The Impact of the Final Lake Agassiz Flood Recorded in Northeast Newfoundland and Northern Scotian Shelves Based on Century-Scale Palynological Data - Abrupt Climate Change: Mechanisms, Patterns, and Impacts - page 147

trations in the last 7000 years. Halodinium is an acritarch of
unknown biological affinities that is abundant in Baffin Bay
fjord sediments [Mudie and Short, 1985]. The greater con-
centrations of Halodinium could represent greater in uence

from Arctic and/or meltwater until about 7.6 ka. The in-
creased concentrations of organic foraminiferal test linings
in the upper 3 m of core 19 could re

ect either greater
productivity or increased carbonate dissolution.
Concentrations of reworked palynomorphs are consistent
throughout core 19, but the presence of reworked Cretaceous
pollen and spores within the AG and the lower carbonate
layers should be noted as well as the presence of reworked
dinocysts of Cretaceous and Mesozoic age. Trilete Cicatri-
cosisporites sp. spores of Upper Jurassic-Cretaceous age
[Batten, 1996] are found at 324 and 343 cm. Mesozoic
Tsugaepollinites [Burden and Holloway, 1985] are found at
the following depths: 324, 343, and 391 to 443 cm. Re-
worked dinocysts include Dapsilidinium pseudocolligerum

Figure 6. Palynomorph concentrations per cm 3 of sediments (times
1000) in core HU87033-19P, Notre Dame Channel. Numbers on the
left are calibrated ages from foraminifera and pollen zonations.
Calibrated ages based on foraminifera are indicated by the asterisks
on the x axis (only ages from planktic foraminifera are shown here).
The pollen-correlated ages are indicated by the greater than
symbols. The gray shading indicates layers with high DC. AG is
Lake Agassiz.

slightly in the Holocene, at the time forests became estab-
lished in North Central Newfoundland (forest vegetation
produces more pollen), sometime around 9.9 ka (around
450 cm), but they are lower in the DC beds, probably due to
dilution by higher sedimentation rates. Pollen concentrations
increase only above 305 cm, i.e., not until after the AG
episode, indicating that the deposition of the AG and the next
DC bed below occurred during episodes of more rapid sedi-
mentation. Dinocysts show a sharp upcore increase around
7 m (circa 10.3 ka) but then drop to late glacial values in the
AG interval.
Halodinium concentrations exhibit a different trend com-
pared to the other categories of palynomorphs, with high
concentrations in the early Holocene but very low concen-

Figure 7. Palynomorph concentrations per cm 3 of sediments (times
10000) in core HU84011-12, St. Anne ' s Basin. Numbers on the left
are calibrated ages from foraminifera and pollen zonations. Ages
based on foraminifera are indicated by the asterisks on the x axis
(only ages from planktic foraminifera are shown here). The pollen-
correlated ages are indicated by the greater than symbols.