Quaternary International, Vol. 10--12,pp. 95-106, 1991.
104(~6182/91 $0.00 +.50
© 1992 INQUA/PergamonPress Ltd
Printed in Great Britain. All rights reserved.
PALEOENVIRONMENTS
OF THE LAST INTERGLACIAL IN NORTHWEST
ATLANTIC REGION AND ADJACENT MAINLAND CANADA
NORTH
A n n e de Vernal,* Gifford H. Millert and Claude Hillaire-Marcel*
*GEOTOP, Universitd du Qudbec ~ Montrdal, CP 8888, Suec. A, Montreal, Qudbec H3C 3P8, Canada
t l N S T A A R , University of Colorado, Boulder, CO 80309-0450, U.S.A.
The paleoenvironmental conditions that prevailed in the northwest North Atlantic regions and adjacent mainland Canada during
the last interglacial are documented through lithostratigraphical and paleontological data in terrestrial sections and marine
cores, with special reference to the deep-sea records that allow global correlations based on their isotopic stratigraphy. The
onshore paleovegetational data and the offshore planktonic faunal and algal records demonstrate much warmer than present
terrestrial and marine environments during the climate optimum of the last interglacial sensu stricto (Isotopic Substage 5e).
Optimal conditions persisted in surface water of the Labrador Sea during the early glacial inception (Isotopic Substage 5e/5d
transition) when extensive ice masses developed over Arctic Canada. A deterioration of sea-surface temperature in Labrador
Sea followed the maximum ~80 peak of Isotopic Substage 5d. During the later part of Stage 5, climatic conditions similar to the
present prevailed over southeastern Canada and a recurrent warming is recorded in south central Labrador Sea; fluctuating ice
volumes in the Canadian Arctic led to episodic dilution of surface water masses in Baffin Bay and the eastern Labrador Sea, and
subarctic conditions apparently prevailed in nearshore environments of Baffin Island despite an ice marginal context.
episode by referring to the terrestrial and marine
stratigraphies.
INTRODUCTION
The last interglacial is commonly considered as an
interval of relatively warm climate throughout the high
THE TERRESTRIAL RECORD
latitudes of the northern hemisphere. However, the last
interglacial sensu lato (Isotopic Stage 5) that spanned Southeastern Canada
In contrast to western Europe where continuous Late
about 55,000 years (130-75 ka) was marked by large
amplitude changes in summer radiation over circumpo- Pleistocene sequences have been recovered (e.g. Woillar regions (e.g. Berger, 1978) that were accompanied lard and Mook, 1982; de Beaulieu and Reille, 1984),
by large scale fluctuations in terrestrial ice volume, as the sedimentary record of the last interglacial in
illustrated through isotopic stratigraphy and sea level northeast North America is discontinuous in time and
variations (up to 70 m; Shackleton, 1977, 1987). In view space. Relatively well preserved Late Pleistocene
of the location of the main centers of ice growth during records are nevertheless found in areas which experithe Quaternary (eastern Canada and Greenland), the enced ice marginal conditions during the last ice age,
paleoenvironmental changes in the northwest North such as the Great Lake region (Fig. 1, region C;
Atlantic regions deserve special attention. However, Karrow, 1990), southern Quebec (Fig. 1, site B;
knowledge of the Late Pleistocene climatostratigraphy Anderson et al., 1990) and the Atlantic provinces of
of these regions is fragmentary, notably because of the Canada (Fig. 1, region C; Mott and Grant, 1985; de
vertical and lateral discontinuity of the corresponding Vernal and Hillaire-Marcel, 1987; Mott, 1990). In
sedimentary records, partly due to glacial erosional many of the records which yielded non-finite 14C ages,
processes. Although paleoclimatic schemes have been the microflora indicates climate conditions as warm or
proposed for the Atlantic provinces of Canada (e.g. warmer than the present. However, the chronological
Mott and Grant, 1985; de Vernal et al., 1986), the control is often too vague to firmly assign a precise age
Hudson Bay region (Shilts, 1984), the eastern Cana- to most interglacial deposits which can belong to any
dian Arctic (e.g. Andrews and Miller, 1984; Miller, part of the last interglacial (from 130 to 75 ka), and
1985) and Greenland (e.g. Funder, 1989), the difficulty eventually may be older. Nevertheless, the paleoecoloof establishing an 'absolute' chronological framework gical study of the numerous non-glacial sequences
often prevents unequivocal correlation with the refer- exposed in Atlantic Canada (Mott et al., 1982; Mott
ence oceanic ~80 climatostratigraphy. The marine and Grant, 1985; de Vernal and Mott, 1986), coupled
record of transitional basins adjacent to eastern Canada with Th/U measurements on associated wood (Causse
and Greenland is therefore of primary interest since it and Hillaire-Marcel, 1986), provided the basis for a
may allow establishment of direct links between the reasonably well constrained regional Late Pleistocene
terrestrial records and the reference oceanic stratigra- stratigraphy (de Vernal et al., 1986, de Vernal and
phy. Herein, we intend to document the paleoenviron- Hillaire-Marcel, 1987a; Fig. 2). This paleoclimatologic
mental changes that took place over the northwest scheme of the last interglacial was established on the
North Atlantic regions during the last interglacial basis of palynological successions observed through
95
96
A. de Vernal et al.
FIG. 1. Map of the northwestern North Atlantic, showing the location of marine sites and terrestrial regions discussed in the
text. The numbers refer to ODP Sites (cf. Srivastava et al., 1987). The arrows illustrate schematically the modern circulation in
surface water masses. The letters refer to the terrestrial sites or regions with a stratigraphy representative of the last interglacial
to which we refer in the text. Region A refers to the Atlantic provinces of Canada, where tens of Late Pleistocene sedimentary
sequences have been studied (for regional synthesis see de Vernal and Hillaire-Marcel, 1987a; Matt, 1990). Site B refers to
sequences studied by Anderson et al. (1990). Region C corresponds to the area around Toronto where reference Late
Pleistocene sections are exposed (see Karrow, 1990). Region D includes several sites along Hudson Bay attributed to the last
interglacial (for regional synthesis see Dredge et al., 1990; Matt and DiLabio, 1990). The Late Pleistocene stratigraphy of region
E (CR = Clyde River site; Q = Quvitu site), along the Baffin Island coast is reported in detail by Miller (1985).
J
~,c.(~
___L
,,o°'~
,,.6,, ¢,,(~Lee
~O ~,o 9o~:
....
~,~"
~(~
ro9
Minimum
r h / U ages
Proposed correlation
with oceanic 180
cLJmotostratigrophy
*Jd
~.~
. . . . . . . . . . . . . . . . . . . . . .
Ill-3
and Late (?7
stage 3
MiddLe
II I-2 b
o
62000 +__ 5000
HI-I
EarLy st.age 3
>,,j
-~.~
1-
II
b
.......
