DID LOCAL GLACIERS ON GREENLAND RESPOND TO THE 8.2 KA EVENT?

Most glacier change research conducted in Greenland has focused on the Greenland Ice Sheet (GrIS) due to its potential future contribution to sea level rise, estimated at approximately 7.4 m. While glacier response to abrupt climate change in the early Holocene has been well constrained for the ice sheet margin, there are few places in Greenland where independent local glacier reconstructions based on direct dating methods are available. This study uses ¹⁰Be dating of pre-Little Ice Age local glacier moraines on the Nuussuaq peninsula in central western Greenland to determine whether glaciers independent of the ice sheet also responded to early Holocene abrupt climate events. Specifically, the objective of this study is to determine whether or not the 9.3 or 8.2 ka events are recorded in local glacier moraine records in western Greenland.

We collected six samples for ¹⁰Be dating from boulders on lateral moraines of two adjacent paleo-valley glaciers located on the southern coast of the Nuussuaq peninsula. In addition, we sampled two erratic boulders perched on bedrock beyond the moraines. Erratic boulders will constrain the timing of deglaciation prior to moraine deposition and the moraine boulder ages will date the deposition of the moraines. We compare the local glacier reconstruction from this study to nearby GrIS margins including: (1) a fast-flowing, marine-terminating margin approximately 100 km from the study area (Jakobshavn Isbræ), and a slow-flowing, land-terminating margin approximately 35 km away (Drygalski Moraines), both of which deposited moraines dating to 9-8 ka, in order to further investigate the complex glacier response to abrupt changes in climate.