
53
387
1373
+
No
Bet
ula
28
39
3156
55
63
7722
43
97
1262
8 11
373
1603
9 14
108
1601
3 27
622
Abs
o-
Jugl
ans
161
lute
Picea
+ 94
+
+ 20
0 +
25 1
193
+ D
ata
Pinu
s 10
54
+
109
+ 20
0 +
+ 19
3 +
161
Salix
61
9 11
78
805
490
1509
87
0 22
38
4209
23
76
6265
34
79
4804
28
91
Am
bros
ia
Art
emis
ia
189
+ 16
1 C
ampa
nula
C
aryo
phyl
lace
ae
42
109
+ +
Chc
nopc
d C
ornp
osita
e-T
u b.
14
94
Cru
cile
rae
Epi
lobi
um
+ +
+ +
+ +
+ G
ram
inea
e 21
11
1 39
27
2 47
1 10
9 16
0 20
0 17
0 25
1
387
+ 16
1 L
egum
inos
ae
161
Myrica
10
54
25 1
193
Pote
ntill
a R
anun
cula
ceae
+
Ros
acm
e 21
20
8 10
9 22
9 R
ubus
20
0 Sa
corb
atus
S
axifr
agac
eae
Typ
ha la
tifol
ia
54
Cyp
ecao
eae
1063
29
79
514
109
283
109
1039
12
03
679
2380
8 13
721
2401
9 25
70
Eri
cace
ae
186
1524
10
7 20
077
2197
0 16
966
1958
5 37
083
2698
9 90
22
8310
16
013
3372
Fi
lical
es
163
283
218
240
401
339
+ +
803
Lyc
opad
ium
cla
v.
+ +
218
160
601
1018
25
1
387
458
Lyc
ovod
ium
sela
go
83
332
58
1034
75
4 65
3 40
0 40
1 84
9 50
1 +
458
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MILLER ET AL. 2849
TABLE 9. Number of pollen (glgdw) according to growth form and moisture preference. Site locations in Table 6. Betula is always included under shrub, although it is at times considered as exotic
Total no. pollen
Site No. taxa (g/gdw) Shrub Grass Exotics Wet % Wet Mesic % Mesic Dry % Dry
Site 0-9 Site 0 -9 Site 0 - 9 Site 0 -9 Site 0-9 Site 0 -9 Site 0 - 9 Site 0-1 Site 0 -1 Site 0-1 Site 0 -6 Site 0 -2 Site 0 - 2 Site 0 -2 Site 0-7 Site 0 -7 Site 0-7 Site 0-8 Site 0-8 Site 0 -8 Site 0 -8 Site 0-8 Site 0 -8 Site 0 -5 Site 0-5 Site 0-5 Isortoq
difference between sites 0-2 and 0-7. The num- bers of taxa are similar to those in Ravenscraig sediments and marginally higher than at the Scott Inlet site (Tables 8, 9). Shrub pollen ex- ceeds or is slightly less than pollen from Grami- noids, and this is quite different from the Scott Inlet spectra (Table 9, Fig. 10). Alnus, Betula, Picea, and Pinus pollen occur in rather low 'absolute' numbers but, because of the small total number of 'absolute' pollen (Table 8), the per- centage of Betula is similar to that recorded in the early Holocene, whereas Alnus was not found in either of the two early Holocene sites (Fig. 10). Otherwise, the pollen assemblages are similar to present values. Significant numbers of Lycopodium selago spores occur and this con- trasts with the Holocene records. The Lyco- podium may indicate the presence of significant snowbed sites and wet, peaty soil (cf. Table 9), or could represent differential preservation and transportation (J. V. Matthews, Jr., personal communication, 1976).
