@article {2708,
	title = {Multiple independent records of local glacier variability on Nuussuaq, West Greenland, during the Holocene},
	journal = {Quaternary Science Reviews},
	volume = {215},
	year = {2019},
	month = {Jan-07-2019},
	pages = {253 - 271},
	abstract = {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{\textemdash}proglacial lake sediment analysis, cosmogenic 10Be surface-exposure dating, and in situ 14C burial modeling{\textemdash}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{\textendash}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{\textendash}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.},
	keywords = {Cosmogenic 10Be, Cosmogenic in situ 14C, Greenland, Holocene, lake sediment, Mountain glaciers, Neoglaciation},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2019.05.007},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379118308771},
	author = {Schweinsberg, Avriel D. and Briner, Jason P. and Licciardi, Joseph M. and Bennike, Ole and Lifton, Nathaniel A. and Graham, Brandon L. and Young, Nicol{\'a}s E. and Schaefer, Joerg M. and Zimmerman, Susan H.}
}
@article {2709,
	title = {Holocene mountain glacier history in the Sukkertoppen Iskappe area, southwest Greenland},
	journal = {Quaternary Science Reviews},
	volume = {197},
	year = {2018},
	month = {Jan-10-2018},
	pages = {142 - 161},
	abstract = {Mountain glaciers and ice caps (GIC) independent of the Greenland Ice Sheet respond rapidly to climate variations and records of their past extent provide information on the natural envelope of climate variability. Here, we use a multi-proxy approach that combines proglacial lake sediment analysis, cosmogenic nuclide surface-exposure dating (in situ 10Be and 14C), and radiocarbon dating of recently ice-entombed moss to generate a centennial-scale record of Holocene GIC fluctuations in southwestern Greenland. Following local deglaciation \~{}10-9 ka, sediments from proglacial Crash Lake record a glacier advance at \~{}9 ka that is indistinguishable from nearby ice sheet moraines, implying a synchronous response of GIC and the Greenland Ice Sheet to a centennial-scale climate event. Following this local glacier advance, GIC experienced net recession until \~{}4.6 ka. Radiocarbon ages of in situ moss (n = 29) and Crash Lake sediments reveal intervals of glacier expansion at \~{}1.8, 1.2 and 0.7 ka that are superimposed on an overall trend of net glacier expansion throughout the late Holocene. In situ 14C concentrations from bedrock adjacent to radiocarbon-dated moss samples further constrain the duration of ice cover through the Holocene in this region. We find that our glacier-size proxy records during the past \~{}4 ka are broadly consistent with relatively lower temperatures recorded in GISP2 and occur during, or following, intervals of volcanic perturbations. Thus, we speculate that volcanic activity, although less frequent and intense than in the early Holocene and during the Little Ice Age, may have led to centennial-scale variability imprinted on net glacier expansion due to decreasing summer insolation through the late Holocene.},
	keywords = {Cosmogenic in situ 14C, Glacier fluctuations, Greenland, Holocene, lake sediment, Neoglaciation},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2018.06.014},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379118302531},
	author = {Schweinsberg, Avriel D. and Briner, Jason P. and Miller, Gifford H. and Lifton, Nathaniel A. and Bennike, Ole and Graham, Brandon L.}
}
@article { ISI:000342993200010,
	title = {Radiocarbon age-offsets in an arctic lake reveal the long-term response of permafrost carbon to climate change},
	journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
	volume = {119},
	number = {{8}},
	year = {2014},
	month = {AUG},
	pages = {1630-1651},
	type = {Article},
	abstract = {Continued warming of the Arctic may cause permafrost to thaw and speed the decomposition of large stores of soil organic carbon (OC), thereby accentuating global warming. However, it is unclear if recent warming has raised the current rates of permafrost OC release to anomalous levels or to what extent soil carbon release is sensitive to climate forcing. Here we use a time series of radiocarbon age-offsets (C-14) between the bulk lake sediment and plant macrofossils deposited in an arctic lake as an archive for soil and permafrost OC release over the last 14,500 years. The lake traps and archives OC imported from the watershed and allows us to test whether prior warming events stimulated old carbon release and heightened age-offsets. Today, the age-offset (2ka; thousand of calibrated years before A.D. 1950) and the depositional rate of ancient OC from the watershed into the lake are relatively low and similar to those during the Younger Dryas cold interval (occurring 12.9-11.7ka). In contrast, age-offsets were higher (3.0-5.0ka) when summer air temperatures were warmer than present during the Holocene Thermal Maximum (11.7-9.0ka) and BOlling-AllerOd periods (14.5-12.9ka). During these warm times, permafrost thaw contributed to ancient OC depositional rates that were similar to 10 times greater than today. Although permafrost OC was vulnerable to climate warming in the past, we suggest surface soil organic horizons and peat are presently limiting summer thaw and carbon release. As a result, the temperature threshold to trigger widespread permafrost OC release is higher than during previous warming events.},
	keywords = {carbon cycling, lake sediment, paleoclimatology, permafrost, radiocarbon, Younger Dryas},
	issn = {2169-8953},
	doi = {10.1002/2014JG002688},
	author = {Gaglioti, Benjamin V. and Mann, Daniel H. and Jones, Benjamin M. and Pohlman, John W. and Kunz, Michael L. and Wooller, Matthew J.}
}
@article {1828,
	title = {Impact of human activity on regional forest composition and dynamics in central New England},
	journal = {Ecosystems},
	volume = {1},
	year = {1998},
	month = {Jan-Feb},
	pages = {76-95},
	abstract = {Historical and ecological data from north-central Massachusetts suggest that widespread and intensive human disturbance after European settlement led to a shift in forest composition and obscured regional patterns of species abundance. A paleoecological approach was required to place recent forest dynamics in a long-term context. Pollen and charcoal data from 11 small lakes in north-central Massachusetts were used to reconstruct local vegetation dynamics and fire histories across the region over the past 1000 years. The sites are located across an environmental gradient. Paleoecological data indicate that prior to European settlement, there was regional variation in forest composition corresponding to differences in climate, substrate, and fire regime. Oak, chestnut, and hickory were abundant at low elevations, whereas hemlock, beech, sugar maple, and yellow birch were common at high elevations. Fire appears to have been more frequent and/or intense at lower elevations, maintaining high abundances of oak, and archaeological data suggest Native American populations were greater in these areas. A change in forest composition at higher elevations, around 550 years before present, may be related to the Little Ice Age (a period of variable climate), fire, and/or activity by Native Americans, and led to regional convergence in forest composition. After European settlement, forest composition changed markedly in response to human disturbance and there was a sharp increase in rates of vegetation change. Regional patterns were obscured further, leading to homogenization of broad-scale forest composition. There is no indication from the pollen data that forests are returning to pre-European settlement forest composition, and rates of vegetation change remain high, reflecting continuing disturbance on the landscape, despite regional reforestation.},
	keywords = {awenda provincial park, eastern north-america, european settlement, forest dynamics, history, human disturbance, lake sediment, land-use, new england, paleoecology, patterns, rates of change, united-states, vegetation dynamics},
	isbn = {1432-9840},
	author = {Fuller, T. L.  and Foster, D. R.  and McLachlan, T. S.  and Drake, N.}
}
