Chugach Range, Alaska 6,500 Year Sediment Data, Hallet and Greyling Lakes McKay, N.P.; Kaufman, D.S. McKay, N.P. Kaufman, D.S. PAGES 2k Network PAGES Arctic 2k earth science/paleoclimate/paleolimnology (organic matter,sediment,null,weight percent,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (density,dry sediment,null,gram per cubic centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (biogenic silica,sediment,null,milligram per gram,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (age,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (Hallet Lake>LATITUDE 61.5>LONGITUDE -146.2) Evidence from lake sediments and glacier forefields from two hydrologically isolated lake basins is used to reconstruct Holocene glacier and climate history at Hallet and Greyling Lakes in the central Chugach Mountains of south-central Alaska. Glacial landform mapping, lichenometry, and equilibrium-line altitude reconstructions, along with changes in sedimentary biogenic-silica content, bulk density, and grain-size distribution indicate a dynamic history of Holocene climate variability. The evidence suggests a warm early Holocene from 10 to 6 ka, followed by the onset of Neoglaciation in the two drainage basins, beginning between 4.5 and 4.0 ka. During the past 2 ka, the glacial landforms and lacustrine sediments from the two valleys record a remarkably similar history of glaciation, with two primary advances, one during the first millennium AD, from ~500 to 800 AD, and the second during the Little Ice Age (LIA) from ~1400 to 1900 AD. During the LIA, the reconstructed equilibrium-line altitude in the region was no more than 83-44m (n = 21) lower than the modern, which is based on the extent of glaciers during 1978. Differences between the summer temperature inferred from the biogenic-silica content and the evidence for glacial advances and retreats suggest a period of increased winter precipitation from 1300 to 1500 AD, and reduced winter precipitation from 1800 to 1900 AD, likely associated with variability in the strength of the Aleutian Low. STUDY NOTES: High resolution organic matter, biogenic silica, and dry bulk density data from Hallet and Greyling Lakes, Chugach Range, South Central Alaska. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : McKay, N.P. Investigator : Kaufman, D.S. 2008-11-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/6199 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/chugach2008.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/chugach2008.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/chugach2008.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/chugach2008.txt English https://www.ncdc.noaa.gov/paleo/study/6199 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/chugach2008.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/chugach2008.txt McKay, N.P. and D.S. Kaufman.2009Holocene climate and glacier variability at Hallet and Greyling Lakes, Chugach Mountains, south-central AlaskaJournal of Paleolimnology411143-15910.1007/s10933-008-9260-0 START YEAR: 6450 cal yr BP * END YEAR: -50 cal yr BP -146.2 61.5 -146.2 61.5