(C) Base of the Ravenscraig Marine Sediments (sites 0-1 and 0-6) (ca. 9800-8200 years BP)
At the beginning of the Holocene, the Lauren- tide Ice Sheet was still extensive (Fig. 1) and the east coast of Baffin Island was a long, thin, and highly irregular stretch of coastline that had probably been ice free for several tens of thousands of years. It is probable that areas of the continental shelf were dry land during the last sea level minimum. Although Alnus and Picea pollen are not present in the moss and soil at the base of the transgressive Ravenscraig marine sediments (locations 2 and 7, Fig. 3; Fig. 10; Table 8), Betula is present in 'absolute' numbers comparable with that recorded at the base of the Scott Inlet eolian sands. However, pollen accumulation is very low at these sites (Table 9); indeed it is two orders of magnitude lower than during Scott Inlet time. This low accumulation could be due to (i) very low real pollen productivity, or (ii) rapid organic accu- mulation. Table 9 indicates shrub pollen makes
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2850 CAN. J. EARTH SCI. VOL. 14, 1977
up - 50% of the total glgdw, and that the dry and suggests that the Clyde area has experienced a mesic indicators are dominant. The Betula pollen climatic deterioration during the late Holocene. could represent small local clones on Baffin (E) Modern Pollen Island (see Fig. or could represent alloch- The modern pollen rain (Fig. 10; Tables 7, 8, thonous pollen from outside the area, either from and 9) is dominated by ~~~~i~~~~ pollen with a West and Funder 1974) Or moderate amount of Salix and Caryophyllaceae possibly from the far west of North America, (pink family). Little exotic pollen (Alnus, Betula, where birch was present in places but pollen Picea, or Pinus) reaches the Clyde area, which is
was very low (Matthews 1975). At currently some 1250 km from the nearest stands one site on southern Cumberland Peninsula of conifers. Tauber trap data indicate 1-2 gains dated 6800 -1 600 Years BP (Qu-2991, Bet&
cm-2 year- 1 of and Betula pollen enter the makes 30% the pollen, thus jndicating region and even smaller quantities of Picea pollen Arctic shrub tundra invaded areas -4" latitude were caught. varied from 0 to 5 grains south of the Clyde area during the close of the ,,-z year-i whereas ~~~~i~~~~ pollen ranged Ravenscraig marine cycle. Although the low pol- from 40 to 339 grains cm-z year-i. ~~~~l pollen len accumulation in the Ravenscraig sediments influx varies between 45 and 513 grains cm-2 probably indicates a severe local climate, we are year- i (Table 7). also open to the interpretation that the low accumulation is due to rapid organic growth Quantitative Palynology and (or) washing-out during the overlying In recent papers on ocean core faunas (e.g. marine phase. In situ continuous sections dated Sachs 1973), use has been made of factor 10 000-5000 years BP are clearly needed to analysis to aid in interpreting present environ- resolve these two alternatives. mental controls on various biological organisms.
( D ) Scott Inlet Eolian Sands-Ravenscraig Such data can then be used in attempts to recon- Marine Sediments Transition (site 0-9) struct past environments throughout suitable (ca. 4500 +years BP) sediment cores, insofar as the information is
Following deposition of the Ravenscraig contained in the variations of, and percentage marine sediments, a soil and vegetation cover variations in, the major taxa (see Imbrie and developed at many sites. This period of environ- Kipp (1971) for extended review). Similar mental stability was succeeded by eolian activity, approaches have been published recently in the both erosional and depositional. The section palynological literature (cf. Birks et al. 1975; under the Scott Inlet eolian sands records the Adam 1974). Quantitative arctic palynology is transition from the local climatic optimum still in its infancy, and there are several problems toward the more severe climate of the last 4000 associated with low pollen accumulation and the years (cf. Miller 1973). importance of far-travelled exotic pollen.
