Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/7786
Authors: | Aciego, S.* Bourdon, B.* Schwander, J.* Baur, H.* Forieri, A.* |
Title: | Toward a radiometric ice clock: uranium ages of the Dome C ice core | Journal: | Quaternary Science Reviews | Series/Report no.: | 19-20/30(2011) | Publisher: | Elsevier Science Limited | Issue Date: | 2011 | DOI: | 10.1016/j.quascirev.2011.06.008 | Keywords: | Radiometric ice clock | Subject Classification: | 02. Cryosphere::02.03. Ice cores::02.03.99. General or miscellaneous | Abstract: | Ice sheets and deep ice cores have yielded a wealth of paleoclimate information based on continuous dating methods while independent radiometric ages of ice have remained elusive. Here we demonstrate the application of (234U/238U) measurements to dating the EPICA Dome C ice core based on the accumulation of 234U in the ice matrix from recoil during 238U decay out of dust bound within the ice. Measured (234U/238U) activity ratios within the ice generally increase with depth while the surface areas of the dust grains are relatively constant. Using a newly designed device for measuring surface area for small samples, we were able to estimate reliably the recoil efficiency of nuclides from dust to ice. The resulting calculated radiometric ages range between 80 ka and 870 ka. Measured samples in the upper 3100 m fall on the previously published age-depth profile. Samples in the 3200–3255 m section show a marked change from 723–870 ka to 85 ka indicating homogenization of the deep ice prior to resetting of the (234U/238U) age in the basal layers. The mechanism for homogenization is likely enhanced lateral ice flow due to high basal melting and geothermal heat flux. |
Appears in Collections: | Article published / in press |
Show full item record
WEB OF SCIENCETM
Citations
27
checked on Feb 10, 2021
Page view(s) 5
454
checked on Apr 24, 2024
Download(s) 20
971
checked on Apr 24, 2024