A MULTI-PROXY LITHOSTRATIGRAPHIC RECORD OF LATE GLACIAL AND HOLOCENE CLIMATE VARIABILITY FROM PIPER LAKE , NOVA SCOTIA

A multi-proxy lithostratigraphic record from Piper Lake, NS reveals environmental variability during the Late Glacial and Holocene. Piper Lake is a small, shallow (6m), closed, basin located in the eastern Nova Scotia Highlands. The site was deglaciated about 14.5 cal. kyr BP and elevated LOI values and relatively low carbon/nitrogen (C/N) isotope ratios indicate the establishment of a productive aquatic environment consistent with Allerød warming. The Late Glacial lake record is punctuated by a thin, very fine-grained, clay layer that is correlative to the Younger Dryas oscillation and was deposited when perennial ice covered the lake.

The post-YD lithostratigraphy indicates the rapid establishment of an increasingly productive and stable landscape. This trend is reversed three times during the Holocene by minerogenic units. A complex 25 cm thick, minerogenic unit unique to Piper Lake was deposited ca. 10.8 - 10.3 cal. kyr BP. This unit represents a period of prolonged environmental instability including subaqueous slumping and may be related to early Holocene cooling recognized in Western Newfoundland. Two thin minerogenic units deposited at ca. 8.0 cal. kyr BP and ca. 4.5 cal. kyr BP were likely the result of regional cooling and are broadly correlative with events noted in the GISP2 ice core record. The Piper Lake core demonstrates an unusually strong response to Holocene environmental change which, we suggest, may result from the lack of influence of the NAO on air temperature in this region. The absence of this signal prevents decadal scale variations in temperature from introducing noise into paleoclimate records that might mask longer duration climate forcing.