The pollen spectra from the base of the Scott We use some of the techniques reported above Inlet eolian sands are rather similar to the to compare similarities between the fossil spectra modern pollen rain recorded in Tauber traps (Fig. 10) and a suite of samples that record the and moss polsters, and are dominated by Gra- modern pollen rain from sites in Labrador- minae with lesser amounts of Salix but signifi- Ungava, northeast Keewatin, and other sites on cantly higher amounts of Cyperaceae pollen. Baffin Island (Fig. 1). Samples from Clyde River, Alnus is present at counts between 93 and 328 Frobisher Bay, Pangnirtung, and Broughton glgdw and is roughly equal to the amount of Island are based on pollen deposited on mosses, Betula pollen. Small, uneven distribution of whereas the data from Hall Beach, Fort Chimo, Pinus and Picea pollen was observed throughout Port Harrison, and another sample from Fro- the 13 cm-thick section (Table 8). The higher bisher Bay are taken from the work of Ritchie amounts of Alnus and Betula, and the increase in and Lichti-Federovitch (1967), where the pollen Salix and Cyperaceae, suggest that the climate was collected in open petrie dishes in weather following deposition of the Ravenscraig marine screens. All data in the analysis have been sediments was possibly wetter and probably reduced to a similar format with Cyperaceae, warmer than present. 'Absolute' pollen accumu- Ericaceae, and Sphagnum (the peat formers) lation is estimated at between 7854 and 21 807 outside the sum used in calculating the pollen glgdw. The contrast in pollen assemblages percents. Eleven taxa were determined to be between ca. 4600 years BP and the present significant for input into statistical routines,
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MILLE
namely Alnus, Betula, Picea, Pinus, Salix, Gramineae, Cyperaceae, Ericaceae, Caryophyl- laceae, Sphagnum, and Filicales. Data consisted of 25 samples of modern pollen, including the 14 modern samples at the top of Fig. 10 from Clyde, and 27 samples of fossil pollen from the various lithostratigraphic units discussed in the previous sections. Two additional samples from the Holocene local thermal maximum at about 5500 years BP have been included from sites near Pangnirtung (Fig. 1). The use of percent data can be misleading for both pollen and marine organisms. Specifically, the importance of the variations in pollen accumulation (g/gdw) is lost (see Table 9). However, in the older units it is doubtful that we can accurately convert pollen accumulation (glgdw) to rate of pollen influx (grains cm-2 yearP1); hence we use percent data for our analyses, despite its limitations.
Principal Components Analysis The assemblages of modern, fossil, and com-
bined (modern and fossil) pollen were run through a Principal Components Analysis (PCA). The statistics and usefulness of this method are discussed by Davis (1973) and Birks et al. (1975). In the modern pollen assemblages, the first PC explains 34% of the variance, whereas in the combined pollen set 24% of the variance is accounted for. Eighty-one percent and 75% of the variance, respectively, are ex- plained by the five factors. These levels of explanation are similar to data from ocean studies (e.g. Sachs 1973, p. 85).
Examination of the loadings of the variables onto the first principal component indicates that the most important variables of the modern pollen rain are exotic tree pollen and Arctic shrub pollen (Pinus, Picea, and Alnus), plus pollen from the Gramineae family. The second PC strongly weights the contribution of Betula, probably shrub birch, and Salix which is a common genus within the tundra. The second component is thus primarily reflecting the pollen production within the tundra of local dwarf shrubs, whereas the first component is strongly weighted by exotic pollen that is travelling into the area during southerly air flows in the late spring and summer months. Climatically, then, the first PC scores are a measure of the strength of southerly air flow into the tundra regions and the natural fallout of pollen downstream from the pollen source. The scores on the second PC are more associated with local climatic conditions and reflect the increasing climatic severity from
R ET AL. 2851
the forest-tundra ecotone to the Low Arctic shrub tundra, to the High Arctic moss and sedge tundra (Cyperaceae is the third strongest con- tributor to the second PC).
Discussion We have used the results of the PC analysis to
compare fossil pollen spectra with possible modern analogues. The modern pollen accumu- lation from moss polsters should provide our 'best' estimate of pollen accumulation onto a peat or soil surface. Modern samples are from sites near present treeline north to Clyde River (Fig. I), covering a wide climatic range (Table 1). The Kuvinilk fossil pollen assemblages are most similar to modern pollen deposition at Frobisher Bay but also show similarities at some levels with modern assemblages from Pangnirtung and Clyde River. In contrast, pollen assemblages from the Cape Christian Interglacial sites are statistically very similar to those from fossil sites near the Isortoq River and Flitaway Lake (Terasmae et al. (1966) and our Table 8), but have no strong affinity with any of the modern pollen assemblages. The high Betula and low Alnus, Pinus, and Picea do, however, have some resemblance to Holocene pollen spectra from Southwest Greenland (Kelly and Funder 1974). J. V. Matthews (personal communication, 1976) has suggested the assemblages resemble those from the Alaskan-Yukon birch zone. Modern counterparts may exist in the Torngat Mountains of northernmost Labrador.
