Adélie Land, East Antarctica Holocene Diatom Abundance Data Crosta, X.; Debret, M.; Denis, D.; Courty, M.A.; Ther, O. Crosta, X. Debret, M. Denis, D. Courty, M.A. Ther, O. earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (MD03-2601>LATITUDE -66.051>LONGITUDE 138.557) Diatom data from a marine sediment core give insight on Holocene changes in sea-surface conditions and climate at high southern latitudes off Adélie Land, East Antarctica. The early to mid-Holocene was warmer than the late Holocene with a transition at ~4000 calendar years B. P. Sea ice was less present and spring-summer growing season was greater during the warm period relative to the cold one, thus limiting sea ice diatom production and favoring more open ocean diatom to develop. The long-term Holocene climatic evolution in East Antarctica is explained by a combination of a delayed response to local seasonal insolation changes coupled to the long memory of the Southern Ocean. Abrupt variations of the diatom relative abundances, indicating rapid climate changes, are superimposed to the Holocene long-term trends. Spectral analyses calculate robust frequencies at ~1600 a (where ŋaŋ is years), ~1250 a, ~1050 a, ~570 a, ~310 a, ~230 a, ~150ŋ125 a, ~110 a, ~90 a, and ~66 a. Such periods are very close to solar activity cyclicities, except for the periods at ~310 a and ~1250 a, which are close to internal climate variability cyclicities. Wavelet analyses estimate the same periods but indicate nonstationary cyclicities. Rapid climate changes at high southern latitudes may therefore be explained by a combination of external (solar) and internal (thermohaline circulation) forcings. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Crosta, X. Investigator : Debret, M. Investigator : Denis, D. Investigator : Courty, M.A. Investigator : Ther, O. 2007-07-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/8453 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/by_contributor/crosta2007 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/by_contributor/crosta2007 English https://www.ncdc.noaa.gov/paleo/study/8453 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/by_contributor/crosta2007 Crosta, X., M. Debret, D. Denis, M. A. Courty, and O. Ther. 2007. Holocene long- and short-term climate changes off Adélie Land, East Antarctica. Geochem. Geophys. Geosyst., 8, Q11009. START YEAR: 10843 cal yr BP * END YEAR: 1000 cal yr BP 138.557 -66.051 138.557 -66.051