8 6 9 0 0 "1" 12000
e
=:11
!
I
,26 oo+,5ooo
Substage 5a
Substage 5e (--5c ?)
.•
rO*/o
<l*/o
FIG. 2. Summarized Late Pleistocene palynostratigraphy, established from a composite sequence of the Atlantic provinces o~
Canada (region A on Fig. 1; cf. de Vernal et al., 1986).
Paleoenvironments of the Last Interglacial
composite sequences, and consists of two distinct
palynostratigraphical units.
(1) Unit I has been identified in several sections and
dated to about 120 ka (de Vernal et al., 1986). This unit
is characterized by pollen assemblages dominated by
Pinus and Ostrya which reflect the existence of
hydroclimatic conditions drier than present and annual
temperatures at least 4°C warmer than at present over
Atlantic Canada (Mott, 1990). At some locations, the
pollen assemblages of Unit I replace tundra-type
assemblages reflecting cold conditions which have been
attributed to the penultimate glacial episode (Illinoian;
Mott and Grant, 1985). Unit I no doubt corresponds to
the early part of the last interglacial and can be
correlated with the Isotopic Substage 5e of the oceanic
stratigraphy.
(2) The palynostratigraphical unit II, dated to about
85 ka (Causse and Hillaire-Marcel, 1986) has been
identified in several sections, including one (Addington
Forks section; cf. Mott and Grant, 1985) where it
appears to overlie Unit I. Unit II is notably characterized by high percentages of A b i e s and the occurrence
of Tsuga and Fagus, indicating cool temperate and
humid climate conditions similar to the present (Mott et
al., 1982; de Vernal and Mott, 1986). In most sequences, Unit II is followed by a third unit with
dominant Picea pollen and decreased percentages of
thermophilous tree taxa. Such a transition marks a
significant regional cooling that may be attributed to
the climatic transition at the end of the last interglacial
(Isotopic Stage 5/4 transition; de Vernal et al., 1986).
Lacking from the stratigraphy of the Atlantic provinces of Canada is evidence for major climate reversals during the last interglacial. If the regional climatostratigraphical scheme summarized above is correct,
the last interglacial sensu lato would have been marked
by a gradual cooling trend rather than by cyclical
climate changes as observed elsewhere, such as in
western Europe (e.g. Guiot et al., 1989). This would
point to discrepancies in climate variations over eastern
and western North Atlantic regions, as during the
younger Dryas for example (e.g. Broeker et al., 1985).
H u d s o n Bay L o w l a n d s
Non-glacial deposits that represent interglacial and
interstadial ice-free intervals are exposed in sections
along streams draining the Hudson Bay Lowland (Fig.
1, region D), the geographic center of the former
Laurentide Ice Sheet. Paleocurrent directions associated with these deposits indicate unimpeded drainage
into Hudson Bay, thereby requiring that the bay, and
its connection to the open ocean through Hudson
Strait, were free of glacier ice. Sub-till exposures of
marine sediments and forest beds in the Lowland were
first reported by Bell (1887), but systematic analysis of
the ecological indicators was delayed until the studies
of Terasmae and Hughes (1960). The results of
research carried out over the last decade on the
stratigraphy in the Lowland is summarized by Mott and
97
DiLabio (1990), Dredge et al. (1990) and Thorleifson et
al. (1992).
Locally, inter-till sediments include a complete
deglacial sedimentation cycle, similar to that of the last
deglaciation, beginning with a marine facies deposited
during isostatic readjustment from an earlier interval of
glacial loading, followed by peat and/or forest litter
indicative of a terrestrial environment similar to present. Base level for the fluvial systems draining the
Lowland was lower than present, suggesting a more
complete glacio--isostatic recovery than has yet occurred in the present interglacial. At some sites, the
uppermost unit consists of glacio--lacustrine silts interpreted to reflect ponding of regional rivers by a newly
formed ice sheet. The complete succession was formally named the Missinaibi Formation by Skinner (1973),
with the basal marine sediments, the Bell Sea member,
deposited during a glacio-isostatic high sea level
episode. Non-glacial waterlain sediments are found
between till sheets that stratigraphically overlie the
Missinaibi Formation and correlate throughout the
Hudson Bay Lowlands (e.g. Skinner, 1973; Dredge and
Nielsen, 1985; Thorleifson et al., 1992), although at no
site is the Missinaibi Formation directly overlain by
inter-till organic-bearing deposits. The stratigraphic
position of many of the isolated occurrences of inter-till
organic beds is uncertain. The pollen assemblages in
these beds are generally dominated by Picea (40-60%),
with modest percentages of Pinus (20-30%) and Betula
(ca. 10%), indicating vegetation and climate rather
similar to the present day. Neither the taxonomic
composition nor the vegetation succession are sufficiently different between sites to evaluate whether the
organic accumulations are representative of a single
interglaciation, or whether they represent two or more
warm, ice-free intervals.
The Missinaibi Formation has been correlated with
the last interglacial (e.g. Prest, 1970), based on its
geographic location, sea level considerations, and the
presence of terrestrial vegetation similar to present.
Stuiver et al. (1978) obtained a radiocarbon age of
>72,500 BP on wood from the forest beds using
isotopic enrichment techniques. Mean amino acid D/L
(alle/Ile) ratios in Hiatella arctica from the Bell Sea
member range from 0.22 to 0.24 (Andrews et al., 1983;
Wyatt, 1989; Thorleifson et al., 1992), compatible with,
but no younger than a last interglacial age for the event.
The correlation and absolute age of other inter-till nonglacial sediments across the Lowland is uncertain, and
has been hampered by the lack of suitable material for
absolute dating. Amino acid D/L ratios have been
measured in molluscan fossils from associated marine
beds and as erratics in till (Andrews et al., 1983; Wyatt,
1989), and from wood in the forest beds (Nielsen et al.,
1986). The D/L ratios have been used to correlate
disjunct deposits (Dredge et al., 1990; Thorleifson et
al., 1992), and to define a preliminary absolute chronostratigraphy assuming the Missinaibi formation is of
last interglacial age (Andrews et al., 1983). Thermoluminescence dating has also been used to date waterlain
98
A. de Vernal et al.
inter-till sediments at 32--46 ka (Berger and Nielsen,
1990), and 73 __+ 10 ka (Forman et al., 1987). Amino
acid D/L ratios from the latter site on in situ molluscs of
the Prest Sea (Thorleifson et al., 1992) support correlation of the Missinaibi Formation to the last interglaciation.