The comparisons between fossil and modern eastern Canadian Arctic pollen assemblages indicate that the last interglaciation and the early Foxe interstadial were equivalent to a northward displacement of the modern tundra zones. During the Cape Christian Interglacia- tion, the Clyde foreland was covered by Low Arctic shrub tundra, although the treeline was probably further south and possibly did not extend onto Baffin Island. During Kuvinilk time, the Clyde area was characterized by pollen assemblages that resemble those collected today near Pangnirtung. During the Holocene, fossil pollen spectra have only been somewhat better (i.e. more shrub pollen) than at present.
Glacial and Climatic Changes During the Last Interglacial - Glacial Cycle
Cape Christian Interglaciation Palynologically, the Cape Christian Inter-
glaciation is correlated with interglacial deposits of north-central Baffin Island (cf.-Terasmae et al.
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2852 CAN. J. EARTH
1966) which contain macrofossils indicative of Low Arctic shrub tundra. Based on the modern pollen rain, conditions on the Clyde foreland during this interval indicate an analogue with northernmost Labrador, southern Baffin Island, or possibly West Greenland. July temperatures may have been as much as 3°C higher than today, with a longer growing season and possibly more precipitation.
The Cape Christian soil at profile 10 has a reddish B horizon and is a much more strongly developed soil than that developed on late Foxe marine deposits during the present interglacia- tion (thin 0 horizon overlying oxidized sand). The better-developed soil and more abundant vegetation recorded in the Cape Christian sediments suggests that the duration of the last interglaciation may have been longer than the Holocene. In addition, the increase of the allo- iso ratio in the combined fraction, from 0.10 to 0.16 between the early Foxe Kuvinilk and pre-Foxe Cape Christian marine sediment.^ (Fig. 4), indicates that the intervening period was long, although the higher interglacial temperatures may, in part, account for the difference in ratios.
The Cape Christian marine sediments contain a marine bivalve assemblage with similarities to that of the Holocene marine optimum. The evi- dence presented in this paper indicates that the last interglaciation was rather more favorable climatically than are present conditions in the Clyde area. This generalization appears to apply to other Arctic sites of the last interglaciation as well. For example, Blake (1974) has presented a wide variety of data on units assigned to the Stuart River Interglaciation (no. 16, Fig. 1). Moss and insect remains indicate conditions more favorable than those that prevail today. On southwest Banks Island, Kuc (1974) has de- scribed the major interglacial site at Worth Point (no. 17, Fig. 1). The presence of larch stumps and other bioclimatic indicators give evidence that ". . . the growing period on the west coast of Banks Island which is now 72-85 days long was distinctly longer during interglacial time" (Kuc 1974, p. 231).
Early Foxe Glaciation (Clyde Stade) The Cape Christian soil represents a deposi-
tional hiatus when relative sea level was <5 m as1 and probably close to present. The Kuvinilk marine sediments represent a rise of relative sea level to > 25 m asl, caused by the glacio-isostatic
SCI. VOL. 14, 1977
depression of the outer coast as the Laurentide Ice Sheet developed on the Baffin Island plateau.
The Clyde stade represents the most extensive advance of the last glaciation. The similar amino acid ratios from the marine units above and beneath the Clyde till suggest that the associated ice advance remained at its maximum for a relatively short period (< 10 000 years). The mollusc assemblages in the marine sediments suggest that outlet glaciers flowed into marine waters that were Subarctic in type. Organic sediments laid down along the outer coast during Kuvinilk time contain a pollen assemblage that ranks midway between the mild climate of the Cape Christian Interglaciation and the Holocene, and includes a low but consistent influx of exotic pollen.
Our combined data suggest that the climate of the Clyde area during the early stade of the last glaciation was milder than present and possibly analogous to the present climate of West Green- land at the same latitude. West Greenland today maintains an extensive ice cover despite a climate milder than that of eastern Baffin Island (Table 1). Thus, our evidence lends support to the reconstruction of the net mass balance of the Greenland Ice Cap at Camp Century (no. 13, Fig. l), which suggested a two to fourfold increase in net accumulation between ca. 115 000 and 70 000 years BP (Andrews et al. 1974). Such an increase in accumulation, combined with temperatures no different from present, is adequate to cause extensive glacierization of the eastern Canadian Arctic (Williams 1975).
