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Marcel et al. [1994], Rashid et al. [2003a], and Rashid and
Piper [2007], than the 0.5
‰
change at H0. No other well-
controlled core from the central or southern Labrador Slope
or Labrador Rise contains a H0 carbonate-rich layer
[Rashid et al., 2003a; Rashid and Piper, 2007].
Core Hu91045-06 (hereinafter Hu91-06) was retrieved at
534 m water depth from Cartwright Saddle on the Labrador
Shelf [Hillaire-Marcel et al., 1994, 2007]. It contains a high-
carbonate bed from 510 to 540 cm, with an underlying
published date from benthic foraminifera of 11.55 ka at
605 cm, indicating that the high-carbonate bed correlates
either to the Noble Inlet or the 10.2 ka Gold Cove event
[Miller and Kaufman, 1990; Kaufman et al., 1993; Rashid et
al., 2008]. The bottom of the core is undated, suggesting that
either there is no H0 bed or that it was not penetrated.
Nearby cores Hu87033-17 and Hu87033-18 [Andrews et al.,
1999] also contain a carbonate-rich bed underlain by a date
of 10.51 ka from a mollusk shell. The base of core Hu87-18,
which appears not to contain a deeper carbonate-rich bed,
has an age of 13.80 ka from N. pachyderma (s); this date is
older than the YD period. In the only other long core on the
Labrador Shelf intersecting the YD interval, in Karlsefni
Trough [Hall et al., 1999], the YD interval is marked by an
unconformity, probably due to advance of continental ice.
On the southern slope of Orphan Basin, carbonate-rich
beds in cores Hu2003033-19 and Hu2003033-24 (hereinaf-
ter Hu03-19 and Hu03-24) are well constrained by numerous
published
14
C-AMS dates [Hillaire-Marcel et al., 2007;
Tripsanas and Piper, 2008a]. In Hu03-19, H1 is constrained
by an underlying date of 18.08 ka and is overlain by a
distinctive red meltwater plume facies found throughout the
Orphan Basin. The overlying carbonate-rich bed from 190 to
210 cm is dated only 10.38 ka at 180 cm. In Hu03-24, H1 is
constrained by an underlying age of 18.07 ka and is also
immediately overlain by the red meltwater plume facies. The
overlying carbonate-rich bed, which stratigraphically corre-
lates with nearby core Hu03-19, is bracketed by ages of
11.29 and 9.54 ka, implying that it correlates with either the
Noble Inlet or the 10.2 ka Gold Cove event [Rashid et al.,
2008]. This same stratigraphy, with H1, a red meltwater
facies bed, and then an early Holocene carbonate-rich bed,
is recognized in an additional 12 cores throughout the Or-
phan Basin [Tripsanas and Piper, 2008a]. No H0 carbonate-
rich bed was recognized.
Core Hu91-94 off Orphan Knoll (3448 m water depth)
contains multiple H layers characterized by high carbonate,
a basal peak in coarse fraction, and variation in
δ
Figure 4.
Core Hu97-11twc (trigger weight core) from the slope
seaward of Hudson Strait showing (a) sediment facies, (b) carbonate
(%), (c)
18
OinN. pachyderma (s), and (d)
14
C-AMS dates (ka)
versus depth (m). It was collected at 2640 m water depth from the
rise off Hudson Strait. Horizontal gray bar represents H2.
δ
dates of 12.74 and 12.79 ka (Figure 5c) [Barber, 2001].
Nearby core Hu87033-09 has an unusual carbonate and
calcite/dolomite pro
le (Figure 5d), quite unlike other re-
cords from this region, which may be the result of one or
more debris
flow deposits in this core [Barber, 2001].
4.2. Distal H0 Records in the Labrador Sea
y reassess cores from the literature in the central
and southern Labrador Sea that may contain the H0 layer.
Core Hu84-21, seaward of Okak Trough at 2853 m water
depth, has previously been reported to contain H0 [de
Vernal and Hillaire-Marcel, 1987; Hillaire-Marcel et al.,
2007]. Five published
14
C-AMS dates converted to cali-
brated ages (Figure 6) were used to constrain the stratigra-
phy between core top and 180 cm, and the stratigraphy of
rest of the interval was obtained by age extrapolation
assuming a constant sedimentation rate. The issue is
whether a high-carbonate bed between 212 and 236 cm is
H0 or H1. Insuf
We brie
cient core sample remains to date this
interval. We suggest that the previous interpretation of H0
in this core is not robust, and therefore, its identi
18
O
Nps
[Hillaire-Marcel et al., 1994]. H0 was convincingly recog-
nized between 167 and 184 cm, where the boundary at the
base is constrained by dates of 13.05 and 13.03 ka and the
bed is overlain by a date of 10.207 ka (Figure 7).
cation
remains an open question. However, the transition from the
enriched
18
O
Nps
to 1.2
more depleted across this high-
carbonate bed is closer in magnitude to the change in
isotopic values at H1, for example, as shown by Hillaire-
δ
‰
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