{"NOAAStudyId":"14730","contactInfo":{"address":"325 Broadway, E/NE31","city":"Boulder","constraints":"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.","country":"USA","dataCenterUrl":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data","email":"paleo@noaa.gov","fax":"303-497-6513","longName":"National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce ","phone":"303-497-6280","postalCode":"80305-3328","shortName":"DOC/NOAA/NESDIS/NCEI","state":"CO","type":"CONTACT INFORMATION"},"contributionDate":"2013-03-11","dataPublisher":"NOAA","dataType":"PALEOLIMNOLOGY","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/lake","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-lake-14730.xml","doi":null,"earliestYearBP":2976,"earliestYearCE":-1026,"entryId":"noaa-lake-14730","funding":[],"investigators":"Larsen, D.J.; Miller, G.H.; Geirsdóttir, A.; Thordarson, T.","mostRecentYearBP":-52,"mostRecentYearCE":2002,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/14730","originalSource":null,"publication":[{"abstract":"A suite of environmental proxies in annually laminated sediments from Hvítárvatn, a proglacial lake in the central highlands of Iceland, are used to reconstruct regional climate variability and glacial activity for the past 3000 years. Sedimentological analysis is supported by tephrostratigraphy to confirm the continuous, annual nature of the laminae, and a master varve chronology places proxies from multiple lake cores in a secure geochronology. Varve thickness is controlled by the rate of glacial erosion and efficiency of subglacial discharge from the adjacent Langjökull ice cap. The continuous presence of glacially derived clastic varves in the sediment fill confirms that the ice cap has occupied the lake catchment for the duration of the record. Varve thickness, varve thickness variance, ice rafted debris, total organic carbon (mass flux and bulk concentration), and C:N of sedimentary organic matter, reveal a dynamic late Holocene climate with abrupt and large-scale changes in ice-cap size and landscape stability. A first-order trend toward cooler summers and ice-cap expansion is punctuated by notable periods of rapid ice cap growth and/or landscape instability at ca 1000 BC, 600 BC, 550 AD and 1250 AD. The largest perturbation began ca 1250 AD, signaling the onset of the Little Ice Age and the termination of three centuries of relative warmth during Medieval times. Consistent deposition of ice-rafted debris in Hvítárvatn is restricted to the last 250 years, demonstrating that Langjökull only advanced into Hvítárvatn during the coldest centuries of the Little Ice Age, beginning in the mid eighteenth century. This advance represents the glacial maximum for at least the last 3 ka, and likely since regional deglaciation 10 ka. The multi-centennial response of biological proxies to the Hekla 3 tephra deposition illustrates the significant impact of large explosive eruptions on local environments, and catchment sensitivity to perturbations.","author":null,"citation":"Larsen, D.J., Miller, G.H., Geirsdóttir, Á., Thordarson, T., 2011. A 3000-year varved record of glacier activity and climate change from the proglacial lake Hvítárvatn. Quaternary Science Reviews 30, 2715-2731.","edition":null,"identifier":{"id":"doi:10.1016/j.quascirev.2011.05.026","type":"doi","url":"http://dx.doi.org/doi:10.1016/j.quascirev.2011.05.026"},"issue":null,"journal":"Quaternary Science Reviews","pages":null,"pubRank":"1","pubYear":2011,"reportNumber":null,"title":"A 3000-year varved record of glacier activity and climate change from the proglacial lake Hvítárvatn, Iceland","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":["Little Ice Age (LIA)","temperature","Arctic","Medieval Warm Period"],"site":[{"NOAASiteId":"55169","geo":{"geoType":"Feature","geometry":{"coordinates":["64.64172","-19.83995"],"type":"POINT"},"properties":{"easternmostLongitude":"-19.83995","maxElevationMeters":"422","minElevationMeters":"422","northernmostLatitude":"64.64172","southernmostLatitude":"64.64172","westernmostLongitude":"-19.83995"}},"locationName":"Continent>Europe>Northern 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