Mid Foxe Glaciation (Ayr Lake Stade) I A significant interval of time is represented by I
the hiatus between the Kuvinilk and Kogalu members. Molluscs from the latter have allo-iso ratios (free) of ca. 0.29 compared to ca. 0.56 in the youngest Kuvinilk fossils. Such a difference suggests a break of > lo4 rather than lo3 years. Once again, amino acid ratios are similar both above and below the Ayr Lake till and lead us to conclude that the maximum stand of the Ayr Lake stade was relatively short (< lo4 years). Bivalve assemblages in the upper marine sedi- ments are relatively rich; benthic foraminifera assemblages in the same sediments also indicate ameliorated marine conditions of interglacial- interstadial rank (Feyling-Hanssen 19763). Therefore, the marine environment during the end of the Ayr Lake stade was Subarctic and, by
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inference, the terrestrial climate may have been similar to that which prevailed during Kuvinilk time. As yet, we have no terrestrial or nearshore organic-rich sediments to test this hypothesis.
What is the age of this glacial-interstadial I complex? Radiocarbon dates on the youngest
Kogalu fossils provide minimum dates with the oldest date at 47 700 f 700 years BP (Table 3). 1 The presence of Subarctic water in Baffin Bay during the local early and mid Foxe glaciations may be evident in the high 6180 values between ca. 115 000 and ca. 70 000 years BP (Dansgaard et al. 1971) on the Greenland Ice Cap. An upper limit of this interval therefore could be close to 70 000 years BP.
Partial correlatives of the Kogalu marine sediments farther south on Baffin Island include deposits assigned to the Quajon interstade (Pheasant and Andrews 1973) and the Cape Broughton Interstade (Feyling-Hanssen 1976~). How the Baffin Island record correlates with the pollen record and stratigraphy in the unglaciated enclaves of the Yukon Territory (Lichti-Federo- vitch 1973, 1974) remains to be seen, but her data indicate that a cold early Wisconsin gave way to a ". . . milder climate in the mid-interstadial period favoring tree growth in the Old Crow Plain (no. 18, Fig. 1) with a reversion to colder tundra climates before the Late Wisconsin stadial" (Lichti-Federovitch 1973, p. 563). Material I4C dated >42 000 years BP (GSC- 1297) occurs aborle sediment deposited during this mild interstadial. A long nonglacial interval is recorded at many sites within the margins of the Cordilleran Ice Sheet and within the moun- tains of southern Alaska and the Yukon Terri- tory (cf. Denton 1974; Fulton 1975). Radio- carbon dates from the lowermost sediments of the Boutellier nonglacial interval (Denton 1974; Fig. 12) extend back to >49 000 years BP (Y-1481). Thus the Mirror Lake Icefield glacia- tion and the Ayr Lake stade of eastern Baffin Island may be correlative.
Late Foxe Glaciation and Postglacial Events A long nonglacial interval prior to the last
major advance of local glaciers and ice sheet margins is obvious in many records from northern areas (e.g. Denton 1974; Hamilton and Porter 1975; Funder and Hjort 1973). Other data from Russia and northern Europe have been reviewed by Dreimanis and Raukas (1975). In eastern Baffin Island we have yet to find dated
sediment from this interval, and in the Clyde cliff sections itis marked by an unconformity between the Kogalu and overlying Ravenscraig marine sediments. However, the terrestrial moraine record reveals a number of end and lateral moraines between the coastal moraines of the Ayr Lake stade and the ca. 8500 years BP Cockburn moraines near the fiord heads. Although the ages of these intermediate moraines are unknown, they are illustrated schematically in Fig. 11. Computer simulation of isostatic and eustatic sea level variations (cf. Andrews 1975) indicates that relative sea level was below present during the late Foxe glacial maximum. This conclusion is supported by the evidence for submerged glaciomarine deltas in areas south of Broughton Island (Miller 1975) and unpublished echo soundings north of Broughton Island that indicate submerged terraces and beaches.
