Okpilak Lake, Alaska 14,500 Year Multiproxy Sediment Data Oswald, W.; Gavin, D.G.; Anderson, P.M.; Brubaker, L.B.; Hu, F.S. Oswald, W. Gavin, D.G. Anderson, P.M. Brubaker, L.B. Hu, F.S. Arctic Little Ice Age (LIA) PAGES Arctic 2k earth science/paleoclimate/paleolimnology (magnetic susceptibility,sediment,null,dimensionless (SI system),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 (organic matter,sediment,null,percent,null,paleolimnology,null,loss on ignition,N,null) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Okpilak Lake>LATITUDE 69.4081>LONGITUDE -144.0489) Analyses of lithology, organic-matter content, magnetic susceptibility, and pollen in a sediment core from Okpilak Lake, located in the northeastern Brooks Range, provide new insights into the history of climate, landscape processes, and vegetation in northern Alaska since 14,500 cal year BP. The late-glacial interval (>11,600 cal year BP) featured sparse vegetation cover and the erosion of minerogenic sediment into the lake from nearby hillslopes, as evidenced by Cyperaceae-dominated pollen assemblages and high magnetic susceptibility (MS) values. Betula expanded in the early Holocene (11,600-8,500 cal year BP), reducing mass wasting on the landscape, as reflected by lower MS. Holocene sediments contain a series of silt- and clay-dominated layers, and given their physical characteristics and the topographic setting of the lake on the braided outwash plain of the Okpilak River, the inorganic layers are interpreted as rapidly deposited fluvial sediments, likely associated with intervals of river aggradation, changes in channel planform, and periodic overbank flow via a channel that connects the river and lake. The episodes of fluvial dynamics and aggradation appear to have been related to regional environmental variability, including a period of glacial retreat during the early Holocene, as well as glacial advances in the middle Holocene (5,500-5,200 cal year BP) and during the Little Ice Age (500-400 cal year BP). The rapid deposition of multiple inorganic layers during the early Holocene, including thick layers at 10,900-10,000 and 9,400-9,200 cal year BP, suggests that it was a particularly dynamic interval of fluvial activity and landscape change. STUDY NOTES: Multiproxy sediment data from Okpilak Lake, Alaska, for the past 14,500 years. Paleoenvironmental proxies measured include lithology, organic-matter content, magnetic susceptibility, and pollen taxa. Okpilak Lake, Alaska: 69°24'29"N, 144°02'56"W, 593m elevation NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Oswald, W. Investigator : Gavin, D.G. Investigator : Anderson, P.M. Investigator : Brubaker, L.B. Investigator : Hu, F.S. 2012-06-30 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/13080 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/okpilak2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/okpilak2012.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/okpilak2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/okpilak2012.xls English https://www.ncdc.noaa.gov/paleo/study/13080 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/okpilak2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/okpilak2012.xls Oswald, W.W., D.G. Gavin, P.M. Anderson, L.B. Brubaker, and F.S. Hu. 2012. A 14,500-year record of landscape change from Okpilak Lake, northeastern Brooks Range, northern Alaska. Journal of Paleolimnology, Vol. 48, No. 1, June 2012, pp. 101-113. DOI: 10.1007/s10933-012-9605-6 START YEAR: 14428 cal yr BP * END YEAR: -47 cal yr BP -144.0489 69.4081 -144.0489 69.4081