Abstract

A palynological record from Bay of Islands (western Newfoundland) was used to investigate differences in timing between paleoceanographic and paleoclimatic events, and episodic cold sea surface temperature (SST) intervals. Sea surface conditions were reconstructed from dinocyst proxy-data and paleobioclimatic transfer functions. Correlation of onshore–offshore pollen records was used to determine ocean–atmosphere interactions.

Between 9.5 and 8.6 ka, cold and lower salinity sea surface conditions and a cold climate may be the result of a large influx of glacial meltwater through the Gulf of St. Lawrence. The marine optimum followed with SST up to 5°C warmer than today until 6.8 ka and coincides with an expansion of boreal forest trees, probably resulting from a climatic amelioration. The terrestrial hypsithermal started only around 6 ka, however, possibly due to the lingering effect of the remaining ice sheet on the regional climate. It coincides with lower summer SST than today.

Increased proportions of spruce and sedge after 3.7 ka suggest a regional cooling trend, which was recorded later in the surface waters of the Bay (800 years ago) and was preceded by an interval of SST warmer than today between 4 and 1 ka.

These results suggest that sea surface conditions in the bay are controlled by the position of the major currents and influx of meltwater, while Newfoundland climate remained under the influence of the Lauren tide ice sheet until 6 ka, after which it was probably controlled by the position of air masses rather than by conditions in the adjacent sea surface.

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