In summary, the Hudson Bay Lowland contains a
complex packet of tills and interbedded non-glacial
sediment. The Missinaibi Formation at the type section
in the Moose River Basin is correlated to the last
interglacial (sensu stricto) on a variety of lines of
evidence. It includes a cool-warm-cool cyclic sequence
of paleoecological indicators, with the interval of
maximum warmth similar to present conditions. Elsewhere, organic-bearing beds of similar character are
correlated to the last interglacial (sensu lato; e.g.
Dredge et aLl 1990), with paleoecological indications
(particularly pollen and beetle) of conditions both
similar to, and cooler than present. The units with
indicators of maximum warmth cannot be conclusively
ascribed to the last interglacial (sensu stricto), but at no
site do the most optimal conditions exceed those of the
Holocene optimum (ca. 5-6 ka BP). Conditions during
the late interglacial (sensu lato) cool interval are
estimated to be 3--4°C lower than present in July
(Dredge et al., 1990), although this may have been well
after ice-sheet growth began elsewhere in northern
Canada, as the first indications of the Wisconsin
Glaciation are of an ice margin advancing into the area
from the NE. We conclude that the last interglacial
sensu stricto was broadly similar to the present;
maximum last interglacial warmth was similar to the
Mid-Holocene optimum, although climatic interpretations may be limited by the relative insensitivity of
many of the sites within the boreal forest biome.
Eastern Canadian Arctic
Coastal exposures along northeastern Baffin Island
(Fig. 1, region E) contain interbedded glacial, glacialmarine, marine and occasional eolian sediment, with
evidence of intermittent subaerial exposure. The
buried surfaces are marked by soils or organic accumulations, most of which contain pollen. Based on
stratigraphic position, relative sea level inferences, and
limiting age control supplied by radiocarbon dates and
amino acid D/L ratios on in situ molluscs from underand over-lying marine beds, some of the paleosurfaces
have been ascribed to the last interglaciation (sensu
stricto). The floral evidence and paleoecological interpretations are given by Miller et al. (1977), Mode
(1985), and Andrews et al. (1986). The working
definition for the last interglacial is the deposit closest
to the present surface that requires relative sea level
near present, has a non-finite radiocarbon age, and
faunal or floral evidence requiring terrestrial summer
temperatures higher than present (Miller et al., 1992);
inshore marine surface waters were warmer than
present more than once during Isotope Stage 5 and
cannot be used to identify the last interglacial sensu
stricto. Although we recognize the inherent limitations
of this definition, the lack of secure chronological
control precludes a more rigorous, climate-independent definition.
The Kogalu aminozone (Miller, 1985) is considered
to represent the last interglacial sensu lato; it includes
terrestrial sediments of last interglacial sensu stricto
age, as well as glacial, glacio-marine, and marine
sediments deposited later during Isotope Stage 5.
Pollen samples from levels deposited within the Kogalu
aminozone on Qivitu Peninsula contain 6-12% Betula,
well above the current levels (2%; cf. Mode, 1985).
Betula percentages exceed the 5% at present only in
areas within the range of shrub birch; consequently, it
is inferred that birch was growing on the peninsula at
that time, north of its present limit. At Clyde the
present influx of Betula pollen is less than 1%, yet
several pollen samples from buried organic-rich horizons with non-finite radiocai'bon dates contain 20 to
more than 50% Betula (Mode, 1985); they are interpreted to indicate that shrub birch was growing on the
foreland, more than 300 km north of its present limit.
The precise chronostratigraphic position of these samples is not always established, but buried soils found at
three localities directly beneath Kogalu aminozone
marine sediments contain more than 50% Betula
(Mode, 1985). Two of the buried soils were developed
on Cape Christian marine sands, subsequently glacially
overridden, and are overlain by sediment of the Kogalu
aminozone. They satisfy the working definition to be of
last interglacial age, and contain pollen assemblage
dominated by Betula, and significant percentages of
A l n u s (Miller et al., 1977). Both the absolute abundances and pollen assemblages at all three sites indicate
terrestrial summer temperatures well above the Holocene optimum. Miller et al. (1977) defined the Cape
Christian interglacial based on the pollen assemblages
in two of these soils, and correlated it with the last
interglacial sensu stricto. Recently, the absolute ages of
the aminozones have been revised (Miller, 1985), but
the soils on which the Cape Christian Interglaciation
was defined are in the correct stratigraphic position to
be of last interglacial age, although an older age cannot
be excluded.
The Cape Christian Interglacial at Clyde was correlated with the organic beds at Flitaway Lake and the
Isortoq beds near the Barnes Ice Cap (Terasmae et al.,
1966; Miller et al., 1977). However, the deposits in the
vicinity of the Barnes Ice Cap are now recognized to be
of pre-Quaternary age, hence the correlation is invalidated.
Despite uncertainties with precise chronologies, pollen analysis of three paleosurfaces directly underlying
the Kogalu aminozone and of several other organic
horizons from within sediments of the Kogalu aminozone, document Betula at levels indicating shrub birch
was growing 100--300 km north of its Holocene limit.
Based on the pollen assemblages in the paleosurfaces at
Clyde, summer temperatures must have been 3°C
higher than present, with ecological conditions similar
99
Paleoenvironments of the Last Interglacial
to those of northernmost Labrador or southern Greenland.
THE MARINE RECORD
Proposed
isotopic
sto~es
~m 0 | (°/oo)
/
4
TWC
,
Q.
/
In the northwest North Atlantic, the Labrador Sea
and Baffin Bay constitute subpolar and polar deep-sea
basins adjacent to eastern Canada• These basins contain good records of regional climate changes in
relation to the glacial fluctuations of the Quaternary:
(1) in view of their location proximal to the main
centers of ice growth, they constituted transitional
basins between the ice sheets and the open ocean; (2)
surface water mass circulation in these subpolar basins
plays a major role in the northward heat transport that
controls the hydroclimatic regime of northeastern
Canada; and (3) high rates of sediment accumulation
(> 5 cm/ka; e.g. de Vernal, 1986) make possible high
time resolution studies.
Since the late seventies, several studies have been
undertaken to establish the regional climatostratigraphy in the Labrador Sea and Baffin Bay (Aksu, 1981;
Fillon and Duplessy, 1980; de Vernal, 1986). However,
because of the high sedimentation rates that characterize these basins, most piston cores did not penetrate
deposits of the last interglacial optimum. It was only
during Leg 105 of the Ocean Drilling Program (ODP)
in 1985 that hydraulic coring allowed recovery of longer
sequences spanning the Late Pleistocene (cf. Srivastava
et al., 1987).
