noaa-lake-16279 Abrupt Holocene climate transitions in the northern North Atlantic region recorded by synchronized lacustrine records in Iceland Geirsdóttir, A.; Miller, G.H.; Larsen, D.J.; Olafsdottir, S. Abrupt Holocene climate transitions in the northern North Atlantic region recorded by synchronized lacustrine records in Iceland 2014-02-25 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/16279 Investigator A. Geirsdóttir Investigator G.H. Miller Investigator D.J. Larsen Investigator S. Olafsdottir earth science paleoclimate paleolimnology carbon/nitrogen,sediment,null,dimensionless,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology volume magnetic susceptibility,sediment,null,dimensionless (SI system),null,paleolimnology,null,gamma ray attenuation porosity evaluation,N,null earth science paleoclimate paleolimnology carbon/nitrogen,sediment,null,dimensionless,null,paleolimnology,resampled,null,N,null earth science paleoclimate paleolimnology carbon/nitrogen,sediment,null,standard deviation unit,null,paleolimnology,normalized|resampled,null,N,null earth science paleoclimate paleolimnology organic carbon,sediment,null,standard deviation unit,null,paleolimnology,normalized|resampled,null,N,null earth science paleoclimate paleolimnology carbon,sediment,null,percent,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology biogenic silica,sediment,null,standard deviation unit,null,paleolimnology,normalized|resampled,null,N,null earth science paleoclimate paleolimnology volume magnetic susceptibility,sediment,null,standard deviation unit,null,paleolimnology,normalized|resampled,gamma ray attenuation porosity evaluation,N,null earth science paleoclimate paleolimnology sedimentation rate,sediment,null,centimeter per year,null,paleolimnology,resampled,null,N,null earth science paleoclimate paleolimnology sedimentation rate,sediment,null,standard deviation unit,null,paleolimnology,normalized|resampled,null,N,null earth science paleoclimate paleolimnology age,null,null,calendar year before present,null,paleolimnology,null,null,N,present is 2000 AD earth science paleoclimate paleolimnology organic carbon,sediment,null,milligram per gram,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology organic carbon,sediment,null,percent,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology density,sediment,null,gram per cubic centimeter,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology sedimentation rate,sediment,null,centimeter per year,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology biogenic silica,sediment,null,percent,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology carbon,sediment,null,percent,null,paleolimnology,resampled,null,N,null earth science paleoclimate paleolimnology organic carbon,sediment,null,percent,null,paleolimnology,resampled,null,N,null earth science paleoclimate paleolimnology volume magnetic susceptibility,sediment,null,dimensionless (SI system),null,paleolimnology,resampled,gamma ray attenuation porosity evaluation,N,null earth science paleoclimate paleolimnology biogenic silica,sediment,null,percent,null,paleolimnology,resampled,null,N,null earth science paleoclimate paleolimnology density,sediment,null,gram per cubic centimeter,null,paleolimnology,resampled,null,N,null earth science paleoclimate paleolimnology biogenic silica,sediment,null,milligram per gram,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology delta 13C,organic matter,null,per mil VPDB,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology delta 13C,organic matter,null,standard deviation unit,null,paleolimnology,normalized|resampled,null,N,null earth science paleoclimate paleolimnology biogenic silica,sediment,null,milligram per gram,null,paleolimnology,resampled,null,N,null earth science paleoclimate paleolimnology delta 13C,organic matter,null,per mil VPDB,null,paleolimnology,resampled,null,N,null earth science paleoclimate paleolimnology age,null,null,calendar year before present,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology density,sediment,null,standard deviation unit,null,paleolimnology,normalized|resampled,null,N,null earth science paleoclimate paleolimnology carbon,sediment,null,standard deviation unit,null,paleolimnology,normalized|resampled,null,N,null earth science paleoclimate paleolimnology magnetic susceptibility earth science paleoclimate paleolimnology carbon isotopes earth science paleoclimate paleolimnology physical properties earth science paleoclimate paleolimnology geochemistry geoscientificInformation Arctic Little Ice Age (LIA) Medieval Warm Period abrupt climate change 10300 cal yr BP -56 cal yr BP Complete 64.613723 65.055846 -21.625757 -19.843769 38 38 Continent Europe Northern Europe Iceland Lake Hvítárvatn>LATITUDE 64.613723>LONGITUDE -19.843769 Continent Europe Northern Europe Iceland Lake Haukadalsvatn>LATITUDE 65.055846>LONGITUDE -21.625757 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Geirsdóttir Á., G.H. Miller, D.J. Larsen, S. Ólafsdóttir 2013 Quaternary Science Reviews 70 48-62 dx.doi.org/10.1016/j.quascirev.2013.03.010

Two high-sediment-accumulation-rate Icelandic lakes, the glacial lake Hvítárvatn and the non-glacial lake Haukadalsvatn, contain numerous tephra layers of known age, which together with highresolution paleomagnetic secular variations allow synchronization with a well-dated marine core from the shelf north of Iceland. A composite standardized climate record from the two lakes provides a single time series that efficiently integrates multi-proxy data that reflect the evolution of summer temperatures through the Holocene. The first-order trends in biogenic silica (BSi), d13C, and C:N rise relatively abruptly following deglaciation, reaching maximum values shortly after 8 ka following a complex minimum between 8.7 and 8.0 ka. The Holocene Thermal Maximum (HTM) in the lakes is marked by all proxies, with a sharp transition out of the 8 ka cold event into peak summer warmth by 7.9 ka, and continuing warm with some fluctuations until 5.5 ka. Decreasing summer insolation after the HTM is reflected by incremental cooling, initially w5.5 ka, with subsequent cold perturbations recorded by all proxies 4.3 to 4.0 ka and 3.1 to 2.8 ka. The strongest disturbance occurred after 2 ka with initial summer cooling occurring between 1.4 and 1.0 ka, followed by a more severe drop in summer temperatures after 0.7 ka culminating between 0.5 and 0.2 ka. Following each late Holocene cold departure, BSi re-equilibrated at a lower value independent of the sediment accumulation rate. Some of the abrupt shifts may be related to Icelandic volcanism influencing catchment stability, but the lack of a full recovery to pre-existing values after the perturbation suggests increased periglacial activity, decreased vegetation cover, and glacier growth in the highlands of Iceland. The similarity in timing, direction and magnitude of our multi-proxy records from glacial and non-glacial lakes, and from the adjacent marine shelf, suggests that our composite record reflects large-scale shifts in ocean/atmosphere circulation throughout the northern North Atlantic. STUDY NOTES: Keywords - Iceland, Lake sediment, Holocene paleoclimate, Abrupt climate transitions, 8.2 Event, Holocene Thermal Maximum, Neoglaciation, Medieval warm period, Little Ice Age.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hak-geirsdottir-2013-raw-d13c-cn-bsi.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-raw-cn.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-resampled-sar.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-resampled-bsi.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-raw-tc.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-raw-density.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-resampled-tc.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hak-geirsdottir-2013-resampled-d13c-cn-bsi.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-raw-bsi.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hak-geirsdottir-2013-resampled-sar-toc-ms.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hak-geirsdottir-2013-raw-sar-toc-ms.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-resampled-density.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-raw-d13c.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-raw-sar.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-resampled-cn.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvt-geirsdottir-2013-resampled-d13c.txt USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11