noaa-lake-15309 Non-linear Holocene climate evolution in the North Atlantic: a high resolution, multi-proxy record of glacier activity and environmental change from Hvitarvatn, central Iceland Larsen, D.J.; Miller, G.H.; Geirsdóttir, A.; Olafsdottir, S. Non-linear Holocene climate evolution in the North Atlantic: a high resolution, multi-proxy record of glacier activity and environmental change from Hvitarvatn, central Iceland 2012-01-02 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/15309 Investigator D.J. Larsen Investigator G.H. Miller Investigator A. Geirsdóttir Investigator S. Olafsdottir earth science paleoclimate paleolimnology grain size class,sediment,null,percent,null,paleolimnology,null,null,N,silt plus clay earth science paleoclimate paleolimnology delta 13C,sediment,null,per mil VPDB,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology nitrogen,sediment,null,percent,null,paleolimnology,null,elemental analysis,N,null earth science paleoclimate paleolimnology age,null,null,calendar year before present,null,paleolimnology,null,null,N,varve counting earth science paleoclimate paleolimnology density,sediment,null,gram per cubic centimeter,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology volume magnetic susceptibility,sediment,null,dimensionless (SI system),null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology organic carbon,sediment,null,gram per square centimeter per year,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology carbon/nitrogen,sediment,null,dimensionless,null,paleolimnology,null,elemental analysis,N,lake is devoid of inorganic carbon; total organic carbon = total carbon earth science paleoclimate paleolimnology ice rafted debris,sediment,null,count,null,paleolimnology,null,null,N,size fraction > 2mm earth science paleoclimate paleolimnology biogenic silica,sediment,null,percent,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 carbon,sediment,null,percent,null,paleolimnology,null,elemental analysis,N,lake is devoid of inorganic carbon; total organic carbon = total carbon earth science paleoclimate paleolimnology age,null,null,calendar year before present,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology magnetic susceptibility earth science paleoclimate paleolimnology physical properties earth science paleoclimate paleolimnology geochemistry geoscientificInformation Arctic Glacial Little Ice Age (LIA) Medieval Warm Period 12190 cal yr BP -56 cal yr BP Complete 64.64172 64.64172 -19.83995 -19.83995 422 422 Continent Europe Northern Europe Iceland Lake Hvítárvatn03-1>LATITUDE 64.64172>LONGITUDE -19.83995 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

325 Broadway, E/NE31

Boulder CO 80305-3328 USA online ASCII Larsen, D.J., Miller, G.H., Geirsdottir, A., Olafsdottir, S. 2012 Quaternary Science Reviews 39 14 - 25

Iceland is well situated to monitor North Atlantic Holocene climate variability. Terrestrial sites there offer the potential for well-dated, high-resolution, continuous records of environmental change and/or glacier activity. Laminated sediments from the proglacial lake Hvítárvatn provide a continuous record of environmental change and the development of the adjacent Langjökull ice cap for the past 10.2 ka. Replicate lake sediment cores, collected from multiple locations in the basin, are placed in a secure geochronology by splicing a varve chronology for the past 3 ka with a tephra-constrained, paleomagnetic secular variation derived chronology for older sediments. Multiple proxies, including sedimentation rate, bulk density, ice-rafted debris, sediment organic matter, biogenic silica, and diatom abundance, allow annual to multi-decadal resolution and reveal a dynamic Holocene terrestrial climate. Following regional deglaciation of the main Iceland Ice Sheet, summer temperatures were high enough that mountain ice caps had already melted, or were contributing insignificant sediment to the lake. Pronounced increases in sedimentation rate, sediment density, and the influx of terrestrial organic matter, between 8.7 and 7.9 ka suggest early Holocene warmth was interrupted by two distinct pulses of cold summers leading to widespread landscape destabilization and possibly glacier growth. The Holocene thermal maximum (HTM; 7.9 to 5.5 ka) was characterized by high within-lake productivity and ice-free conditions in the watershed. Neoglaciation is recorded as a non-linear transition toward cooler summers, landscape destabilization, and the inception and expansion of Langjökull beginning ca 5.5 ka, with notable increases in ice cap size and landscape instability at 4.2 and 3.0 ka. The past two millennia are characterized by the abrupt onset of sustained cold periods at ca 550 and 1250 AD, separated by an interval of relative warmth from ca 950 to 1150 AD. The greatest Holocene extent of Langjökull occurred in the nineteenth century and is coincident with peak landscape instability, followed by ice recession throughout the twentieth century.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-geochem.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-varve-psv.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-grain-size.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-bsi.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-density-ms.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-ird.txt USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11