In the Labrador Sea, two main sequences include the
last interglacial: one is from south central Labrador Sea
(ODP Site 647 and cores 84-030-001/-002/-003; Fig. 3)
and the other was collected on the southwest Greenland rise (ODP Site 646; Fig. 4). In central Baffin Bay,
the most probable interglacial sequence is from the
ODP Site 645 (Fig. 5). These three sequences constitute a south to north transect from subpolar regions
adjacent to the North Atlantic•
South Central Labrador Sea
In south central Labrador Sea (Site 647), surface
water masses represent a westward branch of the warm
North Atlantic Drift, these mix with cold water from
the Labrador Current to form a mid-ocean gyre. At
Site 647, sedimentation rates were about 5 crn/1000
years throughout the Late Pleistocene. In addition to
ODP cores, the collection of site survey piston cores
(84-030-001/-002/-033) made possible high resolution
studies (sampling interval of 5 cm, i.e. ca. 1000 years
time resolution) for isotopic and micropaleontological
analyses.
The isotopic stratigraphy of south central Labrador
Sea conforms to that of the open ocean, allowing global
correlation. However, the amplitude of 8180 fluctuations is up to 3.1%o, notably at the Isotopic Stage 6/5
boundary (Fig. 3A) which is attributed to significant
dilution in surface water due to the direct meltwater
discharge from the Laurentide Ice sheet at the time of
ice decay (cf. de Vernal and Hillaire-Marcel, 1987b,c).
3
2
.....
.
-
.
j
I
--.. __
"~'_.F
2
P o
"~"
3
__
,
2
------~r------ --
--'~¢'~--
--
~==----~;-
~ - 5 b
-
.~
5c
E
:2.
_
-
5d
i
JO
£
6
'.~
,.2:
.... ~
6
-;~
~"i~
"L'-..~t
.~.____._:
s
. ~ .
I0
FIG. 3. Summarized stratigraphy in cores 84-030-001 and 84-030-003
(ODP Site 647 on Fig. 1). A, Oxygen Isotope stratigraphy after de
Vernal and Hillaire-Marcel (1987b) and Scott et al. (1989).
The glacial/last interglacial transition in the isotopic
stratigraphy (Stages 6/5) was rapidly followed by the
development of subarctic microfauna (Fig. 3B) and
microflora (Fig. 3C) in surface water masses• The
dinoflagellate cyst assemblages indicate the establishment of conditions much warmer than present, by
about 4°C in summer, during the climate optimum of
the Isotopic Substage 5e. Both planktonic foraminifers
(Scott et al., 1989) and dinoflagellate cyst assemblages
(de Vernal, 1986) indicate that subarctic conditions
prevailed in surface water masses during the subsequent ice-sheet inception of Isotopic Substage 5d. The
persistence of optimal climate conditions during the
trend of increasing 8180 values at the Isotopic
Substage 5e/5d transition is also shown by planktonic
foraminifer assemblages in some sequences of the open
North Atlantic domain (CLIMAP, 1984). An impoverishment of planktonic assemblages is recorded at the
maximum i51so peak of Isotopic Substage 5d and
through most of Substage 5c. It is attributed to a strong
cooling in surface waters. Late in the last interglacial
(Substages 5b and 5a) a recurrence of subarctic
conditions, as warm or warmer than present, marked
A. de Vernal et el.
100
~teO - vs PDB
(%)
g
i
TWC
PLanktonic
Foraminifer
Concentrations
~. to
o ~
oo
i
"~
i
( X 10 3 . c m - 3
Sub-arctic
species
(%)
)
y
o
-
-
-
-
2
0
3
T-2
50
5b
5c
~
4
6
6
I
I
I
I
5
4
3
2
0
I
I
J
I
2
3
0
1
I
20
60
I
IO0
Dinoftaget Late cysts
AssembLage
PoLLen
assemblage
m
E
t,
o~
E
1:3
3
.{:
"~
•--
=t o =4 =
m
"--
"--
~o~
~o ~
~ i a o vs PDB
(%1
g
~"
]
1
[Nap
I ]
Trees
Pinus
O
I
8
I
=o
TWC
~.~
2
3
4
P o
_--
I
~5b
5c
2
g
3
_ _
j
JJ
0
~]x
I I J
2
0
I
IO0.cm-3
2
0
I
I
I
2
I
0
I
I
]
I
I
J
E
I
I
[
I 1
2
3
5
4
3
z
0
50
too
0
2
(%)
3
x IO0.cm-3
FIG. 3. Summarized stratigraphy in cores 84-030-001 and 84-030-003 (ODP Site 647 on Fig. 1). B, Planktonic foraminifer
stratigraphy (Scott et al., 1989): the subarctic species include all planktonic foraminifers except Neogloboquadrina pachyderma
leftcoiling. C, Palynostratigraphy (de Vernal and Hillaire-Marcel, 1987a). The dinoflagellate cyst assemblages are expressed in
term of concentrations: Impagidinium spp., Nematosphaeropsis labyrinthus and Bitectatodinium tepikiense constitute temperate
to subarctic indicators. In the summary, pollen assemblage NAP stands for non-arboreal pollen and the trees include mainly
Pinus and Picea.
Paleoenvironments of the Last Interglacial
101
~180 VS P D B
..~
Plonktonic
forominifer
< 63/~m
froction
N. p o c h y d e r m o
dex.
G butkoides
(%1
( x IO~lg -I )
G. q u i n q u e t o b o
(*I.1
N.
(%1
l~
p o c h y d e r m o sin. ~ ~
(%)
l
I
t
I
3
2
~'~°
m
"
tO
q',0
.:- -:
v
' ~o ~
5
lO
15 0
I0 0
5
5
I0
1.5
20 0
5
~
-~
o
E
I0 0
E
5
I0
~ ,.
~
15
20
4
E
8
._
o
5
=
~,
.=_
~ ~
"
-
.~_
~
i
~
~
~
ll
.-
._o
c
m~
~ ~
._~
.-
== ~
~
~
I
g
~
180 v s P B D ( * / . )
t
t
2
L
~
"
= - ;L
•
2
2
I i=
4
I
6
12
4
I
2
:
4
I
4
3
2
~. xlOOO, c m x I00 cm• -25.cm-
FIG. 4. Summarized Late Pleistocene stratigraphy at ODP Site 646 (cf. Aksu et al., 1989). A, Sand, planktonic foraminifer and
b~sO stratigraphy. N. pachyderma dextrogyre, G. bulloides and G. quinqueloba are the three main subarctic species of the
assemblage. B, Dinoflagellate cyst stratigraphy• Note that Spiniferites mirabilis is a cool temperate taxa indicating sea surface
temperature at least 14°C during summer (Turon, 1984). which is 6°C warmer than present•
surface water masses. The stratigraphy of the south
central Labrador Sea appears, therefore, to be characterized by a discrepancy between ice fluctuations as
recorded in the 180 stratigraphy, and changes in
surface water masses, as shown by micropaleontological analyses, demonstrating that the early ice inception
of Isotopic Substage 5d preceded the cooling trend in
regional surface waters.
