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. Larsen, D.J. Miller, G.H. Geirsdóttir, A. Olafsdottir, S. Arctic Glacial Little Ice Age (LIA) Medieval Warm Period 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 earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Lake Hvítárvatn03-1>LATITUDE 64.64172>LONGITUDE -19.83995) 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. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Larsen, D.J. Investigator : Miller, G.H. Investigator : Geirsdóttir, A. Investigator : Olafsdottir, S. 2012-01-02 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/15309 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-geochem.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-varve-psv.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-grain-size.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-bsi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-density-ms.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-ird.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-geochem.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-varve-psv.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-grain-size.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-bsi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-density-ms.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-ird.txt English https://www.ncdc.noaa.gov/paleo/study/15309 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-geochem.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-varve-psv.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-grain-size.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-bsi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-density-ms.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/iceland/hvitarvatn2012-ird.txt Larsen, D.J., Miller, G.H., Geirsdottir, A., Olafsdottir, S.2012Non-linear Holocene climate evolution in the North Atlantic: a high resolution, multi-proxy record of glacier activity and environmental change from Hvitarvatn, central Iceland.Quaternary Science Reviews3914 - 25 START YEAR: 12190 cal yr BP * END YEAR: -56 cal yr BP -19.83995 64.64172 -19.83995 64.64172