The available field data suggest that the Clyde foreland has not been covered by Laurentide outlet glaciers since the mid Foxe glaciation (Ayr Lake stade). The outline of the late Foxe glacial maximum on eastern Baffin Island is given in Miller and Dyke (1974). Dates on shell and plant remains from the outer coast indicate that the late Foxe transgression occurred between 10 000 and 8000 years BP, depending on local glacio- isostatic conditions. The preliminary pollen record from the early Holocene shows that Betula pollen reached the area at times when it was sparse or absent in the western Canadian Arctic (Matthews 1975), West Greenland (Kelly and Funder 1974; Fredskild 1973), and in northernmost Labrador (S. K. Short, unpub- lished data, 1976), sites that are currently more favorable for the growth of dwarf birch. How- ever, no Alnus, Picea, or Pinus are recorded in either early Holocene collection, and the pollen accumulation (g/gdw) at site 0-6 (9880 + 200 years BP), an in situ moss, is one of the lowest recorded in the Clyde area. The relative pollen diagrams suggest an increase in aridity between the early to mid Holocene and the late Holocene- present (Fig. 10) with grass exceeding sedge pollen. Over much of eastern Baffin Island, early to mid Holocene peat deposits are overlain by eolian sands indicative of deteriorating climatic conditions and increased aridity.
The stratigraphic subdivisions proposed in this paper (Fig. 4) are broadly supported by Feyling- Hanssen's (19766, 1977) biostratigraphic zona- tions; the main difference being that our field
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2854 CAN. J . EARTH SCI. VOL. 14, 1977
Member
7 - \
Kuvlnilk 057 0 1 0 2 2 5 m worm ..p.-.
Clyde ti11 9 . 2 Member 0 % o:o, 0
- P - . ~ < 5, 010 >22m warm 1 1 1 /
,--=- ' (\. " " -
&il lormanq 1ntorro1:Cope Cnr~rlman Inltrplociol < 5 m - 1 h*a~h/b~*ch~2e&- $::'\ Cope Cnrmrtian marine redimenlr 0.66 0.168 ,t!irn Wormlbh ' ?
90hm 0 ,L. -
FIG. 1 1 . Summary time-distance diagram and paleoecological changes for the Clyde foreland area based on the stratigraphy and variations in the marine faunas and terrestrial pollen record. The dotted line between the Ayr Lake till and Ravenscraig unit represents, schematically, the occurrence of several sets of moraines (as yet undated) between the coastal moraines of the Ayr Lake stade and the late Foxe Cockburn moraines near the fiord heads. (1) Amino acid rates of D - alloisoleucine to L- isoteucine in the free (F) and combined (C) amino acid fractions; ND = not detectable. R ) Foraminifera zonations are from Feyling-Hanssen (19766).
studies and amino acid data suggest that his Islandiella isIandica subzone can be divided into two members (Kuvinilk and Kogalu members), each representative of a distinct glacial stade. Profile 2 is particularly significant in this regard, as it is in this section that the Kogalu Member is in direct stratigraphic superposition above the Kuvinilk Member. In addition, we indicate that the Ayr Lake till represents the most recent glacial advance to reach the foreland, and dis- agree with Feyling-Hanssen's (19763, p. 87) suggestion that his drift 1 may represent the deposits of a late Wisconsin (Foxe) glacier.
Interstades us. Interglaciations One of the intriguing problems arising from
this study is the definition and characterization of past interglaciations. Pollen from the Cape Christian soil reflects a more diverse terrestrial vegetation and a stronger Low Arctic character than any recorded during the Holocene, and can be classified unequivocally as interglacial in character. However, even the pollen diagrams in Kuvinilk time have more Low Arctic shrub pollen than the Holocene optimum assemblages,
whereas the current pollen rain at Clyde is quite impoverished.
The marine faunas are similarly troubling. Marine bivalve (this paper) and benthic fora- minifera (Feyling-Hanssen 1976b, 1977) assem- blages from Kogalu and Kuvinilk marine sediments are of interglacial character, reflecting a Subarctic marine environment in an area that today is dominated by Arctic surface water. The marine environment along the east coast of Baffin Island is primarily controlled by the intensity of the West Greenland current. In late Foxe times, Subarctic marine surface waters did not reach eastern Baffin Island until ca. 8400 years BP, during theJinal stages of collapse of the Laurentide Ice Sheet even though the coastal margins had been ice-free for thousands of years. By implication, the Laurentide Ice Sheet under- went similar drastic reductions in volume during previous interstades; alternatively, other factors influenced the strength of the West Greenland current. Thus, because the inferred terrestrial and marine climates during Kuvinilk time indicate a stronger Low Arctic component than does the current pollen assemblage or marine
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fauna in the Clyde area, the question remains: How would we interpret deposits with contem- porary characteristics if found in the fossil record?