In the southern Labrador Sea record, the pollen
content of sediments provides additional information
on paleoclimates as they relate to the terrestrial
vegetation of the surrounding land masses and to
subsequent transport through atmospheric circulation
(de Vernal and Hillaire-Marcel, 1987b). L o w pollen
concentrations and the dominance of P i n u s throughout
most of the sequence reflect long distance atmospheric
input controlled by S W - N E trending air masses (in
summer), as at the present time. H o w e v e r , the interval
spanning the late Substage 5c through 5a is marked by
increased pollen influx with moderately high Picea
percentages. Together, these indicate a relatively close
vegetational source dominated by boreal forest• In-
102
A. de Vernal et al.
o
E
¢3
n
.=_
.~
O-
13.
~o
~
PoLLen
concentration
~[80
&
vs PDB oo
(%°)
rn
I
•
-5,--
I
i
t
!
t
e¢
i
i
tO
?~_
i-0
60
60
!1
~_t_
j j!
.j!
tO
i
50
2O
20
IO
I0
IO
I0
60
I0
I(
3O
2O
400
5
I
x IO00.cm-
fO
4
3
2
zl x I00, cm-
FIG. 4. Summarized Late Pleistocene stratigraphy at ODP Site 646 (cf. Aksu et al., 1989). C, Pollen and spore stratigraphy•
Oinofloget LaLe cysts
AssembLage
a.
a.
_c~
-¢:: o~.~.
"
~.
E
E
.3
~E
ol
~x
=~
~ &..9
m~
~E
o~
~,._~o
O. ~-- ,,~..~ ---
E o~
Prequater no r y
paLynomorph
concentration
03
-~
~180 vs / PDB
(%*)
|
I
I
I
I
t)
~-
[
i
i
-~
5 --I----
l0 ---I .-- --
15"
"
---z5a
'
I
•
I
,,
20--
• !
p
0 100
O0.crn 3
IO0
400
300
J
500
im.
r
I
600
I
12oo
I
I
5 4 3 z
I
I
5e
I0 cm-3
FIG. 5. Summarized Late Pleistocene palynostratigraphy and 6t80 stratigraphy at ODP Site 645 (cf. Hillaire-Marcel et al.,
1989).
Paleoenvironments of the Last Interglacial
203
controlled by SW-NE atmospheric trends from the
spruce forest of eastern Canada (de Vernal and
Hillaire-Marcel, 1987c). Such is not the case for pollen
and spore assemblages of the lower part of the last
interglacial. The absence of correlation with the palynostratigraphy of eastern Canada (cf. supra) indicates
northeastern North America did not constitute the
principal vegetational source. Moreover, the very high
Eastern Labrador Sea
In the eastern Labrador Sea, off southwest Green- concentrations, an order of magnitude higher than
land, surface water circulation is controlled by the West present, indicate a much more proximal vegetational
Greenland Current, which is formed by a westward source that was probably located on Greenland. In fact,
branch of the North Atlantic Drift mixing with the the overall pollen and spore assemblages of the Isotopic
polar East Greenland Current. Hydraulic piston coring Substage 5e suggests input from different sources: long
at ODP Site 646 permitted the recovery of a complete distance atmospheric inputs from the southwest (see
Late Pleistocene sequence. Sediment accumulation the Pinus curve) and a dominant input from a proximal
rates are variable through the sequence, averaging 9 shrub-tundra type vegetation. The latter may be
cm/1000 years (Hillaire-Marcel et al., 1989; Aksu et al., attributed to fluvial, inputs from Greenland, which
1989). The higher sampling resolution allowed by ODP strongly suggests that large areas of southern Green(20 cm) led to isotopic and micropaleontological studies land were free of ice (see also Reeh, 1991) and
occupied by a dense vegetation dominated by shrubs
with an average time resolution of 2200 years.
Despite large amplitude fluctuations in the 6180 and Pteridophytes. The high percentages of Osmunda
record (up to 3%o), the isotopic stratigraphy is not as cf. cinnamomea, which has a modern distribution south
clear as in southern Labrador Sea. Isotopic Substage 5e of 51°N in eastern Canada, indicates the existence of
is easily distinguished but other subdivisions within subarctic or even cool temperate regional climates
Stage 5 would be arbitrary. Full subarctic conditions (Hillaire-Marcel and de Vernal, 1989). Such a climate
were established in surface water masses rapidly after is favorable for forest development, which was probthe glacial/last interglacial transition as shown by the ably limited on Greenland because its insular context
planktonic foraminifer (Fig. 4A) and dinoflagellate cyst was unfavorable for rapid tree migration. Following the
(Fig. 4B) assemblages. Both microfossil assemblages Isotopic Substage 5e there is a decrease in pollen
indicate much warmer conditions than present, with concentration concomitant with increased Picea persummer temperature of about 14°C. As in the southern centages. This trend suggests decreasing inputs from
Labrador Sea, such subarctic conditions prevailed the proximal southern Greenland source and the
during the terrestrial ice inception of the Isotopic restoration of input from eastern Canada, controlled by
Substage 5e/5d transition, also suggesting ice growth SW-NE to WSW-ENE air mass trajectories. Thus, the
started before cooling of surface water masses. The assemblages reflect the existence of spruce forest to
increase in 6180 values related to terrestrial ice growth tundra in eastern Canada during the upper part of the
in the Substage 5e/5d transition is accompanied by last interglacial, while a decline in the vegetational
increased accumulation of coarse debris due to ice cover on Greenland may have been due to significant
rafting and, therefore, to glacial activity. An impover- ice growth.
ishment of the planktonic foraminifer and dinoflagellate cyst assemblages coincides with a first maximum Central Baffin Bay
6aSo peak, which probably belongs to the Isotopic
Baffin Bay constitutes an epicontinental basin
Substage 5d. The upper part of Isotopic Stage 5 is bounded to the north by the Canadian Arctic Archipecharacterized by polar planktonic foraminifer assem- lago and isolated from the Labrador Sea by the Davis
blages and by relatively sparse dinoflagellate cyst Strait, which has a sill at about 800 m of depth. Surface
assemblages. Despite a subarctic component related to water masses are characterized by the penetration of a
tenuous but persistent penetration of North Atlantic northward West Greenland Current branch to the east
water into Labrador Sea, the overall dinoflagellate cyst and Arctic water outflow through the Archipelago
assemblages reveal low productivity in surface water channels forming the cold Baffin Land Current that
masses, probably due to dense seasonal sea ice cover. flows southward to the west. Both currents mix to form
Nevertheless, abundance peaks with dominant Brigan- a gyre in central Baffin Bay. Baffin Bay is characterized
tedinium spp. are associated with episodes of higher by a shallow lysocline responsible for calcium carbonproductivity under low salinity conditions (< 30%0; ate dissolution in deep sea sediments. Because of
Mudie and Short, 1985) related to meltwater discharges dissolution and low biogenic productivity, planktonic
along the Greenland margins.
foraminifers are not abundant in Baffin Bay cores (e.g.
