The Role of Hudson Strait Outlet in Younger Dryas Sedimentation in the Labrador Sea - Abrupt Climate Change: Mechanisms, Patterns, and Impacts - page 102

18 OinN. pachyderma (s), (c) >120 µm (%), and (d) 14 C-AMS (ka) versus
depth (m) are plotted from core Hu91-94 [Hillaire-Marcel et al., 1994]. It was retrieved at 3448 m water depth from the

Figure 7. Down-core (a) carbonate (%), (b) δ

flank of Orphan Knoll. Horizontal gray bars indicate H0 and H1 [de Vernal et al., 2001]. Note that a minor reversal of 21
years between two 14 C-AMS dates at 1.88 and 1.93 m was observed; according to Hillaire-Marcel et al. [2007], this
difference was statistically insigni cant and could be discarded.

the YD period (12.896 to 11.703 ka) by acquiring 86 14 C-
AMS dates correlating the Lake Kråkenes chronology with
the GICC05 chronology and the Asian monsoon records
[Dykoski et al., 2005; Wang et al., 2008], and our revised
chronology for the identi

5.2. Reliability of Identification of the YD in the Northwest
Labrador Sea Cores

In both cores Hu97-09 and 97-16, H1 has been identi ed

with con dence on the basis of radiocarbon dating and in

Hu97-16 is further supported by the identi

cation of YD/H0 event from the
Labrador margin is well within their estimated errors.

cation of H2
(Figure 2). Dates bounding the H layers are consistent with
dates in intervening hemipelagic sediment, indicating that
any old carbon effect is minor. Even if the uncertainty in

5.3. Source of Sediment to the H0 Layer

Δ R

values was as great as 1000 years, our identi cation of H1

and H2 would not change. The bounding dates of 13.02 and
13.25 ka below H0 and 11.99 and 11.14 ka above H0 in the
two cores mean that the bed identi

In all but one core from around the Hudson Strait outlet,
the calcite/dolomite ratio is no different in H0 from what it
is in H1 and H2 (Figure 5). The record in core Hu87033-09
is clearly abnormal (Figure 5d), probably due to a debris

ed as H0 can neither be

reasonably correlated with the 10.1 10.4 ka Gold Cove event

[Kaufman et al., 1993; Rashid et al., 2008] nor the 15.6

- flow deposit being sampled. Furthermore, counting of IRD

in H2, H1, and H0 in core Hu97-16 (Figure 2) shows no
signi

-
16.9 ka H1 event [Severinghaus et al., 2009; Wang et al.,
2008], even if the uncertainty in

cant difference in the relative abundance of limestone
and dolostone [Rashid et al., 2003a]. This means that the
same source discharging through Hudson Strait supplied

R is hundreds of years.
Bakke et al. [2009] have precisely constrained the duration of

Δ