Acknowledgements Responsibilities for this paper are as follows:
Miller performed the field stratigraphic desctip- tions, collected the fossil mollusc and palyno- logical samples, and ran the amino acid analyses at the Geophysical Laboratory, Washington, D.C. Dr. P. E. Hare generousIy provided analyzer time and technicaI advice. A fellowship from the Carnegie Institution of Washington to Miller for support of the amino acid g o - chsonology is gratefully acknowledged. Andrews was responsible for the marine bivalve analyses, quantitative assessment of the pollen diagrams using multivariate statistical procedures, and, together with Miller, prepared and discussed the glacial chronology. Short prepared and counted the pollen slides, constructed the pollen diagrams and assisted in their interpretation. M. Anderson provided able assistance during the field work; additional support in the field was generously provided by personnel at the U.S. Coast Guard station at Cape Christian. The field and labora- tory programs were supported by National Science Foundation grant GA-41562 to Andrews.
Geographic, Universitk de Liege, Likge, Belgium. pp. 118-133.
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(14000 to 9000 BP): a test based on glacial rebound. Geology, 4, pp. 617-620. - 1976. Radiocarbon date list 111, B a n Island,
N.W.T., Canada. INSTAAR Occ. Paper No. 21, Uni- versity of Colorado, Boulder, Colorado, 49 pp.
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ANDREWS, J. T., and IVES, J. D. 1972. Late- and postgla- cia1 events (< 10 000 BP) in the eastern Canadian Arctic with particular reference to the Cockburn Moraines and break-up of the Laurentide Ice Sheet. I n Climatic changes in Arctic areas during the last 10000 years. Edited b y Y. Vasari ei al. Symposium at University of Oulu, Oulu, Finland, Acta Univ. Ouluensis, Ser. A, Geol. No. 1, pp. 149-174.
ANDREWS, J. T., and MILLER, G. H. 1976. Quaternary glacial chronology of the eastern Canadian Arctic: A review and a contribution on amino acid dating of Quaternary molluscs from the Clyde cliffs. I n Quater- nary stratigraphy of North America. Edited by W. C. Mahanney, Dowden, Hutchison, and Ross. Strouds- burg, PA. pp. 1-32.
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ANDREWS, J. T.. SZABO, B. J., and ISHERWOOD, W. 1975. - Birkeland, Larson, and Miller. Radiocarbon Multiple tills, radiometric ages, and assessment of the
dating of the shell and organic samples was Wisconsin glaciation in Eastern Baffin Island, N.W.T., Canada: a progress report. Arctic &Alpine Research, 7,
carried out by Dr. M. Stuiver, University of pp. 39-60. Washington, Seattle; additional radiocarbon BADA, J. L., and SCHROEDER, R. A. 1972. Racemization of dates have been kindly provided by Dr. R. Isolencine in calcareous marine sediments: kinetics and
Stuckenrath. ~ ~ i ~ h ~ ~ ~ i ~ d ~ ~ ~ ~ i ~ ~ ~ i ~ ~ and D ~ . W. mechanism. Earth and Planetary Science Letters, 15, pp. 1-11.
J r ' y su;vey of Canada. Modern BARRY, R. G., and IVES, J. D. 1974. Introduction I n Arctic pollen ~ l s t e r s and Tauber tmp data were pro- and alpine environments. Edited b y J . D. Ives, and R. G. vided by Dr. H. Nichols. INSTAAR, University Barry. Methuen & Co. Ltd., London England. pp. 1-16. of Colorado with support from NSF grant BIRKS, H. J. B., WEBB, T., 111, and BERTI, A. A. 1975.
GB-3349J. ~ j ~ . , ~ l ~ also helped interptet the Numerical analysis of pollen samples from central Canada: a comparison of methods. Review of
pollen diagrams. We hare benefited from the Palaeobotany and Palynology ,20, pp. 133-169. exchange of ideas with several individuals. BLAKE. w.. JR. 1972. Climatic im~lications of notably Drs. D. Laurson, R. W. ~ e ~ l i n ~ : Hanssen, 0. H. L ~ k e n , P. E. Hare, and R. H. Fillon. Dr. S. J. Porter provided detailed com- mentary on the manuscript; Dr. P. W. Birkeland and the journal reviewers also provided significant input. We thank all of these individuals for their constructive advice.
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