Sediments from Site 646 are characterized by rela- Aksu, 1981, 1983), preventing the establishment of a
tively abundant pollen grains and spores, especially in continuous isotopic stratigraphy. In addition, because
the Isotopic Substage 5e interval (Fig. 4C). From high of the epicontinental character of the basin, the isotopic
resolution studies of Holocene sediments, it has been stratigraphy has a predominantly regional signature
demonstrated that postglacial pollen inputs are mainly with large amplitude fluctuations: any melting event
fluxes from eastern Canada are related to trajectories
during summer of WSW-ENE to W-E air masses. Such
influxes also suggest the existence of spruce forest and
subarctic climate, similar to the present, along the
eastern Canadian coasts during the later part of the last
interglacial.
104
A. de Vernal et al.
would contribute to strong dilution in water masses and
make correlations with the world ocean isotopic stratigraphy difficult. The peculiar character of isotopic
records from Baffin Bay and Davis Strait has led to
controversial chronostratigraphic interpretations (e.g.
Aksu, 1981; Mudie and Aksu, 1984; de Vernal et al.,
1987). The establishment of a magnetostratigraphy at
ODP Site 645, in addition to AMS-14C dates on
planktonic foraminifers allowed to establish a reasonably well constrained isotopic stratigraphy spanning
approximately 125 ka in a ca. 22 m composite sequence
(Fig. 5; Hillaire-Marcel et al., 1989).
The base of this sequence is marked by low 6180
values and subarctic dinoflagellate cyst assemblages
that are indicative of much warmer conditions than
present, with summer temperature up to about 10°C.
This interval is attributed to Isotopic Substage 5e
although independent confirmation is lacking. The
pollen assemblage of this particular interval is characterized by relatively high concentrations (up to 800
grains/cm3) as compared to the rest of the sequence.
The moderately high percentages of Picea reflect a
northward position of the boreal forest limit as compared to the present and/or strong northward atmospheric trends; the significant occurrence of Betula,
A l n u s crispa and herb pollen suggests the existence of
shrub tundra on the surrounding land masses. Such an
assemblage may allow correlations with the buried
paleosols of Baffin Island, which contain abundant
Betula pollen grains and have been attributed to the last
interglaciation (Terrasmae et al., 1966; Miller et al.,
1977; Mode, 1985). Above the interval associated with
the Isotopic Substage 5e, increases in 5XSo values and
impoverishment of dinoflagellate cyst and pollen
assemblages are related to the early glacial inception
and cooling in regional surface waters. Throughout the
Isotopic Stage 5, fluctuations in 6180 values and peaks
of Brigantedinium spp. and Algidasphaeridium? minutum, together indicate episodic phases of meltwater
discharge from the ice caps on surrounding lands. The
most salient feature in the Baffin Bay record is
undoubtedly the abundance of reworked preQuaternary palynomorphs that characterize Isotopic
Substages 5d-5a. These palynomorphs indicate intense
erosion of the Canadian Arctic Archipelago where the
original sedimentary formations occur. On this basis
and from field evidence (e.g. Miller et al., 1977, 1992;
Andrews et al., 1984; Klassen, 1985), it has been
argued that maximum glacial activity in eastern Arctic
Canada occurred early during the Late Pleistocene,
probably during Isotopic Substages 5d-5a. Deep-sea
evidence for meltwater discharge, and the occurrence
of subarctic nearshore faunal assemblages along Baffin
Island and Greenland coasts (Miller et al., 1977, 1992),
indicate phases of subpolar-type climate during the
later part of the last interglacial.
SUMMARY
The overview of paleoecological trends throughout
the last interglacial sensu lato in the northwest North
Atlantic regions allow some considerations about
environmental changes in relation to climate and glacial
fluctuations.
(1) Much warmer conditions than the present prevailed from the south to north along the eastern
Canadian coast, in southern Greenland, and in surface
waters of adjacent marine basins during the climatic
optimum of Isotopic Substage 5e, and no doubt much
longer at some locations, at least in the Labrador Sea.
(2) The global ice volume increase of the Isotopic
Substage 5e/5d transition corresponds to initial ice
sheet growth, which no doubt affected Arctic Canada
and perhaps extended southward over Hudson Bay.
However, warm optimal conditions persisted, notably
in Labrador Sea, until the ice volume reached its early
maximum extent (peak of Substage 5d). Relatively
warm surface waters during the glacial inception
probably contributed to the northward transport of
warm and humid air masses favorable for precipitation
and ice accumulation over circum-Arctic regions.
(3) Paleoenvironmental data of the upper part of the
last interglacial indicate relatively warm conditions,
similar to the present, over southeastern Canada and
the southern Labrador Sea, which was characterized by
the advection of temperate North Atlantic waters. At
that time, the eastern Canadian Arctic was marked by
intense glacial activity with ice margin fluctuations that
led to episodic flows of meltwater discharge offshore.
The development of a subarctic fauna in nearshore
environments during phases of ice retreat suggest
warming of surface water masses late in Isotope Stage
5.
Throughout the last interglacial, the regions adjacent
to the northwest North Atlantic were marked by large
amplitude environmental changes, especially a t the
highest latitudes where terrestrial areas experienced ice
growth. From the marine and terrestrial data it appears
clear that the glacial inception (Substages 5e/5d transition) occurred in circum-Arctic regions while optimal
climate conditions, warmer than present, prevailed
elsewhere. It is also clear that climatic conditions
similar to the present existed during the later part of the
last interglacial despite extensive glacial activity in the
eastern Canadian Arctic. Although glacial fluctuations
no doubt occurred in northeastern Canada, the available non-glacial proxy-climatic data from both terrestrial and marine environments of the northwest North
Atlantic regions lack evidence for a cyclicity in phase
with the global oceanic 6180 stratigraphy and insolation variations during the last interglacial interval.
ACKNOWLEDGEMENTS
We sincerelythank all the participantsto the NATO workshopon
the last interglacialfor their stimulatingdiscussions.We are grateful
to Michelle Laithier (UQAM) for the drawing of figures.
G.H. Milleracknowledgeslong term support fromthe Divisionof
Earth Sciencesat the US NationalSciencefoundation.A. de Vernal
and C. Hillaire-Marcel acknowledge support from The F.C.A.R.
Funds of Quebec, and NSERC-Canada.
Paleoenvironments of the Last Interglacial
REFERENCES
Aksu, A.E. (1981). Late Quaternary stratigraphy, paleoenvironments and sedimentary history of Baffin Bay and Davis Strait,
Ph.D. Thesis, Dalhousie University, Halifax, 771 p.
