Lake Kalliojärvi, Finland 4,000 Year Varve Thickness Data Saarni, S.; Saarinen, T.; Dulski, P. Saarni, S. Saarinen, T. Dulski, P. earth science/paleoclimate/paleolimnology (absorbance,sediment,null,dimensionless,null,paleolimnology,raw,x-ray densitometry,N,Light sum (accumulation of minerogenic clasts) - summation of the area below the x-ray density curve in grayscale values for each varve) earth science/paleoclimate/paleolimnology (depth,null,null,millimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (varve thickness,null,null,millimeter,null,paleolimnology,raw,null,N,null) earth science/paleoclimate/paleolimnology (age,null,null,year Common Era,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (Lake Kalliojärvi>LATITUDE 63.227>LONGITUDE 25.366) Clastic-organic varved sediments from the boreal Lake Kalliojärvi, Central Finland, record changes in snow accumulation for more than 4000 years. The varve record was reconstructed using digital image analysis from 4132 varve yr BP to present with 2.2% counting error and is supported by paleomagnetic data. Two laminae are identified in a typical varve structure: (1) the minerogenic lamina, which accumulates during spring as a result of catchment erosion triggered by spring floods and (2) the organic lamina, which is composed of allochthonous and autochthonous organic matter that accumulates during summer, autumn, and winter. The minerogenic influx is related to variations in snow accumulation and follows the different phases of the North Atlantic Oscillation (NAO). Decreased snow accumulation is related to a weakened NAO phase. Thus, the minerogenic influx record provides additional information about NAO variation. The Fe/Mn ratio is related to changes in redox conditions at the lake floor. The oxygen availability in the lake floor depends on the duration of the ice cover during winter. Strengthened Siberian High (SH) causes colder autumn and winter temperatures and therefore leads to extended duration of ice cover. Fe/Mn can be considered as a proxy for SH. The sediment record suggests pronounced, generally positive but strongly fluctuating NAO phase, from ca. 4100 to 3200 varve yr BP. Periods of strengthened SH are observed at 3900-3600, 1900-1500, and 1200-750 varve yr BP. Our study suggests that NAO and SH operate individually, are not clearly linked, and do not entirely block each other. STUDY NOTES: Varve thickness data from Lake Kalliojärvi, Eastern Finland for the past 4,000 years NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Saarni, S. Investigator : Saarinen, T. Investigator : Dulski, P. 2017-06-06 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/22194 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/finland/kalliojarvi2016varve.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/finland/kalliojarvi2016varve.txt English https://www.ncdc.noaa.gov/paleo/study/22194 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/finland/kalliojarvi2016varve.txt Saija Saarni, Timo Saarinen, Peter Dulski2016Between the North Atlantic Oscillation and the Siberian High: A 4000-year snow accumulation history inferred from varved lake sediments in FinlandThe Holocene263423-43110.1177/0959683615609747 START YEAR: -2183 AD * END YEAR: 1900 AD 25.366 63.227 25.366 63.227