Multiple independent records of local glacier variability on Nuussuaq, West Greenland, during the Holocene

The sensitivity of mountain glaciers to small-scale climate fluctuations makes records of their past extent among the best proxies for identifying spatio-temporal climate variability. Here we build on the few existing Holocene records of local glacier change in Greenland by using three independent geochronological methods—proglacial lake sediment analysis, cosmogenic ¹⁰Be surface-exposure dating, and in situ ¹⁴C burial modeling—to reconstruct continuous records of Holocene glacier variability on Nuussuaq, West Greenland. ¹⁰Be ages of perched boulders indicate eastern Nuussuaq was deglaciated between ∼11.0 and 10.5 ka. Radiocarbon-dated sediments from two lakes on Nuussuaq contain mineral-rich layers between ∼9.6 and 9.0 and ∼8.7–8.0 cal ka BP that may be correlative with nearby ice sheet moraines deposited in the early Holocene. Multiple proxies for glacier size indicate frequent, high-amplitude glacier fluctuations superimposed on net glacier growth during the late Holocene, with significant ice expansion phases at ∼3.7 ka, 2.8 ka, and throughout the past ∼2 ka. Mean ¹⁰Be ages from five nested moraine crests confirm that local glacier extents on Nuussuaq culminated during both the Little Ice Age [∼1470 C.E. (n = 3)and 1750 C.E. (n = 3)]and the preceding centuries (∼520–1320 C.E.; n = 11). Results reveal that local glaciers on Nuussuaq episodically advanced and retreated at centennial timescales throughout the Holocene, most likely in response to regional climate changes in West Greenland superimposed on the progressive insolation-driven cooling trend in the Northern Hemisphere. Our new ¹⁰Be moraine chronologies coupled with other glacier-size proxies corroborate an emerging pattern of significant summer cooling and glacier expansion in the centuries prior to the Little Ice Age in the Arctic.