Aksu, A.E. (1983). Holocene and Pleistocene dissolution cycles in
deep-sea cores from Baffin Bay and Davis Strait: paleoceanographic implications. Marine Geology, 53, 331-348.
Aksu, A.E., de Vernal, A. and Mudie, P.J. (1989). High-resolution
foraminiferal, palynological and stable isotopic records of upper
Pleistocene sediments from Labrador Sea: paleoclimatic and
paleoceanographic trends. Proceedings of the Ocean Drilling
Program, 105B, 617-652.
Anderson, T.W., Matthews, J.V., Mott, R.J. and Richard, H.S.
(1990). The Sangamon Pointe-Fortune Site, Ontario-Qu6bec
border. Gdographie physique et Quaternaire, 44, 271-287.
Andrews, J.T. and Miller, G.H. (1984). Quaternary glacial and
nonglacial correlations for the eastern Canadian Arctic. In: Fulton,
R.J. (ed.), Quaternary stratigraphy of Canada, pp. 101-116.
Geological Survey of Canada, 84-10.
Andrews, J.T., Shilts, W.W. and Miller, G.H. (1983). Multiple
deglaciations of the Hudson Bay Lowlands, Canada, since deposition of the Missinaibi (Last-Interglacial?) formation. Quaternary
Research, 19, 18--37.
Andrews, J.T., Miller, G.H., Vincent, J.-S. and Shilts, W.W. (1984).
Quaternary correlations in Arctic Canada. In: Fulton, R.J. (ed.),
Quaternary stratigraphy of Canada, pp. 127-134. Geological
Survey of Canada, 84-10.
Andrews, J.T., Aksu, A., Kelly, M., Klassen, R., Miller, G.H.,
Mode, W.N. and Mudie, P. (1986). Land/ocean correlations
during the last interglacial/glacial transition, Baffin Bay, northwestern North Atlantic: A review. Quaternary Science Reviews, 4,
333-355.
Bell, R. (1887). Exploration of portions of the Attawapiskat and
Albany rivers. Geological Survey of Canada, Annual Report, 1886,
Pt. G.
Berger, A.L. (1978). Long term variations of caloric insolation
resulting from the earth's orbital elements. Quaternary Research,
9, 137-167.
Berger, G.W. and Nielsen, E. (1990). Evidence from thermoluminescence dating for Middle Winconsinan deglaciation in the
Hudson Bay Lowland of Manitoba. Canadian Journal of Earth
Sciences, 28, 240-249.
Broeker, W.S., Peteet, D. and Rind, D. (1985). Does the oceanatmosphere system have more than one stable mode of operation?
Nature, 315, 21-25.
Causse, C. and Hillaire-Marcel, C. (1986). G6ochimie des familles U
et Th dans la mati~re organique fossile des d6p6ts interglaciaires et
interstadiaires de l'est du Canada: potentiel radiochronologique.
Geological Survey of Canada, 86.1B, 11-18.
CLIMAP Project members (1984). The last Interglacial Ocean.
Quaternary Research, 21, 123-224.
de Beaulieu, J.-L. and Reille, M. (1984). A long upper Pleistocene
pollen record from Les Echets near Lyon, France. Boreas, 13, 111132.
de Vernal, A. (1986). Analyses palynologiques et isotopiques de
s6diments de lamer du Labrador et de la baie de Baffin: 616ments
d'une climatostratigraphie du Quaternaire sup6rieur dans l'est du
Canada, Ph.D Thesis, Universit6 de Montr6al, 214 p.
de Vernal, A. and Hiilaire-Marcel, C. (1987a). Climatostratigraphie
du Pl6istoc~ne sup6rieur dans les provinces atlantiques du Canada.
L'Anthropologie, 91, 93-107.
de Vernal, A. and Hillaire-Marcel, C. (1987b). El6ments d'une
climatostratigraphie du P16istoc~ne moyen et sup6rieur dans l'est
du Canada par l'analyse palynologique et isotopique du forage 84030-003, mer du Labrador. Canadian Journal of Earth Sciences, 24,
1886-1902.
de Vernal, A. and Hillaire-Marcel, C. (1987c). Marginal paleoenvironments of the eastern Laurentide ice sheet and timing of the last
ice maximum and retreat. G(ographie physique et Quaternaire,
XLI, 265-277.
de Vernal, A. and Mott, R.J. (1986). Palynostratigraphie et
pal6oenvironnements du Pl6istoc~ne sup6rieur dans la r6gion du
lac Bras d'Or, ile du Cap-Breton, NouveUe-Ecosse. Canadian
Journal of Earth Sciences, 23, 491-503.
de Vernal, A., Causse, C., Hillaire-Marcel, C., Mott, R.J. and
Occhietti (1986). Palynostratigraphy and Th/U ages of Upper
Pleistocene interglacial and interstadial deposits on Cape-Breton
Island, Eastern Canada. Geology, 14, 554-559.
105
de Vernal, A., Hillaire-Marcel, C., Aksu, A.E. and Mudie, P.J.
(1987). Palynostratigraphy and chronostratigraphy of Baffin Bay
deep sea cores: climatostratigraphic implications. Palaeogeography, Palaeoclimatology, Palaeoecology. 61, 97-105.
Dredge, L.A. and Nielsen, E. (1985). Glacial and interglacial
deposits in the Hudson Bay Lowlands: a summary of sites in
Manitoba. Geological Survey of Canada, 85-1A, 247-257.
Dredge, L.A., Morgan, A.V. and Nielsen, E. (1990). Sangamon and
pre-Sangamon interglaciations in the Hudson Bay Lowlands of
Manitoba. Gdographie physique et Quaternaire, 44, 319-336.
Fillon, R.H. and Duplessy, J.-C. (1980). Labrador Sea bio-, tephra,
oxygen isotopic-stratigraphy and late Quaternary paleoceanographic trends. Canadian Journal of Earth Sciences, 17, 831-854.
Forman, S.L., Wintle, A.G., Thorleifson, L.H. and Wyatt, P.H.
(1987). Thermoluminescence properties and age estimates of
Quaternary raised-marine sediments, Hudson Bay Lowland, Canada. Canadian Journal of Earth Sciences, 24, 2405-2411.
Funder, S. (1989). Quaternary geology of ice free areas and adjacent
shelves of Greenland. In: Fulton, R.J. (ed.), Quaternary geology
of Canada and Greenland, pp. 742-792. Geological Survey of
Canada, Geology of Canada, 1.
Guiot, J., Pons, A., de Beaulieu, J.-L. and Reille, M. (1989). A
140,000 year climatic reconstruction from two European pollen
records. Nature, 338, 309-313.
