noaa-lake-6204 Lake A, Ellesmere Island 1,000 Sedimentary Pellet Data Tomkins, J.D.; Lamoureux, S.F.; Antoniades, D.; Vincent, W.F. Lake A, Ellesmere Island 1,000 Sedimentary Pellet Data 2008-11-01 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/6204 Investigator J.D. Tomkins Investigator S.F. Lamoureux Investigator D. Antoniades Investigator W.F. Vincent earth science paleoclimate paleolimnology age,null,two standard deviations,year,null,paleolimnology,null,null,N,Estimated cumulative dating error at the base of each marker bed interval (yr) earth science paleoclimate paleolimnology age at sample end,null,null,year Common Era,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology mineral matter,sediment,null,count per year,null,paleolimnology,null,null,N,Mean annual frequency of sedimentary pellets (pellets/yr) earth science paleoclimate paleolimnology age at sample start,null,null,year Common Era,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology physical properties geoscientificInformation PAGES 2k Network PAGES Arctic 2k 933 cal yr BP -55 cal yr BP Complete 83 83 -75.5 -75.5 4 4 Continent North America Canada Nunavut Lake A, Ellesmere Island>LATITUDE 83>LONGITUDE -75.5 None 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. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

325 Broadway, E/NE31

Boulder CO 80305-3328 USA online ASCII Tomkins, J.D., S.F. Lamoureux, D. Antoniades, and W.F. Vincent 2009 Journal of Paleolimnology 41 1 225-242 10.1007/s10933-008-9255-x

Sediment aggregates ("sedimentary pellets") within the sedimentary record of Lake A (83deg00'N, 75deg30'W), Ellesmere Island, Canada, are used to construct a 1000 year proxy record of ice-cover extent and dynamics on this perennially ice-covered, High Arctic lake. These pellets are interpreted to form during fall or early winter when littoral sediment adheres to ice forming around the lake's periphery or during summer through the development of anchor ice. The sediment likely collects in ice interstices and is concentrated in the upper ice layers through summer surface ice melt and winter basal ice growth. The pellets remain frozen in the ice until a summer or series of summers with reduced ice cover allows for their deposition across the lake basin. Sedimentary pellet frequency within multiple sediment cores is used to develop a chronology of ice-cover fluctuations. This proxy ice-cover record is largely corroborated by a record of unusual sedimentation in Lake A involving iron-rich, dark-orange to red laminae overlying more diffuse laminae with a lighter hue. This sediment sequence is hypothesized to represent years with reduced ice cover through increased chemocline ventilation and iron deposition. During the past millennium, the most notable period of inferred reduced ice cover is ca. 1891 AD to present. Another period of ice cover mobility is suggested ca. 1582-1774 AD, while persistent ice cover is inferred during the 1800s and prior to 1582 AD. The proxy ice-cover record corresponds well with most regional meltseason proxy temperature and paleoecological records, especially during the 1800s and 1900s. STUDY NOTES: This is a 989-year record of mean annual macroscopic (visible with the unaided eye) sedimentary pellet frequency between marker bed intervals (dated using an age-depth model based on a varve chronology), incorporating data from 11 sediment cores from Lake A, Ellesmere Island.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/ellesmere/lake-a2008.xls GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/ellesmere/lake-a2008.txt USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11