Hillaire-Marcel, C. and de Vernal, A. (1989). Isotopic and palynological records of the Late Pleistocene in eastern Canada and
adjacent basins. G~ographie physique et Quaternaire, 43,263-290.
Hillaire-Marcel, C., de Vernal, A., Aksu, A.E. and Macko, S.
(1989). High-resolution isotopic and micropaleontological studies
of upper Pleistocene sediments at ODP Site 645, Baffin Bay.
Proceedings of the Ocean Drilling Program, 105B, 599-616.
Karrow, P.F. (1990). Interglacial beds at Toronto, Ontario. G~ographie physique et Quaternaire, 44, 289-297.
Klassen, R.A. (1985). An outline of glacial history of Bylot Island,
District of Franklin, N.W.T. In: Andrews, J.T. (ed.), Quaternary
Environments: Baffin Island, Baffin Bay, and West Greenland, pp.
5428-5460. Allen and Unwin.
Miller, G.H. (1985). Aminostratigraphy of Baffin Island shellbearing deposits. In: Andrews, J.T. (ed.), Quaternary Environments: Baffin Island, Baffin Bay, and Western Greenland, pp. 394427. Allen and Unwin.
Miller, G.H., Andrews, J.T. and Short, S.K. (1977). The last
interglacial-glacial cycle, Clyde foreland, Baffin Island, N.W.T.:
stratigraphy, biostratigraphy, and chronology. Canadian Journal of
Earth Sciences, 14, 2824-2857.
Miller, G.H., Funder, S., de Vernal, A. and Andrews, J.T. (1992).
Timing and character of the last interglacial-glacial transition in
the Eastern Canadian Arctic and Northwest Greenland. In: Clark,
P.U. and Lea, P. (eds), The last interglacial~glacial transition in
North America. Geological Society of America, Special Paper 270
(in press).
Mode, W.N. (1985). Pre-Holocene pollen and molluscan records
from eastern Baffin Island. In: Andrews, J.T. (ed.), Quaternary
Environments: Baffin Island, Baffin Bay, and West Greenland, pp.
502-519. Allen and Unwin.
Mott, R.J. (1990). Sangamon forest history and climate in Atlantic
Canada. G~ographie physique et Quaternaire, 44, 257-270.
Mott, R.J. and DiLabio, N.W. (1990). Paleoecology of organic
deposits of probable last interglacial age in northern Ontario.
G~ographie physique et Quaternaire, 44, 309-318.
Mott, R.J. and Grant, D.R. (1985). Pre-late Wisconsinan environments in Atlantic Canada. GOographiephysique et Quaternaire, 39,
239-254.
Mott, R.J., Anderson, T.W. and Matthews, J.V. (1982). Pollen and
macrofossil study of an interglacial deposit in Nova Scotia.
Gdographie physique et Quaternaire, 36, 197-208.
Mudie, P.J. and Aksu, A.E. (1984). Paleoclimate of Baffin Bay from
300,000 year record of foraminifera, dinoflagellates and pollen.
Nature, 312, 630-634.
Mudie, P.J. and Short, S.K. (1985). Marine palynology of Baffin
Bay. In: Andrews, J.T. (ed.), Quaternary Environments: Baffin
Island, Baffin Bay, and West Greenland, pp. 263-308. Allen and
Unwin.
Nielsen, E., Morgan, A., Mott, R.J., Rutter, N.W. and Causse, C.
(1986). Stratigraphy, paleoecology, and glacial history of the
Gillam area, Manitoba. Canadian Journal of Earth Sciences, 23,
1641-1661.
Prest, V.K. (1970). Quaternary Geology of Canada. In: Douglas,
R.J.W. (ed.), Geology and Economic Minerals of Canada, pp.
676-758. Ottawa.
106
A. de Vernal et al.
Reeh, N. (1991). The last interglacial as recorded in the Greenland
ice sheet and Canadian Arctic ice caps. Quaternary International,
10--12, 123-142.
Scott, D.B., Mudie, P.J., de Vernal, A., Hillaire-Marcel, C., Baki,
V., MacKinnon, K.D., Medioli, F.S. and Mayer, L. (1989).
Lithostratigraphy, biostratigraphy and stable isotope stratigraphy
of cores from ODP Leg 105 Site Surveys, Labrador Sea and Baffin
Bay. Proceedings of the Ocean Drilling Program, 105B, 561-582.
Shackleton, N.J. (1977). The oxygen isotope stratigraphic record of
the late Pleistocene. Philosophical Transactions of the Royal
Society of London, 280, 169-182.
Shackleton, N.J. (1987). Oxygen Isotopes, ice volume and sea level.
Quaternary Science Reviews, 6, 183-190.
Shilts, W.W. (1984). Quaternary events - - Hudson Bay lowland and
southern district of Keewatin. In: Fulton, R.J. (ed.), Quaternary
stratigraphy of Canada, pp. 1117-1126. Geological Survey of
Canada, 84-10.
Skinner, R.G. (1973). Quaternary stratigraphy of the Moose River
Basin, Ontario. Geological Survey Canada, Bulletin 225, 77 pp.
Srivastava, S., Arthur, M., Clement, B. (1987). Proceedings of the
Ocean Drilling Program, Volume 105, Part A - - Initial Report,
Texas A and M University, 917 p.
Stuiver, M., Heusser, C.J. and Yang, I.C. (1978). North American
glacial history extended to 75,000 years ago. Science, 200, 16--21.
Terasmae, J. and Hughes, O.L. (1960). A palynological and
geological study of Pleistocene deposits in the James Bay lowlands,
Ontario, Geological Survey of Canada, Bulletin 62, 15 p.
Terasmae, J., Weber, P.J. and Andrews, J.T. (1966). A study of late
Quaternary plant bearing beds in north central Baffin Island,
Canada. Arctic, 19, 296--318.
Thorleifson, L.H., Wyatt, P.H., Shilts, W.W. and Nielsen, E.
(1992). Hudson Bay Lowland Quaternary stratigraphy: evidence
for Early Wisconsin glaciation centered in Quebec. In: Clark, P.U.
and Lea, P. (eds), The last interglacial~glacial transition in North
America. Geological Society of America, Special Paper 270 (in
press).
Turon, J.-L. (1984). Le palynoplancton dans l'environnement actuel
de l'Atlantique Nord oriental. Evolution climatique et hydroiogique depuis le dernier maximum glaciaire, Th6se de Doctoral ~s
Sciences, Universit6 de Bordeaux, 313 p.
Woillard, G. and Mook, W.G. (1982). Carbon dates at Grande Pile:
Correlation of land sea chronologies. Science, 215, 159-161.
Wyatt, P.H. (1989). The stratigraphy and amino acid chronology of
Quaternary sediments in central Hudson Bay Lowland. M.Sc.
Thesis, University of Colorado, Boulder, Colorado, 119 pp.